Usmle Physiology Svereson Import

Front 1

In a ventricular pacemaker cell, what phase of the action potential is affected by NE?

Back 1

Phase 4; NE increases the slope of the prepotential, allowing threshold to be reached sooner, and increases the rate of firing.

Front 2

Anatomical and alveolar dead spaces together constitute what space?

Back 2

Physiologic dead space is the total dead space of the respiratory system.

Front 3

What three organs are necessary for the production of vitamin D3(cholecalciferol)?

Back 3

Skin,
liver,
kidneys

Front 4

What is the effect of LH on the production of adrenal androgens?

Back 4

LH has no effect on the production of adrenal androgens; ACTH stimulates adrenal androgen production.

Front 5

What four conditions result in secondary hyperaldosteronism?

Back 5

1. CHF
2. Vena caval obstruction or constriction
3. Hepatic cirrhosis
4. Renal artery stenosis

Front 6

What are the five hormones produced by Sertoli cells?

Back 6

1. Androgen-binding protein
2 Antimüullerian hormone
3 Estradiol (E2)
4 Inhibin
5 Meiosis inhibiting factor (in fetal tissue)

Front 7

What is the term for the negative resting membrane potential moving toward threshold?

Back 7

Depolarization (i.e., Na+ influx)

Front 8

Does the left or right vagus nerve innervate the SA node?

Back 8

Right vagus innervates the SA node and the left vagus innervates the AV node

Front 9

How does ventricular repolarization take place, base to apex or vice versa?

Back 9

Repolarization is from base to apex and from epicardium to endocardium.

Front 10

What is the term for any region of the respiratory system that is incapable of gas exchange?

Back 10

Anatomical dead space, which ends at the level of the terminal bronchioles.

Front 11

What four factors shift the Hgb-O2 dissociation curve to the right? What is the consequence of this shift?

Back 11

Increased CO2, H+, temperature, and 2, 3-BPG levels all shift the curve to the right, thereby making the O2 easier to remove (decreased affinity) from the Hgb molecule.

Front 12

What two factors result in the apex of the lung being hypoperfused?

Back 12

Decreased pulmonary arterial pressure (low perfusion) and less-distensible vessels (high resistance) result in decreased blood flow at the apex.

Front 13

What is the ratio of pulmonary to systemic blood flow?

Back 13

1:1. Remember, the flow through the pulmonary circuit and the systemic circuit are equal.

Front 14

To differentiate central from nephrogenic diabetes insipidus, after an injection of ADH, which will show a decreased urine flow?

Back 14

Central. Remember, there is a deficiency in ADH production in the central form.

Front 15

In what area of the GI tract are water-soluble vitamins absorbed?

Back 15

Duodenum

Front 16

What wave is the cause of the following venous pulse deflections?
• The rise in right atrial pressure secondary to blood filling and terminating when the tricuspid valves opens

Back 16

V wave

Front 17

What wave is the cause of the following venous pulse deflections?
• The bulging of the tricuspid valve into the right atrium

Back 17

C wave

Front 18

What wave is the cause of the following venous pulse deflections?
• The contraction of the right atrium

Back 18

A wave

Front 19

What are the four functions of saliva?

Back 19

1. Provide antibacterial action
2. Lubricate
3. Begin CHO digestion
4. Begin fat digestion

Front 20

When a person goes from supine to standing, what happens to the following?
• Dependent venous pressure

Back 20

Increases

Remember, the carotid sinus reflex attempts to compensate by increasing both TPR and heart rate.


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Front 21

When a person goes from supine to standing, what happens to the following?
• Dependent venous blood volume

Back 21

Increases

Remember, the carotid sinus reflex attempts to compensate by increasing both TPR and heart rate.


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Front 22

When a person goes from supine to standing, what happens to the following?
• Cardiac output

Back 22

Decreases

Remember, the carotid sinus reflex attempts to compensate by increasing both TPR and heart rate.

Front 23

When a person goes from supine to standing, what happens to the following?
• BP

Back 23

Decreases

Remember, the carotid sinus reflex attempts to compensate by increasing both TPR and heart rate.


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Front 24

When does the hydrostatic pressure in Bowman's capsule play a role in opposing filtration?

Back 24

It normally does not play a role in filtration but becomes important when there is an obstruction downstream.

Front 25

What happens to intrapleural pressure when the diaphragm is ontracted during inspiration?

Back 25

Intrapleural pressure decreases (becomes more negative).

Front 26

What is used as an index of cortisol secretion?

Back 26

Urinary 17-OH steroids

Front 27

If the pH is low with increased CO2 levels and decreased HCO3- levels, what is the acid-base disturbance?

Back 27

Combined metabolic and respiratory acidosis

Front 28

What is the term that refers to the number of channels open in a cell membrane?

Back 28

Membrane conductance (think conductance = channels open)

Front 29

What are the five tissues in which glucose uptake is insulin independent?

Back 29

1. CNS
2. Renal tubules
3. Beta Islet cells of the pancreas
4. RBCs
5. GI mucosa

Front 30

Place in order from fastest to slowest the rate of gastric emptying for CHO, fat, liquids, and proteins.

Back 30

Liquids, CHO, protein, fat

Front 31

Is most of the coronary artery blood flow during systole or diastole?

Back 31

Diastole. During systole the left ventricle contracts, resulting in intramyocardial vessel compression and therefore very little blood flow in the coronary circulation.

Front 32

What modified smooth muscle cells of the kidney monitor BP in the afferent arteriole?

Back 32

The JG cells

Front 33

What are the three functions of surfactant?

Back 33

1. Increase compliance
2. Decrease surface tension
3. Decrease probability of pulmonary edema formation

Front 34

Name the hormone—glucagon, insulin, or epinephrine:
• Glycogenolytic, gluconeogenic, lipolytic, glycolytic, and stimulated by hypoglycemia

Back 34

Epinephrine

Front 35

Name the hormone—glucagon, insulin, or epinephrine:
• Glycogenolytic, gluconeogenic, lipolytic, glycolytic, proteolytic, and stimulated by hypoglycemia and AAs

Back 35

Glucagon

Front 36

Name the hormone—glucagon, insulin, or epinephrine:
• Glycogenic, gluconeogenic, lipogenic, proteogenic, glycolytic, and stimulated by hyperglycemia, AAs, fatty acids, ketosis, ACh, GH, and Beta-agonist

Back 36

Insulin

Front 37

Is the hydrophobic or hydrophilic end of the phospholipids of the cell membrane facing the aqueous environment?

Back 37

Hydrophilic (water-soluble) end faces the aqueous environment and the hydrophobic (water-insoluble) end faces the interior of the cell.

Front 38

What type of muscle is characterized by no myoglobin, anaerobic glycolysis, high ATPase activity, and large muscle mass?

Back 38

White muscle; short term too

Front 39

What percentage of CO2 is carried in the plasma as HCO3- ?

Back 39

90% as HCO3-, 5% as carbamino compounds, and 5% as dissolved CO2

Front 40

What is the most potent male sex hormone?

Back 40

Dihydrotestosterone

Front 41

With a decrease in arterial diastolic pressure, what happens to
• Stroke volume?

Back 41

Decreases

Front 42

With a decrease in arterial diastolic pressure, what happens to
• TPR?

Back 42

Decreases

Front 43

With a decrease in arterial diastolic pressure, what happens to
• Heart rate?

Back 43

Decreases

Front 44

What linkage of complex CHOs does pancreatic amylase hydrolyze? What three complexes are formed?

Back 44

Amylase hydrolyzes alpha-1, 4-glucoside linkages, forming alpha-limit dextrins, maltotriose, and maltose.

Front 45

Does the heart rate determine the diastolic or systolic interval?

Back 45

Heart rate determines the diastolic interval, and contractility determines the systolic interval.

Front 46

On a graphical representation of filtration, reabsorption, and excretion, when does glucose first appear in the urine?

Back 46

At the beginning of splay is when the renal threshold for glucose occurs and the excess begins to spill over into the urine.

Front 47

What is the relationship between preload and the passive tension in a muscle?

Back 47

They are directly related; the greater the preload, the greater the passive tension in the muscle and the greater the prestretch of a sarcomere.

Front 48

What is the rate-limiting step in the synthetic pathway of NE at the adrenergic nerve terminal?

Back 48

The conversion of tyrosine to dopamine in the cytoplasm

Front 49

How many days prior to ovulation does LH surge occur in the menstrual cycle?

Back 49

1 day prior to ovulation

Front 50

How are flow through the loop of Henle and concentration of urine related?

Back 50

As flow increases, the urine becomes more dilute because of decreased time for H2O reabsorption.

Front 51

What is the PO2 of aortic blood in fetal circulation?

Back 51

60%

Front 52

How do elevated blood glucose levels decrease GH secretion? (Hint: what inhibitory hypothalamic hormone is stimulated by IGF-1?)

Back 52

Somatotrophins are stimulated by IGF-1, and they inhibit GH secretion. GHRH stimulates GH secretion.

Front 53

What segment of the nephron has the highest concentration of inulin? Lowest concentration of inulin?

Back 53

Terminal collecting duct has the highest concentration and Bowman's capsule has the lowest concentration of inulin.

Front 54

What type of resistance system, high or low, is formed when resistors are added in a series?

Back 54

A high-resistance system is formed when resistors are added in a series.

Front 55

What hormones, secreted in proportion to the size of the placenta, are an index of fetal well-being?

Back 55

hCS and serum estriol, which are produced by the fetal liver and placenta, respectively, are used as estimates of fetal well-being.

Front 56

What primary acid-base disturbance is caused by an increase in alveolar ventilation (decreasing CO2 levels) resulting in the reaction shifting to the left and decreasing both H+ and HCO3- levels?

Back 56

Respiratory alkalosis (summary: low CO2, low H+, slightly low HCO3-)

Front 57

What respiratory center in the caudal pons is the center for rhythm promoting prolonged inspirations?

Back 57

Apneustic center (deep breathing place)

Front 58

What area of the GI tract has the highest activity of brush border enzymes?

Back 58

Jejunum (upper)

Front 59

What is the term to describe the increased rate of secretion of adrenal androgens at the onset of puberty?

Back 59

Adrenarche

Front 60

What period is described when a larger-than-normal stimulus is needed to produce an action potential?

Back 60

Relative refractory period

Front 61

Does T3 or T4 have a greater affinity for its nuclear receptor?

Back 61

T3 has a greater affinity for the nuclear receptor and therefore is considered the active form.

Front 62

What are the three main functions of surfactant?

Back 62

1. Lowers surface tension, so it decreases recoil and increases compliance
2. Reduces capillary filtration
3. Promotes stability in small alveoli by lowering surface tension

Front 63

What is the only important physiological signal regulating the release of PTH?

Back 63

Low interstitial free Ca2+ concentrations

Front 64

What endocrine abnormality is characterized by the following changes in PTH, Ca2+, and inorganic phosphate (Pi)?
• PTH decreased, Ca2+ increased, Pi increased

Back 64

Secondary hypoparathyroidism (vitamin D toxicity)

Front 65

What endocrine abnormality is characterized by the following changes in PTH, Ca2+, and inorganic phosphate (Pi)?
• PTH increased, Ca2+ decreased, Pi decreased

Back 65

Secondary hyperparathyroidism (vitamin D deficiency, renal disease)

Front 66

What endocrine abnormality is characterized by the following changes in PTH, Ca2+, and inorganic phosphate (Pi)?
• PTH decreased, Ca2+ decreased, Pi increased

Back 66

Primary hypoparathyroidism

Front 67

What endocrine abnormality is characterized by the following changes in PTH, Ca2+, and inorganic phosphate (Pi)?
• PTH increased, Ca2+ increased, Pi decreased

Back 67

Primary hyperparathyroidism

Front 68

What is the amount in liters and percent body weight for the following compartments?
• ECF

Back 68

14 L, 33% of body weight

Front 69

What is the amount in liters and percent body weight for the following compartments?
• Interstitial fluid

Back 69

9.3 L, 15% of body weight

Front 70

What is the amount in liters and percent body weight for the following compartments?
• ICF

Back 70

28 L, 40% of body weight

Front 71

What is the amount in liters and percent body weight for the following compartments?
• Vascular fluid

Back 71

4.7 L, 5% of body weight

Front 72

What is the amount in liters and percent body weight for the following compartments?
• Total body water

Back 72

42 L, 67% of body weight

Front 73

What hormone is secreted by the placenta late in pregnancy, stimulates mammary growth during pregnancy, mobilizes energy stores from the mother so that the fetus can use them, and has an amino acid sequence like GH?

Back 73

Human chorionic somatomammotropin (hCS) or human placental lactogen (hPL)

Front 74

What thyroid abnormality has the following?
• TRH decreased, TSH decreased, T4 increased

Back 74

Graves disease (Increased T4 decreases TRH and TSH through negative feedback.)

Front 75

What thyroid abnormality has the following?
• TRH increased, TSH decreased, T4 decreased

Back 75

Secondary hypothyroidism/pituitary (Low TSH results in low T4 and increased TRH because of lack of a negative feedback loop.)

Front 76

What thyroid abnormality has the following?
• TRH decreased, TSH decreased, T4 decreased

Back 76

Tertiary hypothyroidism/hypothalamic (Low TRH causes all the rest to be decreased because of decreased stimulation.)

Front 77

What thyroid abnormality has the following?
• TRH increased, TSH increased, T4 decreased

Back 77

Primary hypothyroidism (Low T4 has a decreased negative feedback loop, resulting in both the hypothalamus and the anterior pituitary gland to increase TRH and TSH release, respectively.)

Front 78

What thyroid abnormality has the following?
• TRH decreased, TSH decreased, T4 increased

Back 78

Secondary hyperthyroidism (Increased TSH results in increased T4 production and increased negative feedback on to hypothalamus and decreased release of TRH.)

Front 79

What two stress hormones are under the permissive action of cortisol?

Back 79

Glucagon and epinephrine

Front 80

If the radius of a vessel doubles, what happens to resistance?

Back 80

The resistance will decrease one-sixteenth of the original resistance.

Front 81

What prevents the down-regulation of the receptors on the gonadotrophs of the anterior pituitary gland?

Back 81

The pulsatile release of GnRH

Front 82

True or false? Epinephrine has proteolytic metabolic effects.

Back 82

False. It has glycogenolytic and lipolytic actions but not proteolytic.

Front 83

What is the only 17-hydroxysteroid with hormonal activity?

Back 83

Cortisol, a 21-carbon steroid, has a -OH group at position 17.

Front 84

Does the oncotic pressure of plasma promote filtration or reabsorption?

Back 84

The oncotic pressure of plasma promotes reabsorption and is directly proportional to the filtration fraction.

Front 85

Why is the base of the lung hyperventilated when a person is standing upright?

Back 85

The alveoli at the base are small and very compliant, so there is a large change in their size and volume and therefore a high level of alveolar ventilation.

Front 86

By removing Na+ from the renal tubule and pumping it back into the ECF compartment, what does aldosterone do to the body's acid-base stores?

Back 86

The removal of Na+ results in the renal tubule becoming negatively charged. The negative luminal charge attracts both K+ and H+ into the renal tubule and promotes HCO3- to enter the ECF and results in hypokalemic alkalosis.

Front 87

What hormone causes contractions of smooth muscle, regulates interdigestive motility, and prepares the intestine for the next meal?

Back 87

Motilin

Front 88

What two vessels in fetal circulation have the highest PO2 levels?

Back 88

Umbilical vein and ductus venosus (80%)

Front 89

How many days prior to ovulation does estradiol peak in the menstrual cycle?

Back 89

2 days prior to ovulation

Front 90

What serves as a marker of endogenous insulin secretion?

Back 90

C-peptide levels

Front 91

What is the term for the total volume of air moved in and out of the respiratory system per minute?

Back 91

Total ventilation (minute ventilation or minute volume)

Front 92

What is the renal compensation mechanism for alkalosis?

Back 92

Increase in urinary excretion of HCO3-, shifting the reaction to the right and increasing H+

Front 93

What is a sign of a Sertoli cell tumor in a man?

Back 93

Excess estradiol in the blood

Front 94

In the systemic circulation, what blood vessels have the largest pressure drop? Smallest pressure drop?

Back 94

Arterioles have the largest drop, whereas the vena cava has the smallest pressure drop in systemic circulation.

Front 95

What is the major stimulus for cell division in chondroblasts?

Back 95

IGF-1

Front 96

What are two causes of diffusion impairment in the lungs?

Back 96

Decrease in surface area and increase in membrane thickness (Palv O2 > PaO2)

Front 97

What are the four effects of suckling on the mother?

Back 97

1. Increased synthesis and secretion of oxytocin
2. Increased release of PIF by the hypothalamus
3. Inhibition of GnRH (suppressing FSH/LH)
4. Milk secretion

Front 98

A migrating myoelectric complex is a propulsive movement of undigested material of undigested material from the stomach to the small intestine to the colon. During a fast, what is the time interval of its repeats?

Back 98

It repeats every 90 to 120 minutes and correlates with elevated levels of motilin.

Front 99

With an increase in arterial systolic pressure, what happens to
• Stroke volume?

Back 99

Increases

Front 100

With an increase in arterial systolic pressure, what happens to
• Vessel compliance?

Back 100

Decreases

Front 101

With an increase in arterial systolic pressure, what happens to
• Heart rate?

Back 101

Decreases

Front 102

What enzyme is needed to activate the following reactions?
• Trypsinogen to trypsin

Back 102

Enterokinase

Front 103

What enzyme is needed to activate the following reactions?
• Chymotrypsinogen to chymotrypsin

Back 103

Trypsin

Front 104

What enzyme is needed to activate the following reactions?
• Procarboxypeptidase to carboxypeptidase

Back 104

Trypsin

Front 105

In a ventricular pacemaker cell, what phase of the action potential is affected by ACh?

Back 105

Phase 4; ACh hyperpolarizes the cell via increasing potassium conductance, taking longer to reach threshold and slowing the rate of firing.

Front 106

What is the most potent stimulus for glucagon secretion? Inhibition?

Back 106

Hypoglycemia for secretion and hyperglycemia for inhibition

Front 107

What is the term for the summation of mechanical stimuli due to the skeletal muscle contractile unit becoming saturated with calcium?

Back 107

Tetany

Front 108

What form of renal tubular reabsorption is characterized by low back leaks, high affinity of a substance, and easy saturation? It is surmised that the entire filtered load is reabsorbed until the carriers are saturated, and then the rest is excreted.

Back 108

A transport maximum (Tm) system

Front 109

In an adrenergic nerve terminal, where is dopamine converted to NE? By what enzyme?

Back 109

Dopamine is converted into NE in the vesicle via the enzyme dopamine-Beta-hydroxylase.

Front 110

Is the clearance for a substance greater than or less than for inulin if it is freely filtered and secreted? If it is freely filtered and reabsorbed?

Back 110

Filtered and secreted: Cx > Cin (i.e., PAH). Filtered and reabsorbed: Cx < Cin (i.e., glucose), where Cx = clearance of a substance and Cin = clearance of inulin.

Front 111

What is the term for the load on a muscle in the relaxed state?

Back 111

Preload. It is the load on a muscle Prior to contraction.

Front 112

The surge of what hormone induces ovulation?

Back 112

LH

Front 113

What are the two best indices of left ventricular preload?

Back 113

LVEDV and LVEDP (left ventricular end-diastolic volume and end-diastolic pressure, respectively)

Front 114

What stage of male development is characterized by the following LH and testosterone levels?
• LH pulsatile amplitude and levels increase, with increased testosterone production.

Back 114

Puberty

Front 115

What stage of male development is characterized by the following LH and testosterone levels?
• Both LH and testosterone levels drop and remain low.

Back 115

Childhood

Front 116

What stage of male development is characterized by the following LH and testosterone levels?
• LH secretion drives testosterone production, with both levels paralleling each other.

Back 116

Adulthood

Front 117

What stage of male development is characterized by the following LH and testosterone levels?
• Decreased testosterone production is accompanied by an increase in LH production.

Back 117

Aged adult

Front 118

What primary acid-base disturbance is caused by a loss in fixed acid forcing the reaction to shift to the right, thereby increasing HCO3- levels?

Back 118

Metabolic alkalosis (summary: high pH, low H+ and high HCO3-)

Front 119

When referring to a series circuit, what happens to resistance when a resistor is added?

Back 119

Resistance increases as resistors are added to the circuit.

Front 120

Why is there an increase in prolactin if the hypothalamic-pituitary axis was severed?

Back 120

Because the chronic inhibition of dopamine (PIF) on the release of prolactin from the anterior pituitary gland is removed, thereby increasing the secretion of prolactin.

Front 121

Why is the clearance of creatinine always slightly greater than the clearance of inulin and GFR?

Back 121

Because creatinine is filtered and a small amount is secreted

Front 122

What acid form of H+ in the urine cannot be titrated?

Back 122

NH4+(ammonium)

Front 123

Regarding the venous system, what happens to blood volume if there is a small change in pressure?

Back 123

Because the venous system is more compliant than the arterial vessels, small changes in pressure result in large changes in blood volume.

Front 124

In what stage of sleep is GH secreted?

Back 124

Stages 3 and 4 (NREM)

Front 125

Where does the conversion of CO2 into HCO3- take place?

Back 125

In the RBC; remember, you need carbonic anhydrase for the conversion, and plasma does not have this enzyme.

Front 126

From the fourth month of fetal life to term, what secretes the progesterone and estrogen to maintains the uterus?

Back 126

The placenta

Front 127

What two factors are required for effective exocytosis?

Back 127

Calcium and ATP are required for packaged macromolecules to be extruded from the cell.

Front 128

What is the best measure of total body vitamin D if you suspect a deficiency?

Back 128

Serum 25-hydroxy-vitamin D (25-OH-D)

Front 129

What hormone is required for 1, 25-dihydroxy-vitamin D (1, 25-diOH-D) to have bone resorbing effects?

Back 129

PTH

Front 130

Is bone deposition or resorption due to increased interstitial Ca2+concentrations?

Back 130

Bone deposition increases with increased Ca2+ or PO 4- concentrations, whereas resorption (breakdown) is increased when there are low levels of Ca2+ or PO4-.

Front 131

The opening of what valve indicates the termination of isovolumetric relaxation phase of the cardiac cycle?

Back 131

Opening of the mitral valve indicates the termination of the isovolumetric relaxation phase and the beginning of the ventricular filling phase.

Front 132

Why is there a decrease in the production in epinephrine when the anterior pituitary gland is removed?

Back 132

The enzyme phenyl ethanolamine N-methyltransferase (PNMT), used in the conversion of epinephrine, is regulated by cortisol. Removing the anterior pituitary gland decreases ACTH and therefore cortisol.

Front 133

Name the period described by the following statement: no matter how strong a stimulus is, no further action potentials can be stimulated.

Back 133

Absolute refractory period is due to voltage inactivation of sodium channels.

Front 134

How many carbons do estrogens have?

Back 134

Estrogens are 18-carbon steroids. (Removal of one carbon from an androgen produces an estrogen.)

Front 135

True or false? The alveolar PO2 and PCO2 levels match the pulmonary end capillary blood levels.

Back 135

True. Because of intrapulmonary shunting, there is a slight decrease in PO2 and increase in PCO2 between the pulmonary end capillary blood and the systemic arterial blood.

Front 136

In high altitudes, what is the main drive for ventilation?

Back 136

The main drive shifts from central chemoreceptors (CSF H+) to peripheral chemoreceptors monitoring low PO2 levels.

Front 137

Describe what type of fluid is either gained or lost with the following changes in body hydration for the ECF volume, ICF volume, and body osmolarity, respectively:
• ECF, decrease; ICF, no change; body, no change

Back 137

Loss of isotonic fluid (diarrhea, vomiting, hemorrhage)

Front 138

Describe what type of fluid is either gained or lost with the following changes in body hydration for the ECF volume, ICF volume, and body osmolarity, respectively:
• ECF, increase; ICF, increase; body, decrease

Back 138

Gain of hypotonic fluid (water intoxication or hypotonic saline)

Front 139

Describe what type of fluid is either gained or lost with the following changes in body hydration for the ECF volume, ICF volume, and body osmolarity, respectively:
• ECF, decrease; ICF, decrease; body: increase

Back 139

Loss of hypotonic fluid (alcohol, diabetes insipidus, dehydration)

Front 140

Describe what type of fluid is either gained or lost with the following changes in body hydration for the ECF volume, ICF volume, and body osmolarity, respectively:
• ECF: increase; ICF: no change; body: no change

Back 140

Gain of isotonic fluid (isotonic saline)

Front 141

Describe what type of fluid is either gained or lost with the following changes in body hydration for the ECF volume, ICF volume, and body osmolarity, respectively:
• ECF, increase; ICF, decrease; body, increase

Back 141

Gain of hypertonic fluid (mannitol or hypertonic saline)

Front 142

What hormone excess produces adrenal hyperplasia?

Back 142

ACTH

Front 143

Is there more circulating T3 or T4 in plasma?

Back 143

T4; because of the greater affinity for the binding protein, T4 has a significantly (nearly fifty times) longer half-life than T3.

Front 144

Why is the cell's resting membrane potential negative?

Back 144

The resting membrane potential of the cell is -90 mV because of the intracellular proteins.

Front 145

True or false? Thyroid size is a measure of its function.

Back 145

False. Thyroid size is a measure of TSH levels (which are goitrogenic).

Front 146

If the radius of a vessel is decreased by half, what happens to the resistance?

Back 146

The resistance increases 16-fold.

Front 147

What neurotransmitter is essential for maintaining a normal BP when an individual is standing?

Back 147

NE, via its vasoconstrictive action on blood vessels

Front 148

What form of diabetes insipidus is due to an insufficient amount of ADH for the renal collecting ducts?

Back 148

Central/neurogenic diabetes insipidus; in the nephrogenic form there is sufficient ADH available, but the renal collecting ducts are impermeable to its actions.

Front 149

Name the three methods of vasodilation via the sympathetic nervous system.

Back 149

1. Decrease alpha-1 activity
2. Increase Beta-2 activity
3. Increase ACh levels

Front 150

What hormone is characterized by the following renal effects?
• Calcium reabsorption, phosphate excretion

Back 150

PTH

Front 151

What hormone is characterized by the following renal effects?
• Calcium excretion, phosphate excretion

Back 151

Calcitriol

Front 152

What hormone is characterized by the following renal effects?
• Calcium reabsorption, phosphate reabsorption

Back 152

Vitamin D3

Front 153

True or false? Progesterone has thermogenic activities.

Back 153

True. Elevated plasma levels of progesterone can raise the body temperature 0.5° to 1.0°F.

Front 154

How long is the transit time through the small intestine?

Back 154

2 to 4 hours

Front 155

Where is the last conducting zone of the lungs?

Back 155

Terminal bronchioles. (No gas exchange occurs here.)

Front 156

True or false? Cortisol inhibits glucose uptake in skeletal muscle.

Back 156

True; cortisol inhibits glucose uptake in most tissue, making it available for neural tissue use.

Front 157

What percentage of cardiac output flows through the pulmonary circuit?

Back 157

100%; the percentage of blood flow through the pulmonary and systemic circulations are equal.

Front 158

Name the Hgb-O2 binding site based on the following information:
• Least affinity for O2; requires the highest PO 2 levels for attachment (approx. 100 mm Hg)

Back 158

Site 4

Front 159

Name the Hgb-O2 binding site based on the following information:
• Greatest affinity of the three remaining sites for attachment; requires PO2 levels of 26 mm Hg to remain attached

Back 159

Site 2

Front 160

Name the Hgb-O2 binding site based on the following information:
• Remains attached under most physiologic conditions

Back 160

Site 1

Front 161

Name the Hgb-O2 binding site based on the following information:
• Requires a PO2 level of 40 mm Hg to remain attached

Back 161

Site 3

Front 162

Which three factors cause the release of epinephrine from the adrenal medulla?

Back 162

1. Exercise
2. Emergencies (stress)
3. Exposure to cold


(The three Es)

Front 163

How many ATPs are hydrolyzed every time a skeletal muscle cross-bridge completes a single cycle?

Back 163

One, and it provides the energy for mechanical contraction.

Front 164

Why would a puncture to a vein above the heart have the potential to introduce air into the vascular system?

Back 164

Venous pressure above the heart is subatmospheric, so a puncture there has the potential to introduce air into the system.

Front 165

What type of saliva is produced under parasympathetic stimulation?

Back 165

High volume, watery solution; sympathetic stimulation results in thick, mucoid saliva.

Front 166

In what area of the GI tract does iron get absorbed?

Back 166

Duodenum

Front 167

Why is the apex of the lung hypoventilated when a person is standing upright?

Back 167

The alveoli at the apex are almost completely inflated prior to inflation, and although they are large, they receive low levels of alveolar ventilation.

Front 168

What pancreatic islet cell secretes glucagons?

Back 168

alpha-Cells; glucagon has stimulatory effects on -cells and inhibitory effects on -cells.

Front 169

What are the four characteristics of all protein-mediated transportation?

Back 169

1. Competition for carrier with similar chemical substances
2. Chemical specificity needed for transportation
3. Zero-order saturation kinetics (Transportation is maximal when all transporters are saturated.)
4. Rate of transportation faster than if by simple diffusion

Front 170

What is secretin's pancreatic action?

Back 170

Secretin stimulates the pancreas to secrete a HCO3--rich solution to neutralize the acidity of the chyme entering the duodenum.

Front 171

Why is there an increase in FF if the GFR is decreased under sympathetic stimulation?

Back 171

Because RPF is markedly decreased, while GFR is only minimally diminished; this results in an increase in FF (remember FF = GFR/RPF).

Front 172

What triggers phase 3 of the action potential in a ventricular pacemaker cell?

Back 172

Rapid efflux of potassium

Front 173

What is the primary target for the action of glucagon?

Back 173

Liver (hepatocytes)

Front 174

What is the renal compensation mechanism for acidosis?

Back 174

Production of HCO3-, shifting the reaction to the left and thereby decreasing H+

Front 175

What enzyme found in a cholinergic synapse breaks down ACh? What are the byproducts?

Back 175

Acetylcholinesterase breaks ACh into acetate and choline (which gets resorbed by the presynaptic nerve terminal).

Front 176

What hormone, produced by Sertoli cells, if absent would result in the formation of internal female structures?

Back 176

MIF

Front 177

What happens to the lung if the intrapleural pressure exceeds lung recoil?

Back 177

The lung will expand; also the opposite is true.

Front 178

What two factors determine the clearance of a substance?

Back 178

Plasma concentration and excretion rate

Front 179

What type of muscle contraction occurs when the muscle shortens and lifts the load placed on it?

Back 179

Isotonic contraction

Front 180

What type of potential is characterized as being an all-or-none response, propagated and not summated?

Back 180

Action potential

Front 181

What primary acid-base disturbance is caused by a gain in fixed acid forcing the reaction to shift to the left, decreasing HCO3- and slightly increasing CO2?

Back 181

Metabolic acidosis (summary: low pH, high H+, and low HCO3-)

Front 182

What two pituitary hormones are produced by acidophils?

Back 182

GH and prolactin are produced by acidophils; all others are by basophils.

Front 183

What organ of the body has the smallest AV oxygen difference?

Back 183

The renal circulation has the smallest AV O2 (high venous PO2) difference in the body because of the overperfusion of the kidneys resulting from filtration.

Front 184

What is the titratable acid form of H+ in the urine?

Back 184

H2PO4- (dihydrogen phosphate)

Front 185

What hypothalamic hormone is synthesized in the preoptic nucleus?

Back 185

GnRH

Front 186

What five factors promote turbulent flow?

Back 186

1. Increased tube radius
2. Increased velocity
3. Decreased viscosity
4. Increased number of branches
5. Narrowing of an orifice

Front 187

What is the major hormone produced in the following areas of the adrenal cortex?
• Zona glomerulosa

Back 187

Aldosterone

Remember, from the outer cortex to the inner layer, Salt, Sugar, Sex. The adrenal cortex gets sweeter as you go deeper.

Front 188

What is the major hormone produced in the following areas of the adrenal cortex?
• Zona fasciculata

Back 188

Cortisol

Remember, from the outer cortex to the inner layer, Salt, Sugar, Sex. The adrenal cortex gets sweeter as you go deeper.

Front 189

What is the major hormone produced in the following areas of the adrenal cortex?
• Zona reticularis

Back 189

DHEA (androgens)

Remember, from the outer cortex to the inner layer, Salt, Sugar, Sex. The adrenal cortex gets sweeter as you go deeper.

Front 190

Where is most of the body's Ca2+ stored?

Back 190

In bone; nearly 99% of Ca2+ is stored in the bone as hydroxyapatite.

Front 191

What is the relationship between ventilation and PCO2 levels?

Back 191

They are inversely related. If ventilation increases, there will be a decrease in PCO2 levels and vice versa.

Front 192

Is T3 or T4 responsible for the negative feedback loop on to the hypothalamus and anterior pituitary gland?

Back 192

T4, as long as T4 levels remain constant, TSH will be minimally effected by T3.

Front 193

What is the signal to open the voltage-gated transmembrane potassium channels?

Back 193

Membrane depolarization is the stimulus to open these slow channels, and if they are prevented from opening, it will slow down the repolarization phase.

Front 194

Increased urinary excretion of what substance is used to detect excess bone demineralization?

Back 194

Hydroxyproline

Front 195

What is the term to describe how easily a vessel stretches?

Back 195

Compliance (think of it as distensibility)

Front 196

What is the ratio of T4:T3 secretion from the thyroid gland?

Back 196

20:1T4T3. There is an increase in the production of T3 when iodine becomes deficient.

Front 197

Do the PO2 peripheral chemoreceptors of the carotid body contribute to the normal drive for ventilation?

Back 197

Under normal resting conditions no, but they are strongly stimulated when PO2 arterial levels decrease to 50 to 60 mm Hg, resulting in increased ventilatory drive.

Front 198

What determines the overall force generated by the ventricular muscle during systole?

Back 198

The number of cross-bridges cycling during contraction: the greater the number, the greater the force of contraction.

Front 199

Where does most circulating plasma epinephrine originate?

Back 199

From the adrenal medulla; NE is mainly derived from the postsynaptic sympathetic neurons.

Front 200

What causes a skeletal muscle contraction to terminate?

Back 200

When calcium is removed from troponin and pumped back into the SR, skeletal muscle contraction stops.

Front 201

What happens to intracellular volume when there is an increase in osmolarity?

Back 201

ICF volume decreases when there is an increase in osmolarity and vice versa.

Front 202

Which CHO is independently absorbed from the small intestine?

Back 202

Fructose; both glucose and galactose are actively absorbed via secondary active transport.

Front 203

When is the surface tension the greatest in the respiratory cycle?

Back 203

Surface tension, the force to collapse the lung, is greatest at the end of inspiration.

Front 204

What adrenal enzyme deficiency results in hypertension, hypernatremia, increased ECF volume, and decreased adrenal androgen production?

Back 204

17-alpha-Hydroxylase deficiency

Front 205

In reference to membrane potential (Em) and equilibrium potential (Ex), which way do ions diffuse?

Back 205

Ions diffuse in the direction to bring the membrane potential toward the equilibrium potential.

Front 206

Under normal conditions, what is the main factor that determines GFR?

Back 206

Hydrostatic pressure of the glomerular capillaries (promotes filtration)

Front 207

The closure of what valve indicates the beginning of the isovolumetric relaxation phase of the cardiac cycle?

Back 207

Closure of the aortic valve indicates the termination of the ejection phase and the beginning of the isovolumetric relaxation phase of the cardiac cycle.

Front 208

What vessels in the systemic circulation have the greatest and slowest velocity?

Back 208

The aorta has the greatest velocity and the capillaries have the slowest velocity.

Front 209

Thin extremities, fat collection on the upper back and abdomen, hypertension, hypokalemic alkalosis, acne, hirsutism, wide purple striae, osteoporosis, hyperlipidemia, hyperglycemia with insulin resistance, and protein depletion are all characteristics of what disorder?

Back 209

Hypercortisolism (Cushing syndrome)

Front 210

What enzyme is essential for the conversion of CO2 to HCO3-?

Back 210

Carbonic anhydrase

Front 211

True or false? The parasympathetic nervous system has very little effect on arteriolar dilation or constriction.

Back 211

True

Front 212

What three lung measurements must be calculated because they cannot be measured by simple spirometry?

Back 212

TLC, FRC, and RV have to be calculated. (Remember, any volume that has RV as a component has be calculated.)

Front 213

What is the venous and arterial stretch receptors' function regarding the secretion of ADH?

Back 213

They chronically inhibit ADH secretion; when there is a decrease in the blood volume, the stretch receptors send fewer signals, and ADH is secreted.

Front 214

What cell converts androgens to estrogens?

Back 214

Granulosa cell

Front 215

What hormone acts on Granulosa cells?

Back 215

FSH

Front 216

How long is the transit time through the large intestine?

Back 216

3 to 4 days

Front 217

Does subatmospheric pressure act to expand or collapse the lung?

Back 217

Subatmospheric pressure acts to expand the lung; positive pressure acts to collapse the lung.

Front 218

What hormone constricts afferent and efferent arterioles (efferent more so) in an effort to preserve glomerular capillary pressure as the renal blood flow decreases?

Back 218

AT II

Front 219

Why is there a minimal change in BP during exercise if there is a large drop in TPR?

Back 219

Because the large drop in TPR is accompanied by a large increase in cardiac output, resulting in a minimal change in BP.

Front 220

What is the effect of insulin on protein storage?

Back 220

Insulin increases total body stores of protein, fat, and CHOs. When you think insulin, you think storage.

Front 221

What is the term for an inhibitory interneuron?

Back 221

Renshaw neuron

Front 222

What triggers phase 0 of the action potential in a ventricular pacemaker cell?

Back 222

Calcium influx secondary to slow channel opening

Front 223

What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron?
• Percentage of original filtered volume left in the lumen

Back 223

At the end of the PCT 25% of the original volume is left

Front 224

What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron?
• Percentage of Na+, Cl-, K+ left in the lumen

Back 224

At the end of the PCT 25% of Na+, Cl-, K+ is left

Front 225

What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron?
• Osmolarity

Back 225

300 mOsm/L

Front 226

What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron?
• Concentration of CHO, AA, ketones, peptides

Back 226

No CHO, AA, ketones, or peptides are left in the tubular lumen.

Front 227

True or false? Enterokinase is a brush border enzyme.

Back 227

False. It is an enzyme secreted by the lining of the small intestine.

Front 228

Where does the synthesis of ACh occur?

Back 228

In the cytoplasm of the presynaptic nerve terminal; it is catalyzed by choline acetyltransferase.

Front 229

What pancreatic islet cell secretes somatostatin?

Back 229

delta-Cells; somatostatin has an inhibitory effect on alpha- and Beta-islet cells.

Front 230

Why is O2 content depressed in anemic patients?

Back 230

Anemic patients have a depressed O2 content because of the reduced concentration of Hgb in the blood. As for polycythemic patients, their O2 content is increased because of the excess Hgb concentrations.

Front 231

What term describes the volume of plasma from which a substance is removed over time?

Back 231

Clearance

Front 232

If capillary hydrostatic pressure is greater than oncotic pressure, is filtration or reabsorption promoted?

Back 232

Filtration; if hydrostatic pressure is less than oncotic pressure, reabsorption is promoted.

Front 233

What cells of the parathyroid gland are simulated in response to hypocalcemia?

Back 233

The chief cells of the parathyroid gland release PTH in response to hypocalcemia.

Front 234

At the base of the lung, what is the baseline intrapleural pressure, and what force does it exert on the alveoli?

Back 234

Intrapleural pressure at the base is -2.5 cm H2O (more positive than the mean), resulting in a force to collapse the alveoli.

Front 235

What hormone is necessary for normal GH secretion?

Back 235

Normal thyroid hormones levels in the plasma are necessary for proper secretion of GH. Hypothyroid patients have decreased GH secretions.

Front 236

What is the signal to open the voltage-gated transmembrane sodium channels?

Back 236

Membrane depolarization is the stimulus to open these channels, which are closed in resting conditions.

Front 237

What hormones are produced in the median eminence region of the hypothalamus and the posterior pituitary gland?

Back 237

None; they are the storage sites for ADH and oxytocin.

Front 238

What is the most energy-demanding phase of the cardiac cycle?

Back 238

Isovolumetric contraction

Front 239

What presynaptic receptor does NE use to terminate further neurotransmitter release?

Back 239

alpha2-Receptors

Front 240

Are salivary secretions hypertonic, hypotonic, or isotonic?

Back 240

Hypotonic, because NaCl is reabsorbed in the salivary ducts

Front 241

What is the effect of T3 on heart rate and cardiac output?

Back 241

T3 increases both heart rate and cardiac output by increasing the number of Beta-receptors and their sensitivity to catecholamines.

Front 242

Why will turbulence first appear in the aorta in patients with anemia?

Back 242

Because it is the largest vessel and has the highest velocity in systemic circulation

Front 243

What is the origin of the polyuria if a patient is dehydrated and electrolyte depleted?

Back 243

If the polyuria begins before the collecting ducts, the patient is dehydrated and electrolyte depleted. If the polyuria originates from the collecting ducts, the patient is dehydrated with normal electrolytes.

Front 244

What is the physiologically active form of Ca2+?

Back 244

Free ionized Ca2+

Front 245

What are the two factors that affect alveolar PCO2 levels?

Back 245

Metabolic rate and alveolar ventilation (main factor)

Front 246

Why is spermatogenesis decreased with anabolic steroid therapy?

Back 246

Exogenous steroids suppress LH release and result in Leydig cell atrophy. Testosterone, produced by Leydig cells, is needed for spermatogenesis.

Front 247

What type of membrane is characterized as being permeable to water only?

Back 247

Semipermeable membrane; a selectively permeable membrane allows both water and small solutes to pass through its membrane.

Front 248

What thyroid enzyme is needed for oxidation of I– to I'?

Back 248

Peroxidase, which is also needed for iodination and coupling inside the follicular cell

Front 249

What is the most important stimulus for the secretion of insulin?

Back 249

An increase in serum glucose levels

Front 250

What term is described as the prestretch on the ventricular muscle at the end of diastole?

Back 250

Preload (the load on the muscle in the relaxed state)

Front 251

What peripheral chemoreceptor receives the most blood per gram of weight in the body?

Back 251

The carotid body, which monitors arterial blood directly

Front 252

What adrenal enzyme deficiency results in hypertension, hypernatremia, and virilization?

Back 252

11-Beta-Hydroxylase deficiency results in excess production of 11-deoxycorticosterone, a weak mineralocorticoid. It increases BP, Na+, and ECF volume along with production of adrenal androgens.

Front 253

What is the term for diffusion of water across a semipermeable or selectively permeable membrane?

Back 253

Osmosis; water will diffuse from higher to lower water concentrations.

Front 254

When do hCG concentrations peak in pregnancy?

Back 254

In the first 3 months

Front 255

How many milliliters of O2 per milliliter of blood?

Back 255

0.2

Front 256

What type of cell is surrounded by mineralized bone?

Back 256

Osteocyte

Front 257

What two forces affect movement of ions across a membrane?

Back 257

Concentration force and electrical force

Front 258

What happens to the resistance of the system when a resistor is added in a series?

Back 258

Resistance of the system increases. (Remember, when resistors are connected in a series, the total of the resistance is the sum of the individual resistances.)

Front 259

What is the greatest component of lung recoil?

Back 259

Surface tension; in the alveoli, it is a force that acts to collapse the lung.

Front 260

Where is ADH synthesized?

Back 260

In the supraoptic nuclei of the hypothalamus; it is stored in the posterior pituitary gland.

Front 261

How is velocity related to the total cross-sectional area of a blood vessel?

Back 261

Velocity is inversely related to cross-sectional area.

Front 262

True or false? Aldosterone has a sodium-conserving action in the distal colon.

Back 262

True. In the distal colon, sweat glands, and salivary ducts, aldosterone has sodium-conserving effects.

Front 263

What form of hormone is described as having membrane-bound receptors that are stored in vesicles, using second messengers, and having its activity determined by free hormone levels.

Back 263

Water-soluble hormones are considered fast-acting hormones.

Front 264

What forms of fatty acids are absorbed from the small intestine mucosa by simple diffusion?

Back 264

Short-chain fatty acids

Front 265

What is the term for the day after the LH surge in the female cycle?

Back 265

Ovulation

Front 266

The opening of what valve indicates the beginning of the ejection phase of the cardiac cycle?

Back 266

Opening of the aortic valve terminates the isovolumetric phase and begins the ejection phase of the cardiac cycle.

Front 267

What is the region of an axon where no myelin is found?

Back 267

Nodes of Ranvier

Front 268

What disorder of aldosterone secretion is characterized by
• Increased total body sodium, ECF volume, plasma volume, BP, and pH; decreased potassium, renin and AT II activity; no edema?

Back 268

Primary hyperaldosteronism (Conn syndrome)

Front 269

What disorder of aldosterone secretion is characterized by
• Decreased total body sodium, ECF volume, plasma volume, BP, and pH; increased potassium, renin, and AT II activity; no edema?

Back 269

Primary hypoaldosteronism (Addison's disease)

Front 270

What four factors affect diffusion rate?

Back 270

1. Concentration (greater concentration gradient, greater diffusion rate)
2. Surface area (greater surface area, greater diffusion rate)
3. Solubility (greater solubility, greater diffusion rate)
4. Membrane thickness (thicker the membrane, slower the diffusion rate)


Molecular weight is clinically unimportant

Front 271

How long after ovulation does fertilization occur?

Back 271

8 to 25 hours

Front 272

What is the name of the force that develops in the wall of the lungs as they expand?

Back 272

Lung recoil, being a force to collapse the lung, increases as the lung enlarges during inspiration.

Front 273

What day of the menstrual cycle does ovulation take place?

Back 273

Day 14

Front 274

How does sympathetic stimulation to the skin result in decreased blood flow and decreased blood volume? (Hint: what vessels are stimulated, and how?)

Back 274

A decrease in cutaneous blood flow results from constriction of the arterioles, and decreased cutaneous blood volume results from constriction of the venous plexus.

Front 275

What two compensatory mechanisms occur to reverse hypoxia at high altitudes?

Back 275

Increase in erythropoietin and increase in 2, 3-BPG, also called 2, 3-diphosphoglycerate (2, 3-P2Gri) (increase in glycolysis)

Front 276

What female follicular cell is under LH stimulation and produces androgens from cholesterol?

Back 276

Theca cell

Front 277

What is the main factor determining FF?

Back 277

Renal plasma flow (decrease flow, increase FF)

Front 278

Where is the action potential generated on a neuron?

Back 278

Axon hillock

Front 279

If free water clearance (CH2O) is positive, what type of urine is formed? And if it is negative?

Back 279

If positive, hypotonic urine (osmolarity <300 mOsm/L); if negative, hypertonic urine (osmolarity > 300 mOsm/L)>>

Front 280

What cell in the heart has the highest rate of automaticity?

Back 280

SA node; it is the reason it is the primary pacemaker of the heart.

Front 281

What is pumped from the lumen of the ascending loop of Henle to decrease the osmolarity?

Back 281

NaCl is removed from the lumen to dilute the fluid leaving the loop of Henle.

Front 282

True or false? In skeletal muscle relaxation is an active event.

Back 282

True. Sarcoplasmic calcium-dependent ATPase supplies the energy to terminate contraction, and therefore it is an active process.

Front 283

What three factors increase simple diffusion?

Back 283

1. Increased solubility
2. Increased concentration gradient
3. Decreased thickness of the membrane

Front 284

What is the pancreatic action of CCK?

Back 284

CCK stimulates the pancreas to release amylase, lipase, and proteases for digestion.

Front 285

What is the rate-limiting step in a conduction of a NMJ?

Back 285

The time it takes ACh to diffuse to the postjunctional membrane

Front 286

Is excretion greater than or less than filtration for net secretion to occur?

Back 286

Excretion is greater than filtration for net secretion to occur.

Front 287

What acid-base disturbance is produced from vomiting?

Back 287

Hypokalemic metabolic alkalosis occurs from vomiting because of the loss of H+, K+, and Cl-.

Front 288

What phase of the menstrual cycle is dominated by estrogen? Progesterone?

Back 288

Follicular phase is estrogen-dependent with increased FSH levels, while the luteal phase is progesterone-dependent.

Front 289

Name the lung measurement based on the following descriptions:
• The amount of air that enters or leaves the lung system in a single breath

Back 289

Tidal volume (VT)

Front 290

Name the lung measurement based on the following descriptions:
• The maximal volume inspired from FRC

Back 290

Inspiratory capacity

Front 291

Name the lung measurement based on the following descriptions:
• Additional volume that can be expired after normal expiration

Back 291

Expiratory reserve volume (ERV)

Front 292

Name the lung measurement based on the following descriptions:
• Maximal volume that can be expired after maximal inspiration

Back 292

Vital capacity (VC)

Front 293

Name the lung measurement based on the following descriptions:
• Volume in the lungs at the end of passive expiration

Back 293

Functional residual capacity (FRC)

Front 294

Name the lung measurement based on the following descriptions:
• Additional air that can be taken in after normal inspiration

Back 294

Inspiratory reserve volume (IRV)

Front 295

Name the lung measurement based on the following descriptions:
• Amount of air in the lungs after maximal expiration

Back 295

Residual volume (RV)

Front 296

Name the lung measurement based on the following descriptions:
• Amount of air in the lungs after maximal inspiration

Back 296

Total lung capacity (TLC)

Front 297

What growth factors are chondrogenic, working on the epiphyseal end plates of bone?

Back 297

Somatomedins (IGF-1)

Front 298

What determines the Vmax of skeletal muscle?

Back 298

The muscle's ATPase activity

Front 299

True or false? All of the hormones in the hypothalamus and anterior pituitary gland are water soluble.

Back 299

True

Front 300

What is the effect of T3 on the glucose absorption in the small intestine?

Back 300

Thyroid hormones increase serum glucose levels by increasing the absorption of glucose from the small intestine.

Front 301

Is the bound form or free form of a lipid-soluble hormone responsible for the negative feedback activity?

Back 301

Free form determines hormone activity and is responsible for the negative feedback loop.

Front 302

What region or regions of the adrenal cortex are stimulated by ACTH?

Back 302

Zona fasciculata and zona reticularis

Front 303

Are the following parameters associated with an obstructive or restrictive lung disorder: decreased FEV1, FVC, peak flow, and FEV1/FVC; increased TLC, FRC, and RV?

Back 303

Obstructive lung disorders. The opposite changes (where you see decrease exchange it for increase and vice versa) are seen in a restrictive pattern.

Front 304

What is the respiratory compensation mechanism for metabolic alkalosis?

Back 304

Hypoventilation, which increases CO2, shifting the reaction to the right and increasing H+

Front 305

During puberty, what is the main drive for the increased GH secretion?

Back 305

Increased androgen secretion at puberty drives the increased GH secretion.

Front 306

What type of potential is characterized as graded, decremental, and exhibiting summation?

Back 306

Subthreshold potential

Front 307

What three organs are responsible for peripheral conversion of T4 to T3?

Back 307

Liver, kidneys, and pituitary gland via 5' deiodinase enzyme

Front 308

The closure of what valve indicates the beginning of isovolumetric contraction?

Back 308

Mitral valve closure indicates the termination of the ventricular filling phase and beginning of isovolumetric contraction.

Front 309

How many carbons do androgens have?

Back 309

Androgens are 19-carbon steroids.

Front 310

At the apex of the lung, what is the baseline intrapleural pressure, and what force does it exert on the alveoli?

Back 310

Baseline apical intrapleural pressure is -10 cm H2O (more negative than the mean) resulting in a force to expand the alveoli.

Front 311

True or false? Renin secretion is increased in 21-β-hydroxylase deficiency.

Back 311

True. Increased renin and AT II levels occur as a result of the decreased production of aldosterone.

Front 312

What are the four ways to increase TPR?

Back 312

1. Decrease the radius of the vessel
2. Increase the length of the vessel
3. Increase the viscosity
4. Decrease the number of parallel channels

Front 313

What form of estrogen is of placental origin?

Back 313

Estriol

Front 314

What term is an index of the effort needed to expand the lungs (i.e., overcomes recoil)?

Back 314

Compliance; the more compliant a lung is, the easier it is to inflate.

Front 315

At which three sites in the body is T4 converted to T3?

Back 315

1. Liver
2. Kidney
3. Pituitary gland (via 5'-deiodinase enzyme)

Front 316

Using Laplace's relationship regarding wall tension, why is the wall tension in an aneurysm greater than in the surrounding normal blood vessel's wall?

Back 316

The wall tension is greater because the aneurysm has a greater radius than the surrounding vessel.

Front 317

What percentage of nephrons is cortical?

Back 317

Seven-eighths of nephrons are cortical, with the remainder juxtamedullary.

Front 318

To what is the diffusion rate indirectly proportional?

Back 318

Diffusion rate is indirectly proportional to membrane thickness and is directly proportional to membranes surface area.

Front 319

ADH is secreted in response to what two stimuli?

Back 319

ADH is secreted in response to increased plasma osmolarity and decreased blood volume.

Front 320

What vessels have the largest total cross-sectional area in systemic circulation?

Back 320

Capillaries

Front 321

How many days before the first day of menstrual bleeding is ovulation?

Back 321

14 days in most women (Remember, the luteal phase is always constant.)

Front 322

What is the major muscle used in the relaxed state of expiration?

Back 322

Under resting conditions expiration is considered a passive process; therefore, no muscles are used. In the active state the abdominal muscles can be considered the major muscle of expiration.

Front 323

What subunit of hCG is used to detect whether a patient is pregnant?

Back 323

The β-subunit; remember, the α-subunit is nonspecific.

Front 324

What happens to capillary oncotic pressure with dehydration?

Back 324

Oncotic pressure increases because of the removal of water.

Front 325

What cells of the kidney are extravascular chemoreceptors for decreased Na+, Cl-, and NaCl?

Back 325

Macula densa

Front 326

What is the effect of insulin on intracellular K+ stores?

Back 326

Insulin increases intracellular K+ stores while decreasing serum K+ levels.

Front 327

What triggers phase 4 of the action potential in a ventricular pacemaker cell?

Back 327

Decreasing potassium conductance, which results in increased excitability

Front 328

What is it called when levels of sex steroids increase, LH increases, and FSH increases?

Back 328

GnRH pulsatile infusion

Front 329

What parasympathetic neurotransmitter of the GI tract stimulates the release of gastrin?

Back 329

Gastrin-releasing peptide (GRP) stimulates G cells to release Gastrin. (All G's)

Front 330

What reflex increases TPR in an attempt to maintain BP during a hemorrhage?

Back 330

The carotid sinus reflex

Front 331

What is the name of the regulatory protein that covers the attachment site on actin in resting skeletal muscle?

Back 331

Tropomyosin

Front 332

Which way does the Hgb-O2 dissociation curve shift in patients with CO poisoning?

Back 332

The pathologic problem with CO poisoning is that CO has 240 times as much affinity for Hgb molecule as does O2, reducing the carrying capacity and shifting the curve to the left, making it difficult to remove the CO molecule from Hgb.

Front 333

What is the main factor determining GFR?

Back 333

Glomerular capillary pressure (increased glomerular capillary pressure, increased GFR and vice versa)

Front 334

What is the effect of hypoventilation on cerebral blood flow?

Back 334

Hypoventilation results in an increase in PCO2 levels and therefore an increase in blood flow.

Front 335

What cells of the thyroid gland are stimulated in response to hypercalcemia?

Back 335

The parafollicular cells of the thyroid (C cells) release calcitonin in response to hypercalcemia.

Front 336

What is the term for the amount of blood in the ventricle after maximal contraction?

Back 336

Residual volume

Front 337

What does failure of PaO2 to increase with supplemental O2 indicate?

Back 337

Pulmonary shunt (i.e., pulmonary embolism)

Front 338

What two substances stimulate Sertoli cells?

Back 338

FSH and testosterone

Front 339

The clearance of what substance is the gold standard of renal plasma flow?

Back 339

Para-aminohippurate (PAH)

Front 340

What bile pigment is formed by the metabolism of bilirubin by intestinal bacteria, giving stool its brown color?

Back 340

Stercobilin

Front 341

Is ACh associated with bronchoconstriction or bronchodilation?

Back 341

Bronchoconstriction is associated with parasympathetic stimulation (ACh), and catecholamine stimulation is associated with bronchodilation (why epinephrine is used in emergency treatment of bronchial asthma.)

Front 342

What are the growth factors released from the liver called?

Back 342

Somatomedins

Front 343

Regarding skeletal muscle mechanics, what is the relationship between velocity and afterload?

Back 343

An increase in the afterload decreases velocity; they are inversely related. (V equals 1 divided by afterload.)

Front 344

What happens to extracellular volume with a net gain in body fluid?

Back 344

The ECF compartment always enlarges when there is a net gain in total body water and decreases when there is a loss of total body water. Hydration status is named in terms of the ECF compartment.

Front 345

What are the six substances that promote the secretion of insulin?

Back 345

1. Glucose
2. Amino acid (arginine)
3. Gastrin inhibitory peptide (GIP)
4. Glucagon
5. β-Agonists
6. ACh

Front 346

Does O2 or CO2 have a higher driving force across the alveolar membrane?

Back 346

O2 has a higher driving force but is only one-twenty-fourth as soluble as CO2. CO 2 has a very small partial pressure difference across the alveolar membrane (47-40 = 7 mmHg), but it is extremely soluble and therefore diffuses readily across the membrane.

Front 347

What is used as an index for both adrenal and testicular androgens?

Back 347

Urinary 17-ketosteroids

Front 348

How are resistance and length related regarding flow?

Back 348

Resistance and vessel length are proportionally related. The greater the length of the vessel, the greater the resistance is on the vessel.

Front 349

Is filtration greater than or less than excretion for net reabsorption to occur?

Back 349

Filtration is greater than excretion for net reabsorption to occur.

Front 350

What hormone, stimulated by epinephrine, results in an increase in lipolysis?

Back 350

Hormone-sensitive lipase, which breaks down triglyceride into glycerol and free fatty acid

Front 351

True or false? Miniature end-plate potentials (MEPPs) generate action potentials.

Back 351

False

Front 352

Is GH considered a gluconeogenic hormone?

Back 352

Yes, it decreases fat and muscle uptake of glucose, thereby increasing blood glucose levels.

Front 353

True or false? Somatic motor neurons innervate the striated muscle of the bulbospongiosus and ischiocavernous muscles and result in ejaculation of semen.

Back 353

True

Front 354

What happens to intraventricular pressure and volume during isovolumetric contraction?

Back 354

As the name indicates, there is no change in volume but there is an increase in pressure.

Front 355

Do high levels of estrogen and progesterone block milk synthesis?

Back 355

Yes, they stimulate the growth of mammary tissue but block milk synthesis. At parturition, the decrease in estrogen lifts the block on milk production.

Front 356

What two factors lead to the development of the bends (caisson disease)?

Back 356

Breathing high-pressure nitrogen over a long time and sudden decompression result in the bends.

Front 357

In what type of circuit is the total resistance always less than that of the individual resistors?

Back 357

Parallel circuit

Front 358

What is the term for days 15 to 28 in the female cycle?

Back 358

Luteal phase

Front 359

What happens to total and alveolar ventilation with
• Increased rate of breathing?

Back 359

With an increased rate of breathing the total ventilation is greater than the alveolar ventilation. Rapid, shallow breathing increases dead space ventilation with little change in alveolar ventilation. (This is hypoventilation).

Front 360

What happens to total and alveolar ventilation with
• Increased depth of breathing?

Back 360

With an increased depth of breathing both the total and alveolar ventilation increase.

This concept is always tested on the boards, so remember it.

Front 361

What pathophysiologic disorder is characterized by the following changes in cortisol and ACTH?
• Cortisol decreased, ACTH increased

Back 361

Primary hypocortisolism (Addison's disease)

Front 362

What pathophysiologic disorder is characterized by the following changes in cortisol and ACTH?
• Cortisol increased, ACTH increased

Back 362

Secondary hypercortisolism (pituitary)

Front 363

What pathophysiologic disorder is characterized by the following changes in cortisol and ACTH?
• Cortisol increased, ACTH decreased

Back 363

Primary hypercortisolism

Front 364

What pathophysiologic disorder is characterized by the following changes in cortisol and ACTH?
• Cortisol decreased, ACTH decreased

Back 364

Secondary hypocortisolism (pituitary)

Front 365

What happens to flow and pressure in capillaries with arteriolar dilation? Arteriolar constriction?

Back 365

Capillary flow and pressure increase with arteriolar dilation and decrease with arteriolar constriction.

Front 366

What has occurred to the renal arterioles based on the following changes in the GFR, RPF, FF, and glomerular capillary pressure?
• GFR ↑, RPF ↑, FF normal, capillary pressure ↑

Back 366

Dilation of afferent arteriole

Front 367

What has occurred to the renal arterioles based on the following changes in the GFR, RPF, FF, and glomerular capillary pressure?
• GFR ↑, RPF ↓, FF ↑, capillary pressure ↑

Back 367

Constriction of efferent arteriole

Front 368

What has occurred to the renal arterioles based on the following changes in the GFR, RPF, FF, and glomerular capillary pressure?
• GFR ↓, RPF ↑, FF ↓, capillary pressure ↓

Back 368

Dilation of efferent arteriole

Front 369

What has occurred to the renal arterioles based on the following changes in the GFR, RPF, FF, and glomerular capillary pressure?
• GFR ↓, RPF ↓, FF normal, capillary pressure ↓

Back 369

Constriction of afferent arteriole

Front 370

Which direction is air flowing when the intra-alveolar pressure is zero?

Back 370

When the intra-alveolar pressure equals zero, there is no airflow.

Front 371

What phase of the female cycle occurs during days 1 to 15?

Back 371

Follicular phase

Front 372

What determines the effective osmolarity of the ICF and the ECF compartments?

Back 372

The concentration of plasma proteins determines effective osmolarity because capillary membranes are freely permeable to all substances except proteins.

Front 373

What region of the brain houses the central chemoreceptors responsible for control of ventilation?

Back 373

The surface of the medulla

Front 374

What is the site of action of cholera toxin?

Back 374

Cholera toxin irreversibly activates the cAMP-dependent chloride pumps of the small and large intestine, producing a large volume of chloride-rich diarrhea.

Front 375

Name the phase of the ventricular muscle action potential based on the following information:
• Slow channels open, allowing calcium influx; voltage-gated potassium channels closed; potassium efflux through ungated channels; plateau stage

Back 375

Phase 2

Front 376

Name the phase of the ventricular muscle action potential based on the following information:
• Slight repolarization secondary to potassium and closure of the sodium channels

Back 376

Phase 1

Front 377

Name the phase of the ventricular muscle action potential based on the following information:
• Fast channels open, then quickly close, and sodium influx results in depolarization

Back 377

Phase 0

Front 378

Name the phase of the ventricular muscle action potential based on the following information:
• Slow channels close, voltage-gated potassium channels reopen with a large influx of potassium, and the cell quickly repolarizes

Back 378

Phase 3

Front 379

Where in the kidney are the long loops of Henle and the terminal regions of the collecting ducts?

Back 379

In the medulla; all the other structures are cortical.

Front 380

What is absorbed in the gallbladder to concentrate bile?

Back 380

Water

Front 381

What type of hormone is described as having intracellular receptors, being synthesized as needed, mostly bound to proteins, and having its activity determined by free hormone levels?

Back 381

Lipid-soluble hormones are considered slow-acting hormones.

Front 382

What are the three stimuli that result in the reninangiotensin-aldosterone secretion?

Back 382

1. Low pressure in the afferent renal arteriole
2. Low sodium sensed by the macula densa
3. Increased β-1-sympathetic stimulation of the JG cells

Front 383

Is there a shift in p50 values with anemia? Polycythemia?

Back 383

The p50 value does not change in either anemia or polycythemia; the main change is the carrying capacity of the blood.

Front 384

What hormone level peaks 1 day before the surge of LH and FSH in the female cycle?

Back 384

Estradiol

Front 385

True or false? Active protein transport requires a concentration gradient.

Back 385

True; it requires both a concentration gradient and ATP to work.

Front 386

Up to how many hours post ejaculation do sperm retain their ability to fertilize the ovum?

Back 386

Up to 72 hours; the ovum losses its ability to be fertilized 8 to 25 hours after release.

Front 387

What type of membrane channel opens in response to depolarization?

Back 387

Voltage-gated channel

Front 388

What are the five effects of insulin on fat metabolism?

Back 388

1. Increased glucose uptake by fat cells
2. Increased triglyceride uptake by fat cells
3. Increased conversion of CHOs into fat
4. Decreased lipolysis in fat tissue
5. Decreased ketone body formation

Front 389

True or false? In a skeletal muscle fiber, the interior of the T-tubule is extracellular.

Back 389

True. They are evaginations of the surface membranes and therefore extracellular.

Front 390

Under resting conditions, what is the main determinant of cerebral blood flow?

Back 390

Arterial PCO2 levels are proportional to cerebral blood flow.

Front 391

On the venous pressure curve, what do the following waves represent?
• A wave?

Back 391

Atrial contraction

Atrial, Contraction, Venous

Front 392

On the venous pressure curve, what do the following waves represent?
• C wave?

Back 392

Ventricular contraction

Atrial, Contraction, Venous

Front 393

On the venous pressure curve, what do the following waves represent?
• V wave?

Back 393

Atrial filling (venous filling)
Atrial, Contraction, Venous

Front 394

What cell type in the bone is responsible for bone deposition?

Back 394

Osteoblast (Remember, blasts make, clasts take)

Front 395

True or false? The blood stored in the systemic veins and the pulmonary circuit are considered part of the cardiac output.

Back 395

False. Cardiac output refers to circulating blood volume. The blood in the systemic veins and the pulmonary circuits are storage reserves and therefore are not considered in cardiac output.

Front 396

What hormone disorder is characterized by the following abnormalities in sex steroids↓, LH↓, and FSH↓?
• Sex steroids , LH , FSH

Back 396

Pituitary hypogonadism

Front 397

What hormone disorder is characterized by the following abnormalities in sex steroids, LH, and FSH?
• Sex steroids ↑, LH ↓, FSH ↓?

Back 397

GnRH constant infusion

Front 398

What hormone disorder is characterized by the following abnormalities in sex steroids↓, LH↑, and FSH↑?
• Sex steroids , LH , FSH ?

Back 398

Primary hypogonadism (postmenopausal women)

Front 399

What are the three characteristics of autoregulation?

Back 399

1. Flow independent of BP
2. Flow proportional to local metabolism
3. Flow independent of nervous reflexes

Front 400

What is the fastest-conducting fiber of the heart? Slowest conduction fiber in the heart?

Back 400

Purkinje cell is the fastest, and the AV node is the slowest.

Front 401

What equals the total tension on a muscle minus the preload?

Back 401

Afterload

Front 402

What follicular cell possesses FSH receptors and converts androgens into estradiol?

Back 402

Granulosa cells

Front 403

What are the primary neurotransmitters at the following sites?
• Postganglionic sympathetic neurons

Back 403

NE

Front 404

What are the primary neurotransmitters at the following sites?
• Chromaffin cells of the adrenal medulla

Back 404

Epinephrine

Front 405

What are the primary neurotransmitters at the following sites?
• Brainstem cells

Back 405

Serotonin

Front 406

What are the primary neurotransmitters at the following sites?
• The hypothalamus

Back 406

Histamine

Front 407

What are the primary neurotransmitters at the following sites?
• All motor neurons, postganglionic parasympathetic neurons

Back 407

ACh

Front 408

What are the primary neurotransmitters at the following sites?
• Autonomic preganglionic neurons

Back 408

ACh

Front 409

What region of the nephron has the highest osmolarity?

Back 409

Tip of the loop of Henle (1200 mOsm/L)

Front 410

What pH (acidotic or alkalotic) is needed for pepsinogen to pepsin conversion?

Back 410

Acid is needed for the activation of pepsin and therefore needed for protein digestion.

Front 411

What is the term for the amount of blood expelled from the ventricle per beat?

Back 411

Stroke volume

Front 412

True or false? Oxytocin initiates rhythmic contractions associated with labor.

Back 412

False. It does increase uterine synthesis of prostaglandins, which increase uterine contractions.

Front 413

Why does carbon monoxide diffusion in the lung (DLCO) decrease in emphysema and fibrosis but increase during exercise?

Back 413

DLCO, an index of lung surface area and membrane thickness, is decreased in fibrosis because of increased membrane thickness and decreased in emphysema because of increased surface area without increase in capillary recruitment; in exercise there is an increase in surface area due to capillary recruitment.

Front 414

What enzyme converts androgens to estrogens?

Back 414

Aromatase

Front 415

The clearance of what substance is the gold standard of GFR?

Back 415

Inulin

Front 416

How does myelination affect conduction velocity of an action potential?

Back 416

The greater the myelination, the greater the conduction velocity.

Front 417

What are the three end products of amylase digestion?

Back 417

1. Maltose
2. Maltotetrose
3. α-Limit dextrans (α-1, 6 binding)

Front 418

Where is most of the airway resistance in the respiratory system?

Back 418

In the first and second bronchi

Front 419

What is the respiratory compensation mechanism for metabolic acidosis?

Back 419

Hyperventilation, which decreases CO2, shifting the reaction to the left and decreasing H+

Front 420

How are resistance and viscosity related regarding flow?

Back 420

Viscosity and resistance are proportionally related. The greater the viscosity, the greater the resistance is on the vessel.

Front 421

T3 increases bone ossification through synergistic effect with what hormone?

Back 421

GH

Front 422

Name the ventricular muscle membrane channel:
• Closed at rest; depolarization causes channels to open slowly

Back 422

Voltage-gated calcium channel

Front 423

Name the ventricular muscle membrane channel:
• Always open

Back 423

Ungated potassium channel

Front 424

Name the ventricular muscle membrane channel:
• Closed at rest; depolarization causes channels to open quickly; will not respond to a second stimulus until cell is repolarized.

Back 424

Voltage-gated sodium channel

Front 425

Name the ventricular muscle membrane channel:
• Open at rest; depolarization is stimulus to close; begin to reopen during the plateau phase and during repolarization

Back 425

Voltage-gated potassium channels

Front 426

What are the three glycogenic organs?

Back 426

Liver, kidney, and GI epithelium

Front 427

Is CO2 a perfusion-or diffusion-limited O2 gas?

Back 427

Since CO2 is 24 times as soluble as O2, the rate at which CO2 is brought to the membrane determines its rate of exchange, making it perfusion-limited a gas. For O2 the more time it is in contact with the membrane, the more likely it will diffuse, making it diffusion-limited.

Front 428

What is the term for the potential difference across a cell membrane?

Back 428

Transmembrane potential (an absolute number)

Front 429

What adrenal enzyme deficiency can be summed up as a mineralocorticoid deficiency, glucocorticoid deficiency, and an excess of adrenal androgens?

Back 429

21-β-Hydroxylase deficiency leads to hypotension, hyponatremia, and virilization.

Front 430

When the ECF osmolarity increases, what happens to cell size?

Back 430

Increase in ECF osmolarity means a decrease in ICF osmolarity, so cells shrink.

Front 431

When does cortisol secretion peak?

Back 431

In early-morning sleep, usually between the sixth and eighth hours

Front 432

What is the term for ventilation of unperfused alveoli?

Back 432

Alveolar dead space

Front 433

What is the bioactive form of thyroid hormone?

Back 433

T3

Front 434

What acid-base disturbance occurs in colonic diarrhea

Back 434

Hypokalemic metabolic acidosis occurs in colonic diarrhea because of the net secretion of HCO3- and potassium into the colonic lumen.

Front 435

What two AAs act as excitatory transmitters in the CNS, generating EPSPs?

Back 435

Glutamine and aspartate

Front 436

What are the three mechanisms of action for atrial natriuretic peptide's diuretic and natriuretic affects?

Back 436

1. Dilation of the afferent arteriole
2. Constriction of the efferent arteriole
3. Inhibition of reabsorption of sodium and water in the collecting ducts

Front 437

In a parallel circuit, what happens to resistance when a resistor is added in parallel

Back 437

Resistance decreases as resistors are added in parallel.

Front 438

What component of the ANS is responsible for movement of semen from the epididymis to the ejaculatory ducts?

Back 438

Sympathetic nervous system

Front 439

What happens to O2 affinity with a decrease in p50?

Back 439

O2 affinity increases with a decrease in the p50, making O2 more difficult to remove from the Hgb molecule.

Front 440

If the ratio of a substance's filtrate and plasma concentrations are equal, what is that substance's affect on the kidney?

Back 440

If the ratio of the filtrate to plasma concentration of a substance is equal, the substance is freely filtered by the kidney.

Front 441

What does a loss of afferent activity from the carotid sinus onto the medulla signal?

Back 441

A loss of afferent activity indicates a decrease in BP, and an increase in afferent activity indicates an increase in BP.

Front 442

What are the five F's associated with gallstones?

Back 442

1. Fat
2. Forty
3. Female
4. Familial
5. Fertile

Front 443

True or false? Menstruation is an active process due to increased gonadal sex hormones?

Back 443

False. It is a passive process due to decreased sex hormones.

Front 444

What happens to the intrapleural pressure when the diaphragm relaxes?

Back 444

Relaxation of the diaphragm increases the intrapleural pressure (becomes more positive).

Front 445

What component of the renin-angiotensin-aldosterone axis increases sodium reabsorption in the proximal convoluted tubules and increases thirst drive?

Back 445

AT II

Front 446

What large-diameter vessel has the smallest cross-sectional area in systemic circulation?

Back 446

The aorta

Front 447

Excess bone demineralization and remodeling can be detected by checking urine levels of what substance?

Back 447

Hydroxyproline (breakdown product of collagen)

Front 448

What happens to the following during skeletal muscle contraction?
• A band

Back 448

No change in length

Front 449

What happens to the following during skeletal muscle contraction?
• I band

Back 449

Shortens

Front 450

What happens to the following during skeletal muscle contraction?
• H zone

Back 450

Shortens

Front 451

What happens to the following during skeletal muscle contraction?
• Sarcomere

Back 451

Shortens

Front 452

What happens to the following during skeletal muscle contraction?
• Actin and myosin lengths

Back 452

No change in length

Front 453

What are the three effects of insulin on protein metabolism?

Back 453

1. Increased amino acid uptake by muscles
2. Decreased protein breakdown
3. Increased protein synthesis

Front 454

What is the main mechanism for exchange of nutrients and gases across a capillary membrane?

Back 454

Simple diffusion; it does not use protein-mediated transport

Front 455

What event signifies the first day of the menstrual cycle?

Back 455

Onset of bleeding

Front 456

Name the muscle type based on the histological features:
• Actin and myosin in sarcomeres; striated; uninuclear; gap junctions; troponin:calcium binding complex; T tubules and SR forming dyadic contacts; voltage-gated calcium channels

Back 456

Cardiac muscle

Front 457

Name the muscle type based on the histological features:
• Actin and myosin in sarcomeres; striated; multinuclear; lacks gap junctions; troponin:calcium binding; T tubules and SR forming triadic contacts; highest ATPase activity; no calcium channels

Back 457

Skeletal muscle

Front 458

Name the muscle type based on the histological features:
• Actin and myosin not in sarcomeres; nonstriated; uninuclear; gap junctions; calmodulin:calcium binding; lacks T tubules; voltage-gated calcium channels

Back 458

Smooth muscle

Front 459

Name the valve abnormality based on the following criteria:
• Back-filling into the left atrium during systole; increased v-wave, preload, left atrial volume, and left ventricular filling

Back 459

Mitral insufficiency

Front 460

Name the valve abnormality based on the following criteria:
• Systolic murmur, increased preload and afterload, decreased aortic pulse pressure and coronary blood flow

Back 460

Aortic stenosis

Front 461

Name the valve abnormality based on the following criteria:
• Diastolic murmur, increased right ventricular pressure, left atrial pressure, and atrial to ventricular pressure gradient; decreased left ventricular filling pressure

Back 461

Mitral stenosis

Front 462

Name the valve abnormality based on the following criteria:
• Diastolic murmur; increased preload, stroke volume, and aortic pulse pressure; decreased coronary blood flow; no incisura; and peripheral vasodilation

Back 462

Aortic insufficiency

Front 463

Circulating levels of what hormone cause the cervical mucus to be thin and watery, allowing sperm an easier entry into the uterus?

Back 463

Estrogen

Front 464

What hormone controls relaxation of the lower esophageal sphincter during swallowing?

Back 464

VIP is an inhibitory parasympathetic neurotransmitter that results in relaxation of the lower esophageal sphincter.

Front 465

What is the term for the difference between systolic and diastolic pressures?

Back 465

Pulse pressure

Front 466

What hormone, produced by the Sertoli cells, is responsible for keeping testosterone levels in the seminiferous tubules nearly 50 times that of the serum?

Back 466

Androgen-binding protein

Front 467

True or false? There are no central O2 receptors.

Back 467

True

Front 468

What cell type of the bone has PTH receptors?

Back 468

Osteoblasts, which in turn stimulate osteoclasts to break down bone, releasing Ca2+ into the interstitium. (Remember, blasts make, clasts take.)

Front 469

What substance is secreted by parietal glands and is required for life?

Back 469

Intrinsic factor (IF)

Front 470

What is the only way to increase O2 delivery in the coronary circulation?

Back 470

Increasing blood flow is the only way to increase O2 delivery in the coronary circulation because extraction is nearly maximal during resting conditions.

Front 471

What is the term for the load a muscle is trying to move during stimulation?

Back 471

Afterload

Front 472

What is the term for days 1 to 7 of the female cycle?

Back 472

Menses

Front 473

What is the term for the force the ventricular muscle must generate to expel the blood into the aorta?

Back 473

Afterload

Front 474

What happens to the tonicity of the urine with increased ADH secretion?

Back 474

The urine becomes hypertonic because of water reabsorption in the collecting duct.

Front 475

What form of renal tubular reabsorption is characterized by high back leak, low affinity for substance, and absence of saturation and is surmised to be a constant percentage of a reabsorbed filtered substance?

Back 475

Gradient-time system

Front 476

What type of circuit is described when the total resistance is always greater than the sums of the individual resistors?

Back 476

Series circuit

Front 477

What hormone excess brings about abnormal glucose tolerance testing, impaired cardiac function, decreased body fat, increased body protein, prognathism, coarse facial features, and enlargements of the hands and feet?

Back 477

Increased secretion of GH postpuberty leading to acromegaly.

Front 478

What happens to V/Q ratio if a thrombus is lodged in the pulmonary artery?

Back 478

The V/Q ratio increases, since the area is ventilated but hypoperfused as a result of the occlusion.

Front 479

What hormone has the following effects: chondrogenic in the epiphyseal end plates of bones; increases AA transport for protein synthesis; increases hydroxyproline (collagen); and increases chondroitin sulfate synthesis?

Back 479

GH, especially IGF-1. GH also increases the incorporation of thymidine in DNA synthesis and uridine in RNA synthesis.

Front 480

True or false? Bile pigments and bile salts are reabsorbed in the gallbladder.

Back 480

False

Front 481

What component of an ECG is associated with the following?
• Conduction delay in the AV node

Back 481

PR interval

Front 482

What component of an ECG is associated with the following?
• Ventricular depolarization

Back 482

QRS complex

Front 483

What component of an ECG is associated with the following?
• Atrial depolarization

Back 483

P wave

Front 484

What component of an ECG is associated with the following?
• Ventricular repolarization

Back 484

T wave

Front 485

Where is the greatest venous PO2 in resting tissue?

Back 485

Renal circulation

Front 486

Near the end of pregnancy, what hormone's receptors increase in the myometrium because of elevated plasma estrogen levels?

Back 486

Oxytocin

Front 487

What respiratory center in the rostral pons has an inhibitory affect on the apneustic center?

Back 487

Pneumotaxic center (short, fast breaths)

Front 488

For what hormone do Leydig cells have receptors?

Back 488

LH

Front 489

What primary acid-base disturbance is cause by a decrease in alveolar ventilation (increasing CO2 levels) resulting in the reaction shifting to the right and increasing H+ and HCO3- levels?

Back 489

Respiratory acidosis (summary: high CO2, high H+, slightly high HCO3-)

Front 490

What lecithin: sphingomyelin ratio indicates lung maturity?

Back 490

2.0 or greater

Front 491

What is the term for the negative resting membrane potential becoming more negative?

Back 491

Hyperpolarization (i.e., K+ influx)

Front 492

What type of resistance system (i.e., high or low) is formed when resistors are added in parallel?

Back 492

A low-resistance system is formed by resistors added in parallel.

Front 493

Why is hypothyroidism associated with night blindness?

Back 493

Thyroid hormones are necessary for conversion of carotene to vitamin A.

Front 494

What is the FiO2 of room air?

Back 494

0.21; it is a fancy way of saying 21% of the air is O2.

Front 495

Where are the lowest resting PO2 levels in a resting individual?

Back 495

Coronary circulation

Front 496

What is the rate-limiting step in the production of steroids?

Back 496

The conversion of CHO to pregnenolone via the enzyme desmolase

Front 497

In the water deprivation test, does a patient with reduced urine flow have primary polydipsia or diabetes insipidus?

Back 497

Primary polydipsia; patients with diabetes insipidus will continue to produce large volumes of dilute urine.

Front 498

True or false? There is an inverse relationship between fat content and total body water.

Back 498

True; the greater the fat, the less the total body water.

Front 499

What is the role of the negative charge on the filtering membrane of the glomerular capillaries?

Back 499

The negative charge inhibits the filtration of protein anions.

Front 500

What cardiac reflex is characterized by stretch receptors in the right atrium, afferent and efferent limbs via the vagus nerve, and increased stretch leading to an increase in heart rate via inhibition of parasympathetic stimulation?

Back 500

Bainbridge reflex

Front 501

Where in the GI tract does the reabsorption of bile salts take place?

Back 501

Bile salts are actively reabsorbed in the distal ileum.

Front 502

What three structures increase the surface area of the GI tract?

Back 502

1. Plicae circularis (3 times)
2. Villi (30 times)
3. Microvilli (600 times)

Front 503

Does physiologic splitting of the first heart sound occur during inspiration or expiration? Why?

Back 503

Splitting of the first heart sound occurs during inspiration because of the increased output of the right ventricle, delaying the closure of the pulmonic valve.

Front 504

How much dietary iodine is necessary to maintain normal thyroid hormone secretion?

Back 504

150 mcg/day is the minimal daily intake needed. Most people ingest 500 mcg/day.

Front 505

What is the central chemoreceptor's main drive for ventilation?

Back 505

CSF H+ levels, with acidosis being the main central drive, resulting in hyperventilation (the opposite being true with alkalosis)

Front 506

What result occurs because of the negative alveolar pressure generated during inspiration?

Back 506

Air flows into the respiratory system.

Front 507

Corticotropin-releasing hormone promotes the synthesis and release of what prohormone?

Back 507

Pro-opiomelanocortin (POMC) is cleaved into ACTH and β-lipotropin.

Front 508

What happens to free hormone levels when the liver decreases production and release of binding proteins?

Back 508

Free hormone levels remain constant, and the bound hormone level changes with a decrease in binding hormones.

Front 509

What type of estrogen is produced in peripheral tissues from androgens?

Back 509

Estrone

Front 510

What changes does more negative intrathoracic pressure cause to systemic venous return and to the pulmonary vessels?

Back 510

Promotes systemic venous return into the chest and increases the caliber and volume of the pulmonary vessels

Front 511

Where is renin produced?

Back 511

In the JG cells of the kidney

Front 512

True or false? Right-sided valves close before the valves on the left side of the heart.

Back 512

False. Right-sided valves are the first to open and last to close.

Front 513

What enzyme is associated with osteoblastic activity?

Back 513

Alkaline phosphatase

Front 514

What is the order of attachment of O2 to Hgb-binding sites in the lung? Order of release from the binding sites in the tissue?

Back 514

Order of attachment is site 1, 2, 3, 4, and for release is 4, 3, 2, 1.

Front 515

What hormone is secreted into the plasma in response to a meal rich in protein or CHO?

Back 515

Insulin

Front 516

What happens to blood flow and pressure downstream with local arteriolar constriction?

Back 516

With arteriolar constriction both the flow and pressure downstream decrease.

Front 517

What occurs when the lower esophageal sphincter fails to relax during swallowing due to abnormalities of the enteric nervous plexus?

Back 517

Achalasia

Front 518

True or false? Ungated channels are always open.

Back 518

True. They have no gates, so by definition they are always open.

Front 519

What component of the ANS is responsible for dilation of the blood vessels in the erectile tissue of the penis, resulting in an erection?

Back 519

Parasympathetics (parasympathetics point, sympathetics shoot)

Front 520

What muscle type is characterized by low ATPase activity, aerobic metabolism, myoglobin, association with endurance, and small muscle mass?

Back 520

Red muscle

Front 521

What happens to diastolic and systolic intervals with an increase in sympathetic activity?

Back 521

Systolic interval decreases secondary to increased contractility; diastolic interval decreases secondary to an increase in heart rate.

Front 522

Circulating levels of what hormone in men is responsible for the negative feedback loop to the hypothalamus and the anterior pituitary gland regulating the release of LH?

Back 522

Testosterone

Front 523

How are pulse pressure and compliance related?

Back 523

They are inversely proportional to each other; as pulse pressure increases, compliance decreases.

Front 524

What three substances stimulate parietal cells?

Back 524

ACh, histamine, and gastrin

Front 525

What two factors result in the base of the lung being hyperperfused?

Back 525

Increased pulmonary arterial pressure (high perfusion) and more distensible vessels (low resistance) result in increased blood flow at the base.

Front 526

True or false? Without ADH the collecting duct would be impermeable to water.

Back 526

True. Without ADH hypotonic urine would be formed.

Front 527

How does ventricular depolarization take place, base to apex or vice versa?

Back 527

Depolarization is from apex to base and from endocardium to epicardium.

Front 528

What are effects of PTH in the kidney?

Back 528

PTH increases Ca2+ reabsorption in the DCT of the kidney and decreases PO4- reabsorption in the PCT.

Front 529

Regarding muscle mechanics, how is passive tension produced?

Back 529

It is produced by the preload on the muscle prior to contraction.

Front 530

Insulin-induced hypoglycemia is the most reliable (by far not the safest) test for what hormone deficiency?

Back 530

GH deficiency

Front 531

In regards to solute concentration, how does water flow?

Back 531

Water flows from a low-solute to high-solute concentrations.

Front 532

Which extravascular chemoreceptor detects low NaCl concentrations?

Back 532

Macula densa

Front 533

If the AV difference is positive, is the substance extracted or produced by the organ?

Back 533

A positive AV difference indicates that a substance is extracted by the organ, and a negative difference indicates that it is produced by the organ.

Front 534

What is used as an index of the number of functioning carriers for a substance in active reabsorption in the kidney?

Back 534

Transport maximum (Tm) occurs when all function carriers are saturated and therefore is an index of the number of functioning carriers.

Front 535

Why is there a transcellular shift in K+ levels in a diabetic patient who becomes acidotic?

Back 535

The increased H+ moves intracellularly and is buffered by K+ leaving the cells, resulting in intracellular depletion and serum excess. (Intracellular hypokalemia is the reason you supplement potassium in diabetic ketoacidosis, even though the serum levels are elevated.)

Front 536

True or false? Catechol-O-methyl transferase (COMT) is not found in smooth muscle, liver, and the kidneys.

Back 536

False. That is precisely where COMT is found; it is not found in adrenergic nerve terminals.

Front 537

What somatomedin serves as a 24-hour marker of GH secretion?

Back 537

IGF-1 (somatomedin C)

Front 538

What receptor is in the smooth muscle cells of the small bronchi, is stimulated during inflation, and inhibits inspiration?

Back 538

Stretch receptors prevent overdistension of the lungs during inspiration.

Front 539

True or false? Thyroid hormones are necessary for normal menstrual cycles.

Back 539

True. They are also necessary for normal brain maturation.

Front 540

What component of the cardiovascular system has the largest blood volume? Second largest blood volume?

Back 540

The systemic veins have the largest blood volume, and the pulmonary veins have the second largest blood volume in the cardiovascular system. They represent the reservoirs of circulation.

Front 541

Serum concentration of what substance is used as a clinical measure of a patient's GFR?

Back 541

Creatinine

Front 542

Where does CHO digestion begin?

Back 542

In the mouth with salivary α-amylase (ptyalin)

Front 543

How does the sympathetic nervous system affect insulin secretion?

Back 543

It decreases insulin secretion.

Front 544

How does cell diameter affect the conduction velocity of an action potential?

Back 544

The greater the cell diameter, the greater the conduction velocity.