Physiology Test 1

Front 1

two phospholipids arranged so that the "tails" face each other make up what?

Back 1

lipid bilayer of the cell membrane

Front 2

are the heads of the phospholipid layers hydrophilic or hydrophobic?

Back 2

hydrophilic
(polar or ionized portions)

Front 3

what two hydrophilic regions are the "heads" in contact with?

Back 3

Extracellular fluid (ECF)
Intracellular fluid (ICF), or cytoplasm

Front 4

what is important in determining the fluidity of cell membranes?

Back 4

the ratio of membrane cholesterol to phospholipids

Front 5

fluidity of the cell membrane is increased by?

Back 5

decreased amount of cholesterol in the membrane

Front 6

fluidity of the cell membrane is decreased by?

Back 6

increased amount of cholesterol in the membrane

Front 7

proteins that are connected to or integrated in the membrane are?

Back 7

integral proteins (transmembrane proteins)

Front 8

what are the functions of integral proteins?

Back 8

ion channels or pumps
carriers for transport processes

Front 9

proteins that are not directly attached to the membrane are?

Back 9

peripheral proteins

Front 10

what are the functions of peripheral proteins?

Back 10

intracellular cytoskeleton
intracellular molecular signaling processes

Front 11

where are carbohydrate portions of glycoproteins of glycolipids located?

Back 11

the outer membrane surface in contact with ECF

Front 12

what are the functions of the cell membrane?

Back 12

*highly selective permeability barrier that regulates the composition of the ICF and allows the ICF to maintain quite a different composition that the ECF
specific membrane receptors
cellular communication

Front 13

where does protein synthesis occur?

Back 13

rough endoplasmic reticulum (RER)

Front 14

what happens at the smooth endoplasmic reticulum?

Back 14

presence of oxidizing enzymes that metabolize foreign chemicals, including drugs

Front 15

what happens at the golgi apparatus?

Back 15

formation of lysosomes and secretory vesicles

Front 16

what is the function of lysosomes?

Back 16

house cleaners
metabolism/degradation
clean up damaged cellular structure, and digestion of foreign matter

Front 17

what are hydrolases and give an example?

Back 17

granules containing digestive enzymes, part of lysosomes
protease

Front 18

what is the function of peroxisomes?

Back 18

intracellular formation of hydrogen peroxide
hydrogen peroxide is reduced to water by the enzyme catalase

Front 19

the site of oxidative phosphorylation in the inner matrix is?

Back 19

mitochondria

Front 20

what is oxidative phosphorylation?

Back 20

process by which nutrients (primarily glucose) are oxidized to yield carbon dioxide and water, while releasing large amount of energy and heat
the liberated energy is then used in the synthesis of ATP

Front 21

what does the cytoskeleton do?

Back 21

provides structural support for the cell membrane and other structures

Front 22

what is the cytoskeleton made up of?

Back 22

filaments (contractile mechanism)
microtubules

Front 23

what is endocytosis?

Back 23

the uptake and internalization of extracellular material and very large molecules by cells using mechanisms requiring energy input in the form of ATP

Front 24

what is the purpose of endocytosis?

Back 24

transport into the cell of very large molecules which cannot use diffusion or carrier-mediates processses
clearance of proteins or pathogens from extracellular compartment followed by intracellular lysosomal digestion and degradation

Front 25

what is receptor-mediated endocytosis?

Back 25

specific uptake of a substance by the cell with plasma membrane surface receptors for that substance (ligand)
allows absorption of specific substances from the ECF which cannot be absorbed by diffusion or transport

Front 26

what is an example of a ligand?

Back 26

low-density lipoproteins (LDL)

Front 27

what is the mechanism of receptor-mediated endocytosis?

Back 27

the membrane properties are altered such that the portion of the membrane to which the ligand is bound retracts inward
inner membrane contractile proteins cause the retracted portion of the membrane to close; a sufficient amount of intracellular calcium ions is necessary for the contractile process which requires ATP

Front 28

when binding occurs in endocytosis what kind of change happens?

Back 28

conformational change

Front 29

on average how many liters of total body water does a human contain?

Back 29

42 L

Front 30

on average how many liters of ICF does a human contain?

Back 30

28 L

Front 31

how much of the total body water is ECF?

Back 31

14 L
1/3

Front 32

what does ECF consist of?

Back 32

intravascular volume (plasma)
interstitial volume

Front 33

plasma volume of ECF?

Back 33

blood volume minus volume of formed cells = 3L

Front 34

what is hematocrit?

Back 34

"packed" red blood cell volume representing the fraction of blood volume that is RBC

Front 35

what is interstitial fluid?

Back 35

the total ECF volume minus plasma volume = 11 L

Front 36

plasma and ISF have the same ionic concentrations but different what?

Back 36

concentrations of plasma proteins which are confined to the plasma space

Front 37

what happens to fluid that escapes from the plasma volume and small quantities of plasma proteins that escape through the capillary wall?

Back 37

returned to circulation via the lymphatic vessels

Front 38

when is calcium toxic?

Back 38

if it gets inside the cells

Front 39

where is sodium more concentrated?

Back 39

outside of the cell

Front 40

where is potassium more concentrated?

Back 40

inside the cell
-major intracellular cation

Front 41

fluid exchange between the ECF and ICF compartments is regulated by what?

Back 41

osmotic forces exerted by small solutes

Front 42

what is osmosis?

Back 42

the net movement of water between compartments due to a concentration difference in water

Front 43

what is osmotic pressure?

Back 43

the amount of pressure required to stop the osmotic movement of water between the two compartments

Front 44

what causes the concentration difference?

Back 44

the presence of dissolved solute particles

Front 45

how is the osmotic pressure determined?

Back 45

by the number of osmotically active particles in solution

Front 46

what is the osmolarity of ECF?

Back 46

300 mOsM

Front 47

what is isosmotic?

Back 47

two solutions exert identical osmotic pressure

Front 48

what is hyperosmotic?

Back 48

if solution A exerts and higher pressure than B, A is hyperosmotic

Front 49

what is hypoosmotic?

Back 49

if solution A exerts a lower pressure than B, than A is hypoosmotic

Front 50

**what is tonicity?

Back 50

osmotic pressure exerted by an aqueous medium affects the volume of cells
isotonic, hypertonic, hypotonic

Front 51

what is isotonic?

Back 51

with respect to plasma, RBC's will have identical cell volume as they do in plasma

Front 52

with respect to plasma, RBC's will shrink (crenation) since the osmotic pressure of the medium is greater than in the RBC

Back 52

hypertonic

Front 53

what is hypotonic?

Back 53

with respect to plasma, RBC's will expand since the osmotic pressure of the medium is lower than the RBC

Front 54

final cell volume depends on what?

Back 54

only on the concentrations of impermeable solutes

Front 55

there is no osmotic pressure when?

Back 55

when a molecule can freely cross the membrane (ex: urea, ethanol)

Front 56

what are the two types of diffusion processes that do not require energy?

Back 56

simple
facilitated

Front 57

simple diffusion is?

Back 57

movement of a substance directly through the cell membrane as determined by the concentration gradient
the substance must have sufficient lipid solubility to dissolve the lipid bilayer and permeate through the membrance

Front 58

what is lipid solubility determined by?

Back 58

partition coefficient (Kp)
the higher the numerical value of Kp, the more lipid soluble a substance is

Front 59

what is a concentration gradient?

Back 59

the tendency for a substance to move from a region of higher concentration to a region of lower concentration

Front 60

increasing the membrane thickness will do what to the rate of diffusion?

Back 60

decrease

Front 61

increasing lipid solubility will do what to the rate of movement?

Back 61

increase

Front 62

increase in the molecular weight will do what to the rate of movement?

Back 62

decrease

Front 63

increasing the membrane area will do what to the rate of movement?

Back 63

increase

Front 64

Facilitated diffusion is?
(carrier mediated)

Back 64

movement of a substance through a cell membrane along its electrochemical gradient which requires a specific carrier molecule (integral protein), no energy is required since a gradient must be present for movement to occur

Front 65

the rate of movement in facilitated diffusion depends on what?

Back 65

all the factors affecting simple diffusion plus above a maximal substance concentration, the carrier molecules are saturated and reach a maximal transport velocity (Vmax)

Front 66

the three properties of carries that apply to both facilitated diffusion and active transport are?

Back 66

chemical specificity
stereospecificity
competition

Front 67

what is active transport?

Back 67

the uphill movement of a substance against its electrochemical gradient requiring energy input

Front 68

what is primary active transport?

Back 68

requires ATP
NaK pump

Front 69

**what happens with the NaK pump?

Back 69

pumps 3 sodium cations out of the cell in exchange for 2 potassium cations to maintain Na concentrations in ECF and K concentrations in ICF

Front 70

how does operating the NaK pump maintain constant cell volume?

Back 70

reduces the ion concentration inside the cell, thereby reducing the osmotic flow of water into the cell

Front 71

what are the two types of secondary active transport?

Back 71

cotransport
countertransport
(stored energy)

Front 72

what is cotransport?

Back 72

the cell creates stored energy during the NaK pump which is then used for transport of other substances
*Na is moving down it's concentration gradient which releases energy

Front 73

the most efficient transport mechanism for capturing glucose is?

Back 73

cotransport

Front 74

what is countertransport?

Back 74

movement of sodium and the other species in opposite directions

Front 75

where is transepithelial transport?

Back 75

GI tract
renal tubules
cells are polarized with respect to transport properties

Front 76

what is the normal resting membrane potential for mammals?

Back 76

-90mV with net negative charge inside the cell

Front 77

what factors contribute to the negative electrical potential difference?

Back 77

electrochemical potential created by K alone and high membrane permeability of K
electrochemical potential created by Na alone and slight membrane permeability of Na through leak channels
action of the NaK pump

Front 78

which molecule has the dominant role in setting the resting membrane potential?

Back 78

Potassium-due to it's higher permeability it exerts the greatest contribution

Front 79

what is an action potential?

Back 79

representation taking place when a stimulus excites a cell

Front 80

what are the stages of an action potential?

Back 80

resting state
depolarization
repolarization

Front 81

resting state of an action potential?

Back 81

polarized membrane (-90mV)

Front 82

depolarization of an action potential?

Back 82

stimulus is applied
membrane becomes permeable to sodium and there is an influx of large numbers of sodium cations through fast sodium channels during phase 0 (upstroke)

Front 83

repolarization of an action potential?

Back 83

sodium channels close, potassium channels open
potassium efflux from the cell

Front 84

what are voltage gated channels and what are the two gates?

Back 84

ion channels which open or close depending on the membrane potential
activation gate
inactivation gate

Front 85

during depolarization what is happening with that activation and inactivation gates?

Back 85

they are both open allowing a rapid sodium influx

Front 86

what is hypocalcemia?

Back 86

if ECF calcium ion concentration falls to about 50% of normal

Front 87

what is low calcium tetany?

Back 87

the cell becomes highly excitable annd may spontaneously discharge in a repetitive manner

Front 88

tetanic contractions of what muscles can be letal?

Back 88

respiratory muscles

Front 89

what is a hyperpolarizing (positive) action potential?

Back 89

past the -90mV where it is supposed to go
membrane potential becomes even more negative than at rest for a few milliseconds after the action potential is over

Front 90

what is the initiation of an action potential?

Back 90

requires a stimulus at the membrane to cause potential to rise from -90mV to a threshold for action potential initiation (-50 to -70mV)

Front 91

what is subthreshold?

Back 91

stimulus fails to elicit an action potential

Front 92

what is electric conduction?

Back 92

local circuits of current flow between excited areas and adjacent areas that open fast sodium channels

Front 93

what is a graded potential?

Back 93

a subthreshold response
it can create the desired physiological response even though an action potential is not generated

Front 94

what are the types of summation of graded potentials?

Back 94

spatial summation
temporal summation

Front 95

what is automaticity?

Back 95

a full action potential is generated
in the resting state, the membrane must be sufficiently permeable to sodium ion or sodium and calcium ions to allow spontaneous depolarization

Front 96

where does hyperpolarization occur?

Back 96

in virtually all excitable cells which exhibit automaticity

Front 97

what kind of response does a graded potential generate?

Back 97

amplitude and velocity decrease as the distance from the point of stimulation increases
at some point it cannot regenerate itself

Front 98

what kind of response does an action potential generate?

Back 98

all or none response; once the membrane is depolarized to threshold, amplitude independent of initiating event

Front 99

can a graded potential be summed? can an action potential be summed?

Back 99

yes
no

Front 100

does a graded potential or an action potential have a refractory period?

Back 100

an action potential

Front 101

is an action potential or a graded potential conducted decrementally?

Back 101

a graded potential
amplitude decreases with distance

Front 102

can an action potential or a graded potential be depolarization or hyperpolarization?

Back 102

action potential-depolarization
graded potential-depolarization and hyperpolarization

Front 103

what is absolute refractory period?

Back 103

no stimulus, no matter how large can cause a new action potential

Front 104

what is relative refractory period?

Back 104

a stronger than normal stimulus can elicit an action potential during the RRP

Front 105

can ion currents be conducted through myelin layers?

Back 105

no

Front 106

what is a node of ranvier?

Back 106

interrupted sheath between adjacent Schwann cells through which an ion movement can occur between axon and ECF

Front 107

what is saltatory conduction?

Back 107

action potentials occur and are regenerated only at nodes, and are conducted from node to node
conserves energy
increase the velocity of nerve conduction

Front 108

what are myocytes?

Back 108

individual muscle fibers in whole muscles that are long, cylindrical multinucleated cells

Front 109

what is the cell membrane of the muscle fiber?

Back 109

sarcolemma

Front 110

what extends the entire length of the fiber and consists of longitudinally arranged bundles of thick and thin myofilaments?

Back 110

myofibrils

Front 111

what are the thick filaments? thin filaments?

Back 111

myosin
actin

Front 112

what is a sarcomere?

Back 112

the portion of the myofibril lying between two successive Z-disks and forms the contractile unit
this is the region in which actin overlaps myosin

Front 113

myosin filaments are made up of?

Back 113

the tail portion
a gobular "head" portion which has an enzymatic site the ATPase activity and a binding site for actin

Front 114

actin filaments are made up of?

Back 114

troponin (strong affinity for calcium)
tropomyosin

Front 115

what is the "power stroke"?

Back 115

after the myosin head attaches to the actin active site the upper portion of the cross-bridge bends, causing the head to tilt towards the arm, the actin filament is "walked" along

Front 116

what happens in contraction?

Back 116

shortening of the sarcomere increasing the overlap of actin and myosin
an action potential is necessary to release calcium for contraction to occur

Front 117

what is the function of fast fibers (type II)?

Back 117

rapid, powerful contractions

Front 118

what is the function of slow fibers (type I)?

Back 118

prolonged contraction

Front 119

what is the energy source for type II fibers?

Back 119

glycolytic enzymes (anaerobic glycolysis)

Front 120

what is the energy soure for type I fibers?

Back 120

oxidative phosphorylation

Front 121

which type of muscle fiber has large numbers of mitochondria?

Back 121

slow fibers

Front 122

which fiber needs less perfusion and fatigues rapidly as glycogen is depleted?

Back 122

fast fibers

Front 123

which muscle fiber has large amounts of myoglobin?

Back 123

slow fibers
(stores oxygen and speeds its transport to mitochondria)

Front 124

what is hypertrophy?

Back 124

increase in the total mass of the muscle; virtually always due to an increase in the number of actin and myosin filaments within each myofibril, resulting in enlargement of the individual muscle fibers

Front 125

what is an increased number of muscle fibers; probably due to linear splitting of previously enlarged fibers?

Back 125

hyperplasia

Front 126

what are satellite cells?

Back 126

may undergo mitosis, for tissue regeneration, resulting in repair following muscle injury
"stem cell of skeletal muscle"
existing in an inactive state but available when needed

Front 127

what is type II atrophy?

Back 127

disuse in patients receiving steroids or with endogenous hypercortisolism
due to lack of use

Front 128

what is denervation?

Back 128

if deprived of normal innervation, skeletal muscle fibers undergo progressive atrophy (neurogenic), beginning almost immediately after loss of nerve supply

Front 129

what is rigor mortis?

Back 129

all muscles in contracture
occurs several hours postmortem
actin and myosin filaments cannot separate since all ATP is exhausted

Front 130

What is the synaptic cleft?

Back 130

the space between the nerve fiber presynaptic membrane and the muscle fiber postsynaptic membrane

Front 131

what happens when an action potential reaches the neuromuscular junction?

Back 131

the channels are opened and calcium ions diffuse from ECF into the interior of the nerve terminal
the calcium ions attract vesicles to the nerve terminal membrane and the vesicles fuse with the membrane allowing exocytosis of ACh into the synaptic cleft

Front 132

what are ACh-gated ion channels?

Back 132

postsynaptic muscle fiber membrane that contains numerous ACh receptors

Front 133

what happens at ACh-gated ion channels?

Back 133

Na, K, and Ca can pass through the opened channel
ACh inactivation occurs through hydrolysis by the enzyme acetylcholinesterase which is present in the basal lamina

Front 134

what are the results of a local end plate potential?

Back 134

an action potential in the whole muscle fiber which stimulates muscle contraction

Front 135

what has been used as a skeletal muscle paralytic agent in surgical procedures?

Back 135

tubocurarine

Front 136

what disease blocks the release of ACh?

Back 136

botulinum toxin
interferes with exocytosis

Front 137

what is a miniature end plate potential?

Back 137

in the resting state, some vesicles may fuse the nerve fiber membrane and release small amounts of ACh

Front 138

what are transverse tubules (T-tubules)?

Back 138

extension of the sarcolemma into the interior of the muscle

Front 139

sarcoplasmic reticulum system consists of?

Back 139

sarcoplasmic tubules
terminal cisternae

Front 140

what is the active transport system of the sarcoplasmic reticulum?

Back 140

system to pump calcium away from the myofibrils back into the endoplasmic reticulum
almost completely removes calcium from the sarcoplasm

Front 141

what is malignant hyperthermia?

Back 141

inherited disorder
anesthetic or relaxant causes sudden and prolonged release of calcium from the sarcoplasmic reticulum
excess heat is produced as a result of increase muscle contraction
severe muscle rigidity

Front 142

what is myasthenia gravis?

Back 142

autoimmune disease in which antibodies are formed against the ACh receptor at the NMJ
the antibodies compete with ACh at the binding sites
generalized muscle weakness
eventually difficulty breathing due to respiratory muscles being involved

Front 143

nonstriated cells containing a single nuclei which actively divide and regenerate is a property of what?

Back 143

smooth muscle

Front 144

what is multi-unit smooth muscle?

Back 144

composed of discrete fibers, each fiber is independent of the others
each fiber can contract independently of others, often innervated by a single nerve ending

Front 145

what is unitary (syncytial) smooth muscle?

Back 145

fibers that contract as a single unit
gap junctions between cell membranes allow low resistance pathways for ion flow and action potential conduction

Front 146

does smooth muscle contain troponin and tropomyosin?

Back 146

No, but still contains actin and myosin

Front 147

what is the first step of smooth muscle contraction?

Back 147

binding of four calcium ions to calmodulin altering its conformation

Front 148

the contraction process of smooth muscle will continue as long as?

Back 148

the regulatory chain is in its active phosphorylated form
and the sarcoplasmic calcium concentration remains above critical level for calmodulin activation

Front 149

what happens when intracellular calcium concentration falls below a critical level in smooth muscle?

Back 149

the enzyme myosin phophatase becomes activated and removes phosphate from the regulatory chain and contraction stops

Front 150

is smooth or skeletal muscle larger?

Back 150

skeletal

Front 151

which muscle has prolonged, tonic duration of contraction?

Back 151

smooth muscle

Front 152

which type of muscle is capable of generating more force?

Back 152

smooth muscle

Front 153

what is principally responsible for smooth muscle action potentials?

Back 153

calcium

Front 154

what are the major routes of calcium entry in smooth muscle?

Back 154

voltage-gated calcium channels
ligand-gated calcium channels
leak channels

Front 155

what two neurons are sympathetic pathways composed of?

Back 155

preganglionic neurons
postganglionic neurons (travels to effector target organ)

Front 156

in the sympathetic nervous system which neurons are short?

Back 156

preganglionic

Front 157

what fiber is not present in innervation of the medulla?

Back 157

postganglionic

Front 158

in the medulla what do preganglionic fibers use as their neurotransmitter?

Back 158

ACh

Front 159

where do parasympathetic nerves originate?

Back 159

cranial nerves

Front 160

what nerve contains 75% of all parasympathetic innervation and supplies the thorax and abdomen?

Back 160

vagus (CN X)

Front 161

what fibers secrete ACh?

Back 161

cholinergic

Front 162

what fibers secrete norepinephrine?

Back 162

adrenergic

Front 163

preganglionic fibers in sympathetic and parasympathetic systems are?

Back 163

cholinergic

Front 164

postganglionic parasympathetics are?

Back 164

cholinergic

Front 165

postganglionic sympathetic fibers have what type of receptors?

Back 165

adrenergic except for sweat glands and piloerector muscles

Front 166

what terminates NE?

Back 166

reuptake into the nerve terminal by an active transport mechanism

Front 167

what are cholinergic receptors classified as?

Back 167

muscarinic or nicotinic

Front 168

where are muscarinic cholinergic receptors located?

Back 168

postganglionic parasympathetic sites

Front 169

where are nicotinic cholinergic receptors located?

Back 169

synapses between preganglionic and postganglionic fibers in both systems

Front 170

what are adrenergic receptors classified as?

Back 170

alpha or beta

Front 171

where are alpha adrenergic receptors found?

Back 171

postganglionic sympathetic sites (smooth muscle)

Front 172

where are beta adrenergic receptors found?

Back 172

postganglionic sympathetic sites that are divided into 3 subtypes

Front 173

what are the three subtypes of the beta receptors?

Back 173

beta 1-visceral organs
beta 2-vascular and visceral smooth muscle
beta 3-fat cells

Front 174

what is the parasympathetic response for the pupil?

Back 174

miosis
contracted (near vision)

Front 175

what is the parasympathetic response for the exocrine glands?

Back 175

copious, watery secretion
(nasal, saliva, RT, GI)

Front 176

cardiac muscle has increased contractility in?

Back 176

sympathetic response

Front 177

SA node has increased rate in?

Back 177

sympathetic response
(pacemaker)

Front 178

vascular shows decreased diameter of blood vessels in?

Back 178

sympathetic

Front 179

bronchiolar shows constricted in ?

Back 179

parasympathetic

Front 180

increased peristalsis in gut wall in? and increased constriction in sphincters?

Back 180

parasympathetic
sympathetic

Front 181

the gall bladder/bile duct is contracted in?

Back 181

parasympathetic

Front 182

the bladder is contracted in?

Back 182

parasympathetic

Front 183

the penis is in erection in?

Back 183

parasympathetic

Front 184

the liver, basal metabolic rate, adrenal medulla, skeletal muscle, fat, and kidney all have responses in?

Back 184

sympathetic

Front 185

sympathetic stimulation of the adrenal medulla results in?

Back 185

release of 20% NE and 80% EPI into the blood and the resulting end organ effects last 5-10 times as long as the effects of sympathetic nerve stimulation alone

Front 186

what is sympathetic tone?

Back 186

stimulation increases vasoconstriction

Front 187

inhibition of normal tone allows for?

Back 187

vasodilation

Front 188

the fight or flight response includes?

Back 188

increased arterial pressure and heart rate
increased blood flow to skeletal muscle
decreased blood flow to the GI and GU tracts
increased blood glucose and metabolic rate
increased glycogenolysis in liver and muscle

Front 189

parasympathetic ANS causes what type of response?

Back 189

localized and discrete

Front 190

sympathetic ANS causes what type of response?

Back 190

fight or flight