Cell Physiology and General Physiology of Excitable Tissues- Physiology PMU 2nd Year

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Cell Physiology and General Physiology of Excitable Tissues- Physiology PMU 2nd Year

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Created by Med Student about 3 years ago
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Question 1

Question
Hormones:
Answer
  • are chemical regulators that are conveyed from one organ to another via the blood stream
  • may be secreted by endocrine glands
  • may be secreted by nerve cells
  • act only on target cells
  • all of the above

Question 2

Question
For an action potential to occur
Answer
  • the stimulus must reach or exceed threshold
  • K+ influx must exceed Na+ efflux
  • The cell membrane must be out of the relative refractory period
  • The cell membrane must be in absolutely refractory period
  • Cl- influx must exceed K+ efflux

Question 3

Question
During the rising phase of the action potential
Answer
  • voltage-gated Na+ channels open
  • voltage-gated K+ channels open
  • voltage-gated Na+ channels close
  • voltage-gated K+ channels close
  • voltage-gated Cl- channels apex

Question 4

Question
The concept of homeostasis
Answer
  • refers to the unwavering control of a physiological set point
  • refers to maintaining physiological functions in a stable condition
  • refers only to the regulation of body temperature
  • refers to maintaining a stable external environment
  • refers to the 'all-or-one' law

Question 5

Question
The plasma membrane
Answer
  • is permeable to lipophilic molecules
  • may contain proteins, which confer iron permeability
  • may burst in hypotonic extracellular solutions
  • can generate action potentials in excitable cells
  • all of the above

Question 6

Question
Overcooling the nerve will cause
Answer
  • decrease of the threshold
  • increase of the liability
  • increase of the excitability
  • increase of the threshold
  • increased release of neurotransmitters

Question 7

Question
The properties of local response:
Answer
  • 'all-or-none’ law
  • transmission with energy consumption
  • without energy consumption
  • summation
  • excitability is decreased

Question 8

Question
A “less negative" membrane potential means:
Answer
  • it is “more positive” than the resting potential
  • it is closer to zero mV
  • the resting membrane potential is closer to the sodium equilibrium
  • slight depolarization
  • all of the above

Question 9

Question
The membrane of a typical resting neuron is largely impermeable to
Answer
  • Na+
  • K+
  • Cl-
  • Ca2+
  • none of the above

Question 10

Question
The ion with the lowest intracellular concentration is:
Answer
  • Na+
  • HCO3
  • Ca2+
  • Mg2+
  • K+

Question 11

Question
The most common intracellular cation is:
Answer
  • calcium
  • sodium
  • potassium
  • phosphorus
  • magnesium

Question 12

Question
What is the normal pH value of body fluid?
Answer
  • 7.15-7.25
  • 7.35-7.45
  • 7.55-7.65
  • 7.00-7.35
  • 6.5-7.5

Question 13

Question
Which of the following requires energy?
Answer
  • Diffusion
  • Osmosis
  • Active transport
  • Facilitated diffusion
  • Filtration

Question 14

Question
Which of the following is not found in the cell membrane?
Answer
  • Cholestrol
  • Phospholipids
  • Proteins
  • Galactose
  • Nucleic acids

Question 15

Question
The local response is:
Answer
  • A potential that is generated as a result of the action of a subthreshold stimulus and propagated along the nerve cell membrane
  • A potential that is generated as a result of the action of a superthreshold stimulus and propagated along the nerve cell membrane
  • A potential that is generated as a result of the action of a subthreshold stimulus and could be registered only at the site of irritation
  • A potential that is generated on the postsynaptic membrane as a result of the action of a mediator
  • A potential that is generated as a result of the action of a superthreshold stimulus and could be registered only at the site of irritation

Question 16

Question
The oculocardiac reflex is an example of:
Answer
  • soma-somatic reflex
  • soma-visceral reflex
  • viscera-somatic reflex
  • viscera-visceral reflex
  • integrated conditioned reflex

Question 17

Question
Norepinephrine is a neurotransmitter with the highest affinity to:
Answer
  • α-adrenergic receptors
  • β-adrenergic receptors
  • α- and β-adrenergic receptors
  • N-choline receptors
  • M-choline receptors

Question 18

Question
The parasympathetic post-ganglionic neurons of the ANS secrete
Answer
  • Nor-epinephrine (98%) and epinephrine (2%)
  • Acetylcholine
  • L-DOPA
  • Nor-epinephrine (2%) and epinephrine (98%)
  • Epinephrine (80%) and nor-epinephrine (20%)

Question 19

Question
The critical (firing) level of depolarization is
Answer
  • a level of AP at which depolarization goes into repolarisation
  • a level of AP at which repolarization goes into depolarization
  • a degree of depolarization of the postsynaptic membrane at which further action of the neurotransmitter is abolished
  • a degree of depolarization of the nerve cell membrane at which its sources of energy are completely exhausted
  • a degree of depolarization of the excitable membrane at which its intensity does not depend on irritant action

Question 20

Question
A structure that permits a neuron to pass an electrical or chemical signal to another cell (neural or otherwise) with excitatory or inhibitory effects is called:
Answer
  • synapse
  • juxtaglomerular apparatus
  • intercalated disc
  • Golgi apparatus
  • modulator

Question 21

Question
H1 receptors are situated an the smooth muscle cell membrane of the:
Answer
  • gastrointestinal tract
  • urinary tract
  • bronchi
  • uterus
  • blood vessels

Question 22

Question
The adrenergic effect an the cardiac conduction system and working myocardium is exercised by affecting:
Answer
  • M-choline receptors
  • α1 receptors
  • α2 receptors
  • β1 receptors
  • β2 receptors

Question 23

Question
The parasympathetic spinal centers, regulating the reservoir functions, are situated in the following
Answer
  • C8-Th1
  • Th1-Th8
  • Th10-L2
  • S2-S4
  • L2-L4

Question 24

Question
Facilitated diffusion is a mechanism:
Answer
  • Connected with loss of energy
  • For transporting substances against their concentration gradient
  • Connected with membrane polarity
  • That works with the help of a carrier in the membrane
  • For transporting lipid soluble substances through the membrane

Question 25

Question
A distinguishing feature of the membrane potential at rest is:
Answer
  • high permeability for K+ ions
  • low permeability for Cl- ions
  • low permeability for Na+ and high for K+ ions
  • the small difference between the equilibrium potentials for Na+ and K+ ions
  • low permeability for Na+

Question 26

Question
Acetylcholine is a neurotransmitter which has:
Answer
  • always an excitatory effect on the postsynaptic membrane
  • always an inhibitory effect on the postsynaptic membrane
  • excitatory or inhibitory effect on the postsynaptic membrane depending on the type of receptors
  • excitatory or inhibitory effect depending on the amount released
  • no effect on the postsynaptic membrane

Question 27

Question
The common expression of excitation is:
Answer
  • the action potential
  • muscle cell contraction
  • nerve cell conduction and excitation
  • glandular cell secretion
  • membrane transport

Question 28

Question
Curare is a substance that blocks
Answer
  • M-choline receptors
  • α-adrenergic receptors
  • β-adrenergic receptors
  • N-choline receptors in neuromuscular synapses
  • all types of cholinoreceptors

Question 29

Question
An example of a ligand dependent membrane is
Answer
  • the postsynaptic membrane
  • the axon membrane
  • the nodes of Ranvier
  • the skeletal muscle cell membrane
  • the axon hillock

Question 30

Question
Throughout the relative refractory period:
Answer
  • the excitability becomes equal to zero
  • the excitability is equal to that at rest
  • the excitability is higher than that at rest
  • accommodation occurs
  • the excitability is lower than that at rest

Question 31

Question
Na/K pump is called electrogenic, because:
Answer
  • exports equal amount of Na+ and K+
  • imports equal amount of Na+ and K+
  • exchanges equal amount of Na+ and K+
  • the exchanged amount of Na+, and K+ is not equal
  • none of the above

Question 32

Question
The conditioned reflexes are:
Answer
  • typical of the species
  • inborn
  • permanent
  • formed on the basis of unconditioned reflexes
  • all of the above

Question 33

Question
Which of the statements is not true:
Answer
  • at the chemical synapse transmission of excitation is one way
  • at most of the electrical synapses transmission is two-way
  • the velocity of transmission of excitation is higher at the chemical synapses than at the electrical ones
  • the velocity of transmission of excitation is greater at the electrical synapses than at the chemical ones
  • when there is continuous excitation at a synapse, fatigue occurs

Question 34

Question
Which is the basic inhibitory neurotransmitter in CNS:
Answer
  • Glutamate
  • Substance P
  • Neuropeptide 4
  • GABA
  • Nitric Oxide

Question 35

Question
The basic factor for the ion asymmetry on both sides of the excitable membrane is
Answer
  • Ca++ pump and the low permeability for Na+
  • Na+ pump and the low permeability for Na+
  • Na+/K+ pump and the low permeability for Na+
  • K+ pump and the high permeability for Na+
  • Iodine pump

Question 36

Question
The velocity of AP propagation along the axon membrane depends on:
Answer
  • the strength of irritation
  • the duration of irritation
  • the cross sectional area of the axon
  • the direction of its propagation
  • the threshold

Question 37

Question
The sympathetic postganglionic neurons secrete:
Answer
  • norepinephrine (98%) and epinephrine (2%)
  • acetylcholine
  • L-DOPA
  • norepinephrine (2%) and epinephrine (98%)
  • epinephrine (20%) and norepinephrine (80%)

Question 38

Question
The result of activated α1-adrenergic receptors is:
Answer
  • relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters
  • constriction of the vessels smooth muscle
  • increased heart rate
  • dilation of the vessels smooth muscle and relaxation of the uterus
  • none of the above

Question 39

Question
The result of activated α2-adrenergic receptors is:
Answer
  • relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters
  • constriction of the vessels smooth muscle
  • increased heart rate
  • dilation of the vessels smooth muscle and relaxation of the uterus
  • none of the above

Question 40

Question
Protein synthesis occurs at the
Answer
  • mitochondria
  • lysosomes
  • within the nucleus
  • ribosomes
  • vacuoles

Question 41

Question
During repolarization of the cell membrane:
Answer
  • Na+ move inside of the cell
  • Na+ move outside of the cell
  • K+ move inside of the cell
  • K+ move outside of the cell
  • Cl- move outside of the cell

Question 42

Question
In a cell, movement of molecules from an area of low concentration to an area of high concentration:
Answer
  • uses facilitated diffusion
  • requires cellular energy
  • is passive transport
  • requires both cellular energy and facilitated diffusion
  • uses its concentration gradient to move

Question 43

Question
Movement of solvent and dissolved substances across a cell membrane by hydrostatic pressure is:
Answer
  • filtration
  • facilitated diffusion
  • osmosis
  • simple diffusion
  • active transport

Question 44

Question
The substance acetylcholine (ACh) is released from synaptic vesicles by the process of:
Answer
  • phagocytosis
  • simple diffusion
  • passive transport
  • exocytosis
  • endocytosis

Question 45

Question
Cell membranes
Answer
  • are formed entirely by protein molecules
  • are impermeable to fat soluble substances
  • in some tissues permit transport of glucose at a greater rate in the presence of insulin
  • are not changed throughout life
  • are permeable to water soluble substances

Question 46

Question
Proteins that are secreted by cells are generally:
Answer
  • not synthesized on ribosomes that are bound to endoplasmic reticulum
  • synthesized in the mitochondria
  • packed in the Golgi apparatus
  • across the cell membrane by endocytosis
  • synthesized in the lysosomes

Question 47

Question
The unique feature in mitochondria is:
Answer
  • myosin
  • actin
  • DNA
  • prothrombin
  • haemoglobin

Question 48

Question
The resting membrane potential of a cell:
Answer
  • is dependent on the permeability of the cell membrane to K+ being greater to Na+
  • falls to zero if Na+/K+ ATPase in the membrane is inhibited
  • is equal to the equilibrium potential for K+
  • is equal to the equilibrium potential of Na+
  • is equal to the equilibrium potential of Cl-

Question 49

Question
Many substances are removed from the cell to the outside by:
Answer
  • pinocytosis
  • chemotaxis
  • phagocytosis
  • exocytosis
  • endocytosis

Question 50

Question
An example of co-transport is:
Answer
  • Na+-K+ pump
  • Ca++ pump
  • Na+-H+ pump
  • Na+ glucose transport
  • Na/Ca pump

Question 51

Question
Mitochondria:
Answer
  • are the Chief site for lipid synthesis
  • are the chief site for protein synthesis
  • are the chief sites for generation of ATP
  • are more numerous in white than in brown fat cells
  • are absent near the membranes of actively secreting cells

Question 52

Question
The endoplasmic reticulum:
Answer
  • is a complex system of intracellular tubules
  • has a membrane structure similar to the cell membrane
  • is associated with ribonucleoprotein
  • is well developed in secretory cells
  • all of the above

Question 53

Question
The mammalian cell membrane:
Answer
  • is seen as an optically dense line using light microscopy
  • consists mainly of protein
  • is more permeable to fat- than to water-soluble particles
  • contains enzymes DNA
  • contains the receptors for steroid hormones

Question 54

Question
Membrane ion channels:
Answer
  • consist mainly of carbohydrates and lipids
  • have a specific structure for each ion species
  • for sodium may be blocked by tetrodotoxin
  • consist mainly of lipids
  • remain open as long as the activating signal is present

Question 55

Question
The speed of conduction of a nerve impulse can be determined by which of the following factors? 1. temperature 2. diameter of axon 3. stimulus frequency 4. myelin sheath; 5. stimulus strength
Answer
  • 1,3, 5 and 4
  • 1, 2 and 3
  • 3 and 1
  • 3 and 2
  • 4, 2 and 1

Question 56

Question
The junction between one neuron and the next, or between a neuron and an effector is called:
Answer
  • a synapse
  • a dendrite
  • a neurotransmitter
  • a ventricle
  • none of the above

Question 57

Question
Which of the following blocks acetylcholine receptor sites causing muscle relaxation?
Answer
  • novocain
  • curare
  • nicotine
  • nerve gases
  • carbon monoxide

Question 58

Question
Transmission across a synapse is dependent on the release of?
Answer
  • neurotransmitters
  • synaptic vesicle
  • neurons
  • receptor proteins
  • hormones

Question 59

Question
Saltatory conduction:
Answer
  • occurs only in myelinated fibres
  • has a slower velocity in cold than in warm conditions
  • is faster than non-saltatory conduction in nerve fibres with diameters around 10 μm
  • transmits impulses with a velocity proportional to fibre diameter
  • all of them

Question 60

Question
An action potential in a nerve fibre:
Answer
  • occurs when its membrane potential is hyperpolarized to a critical level
  • is associated with a transient increase in membrane permeability to sodium
  • is associated with a transient decrease in membrane permeability to potassium
  • induces local response
  • has an amplitude which varies directly with the strength of stimulus