Physiology_Lesson_1_-_Principles_of_Cell_Function-Muscle_Feed_Batch_2026 Flashcards by

Following the principles of osmosis, if a cell were to be placed in a hypertonic solution, what will be the most likely effect?
A. Water moves from outside to inside of a cell
B. Water moves from inside to outside of the cell
C. Water moves freely in and out of the cell with no change in cell volume
D. There will be no net movement of water in the 2 compartments

B. Water moves from inside to outside of the cell

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Oxygen and carbon dioxide enter and leave the cell through which mechanism?
A. Active transport
B. Facilitated diffusion
C. osmosis
D. simple diffusion

D. simple diffusion

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Which of the following components of cell membrane function as ion channels and carriers?
A. Carbohydrates
B. Cholesterol
C. lipids
D. proteins

D. proteins

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The primary determinant of plasma osmolarity is;
A. Calcium
B. Chloride
C. potassium
D. sodium

D. sodium

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For osmosis to occur, a semipermeable membrane must be present which is permeable to:
A, Both solvent and solute
B.The solvent but not the solute
C. the solute but not the solvent
D. neither solvent nor solute

B.The solvent but not the solute

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Tissues capable of oxidative phosphorylation or are metabolically active have high amounts of which of the following organelles?
A. Endoplasmic reticulum
B. Golgi apparatus
C. lysosomes
D. mitochondria

D. mitochondria

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Which of the following IS LOW in ECF?
A. Calcium
B. Chloride
C. glucose
D. sulfates

sulfates

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Percentage of body water is HIGHEST in which of the following?
A. Adult male
B. Obese female
C. newborn
D. elderly senior citizen

C. newborn

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Intracellular fluid is how many percent of body weight?
A. 20
B. 40
C. 60
D. 80

B. 40

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Water will move from ECF to ICF if cells are suspended in this solution:
A. Hypertonic solution
C. Isotonic solution
B. Hypotonic solution
D. all of these

B. Hypotonic solution

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Movement of fluid between ECF and ICF is influenced by:
A. Concentration of water molecules
B. Filtration pressure
C. Osmotic pressure differences
D. Presence of aquaporins

C. Osmotic pressure differences

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In the Gibbs-Donnan effect, the impermeant molecule that attracts osmotically active
particles into the intracellular compartment is:
A. Chloride
B. Potassium
C. proteins
D. sodium

C. proteins

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During instances of cell shrinking. the cell regulates its volume by:
A. Reducing the number of aquaporins
B. Transporting osmotically active particles out of the cell
C. Inhibition of Na+-KATPase activity
D. Rapid uptake of osmotically active particles into the cell

D. Rapid uptake of osmotically active particles into the cell

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Changes in the levels of one of the following ions can affect membrane voltage because of
the great conductance of the cell membrane to:
A. Calcium
B. Chloride
C. sodium
D. potassium

D. potassium

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Regarding vectorial transport across epithelial cells, transport from basolateral aspect of the cell to the apical surface is known as:
A. Absorption
B. Reabsorption
C. secretion
D. all of these

C. secretion

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Which of the following is a function of integral membrane proteins?
A. Provides negative charge to cells
B. Act as solute carriers
C. help control membrane fluidity
D. attaches one cell to the next

B. Act as solute carriers

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Which of the following factors WILL INCREASE membrane fluidity?
A. Low temperatures
B. Low amounts of cholesterol
C. increase in unsaturated fatty acids
D. increase in membrane carbohydrates

C. increase in unsaturated fatty acids

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The Na+-K+ ATPase system transports:
A. 3 potassium inside the cell and 2 sodium outside
B. 3 potassium inside and 2 sodium outside
C. 2 potassium inside and 2 sodium outside
D. 2 potassium inside and 3 sodium outside

D. 2 potassium inside and 3 sodium outside

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Which of the following transport processes is an example of primary active transport?
A Na+-glucose transport
B. Na+-K=ATPase
C. 3Na+-1Ca++ antiporter
D. Na+-H+ transport

B. Na+-K=ATPase

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There will be increased rate of gene transcription if a signaling molecule binds to which of the following?
A. Cell membrane receptors
B. Nuclear receptors
C. both
D. neither

B. Nuclear receptors

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When a signaling molecule or a hormone has “paracrine” effects, this means:
A. It acts on itself, the cell that produced the hormone
B. It acts on nearby or adjacent cells
C. It must travel long distances thru the blood to reach its target cell
D. It travels by ducts to the cell surface

B. It acts on nearby or adjacent cells

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The most common effector of G proteins is:
A. Adenylate cyclase
B. Phosphodiesterase
C. protein kinase
D. phospholipases

A. Adenylate cyclase

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Signaling molecules bind with specificity to their target cell. Which of the following is responsible for this specificity?
A. signaling molecule itself
B. transport proteins
C. receptors
D. second messengers

C. receptors

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Binding of acetylcholine to its receptor will cause activation of
A. G proteins
B. Ion channels
C. tyrosine kinase
D. enzyme linked proteins

B. Ion channels

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31. When a hormone/ligand binds to GPCRs (G-protein coupled receptors), one of the following occurs that signal activation of G protein: A. Reassociation of alpha subunit to beta and gamma subunits B. Internalization of GPCR C. Replacement of GDP with GTP on the alpha subunit D. Conversion of CAMP to AMP

C. replacement of GDP with GTP on the alpha subunit

32. The main effect of this signaling molecule is the release of calcium from the sarcoplasmic reticulum (SR) particularly in smooth muscles in response to some hormones: A. CAMP C. DAG B. cGMP D. Inositol triphosphate

D. Inositol triphosphate

33. The breakdown of cAMP or cGMP with termination of their effects is mediated when G protein alpha subunit binds and activates one of the following: A. calcium B. Phosphatases C. phosphodiesterase D. phosphorylase

C. phosphodiesterase

34. DAG and Inositol triphosphate will be the signaling molecules generated when G protein interacts with which of the following effector molecules? A. Adenylate cyclase B. Guanylate cyclase C. phospholipase A2 D. phospholipase C

D. phospholipase C

35. Second messengers are activated if a hormone/neurotransmitter binds to: A. Cell membrane receptors B. Nuclear receptors C. both D. neither

A. Cell membrane receptors

36. Pro-inflammatory mediators such as prostaglandins, tromboxanes and leukotrienes are produced when G protein activates which of the following effector proteins? A. Adenylate cyclase B. Guanylate cyclase C. phospholipase A2 D. phospholipase C

C. phospholipase A2

37. The hormone insulin activates which of the following transduction pathways? A. Enzyme linked B. G protein pathway C. ion channel linked D. regulated intramembrane proteolysis

A. Enzyme linked

38. Sustained or prolonged continuous exposure to a hormone or signaling molecule will usually cause: A. No change in cellular response B. Increased cellular response C. decreased cellular response over time D. response may increase or decrease over time

C. decreased cellular response over time

39. Activation of cAMP may cause activation or inactivation of downstream intracellular proteins by phosphorylation through activation of which of the following ? A. Protein Kinase A B. Protein Kinase C C. Protein Kinase G D. Tyrosine kinase

A. Protein Kinase A

40. G protein signaling is terminated when: A. A new cAMP molecule is produced B. A new molecule of GTP binds to the alpha subunit C. GTP that is bound to the alpha subunit is hydrolyzed into GDP D. ATP is converted to CAMP

C. GTP that is bound to the alpha subunit is hydrolyzed into GDP

41. This is the MAJOR DETERMINANT of the resting membrane potential: A. Potassium leak channels B. Sodium leak channels C. Nat-K+ATPase pump D. voltage-gated ion channels

A. Potassium leak channels

42. In chemical synapses, this is the role of calcium: A. Responsible for neurotransmitter synthesis B. Involved in neurotransmitter reuptake C. Involved in neurotransmitter release from synaptic vesicles D. Degrades unused neurotransmitters

C. Involved in neurotransmitter release from synaptic vesicles

43. Increased permeability of the postsynaptic membrane to chloride or potassium ions will result to the generation of which of the following? A. Action potentials B. End plate potentials C. excitatory post synaptic potentials (EPSP) D. inhibitory post synaptic potentials (IPSP)

D. inhibitory post synaptic potentials (IPSP)

44. The most common mechanism for postsynaptic excitation is: A. Opening of potassium channels B. Opening of sodium channels C. closure of chloride channels D. closure of calcium channels

B. Opening of sodium channels

45. TRUE of Inhibitory Postsynaptic Potentials; A. Increase in negativity of postsynaptic membrane B. Are usually hyperpolarizing C. Decreases the probability of generating an action potential D. All are correct

D. All are correct

46. The following characterizes electrical synapses EXCEPT: A. No pre and post synaptic elements B. Exhibits synaptic delay C. Transmits impulses faster D. Cells are connected physically via gap junctions

B. Exhibits synaptic delay

47. What is the role of Snare proteins in the presynaptic membrane of chemical synapses? A. Opens voltage gated calcium channels B. Involved in the docking and fusion of vesicles to presynaptic membrane C. Synthesizes neurotransmitters and packages them into vesicles D. Inhibits neurotransmitter release from presynaptic terminals

B. Involved in the docking and fusion of vesicles to presynaptic membrane

48. Neurotransmitter that may undergo enzymatic degradation in the synaptic cleft: A. Acetylcholine B. Dopamine C. epinephrine D. serotonin

A. Acetylcholine

49. Type of neurotransmitter that are highly permeate with no reuptake mechanism and does not undergo enzymatic degradation: A. Gaseous neurotransmitter B. Peptide neurotransmitter C. small molecule neurotransmitter D. all of these

C. Gaseous neurotransmitter

50. The possibility of firing an action potential will be LESS with which of the following membrane voltage? A. -50mv B. -60mv C. -70mv D. -90mv

D. -90mv

51. Which of the following IS CORRECT about action potentials? A. Size and shape remains the same even with greater stimulus B. Amplitude decreases with increase in distance C. Response obtained from stimulus is small D. Impulses are not self-regenerating

A. Size and shape remains the same even with greater stimulus

52. The longest portion of the action potential often lasting for several milliseconds is: A. Depolarization B. Hyperpolarization C. repolarization D. resting membrane

B. Hyperpolarization

53. The charge or voltage within the membrane becomes negative when: A. Positive charged ions leave the cell B. Positive charged ions enter the cell C. Negative charged ions leave the cell D. Positive charged ions cannot leave the cell

A. Positive charged ions leave the cell

54. Action potentials are generated mainly because of A. Antiporters B. Leak channels C. ligand gated channels D. voltage gated ion channels

D. voltage gated ion channels

55. Explosive opening of this channel causes depolarization: A. Nat-KATPase B. Leak channels C. voltage-gated sodium channels D. voltage-gated potassium channels

C. voltage-gated sodium channels

56. Which of the following is responsible for hyperpolarization? A. Closure of sodium inactivation gates B. Increased activity of Na+-K+ATPase C. Slow closure of potassium channels D. Failure of sodium activation gates to open

C. Slow closure of potassium channels

57. At the peak of depolarization, which of the following closes? A. Voltage gated sodium inactivation gates B. Voltage gated potassium channels C. Voltage gated sodium activation gates D. Voltage gated calcium channels

A. Voltage gated sodium inactivation gates

58. Which of the following will increase velocity of impulse conduction? A. Unmyelinated nerve fibers B. Temperature of -10° C C. small diameter nerve fiber D. presence of nodes of Ranvier

D. presence of nodes of Ranvier

59. Repolarization is caused by: A. Opening of both voltage gated sodium and potassium channels B. Closure of both voltage gated sodium and potassium channels C. Closure of voltage gated sodium channels and opening of potassium channels D. Opening of voltage gated sodium channels and closure of potassium channels

C. Closure of voltage gated sodium channels and opening of potassium channels

60. During the absolute refractory period, a second action potential cannot be elicited even with a stronger than normal stimulus because of what reason? A. Sodium inactivation gates are still closed B. Voltage gated potassium channels are closed C. Activation and inactivation gates of sodium are open D. Increased activity of Na+-K_ATPase.

A. Sodium inactivation gates are still closed

61. There is no hyperpolarization phase in the nodes of Ranvier which results to faster impulse conduction due to the lack of which channel? A. Calcium B. Chloride C. potassium D. sodium

C. potassium

62. Blockage of voltage-gated sodium channels by poisons will affect which phase of the action potentials? A. Depolarization B. Hyperpolarization C. repolarization D. resting membrane

A. Depolarization

63. Blockage of voltage-gated sodium channels by poisons will manifest as: A. Seizure B. Psychosis C. Paralysis D. convulsions

C. Paralysis

64. The inactivation gates of sodium channels will only reopen when the cell is in which state? A.Depolarization B. Hyperpolarization C. repolarization D. resting state

D. resting state

65. In tissues such as smooth and cardiac muscles that must contract simultaneously as a unit, flow of ions and impulses from one cell to the next takes place at: A. Hemidesmosomes B. Gap junctions C. tight junctions D. zona adherens

B. Gap junctions

66. In the presynaptic terminals of a synapse, less activation of voltage-gated Calcium channels and less entry of calcium into the presynaptic membrane will result to: A. Generation of EPSPs B. Generation of action potentials C. decreased release of neurotransmitters D. increased opening of sodium channels

C. decreased release of neurotransmitters

67. In the neuromuscular junction of skeletal muscles, binding of acetylcholine to postsynaptic receptors in the sarcolemma will be followed by: A.Activation of G protein B. Increase in cAMP C. opening of sodium ion channels D. release of caicium

C. opening of sodium ion channels

68. In skeletal muscle sarcomere, the light band or I band which is found on either side of the Z line contains primarily this protein: A. Actin B. Myosin C. overlap of actin and myosin filaments D. titin

A. Actin

69. Skeletal muscles can increase their force of contraction by which of the following mechanisms? A. Increase in Ca++ release by sarcoplasmic reticulum (SR) B. Increased entry of extracellular Cat+ C. Increased actin and myosin interactions D. Increased recruitment of more motor units

D. Increased recruitment of more motor units

70. Increased activity of one of the following will result to a fall or decrease in intracellular calcium in skeletal muscles: A. DHPR receptors B. RYR receptors C. 3Na+-1Ca++ antiporter D. SERCA

D. SERCA

71. In general, there are only a small number of muscle fibers in motor units that require: A. Coordination B. Precise control C. strength D. speed

B. Precise control

72. Spread of action potentials in the T tubules of skeletal muscles will cause A. Conformational change in DHPR receptors B. Increased activity of SERCA to reuptake Ca++ into the SR C. Entry of extracellular Ca++ via L-type voltage gated Cat+ channels D. Release of Ca++ via InsP3 gated Cat+ channels in the SR

A. Conformational change in DHPR receptors

73. What is the role of Calcium in skeletal muscle contraction? A. Activates ATPase function of myosin globular heads B. Facilitates the exposure of binding sites in actin thru movement of tropomyosin C. Causes sliding of myosin over actin filaments D. Activates actin and myosin through phosphorylation

B. Facilitates the exposure of binding sites in actin thru movement of tropomyosin

74. Which of the following is energy requiring in skeletal muscles? A. Muscle contraction B. Muscle relaxation C. both D. neither

C. both

75. Which of the following is the source of energy for sustained and prolonged muscle contraction? A. Phosphocreatine B. Glycolysis C. oxidative metabolism D. anaerobic metabolism

C. oxidative metabolism

76. Relaxation of skeletal muscles occur when : A. ATP is hydrolyzed by ATPase in myosin heads B. ATP and nutrients are depleted C. Myosin heads are dephosphorylated D. Intracellular calcium levels fall or decrease

D. Intracellular calcium levels fall or decrease

77. According to the sliding filament theory, binding of myosin heads to actin binding sites leads to which of the following? A. Movement of actin filaments towards the center of the sarcomere B. Movement of myosin filaments towards the center of the sarcomere C. Actin filaments move away from the center and towards the Z line D. Myosin filaments move farther away from actin filaments

A. Movement of actin filaments towards the center of the sarcomere

78. Which of the following IS CORRECT about Type I muscles? A. Have high glycolytic ability B. Has large fiber diameter C. has fast conduction velocity D. has more mitochondria and myoglobin

D. has more mitochondria and myoglobin

79. What is the cause of rigor mortis that is observed soon after a person dies? A. Excessive release of calcium by the SR B. Failure of calcium reuptake by SR C. Formation of permanent actin-myosin interaction due to absence of ATP D. Abnormality in the myosin heads

C. Formation of permanent actin-myosin interaction due to absence of ATP

80. Which of the following best describes isotonic contraction? A. Muscle shortens and tension developed increases B. Muscle shortens and tension developed is constant C. No change in muscle length but tension is increased D. No change in both muscle length and muscle tension

B. Muscle shortens and tension developed is constant

81. According to the force velocity relationship, what will be the effect in the shortening velocity of muscle in the absence of any load? A. Shortening velocity will be maximal B. Shortening velocity decreases C. there will be no shortening at all D. the muscle will be stretched

A. Shortening velocity will be maximal

82. What is the possible cause of fatigue during intense exercise? A. ATP depletion B. Accumulation of lactic acid and waste products C. Accumulation of Cat+ D. Fall in blood supply

B. Accumulation of lactic acid and waste products

83. Myosin heads detach from actin binding sites when: A. New ATP binds to myosin heads B. Intracellular calcium falls C. release of ADP and Pi D. ATP is hydrolyzed to ADP + Pi

A. New ATP binds to myosin heads

84. According to the length-tension relationship graph, excessive increase in muscle length or overstretching of muscle fibers will result to a decrease in contractile force. This is because there will be: A. Collision of actin filaments in the middle of the sarcomere B. Damage to contractile proteins C. Lack of overlap between actin and myosin filaments D. Depletion of energy for actin and myosin interactions

C. Lack of overlap between actin and myosin filaments

85. During prolonged exercise wherein oxygen debt may develop, the source of energy for skeletal muscles under such conditions will be: A. Glycolysis B. Lipid metabolism C. phosphocreatine D. oxidative metabolism

A. Glycolysis

86. Action potentials in cardiac muscles originate from the: A. Atrioventricular node B. Bundle of His C. Purkinje fibers D. Sinoatrial node

D. Sinoatrial node

87. Regulation of cardiac muscle contraction is: A. Thin filament regulated B. Thick filament regulated C. both D. neither

A. Thin filament regulated

88. Cardiac muscle can increase or decrease its rate and force of contraction thru which of the following mechanisms? A. Activation of pacemakers B. Recruitment of more motor units C. Modulating Ca++ influx through L-type voltage gated channels D. Tetanic contractions

C. Modulating Ca++ influx through L-type voltage gated channels

89. MAJORITY of the calcium required by the heart for its contraction comes from the: A. ECF B. Sarcoplasmic reticulum C. both D. neither

B. Sarcoplasmic reticulum

90. Which of the following channels become active during cardiac muscle relaxation? A. 3Na+-1Ca++ antiporter B. DHPR receptors C. RYR receptors D. L type voltage gated channels

A. 3Na+-1Ca++ antiporter

91.. Which of the following causes the release of calcium from the sarcoplasmic reticulum in cardiac muscles? A. Action potentials originating from the T tubules B. Extracellular Ca++ entering through L-type voltage gated channels C. Increased permeability of the SR to calcium D. Activation of SERCA and Calcium ATPase

B. Extracellular Ca++ entering through L-type voltage gated channels

92. Sympathetic stimulation can cause an increase rate and force of cardiac muscle contraction through phosphorylation of phospholamban which then causes: A. Entry of more extracellular calcium into cardiac muscle cells B. Increased stretch of cardiac muscles C. Increased uptake and accumulation of Ca++ by the SR D. Increased sensitivity of the muscle cell to calcium

C. Increased uptake and accumulation of Ca++ by the SR

93. In both skeletal and cardiac muscles, calcium binds to which of the following to initiate muscle contraction? A. Myosin heads B. Calmodulin C. troponin c D. tropomyosin

C. troponin c

94. The latch mechanism" in smooth muscles mean: A. Ability to return to original tension after the muscle is stretched or shortened B. Smooth muscles have greater force or strength than skeletal or cardiac muscle C. Smooth muscle has greater requirement for energy than other types of muscles D. Ability for prolonged tonic contraction with less energy expenditure

D. Ability for prolonged tonic contraction with less energy expenditure

95. The role of calcium in smooth muscle contraction is : A. To cause troponin-tropomyosin interactions B. To bind to troponin and inhibit tropomyosin C. Phosphorylation of myosin heads by activating myosin light chain kinase (MLCK) D. Facilitate ATP binding to myosin heads

C. Phosphorylation of myosin heads by activating myosin light chain kinase (MLCK)

96. Smooth muscle contraction can be initiated by hormones, autonomic nervous system and pharmacologic agents. The common effect of all of these is to increase: A. Intracellular calcium B. Action potentials C. actin myosin interactions D. release of neurotransmitters

A. Intracellular calcium

97. To initiate smooth muscle contraction, calcium binds to: A. Calmodulin C. troponin c B. Myosin D. tropomyosin

A. Calmodulin

98. In smooth muscles, hormones such as Oxytocin and Norepinephrine as well as certain pharmacologic agents can cause release of calcium from the SR even without generating action potentials by way of which channel? A. 3Na+-1Ca++ antiporter B. Inositol triphosphate gated channel C. RYR receptor D. SERCA

B. Inositol triphosphate gated channel

99. According to the length adaptation relationship in smooth muscles: A. There is fast cycling of actin and myosin cross bridges B. Smooth muscles can return to original tension after being stretched or shortened C. Stretching and shortening can decrease smooth muscle force of contraction' D. None of these

B. Smooth muscles can return to original tension after being stretched or shortened

100. The common cause of relaxation in all three types of muscles is: A. Fall in ATP levels B. Decrease in nutrients C. depletion of neurotransmitters D. fall in intracellular calcium

D. fall in intracellular calcium

1. The presence of one of the following differentiates eukaryotic cells from prokaryotic cells: A. Cell membrane B. Gap junctions C. cytoplasmic organelles D. membrane-bound nucleus

D. membrane-bound nucleus

2. Large molecules and even entire cells can be uptake by which of the following processes? A. Facilitated diffusion B. Phagocytosis C. pinocytosis D. receptor-mediated endocytosis

E. Phagocytosis

3. One of the following factors can DECREASE the rate of diffusion: A. Increased temperature B. Increased concentration difference C. decreased number of channels D. decreased viscosity

F. decreased number of channels

4. Which of the following transporters maintains normal cellular ion and voltage gradients and helps maintain cell volume? A. 3Na+-1Ca++ antiporter B. Na+-H+ transporter C. Na+-glucose transporter D. Na+-K+ ATPase

D. Na+-K+ ATPase

5. In the plasma, which is the determinant of oncotic pressure? A. Electrolytes B. Water C. proteins D. solutes

C. proteins

6. In one of the following transport mechanisms, the flow is from high to low concentration but rate of transport approaches max as substrate concentration is increased A. Primary active transport B. Secondary active transport C. facilitated diffusion D. simple diffusion

C. facilitated diffusion