Cell Physiology

Question 1

Permits current flow and electrical coupling between myocardial cells?

Answer 1

Gap junctions

Question 2

Galactose is a competitive inhibitor of glucose transport. In what carrier mediated characteristic?

Answer 2

Competition

Question 3

D-glucose is transported by facilitated diffusion , but the L-isomer is not.
In what carrier mediated characteristic?

Answer 3

Steriospecificity

Question 4

Glucose transport in muscle and adipose cells in downhill and is carrier mediated. In what type of transport?

Answer 4

Facilitated diffusion

Question 5

Na-K-2Cl in the renal thick ascending limb.
In what type of transport?

Answer 5

Co-transport / Symport

Question 6

Na-Glucose cotransport:
Glucose is transported ____________,
Na is transported ______________.

Answer 6

Uphill, Downhill

(glUcose: Uphill)

Question 7

Na-Ca counter-transport : Energy is derived from the _______.

Answer 7

Derived from the downhill movement of Na.

Question 8

What is the osmolarity of a 1M NaCl solution?

Answer 8

2 Osm/L

Osmolarity= g x C
Osmolarity = 2 Osm / mol x 1M
Osmolarity = 2 Osm/L

Question 9

At resting potential, the activation gates are ______ and thus the Na channels are ________?

Answer 9

Closed, Closed

Question 10

True or False.
The activation gate of Na channel in nerve is opened by depolarization.

Answer 10

True

Question 11

True or False.
The inactivation gate of Na channel in nerve is closed by depolarization.

Answer 11

True

Question 12

True or False.
If either the activation or inactivation on the gate of Na channel in nerve is closed, the channel is closed and impermeable to Na.

Answer 12

True

Question 13

Small channels lined with negatively charged groups will be selective for _______ and exclude ___________.

Answer 13

Small Cation, Large solutes and anions.

(Small Negative Cat)

Question 14

Nerve membrane at rest is far more permeable to what solute?

Answer 14

K+ than Na+

Question 15

What is the resting membrane potential of the nerve?

Answer 15

-70mv

Question 16

What is the calculated K equilibrium potential ?

Answer 16

-85mV

Question 17

What is the calculated Na equilibrium potential ?

Answer 17

+65 mV

Question 18

Characteristic shared by simple and facilitated diffusion of glucose?

Answer 18

Occurs down an electrochemical gradient

Question 19

Occurs during the upstroke of the nerve action potential?

Answer 19

Net inward current and the cell interior becomes less negative.

Question 20

True or False.
Depolarization is caused by an inward current and in most muscle types, inward current is carried by Na+

Answer 20

True

Question 21

Correct temporal sequence for events at the neuromuscular junction ? (3)

Answer 21

1. Uptake of Ca into the presynaptic terminal
2. Release of Acetylcholine
3. Depolarization of the muscle end plate

Question 22

Characteristic shared by skeletal muscle and smooth muscle?

Answer 22

Elevation of intracellular Ca for excitation - contraction coupling.

Question 23

Solute responsible dor tetanus?

Answer 23

Calcium

Question 24

A 42 yo Male with myasthenia gravis improves with acetylcholinesterase inhibitor. Basis of improvement?

Answer 24

Levels of ACh at the muscle end plates increases.

Question 25

Effect of myelinating the nerve in the conduction velocity of action potentials?

Answer 25

Increased conduction velocity.

Question 26

Transport of D and L glucose proceeds at the same rate down an electrochemical gradient. In what transport process?

Answer 26

Simple Diffusion According to BRS, only two types of transport occur downhill - simple diffusion & facilitated. If there is no stereospecificity for the D- or L-isomer ,o nce can conclude that the transport is not a carrier mediated. In real life, this is through simple diffusion.

Question 27

Doubles the permeability of a solute in a lipid bilayer?

Answer 27

Doubling the oil/ water partition coefficient of the solute

Question 28

Effect of local anesthetic blocking Na+ channels in nerves?

Answer 28

Decrease the rate of rise of the upstroke of the action potential.

Question 29

Channels opened by acetylcholine at the muscle end-plate ?

Answer 29

Na and K channels and depolarization to a value halfway between the Na and K equilibrium potentials.

Question 30

Defines inhibitory postsynaptic potential?

Answer 30

Hyper-polarizes the postsynaptic membrane by opening a-channels.

Question 31

Result of the inhibition of Na K ATPase. Effect on intracellular calcium?

Answer 31

Increased intracellular Ca concentration

Question 32

Abolishing the Na gradient across the cell membrane will affect which glucose intestinal transport process?

Answer 32

Cotransport

Question 33

Occurs before depolarization of the T tubules in the skeletal muscle?

Answer 33

Depolarization of the sarcolemmal membrane.

Question 34

Inhibitory neurotransmitter in the CNS?

Answer 34

GABA B- Brain

Question 35

What process that Indirectly use ATP in the intestinal cells?

Answer 35

Absorption of glucose by intestinal epithelial cells, occurs by secondary active transport.

Question 36

Causes rigor in skeletal muscles?

Answer 36

A decrease in ATP level

Question 37

Disease with degeneration of dopaminergic neurons?

Answer 37

Parkinson disease

Question 38

Transport process blocked by the drug class PPI.

Answer 38

Primary Active Transport

Question 39

Elevated serum K causes muscle weakness because?

Answer 39

Na channels are closed by depolarization.

Question 40

True or False. Elevated serum K causes depolarization of K equilibrium potential and therefore depolarization of the RMP.

Answer 40

True

Question 41

True or False. Sustained depolarization closes the inactivation gates of Na.

Answer 41

True

Question 42

Occurs after binding of Ca to calmodulin?

Answer 42

Increased myosin light chain kinase

Question 43

68 Male with syndrome of inappropriate anti diuretic hormone, treated with hypertonic saline. Plasma osmolarity before treatment? Choices: a. 235 mOsm / L b. 290 mOsm/L c. 300 mOsm / L d.320 mOsm/L

Answer 43

Pretreatment is hypotonic and hypoosmotic =235 mOsm/ L

Question 44

Solution A & B are separated by a semipermeable membrane that is permeable to K+ but not to Cl- Solution A is 100 mM KCL , SolutionB is 1 mM KCl. How will K+ move?

Answer 44

K+ will diffuse from solution A to solution B until a membrane potential develops with solution A negative with respect to solution B.

Question 45

Solution 1 and 2 are separated by a semipermeable membrane. Solution 1 contains a solute that is too large to cross the membrane. Solution2 2 is pure water. Which solution produces an osmotic pressure?

Answer 45

Solution 1 Since the solutes cannot cross the membrane and thus can pull water from the other solution.

Question 46

Two solutions of NaCl are separated by a membrane that is permeable to Na+ but not to Cl. The NaCl concentration of solution 1 is higher of that solution 2. What happens to both solutes?

Answer 46

Na+ will diffuse from solution 1 to solution 2; diffusion potential will develop at the membrane and solution 1 will become negative with respect to solution 2.

Question 47

Solutions A (10mM urea) and B (5mM urea) are separated by a membrane that is permeable to urea. What happens to the flux of urea when concentration of urea in solution A is doubled?

Answer 47

Triple When urea concentration was doubled in solution A , the concentration difference became 20mM - 5mM = 15mM or three times the difference of the original difference.

Question 48

Solutions A and B are separated by a semipermeable membrane. Solution A contains 1mM of sucrose & 1mM or urea. Solution B contains 1mM sucrose. The reflection coefficient of sucrose is one. The reflection coefficient for urea is zero.Solution A will be what compared to B?

Answer 48

Solution A is hyperosmotic with respect to solution B, and the solution are isotonic. Solution A contains both sugar and urea at concentrations of 1mM, where solution B contains only sucrose at a concentration of 1mM.

Question 49

Basic unit of human body?

Answer 49

Cell

Question 50

RBCs placed on a solution >300

Answer 50

RBCs will shrink

Question 51

Type of muscle fibers not used by sedentary persons?

Answer 51

White muscle fibers, (Fast-Twitch ; Type 2)

Question 52

Source of most energy used for long-term muscle contraction?

Answer 52

Oxidative metabolism

Question 53

Formed when activated myosin heads bind to binding sites in actin?

Answer 53

Cross-bridge attachment

Question 54

Major hallmarks of cancer cells? (2)

Answer 54

1. Loss of cell to cell adhesion 2. Anchorage independent growth

Question 55

Sustained muscle contraction in tetanus , is due to accumulation of?

Answer 55

Calcium intracellularly

Question 56

Temporal summation is caused by?

Answer 56

Recurrent / repetitive inputs

Question 57

Amount of calcium released from SR depends on ?

Answer 57

Amount of calcium stored

Question 58

Occurs during an upstroke of action potential?

Answer 58

1. Net inward current 2. Cell interior becomes less negative

Question 59

Inhibits PDE, causing inhibition of the degradation of cAMP to 5’ AMP?

Answer 59

Caffeine

Question 60

Irreversibly inhibits COX-1 ?

Answer 60

Aspirin

Question 61

When doubled , will also double permeability of solute in a lipid bilayer.

Answer 61

1. Increased oil/ water partition coefficient of solute 2. Decreased radius of solute 3. Decreased membrane thickness J=PA (C1-C2) P= permeability

Question 62

Major cation of the intracellular fluid?

Answer 62

K+ ( Mg is also an ICF cation)

Question 63

Characteristics of ion channels ?

Answer 63

Selectivity based on distribution of charges and size of channels . Eg. Small channel lined with negatively charged groups will exclude large solutes.

Question 64

Small motor neurons innervate __________.

Answer 64

Slow-twitch fibers

Question 65

True or False. Small motor neurons generate smallest force, but not able to maintain levels of force for long periods.

Answer 65

False. They are able to maintain force for long periods. “One, Small , Red, Ox, Endure heat”

Question 66

True of False. Small motor neurons innervate few muscle fibers.

Answer 66

True

Question 67

What causes the repolarization of the action potential?

Answer 67

Outward K+ movement (K+ Efflux)

Question 68

What initiates action potential in the skeletal muscle fiber? a. Sodium b. Calcium c. Both

Answer 68

Sodium

Question 69

What initiates action potential in the smooth muscle fiber? a. Sodium b. Calcium c. Both

Answer 69

Calcium

Question 70

Factors that determine permeability of the membrane? (3)

Answer 70

1. Temperature 2. Types of solutes present 3. Level of cell hydration

Question 71

Confers fluidity to the cell membrane?

Answer 71

Cholesterol

Question 72

Detects dynamic changes?

Answer 72

Nuclear bag fibers

Question 73

Greatest determinant of muscle strength?

Answer 73

Muscle size

Question 74

Which type of solution will make the cell shrink ?

Answer 74

Hypertonic solution

Question 75

Characteristics of Carrier mediated transport? (3)

Answer 75

1. Stereospecificity 2. Saturation 3. Competition

Question 76

Which bind adhesion proteins to the cytoskeleton within cardiac myocytes , thus connecting the cells?

Answer 76

Desmosomes inside intercalated discs

Question 77

Preprohormone is created in the _____________.

Answer 77

Ribosomes

Question 78

3 characteristics of carrier -mediated transport?

Answer 78

SSC 1. Stereospecificity 2. Saturation 3. Competition

Question 79

Pulling apart of 2 chromatids of each chromosome at centromere?

Answer 79

Anaphase

Question 80

Myosin associated bands.

Answer 80

A band & H band

Question 81

Contractile units of myocardial cells?

Answer 81

Sarcomere

Question 82

Muscle fiber involved in muscle endurance?

Answer 82

Type I muscle fiber , Extrafusal

Question 83

Competes with Ach for receptors on the motor end plate?

Answer 83

Curare

Question 84

Examples of Tyramine rich foods? (8)

Answer 84

1. Strong / aged cheese 2. Curated meats/ Smoked meats / Processed meats 3. Pickled / Fermented foods like kimchi 4. Sauces ( Soy sauce, shrimp paste etc.) 5. Soybeans , Fava beans 6. Dried fruits 7. Alcohol 8. Spoiled food

Question 85

Muscle with greatest number of mitochondria?

Answer 85

Cardiac muscle

Question 86

Increases size (girth) of skeletal muscles?

Answer 86

Exercise

Question 87

Precursor of Eicosanoids?

Answer 87

Arachidonic acid

Question 88

Functions of muscles? (11)

Answer 88

1. Mobility 2. Stability 3. Posture 4. Circulation 5. Respiration 6. Digestion 7. Urination 8. Childbirth 9. Vision 10. Organ protection 11. Temperature regulation

Question 89

How many percent of body heat comes from muscle contraction?

Answer 89

85%

Question 90

Cytokine involved in cancer and septic shock?

Answer 90

TNF aka Cachectin

Question 91

Blocking the H+ secretion of the gastric parietal cell mean that you will block this type of transport?

Answer 91

H+ / K- ATPase exchange pump - Primary Active Transport

Question 92

1 motor neuron + All muscle fiber it innervates?

Answer 92

Motor unit

Question 93

Controls and regulates cellular activities?

Answer 93

Nucleus

Question 94

Action potential is inevitable at this membrane potential?

Answer 94

Threshold

Question 95

Binds Myosin to Z lines , Binds Z lines to M line, determines normal stiffness of the ventricular muscle.

Answer 95

Titin - largest protein in the body

Question 96

Stabilizes sarcolemma and prevents contraction - induced rupture?

Answer 96

Dystrophin

Question 97

Basis for rigor mortis?

Answer 97

Lack ATP prevents unbinding of myosin heads from actin binding sites