Aphy102 - Marieb - Chapter 26 - Fluid, Electrolyte, And Acid-Base Balance

Front 1

What percent of an infant is water?

Back 1

73%

Front 2

What happens to total water content throughout life?

Back 2

It decreases

Front 3

Healthy males are about ___ percent water, while females are about ___ percent water.

Back 3

60%, 50%

Front 4

Why do females have less total water content than males?

Back 4

1) Higher body fat

2) Smaller amount of skeletal muscle

Front 5

In old age, what percentage of the body is water?

Back 5

About 45%

Front 6

What are the four main influencing factors regarding water content?

Back 6

1) age

2) gender

3) body fat

4) weight

Front 7

What two major compartments does water occupy?

Back 7

1) Intracellular fluid

2) Extracellular fluid

Front 8

What percentage of our total water content is contained in intracellular fluid?

Back 8

about 66%

Front 9

What are the two major subcompartments of the extracellular fluid?

Back 9

1) Plasma

2) Interstitial fluid

Front 10

What are other examples of extracellular fluid (ECF)?

Back 10

lymph, cerebrospinal fluid, eye humors, synovial fluid, serous fluid, gastrointestinal secretions

Front 11

What percentage of the ECF is found in plasma?

Back 11

20%

Front 12

What percentage of the extracellular fluid (ECF) is found in interstitial fluid?

Back 12

80%

Front 13

Roughly how many liters of water does the average body hold?

Back 13

40L

Front 14

Solutes are broadly classified into which two categories?

Back 14

Electrolytes and nonelectrolytes

Front 15

Which has greater osmotic power: electrolytes or nonelectrolytes?

Back 15

electrolytes

Front 16

What are the major cations and anions in extracellular fluids?

Back 16

Sodium is the chief cation

Chlorine is the chief anion

Front 17

What are the major cations and anions in intracellular fluids?

Back 17

Potassium is the chief cation

Phosphate is the chief anion

Front 18

What substances determine the physical and chemical reactions of fluids?

Back 18

electrolytes

Front 19

Proteins, phospholipids, cholesterol, and neutral fats account for what percentage of the solutes in plasma?

Back 19

90%

Front 20

Proteins, phospholipids, cholesterol, and neutral fats account for what percentage of the solutes in interstitial fluid?

Back 20

60%

Front 21

Proteins, phospholipids, cholesterol, and neutral fats account for what percentage of the solutes in the intracellular compartment?

Back 21

97%

Front 22

Fluid movement among compartments is determined by which two pressures?

Back 22

Osmotic and hydrostatic pressures

Front 23

What system picks up leaked fluid from the blood and returns it to the bloodstream?

Back 23

lymphatic system

Front 24

What is the only fluid that circulates throughout the body and links external and internal environments?

Back 24

Plasma

Front 25

What moves relatively freely between intracellular compartments and interstitial fluid?

Back 25

water

Front 26

How do ion fluxes move between the intracellular compartment and the interstitial fluid?

Back 26

Active transport

Front 27

Nutrients, respiratory gases, and wastes move _______ between the intracellular compartment and interstitial fluid.

Back 27

unidirectionally

Front 28

What is the average necessary daily water input for an adult?

Back 28

2.5L

Front 29

How much of water intake comprises ingested fluid?

Back 29

60%

Front 30

How much of water intake comprises solid food?

Back 30

30%

Front 31

How much of water intake comprises metabolic water or water of oxidation?

Back 31

10%

Front 32

What organs/systems are responsible for water output?

Back 32

1) lungs

2) GI tract

3) Skin

4) Kidneys

Front 33

Urine makes up what portion of total fluid lost?

Back 33

60%

Front 34

What percentage of total fluid lost comes from feces?

Back 34

4%

Front 35

What percentage of total fluid lost comes from insensible losses?

Back 35

28%

Front 36

Define thirst.

Back 36

Thirst is a deep-seated sensation of a desire for water

Front 37

List in detail the specific hypothalamic stimuli for thirst.

Back 37

1) Decline in plasma volume of 10%-15%

2) Increase in plasma osmolarity of 1-2%

3) Baroreceptor input

4) Angiotensin II

Front 38

What factors inhibit thirst?

Back 38

Distension of the GI tract and then osmotic signals

Front 39

On average, how much urine does one output daily?

Back 39

500 mL

Front 40

Electrolyte balance refers to what?

Back 40

Salt balance (even though there are many kinds of electrolytes)

Front 41

What are salts important for?

Back 41

1) Neuromuscular excitability

2) Secretory activity

3) Membrane permeability

4) Controlling fluid movements

Front 42

Why are omega 3s important?

Back 42

1) Help us lose weight

2) Help reduce cancer risk

3) They are critical in brain development for children

Front 43

What are some important sources of bases?

Back 43

Bananas, chocolate, figs, mineral water, potatoes, spinach, watermelon, turnip greens

Front 44

What are some important sources for amino acids?

Back 44

meat, poultry, fish, eggs, milk, beans

Front 45

Where in the kidneys does sodium reabsorption take place?

Back 45

65% happens in the proximal tubules, 25% occurs in loops of Henle

Front 46

What steroid hormone encourages the body to actively reabsorb all sodium?

Back 46

Aldosterone

Front 47

What hormone encourages reabsorption of water along with sodium?

Back 47

ADH (antidiuretic hormone)

Front 48

What mechanism triggers the release of aldosterone?

Back 48

the renin-angiotensin mechanism

Front 49

What microscopic part of the kidney is responsible for renin release (and thus responsible for the release of angiotensin II, and thus aldosterone)?

Back 49

Juxtaglomerular apparatus -- it releases renin due to sympathetic nervous system stimulation, filtrate osmolarity, and decreased stretch (due to decreased blood pressure)

Front 50

What cells are directly stimulated to release aldosterone due to increased K+ levels in the ECF?

Back 50

Adrenal cortical cells

Front 51

What are the effects of aldosterone?

Back 51

diminished urine output and increased blood volume -- it takes effect very slowly

Front 52

What do baroreceptors detect?

Back 52

Blood pressure

Front 53

What happens when baroreceptors detect increased blood pressure?

Back 53

1) Sympathetic nervous system impulses to the kidneys decline

2) Afferent arterioles dilate

3) Glomerular filtration rate rises

4) Sodium and water output increase

Front 54

Since sodium ion concentration determines fluid volume, what do baroreceptors indirectly detect?

Back 54

Sodium

Front 55

Does ANP increase or decrease blood pressure?

Back 55

decrease

Front 56

How does ANP (Atrial Natriuretic Peptide) reduce blood volume and pressure?

Back 56

By inhibiting sodium and water retention and by inhibiting events that promote vasoconstriction

Front 57

What prompts ANP (Atrial natriuretic peptide) to be released?

Back 57

An increase in stretch in the heart atria

Front 58

What effect does ANP have?

Back 58

Increased urine and fluid output

Front 59

What hormone does ANP (Atrial natriuretic peptide) inhibit?

Back 59

antiotensin II

Front 60

What percentage of filtered K+ is lost to urine output?

Back 60

15%

Front 61

How is potassium balance controlled?

Back 61

By adjusting the cortical collecting ducts potassium secretion into filtrate. When K+ levels are low, the amount of secretion and excretion is kept to a minimum.

Front 62

What kind of cells can reabsorb some K+ left in the filtrate?

Back 62

Type A intercalated cells

Front 63

What humoral factor influences principal cells to excrete K+?

Back 63

High levels of potassium in the ECF

Front 64

What hormone stimulates potassium ion secretion by principal cells?

Back 64

Aldosterone

Front 65

In cortical collecting ducts, one K+ is secreted for every ____ reabsorbed.

Back 65

Na+

Front 66

What influence does increased K+ in the ECF of the adrenal cortex have?

Back 66

It stimulates the release of aldosterone and potassium secretion

Front 67

What two hormones control calcium balance?

Back 67

Calcitonin and PTH (parathyroid hormone)

Front 68

PTH (parathyroid hormone) increases calcium levels by targeting:

Back 68

1) Bones (activates osteoclasts to break down bone matrix)

2) Small intestine (enhances intestinal absorption of calcium)

3) Kidneys (enhances calcium reabsorption and decreases phosphate reabsorption)

Front 69

What type of relationship do calcium reabsorption and phosphate secretion have?

Back 69

Inverse

Front 70

Where is filtered phosphate actively absorbed?

Back 70

Proximal tubules

Front 71

In the absence of PTH, what regulates phosphate reabsorption?

Back 71

Transport maximum --- once that is reached, excesses are expelled in urine

Front 72

What does a lower PTH secretion level mean for calcium and phosphate levels?

Back 72

Release of calcium from bone is inhibited, more calcium is expelled in feces and urine, and more phosphate is retained

Front 73

What humoral stimules induces calcitonin release?

Back 73

Rising blood calcium levels -- though its role in calcium and phosphate homeostasis is negligible

Front 74

What's the fourth most abundand cation in the body?

Back 74

magnesium

Front 75

Where is 60% of magnesium in the body found?

Back 75

Bones

Front 76

What percentage of magnesium is found in bone?

Back 76

60%

Front 77

What percentage of magnesium is found in ECF?

Back 77

1%

Front 78

approximately what percentage of magnesium is found in ICF?

Back 78

40%

Front 79

What roles does magnesium play in the human body?

Back 79

1) It plays a role in immune function

2) it improves oxygen delivery to the heart

3) It prevents formation of kidney stones

4) it helps treat ischemic heart disease

Front 80

Where does regulation of excess magnesium occur?

Back 80

the kidney

Front 81

Where does most reabsorption of magnesium occur?

Back 81

In the loop of henle

Front 82

What controls the reabsorption of magnesium?

Back 82

Mostly its plasma concentration

Front 83

About how much magnesium passing through the kidney is reabsorbed?

Back 83

About 95%

Front 84

About how much filtered magnesium is filtered in the glomerulus?

Back 84

About 75%

Front 85

Define "base."

Back 85

A class of compounds opposite to acids, in that they neutralize acids.

They are substances that bond readily with hydrogen ions.

Front 86

Define "alkalosis."

Back 86

A condition in which the blood has a lower concentration of hydrogen ions than normal, and a higher pH level is measured

Front 87

Alkalosis or Alkalemia is in effect when blood pH rises above what level?

Back 87

7.45

Front 88

What's the normal pH of arterial blood?

Back 88

7.4

Front 89

What's the normal pH of venous blood and interstitial fluids?

Back 89

7.35

Front 90

What's the normal pH of intracellular fluids?

Back 90

7.0

Front 91

How do most hydrogen ions originate?

Back 91

Cellular metabolism

Front 92

What are the three sequential steps of hydrogen ion regulation?

Back 92

1) Chemical buffer systems (which act within seconds)

2) Respiratory center in the brain stem (which acts in 1-3 minutes)

3) Renal mechanisms (which require hours or even days to effect changes)

Front 93

Define chemical buffer systems

Back 93

One or two molecules that act to resist pH changes when strong acid or base is added.

Major systems include the bicarbonate buffer system, phosphate buffer system, and protein buffer system

Front 94

What are the three major chemical buffer systems?

Back 94

1) Bicarbonate buffer system

2) Phosphate buffer system

3) Protein buffer system

Front 95

What acid and base make up the bicarbonate buffer system (which happens to be the only truly important ECF buffer)?

Back 95

Carbonic acid (H2CO3)

Sodium Bicarbonate (NaHCO3)

Front 96

What are the acid and base that make up the phosphate buffer system (which is effective in urine and ICF)?

Back 96

Sodium salts of dihydrogen phosphate (acid) (H2PO4)

Monohydrogen phosphate (HPO4)

Front 97

Where is the phosphate buffer system effective?

Back 97

ICF and urine

Front 98

What's an amphoteric molecule?

Back 98

It's a protein molecule that acts as a buffer and can take the role of either a weak acid or a weak base

Front 99

How does the respiratory system regulate pH?

Back 99

It takes advantage of a reversible equilibrium between CO2 and H20 --- and carbonic acid and the hydrogen and bicarbonate ions

Front 100

Define "hypercapnia."

Back 100

excessive CO2 in the blood

Front 101

How does the respiratory system combat hypercapnia (excessive CO2 that results in acidosis)?

Back 101

More rapid breathing

Front 102

What effect does alkalosis have on breathing?

Back 102

Breathing slows, causing H+ to increase and pH to decrease

Front 103

What are the ultimate acid-base regulating organs?

Back 103

the kidneys

Front 104

What's the only organ that can rid the body of metabolic acids (phosphoric, uric, and lactic acids, plus ketones) and prevent metabolic acidosis?

Back 104

the kidney

Front 105

What are the two most important renal mechanisms for regulating acid-base balance?

Back 105

1) Reabsorbing or generating bicarbonate ions

2) Excreting bicarbonate ions

Front 106

Where do hydrogen ions come from?

Back 106

secretion in the PCT and in type A intercalated cells, from the dissociation of carbonic acid

Front 107

What's the most common cause of acid-base imbalance?

Back 107

Respiratory acidosis due to hampered gas exchange

Front 108

What's a common result of hyperventilation?

Back 108

Respiratory alkalosis

Front 109

What's the normal range for bicarbonate ion levels?

Back 109

22-26 mEq/L

Front 110

What's the second most common form of acid-base imbalance?

Back 110

metabolic acidosis

Front 111

What are some common causes of metabolic acidosis?

Back 111

Alcohol consumption, excessive loss of bicarbonate ions, accumulation of lactic acid, shock, ketosis, starvation, and kidney failure

Front 112

What are common causes of metabolic alkalosis?

Back 112

Vomiting out the acidic contents of the stomach, intake of excessive antacids, constipation and thus excessive bicarbonate reabsorption