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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

Question 1 of 60

1

Hormones:

Select one of the following:

  • 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

Explanation

Question 2 of 60

1

For an action potential to occur

Select one of the following:

  • 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

Explanation

Question 3 of 60

1

During the rising phase of the action potential

Select one of the following:

  • 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

Explanation

Question 4 of 60

1

The concept of homeostasis

Select one of the following:

  • 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

Explanation

Question 5 of 60

1

The plasma membrane

Select one of the following:

  • 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

Explanation

Question 6 of 60

1

Overcooling the nerve will cause

Select one of the following:

  • decrease of the threshold

  • increase of the liability

  • increase of the excitability

  • increase of the threshold

  • increased release of neurotransmitters

Explanation

Question 7 of 60

1

The properties of local response:

Select one of the following:

  • 'all-or-none’ law

  • transmission with energy consumption

  • without energy consumption

  • summation

  • excitability is decreased

Explanation

Question 8 of 60

1

A “less negative" membrane potential means:

Select one of the following:

  • 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

Explanation

Question 9 of 60

1

The membrane of a typical resting neuron is largely impermeable to

Select one of the following:

  • Na+

  • K+

  • Cl-

  • Ca2+

  • none of the above

Explanation

Question 10 of 60

1

The ion with the lowest intracellular concentration is:

Select one of the following:

  • Na+

  • HCO3

  • Ca2+

  • Mg2+

  • K+

Explanation

Question 11 of 60

1

The most common intracellular cation is:

Select one of the following:

  • calcium

  • sodium

  • potassium

  • phosphorus

  • magnesium

Explanation

Question 12 of 60

1

What is the normal pH value of body fluid?

Select one of the following:

  • 7.15-7.25

  • 7.35-7.45

  • 7.55-7.65

  • 7.00-7.35

  • 6.5-7.5

Explanation

Question 13 of 60

1

Which of the following requires energy?

Select one of the following:

  • Diffusion

  • Osmosis

  • Active transport

  • Facilitated diffusion

  • Filtration

Explanation

Question 14 of 60

1

Which of the following is not found in the cell membrane?

Select one of the following:

  • Cholestrol

  • Phospholipids

  • Proteins

  • Galactose

  • Nucleic acids

Explanation

Question 15 of 60

1

The local response is:

Select one of the following:

  • 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

Explanation

Question 16 of 60

1

The oculocardiac reflex is an example of:

Select one of the following:

  • soma-somatic reflex

  • soma-visceral reflex

  • viscera-somatic reflex

  • viscera-visceral reflex

  • integrated conditioned reflex

Explanation

Question 17 of 60

1

Norepinephrine is a neurotransmitter with the highest affinity to:

Select one of the following:

  • α-adrenergic receptors

  • β-adrenergic receptors

  • α- and β-adrenergic receptors

  • N-choline receptors

  • M-choline receptors

Explanation

Question 18 of 60

1

The parasympathetic post-ganglionic neurons of the ANS secrete

Select one of the following:

  • Nor-epinephrine (98%) and epinephrine (2%)

  • Acetylcholine

  • L-DOPA

  • Nor-epinephrine (2%) and epinephrine (98%)

  • Epinephrine (80%) and nor-epinephrine (20%)

Explanation

Question 19 of 60

1

The critical (firing) level of depolarization is

Select one of the following:

  • 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

Explanation

Question 20 of 60

1

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:

Select one of the following:

  • synapse

  • juxtaglomerular apparatus

  • intercalated disc

  • Golgi apparatus

  • modulator

Explanation

Question 21 of 60

1

H1 receptors are situated an the smooth muscle cell membrane of the:

Select one of the following:

  • gastrointestinal tract

  • urinary tract

  • bronchi

  • uterus

  • blood vessels

Explanation

Question 22 of 60

1

The adrenergic effect an the cardiac conduction system and working myocardium is exercised by affecting:

Select one of the following:

  • M-choline receptors

  • α1 receptors

  • α2 receptors

  • β1 receptors

  • β2 receptors

Explanation

Question 23 of 60

1

The parasympathetic spinal centers, regulating the reservoir functions, are situated in the following

Select one of the following:

  • C8-Th1

  • Th1-Th8

  • Th10-L2

  • S2-S4

  • L2-L4

Explanation

Question 24 of 60

1

Facilitated diffusion is a mechanism:

Select one of the following:

  • 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

Explanation

Question 25 of 60

1

A distinguishing feature of the membrane potential at rest is:

Select one of the following:

  • 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+

Explanation

Question 26 of 60

1

Acetylcholine is a neurotransmitter which has:

Select one of the following:

  • 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

Explanation

Question 27 of 60

1

The common expression of excitation is:

Select one of the following:

  • the action potential

  • muscle cell contraction

  • nerve cell conduction and excitation

  • glandular cell secretion

  • membrane transport

Explanation

Question 28 of 60

1

Curare is a substance that blocks

Select one of the following:

  • M-choline receptors

  • α-adrenergic receptors

  • β-adrenergic receptors

  • N-choline receptors in neuromuscular synapses

  • all types of cholinoreceptors

Explanation

Question 29 of 60

1

An example of a ligand dependent membrane is

Select one of the following:

  • the postsynaptic membrane

  • the axon membrane

  • the nodes of Ranvier

  • the skeletal muscle cell membrane

  • the axon hillock

Explanation

Question 30 of 60

1

Throughout the relative refractory period:

Select one of the following:

  • 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

Explanation

Question 31 of 60

1

Na/K pump is called electrogenic, because:

Select one of the following:

  • 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

Explanation

Question 32 of 60

1

The conditioned reflexes are:

Select one of the following:

  • typical of the species

  • inborn

  • permanent

  • formed on the basis of unconditioned reflexes

  • all of the above

Explanation

Question 33 of 60

1

Which of the statements is not true:

Select one of the following:

  • 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

Explanation

Question 34 of 60

1

Which is the basic inhibitory neurotransmitter in CNS:

Select one of the following:

  • Glutamate

  • Substance P

  • Neuropeptide 4

  • GABA

  • Nitric Oxide

Explanation

Question 35 of 60

1

The basic factor for the ion asymmetry on both sides of the excitable membrane is

Select one of the following:

  • 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

Explanation

Question 36 of 60

1

The velocity of AP propagation along the axon membrane depends on:

Select one of the following:

  • the strength of irritation

  • the duration of irritation

  • the cross sectional area of the axon

  • the direction of its propagation

  • the threshold

Explanation

Question 37 of 60

1

The sympathetic postganglionic neurons secrete:

Select one of the following:

  • norepinephrine (98%) and epinephrine (2%)

  • acetylcholine

  • L-DOPA

  • norepinephrine (2%) and epinephrine (98%)

  • epinephrine (20%) and norepinephrine (80%)

Explanation

Question 38 of 60

1

The result of activated α1-adrenergic receptors is:

Select one of the following:

  • 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

Explanation

Question 39 of 60

1

The result of activated α2-adrenergic receptors is:

Select one of the following:

  • 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

Explanation

Question 40 of 60

1

Protein synthesis occurs at the

Select one of the following:

  • mitochondria

  • lysosomes

  • within the nucleus

  • ribosomes

  • vacuoles

Explanation

Question 41 of 60

1

During repolarization of the cell membrane:

Select one of the following:

  • 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

Explanation

Question 42 of 60

1

In a cell, movement of molecules from an area of low concentration to an area of high concentration:

Select one of the following:

  • uses facilitated diffusion

  • requires cellular energy

  • is passive transport

  • requires both cellular energy and facilitated diffusion

  • uses its concentration gradient to move

Explanation

Question 43 of 60

1

Movement of solvent and dissolved substances across a cell membrane by hydrostatic pressure is:

Select one of the following:

  • filtration

  • facilitated diffusion

  • osmosis

  • simple diffusion

  • active transport

Explanation

Question 44 of 60

1

The substance acetylcholine (ACh) is released from synaptic vesicles by the process of:

Select one of the following:

  • phagocytosis

  • simple diffusion

  • passive transport

  • exocytosis

  • endocytosis

Explanation

Question 45 of 60

1

Cell membranes

Select one of the following:

  • 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

Explanation

Question 46 of 60

1

Proteins that are secreted by cells are generally:

Select one of the following:

  • 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

Explanation

Question 47 of 60

1

The unique feature in mitochondria is:

Select one of the following:

  • myosin

  • actin

  • DNA

  • prothrombin

  • haemoglobin

Explanation

Question 48 of 60

1

The resting membrane potential of a cell:

Select one of the following:

  • 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-

Explanation

Question 49 of 60

1

Many substances are removed from the cell to the outside by:

Select one of the following:

  • pinocytosis

  • chemotaxis

  • phagocytosis

  • exocytosis

  • endocytosis

Explanation

Question 50 of 60

1

An example of co-transport is:

Select one of the following:

  • Na+-K+ pump

  • Ca++ pump

  • Na+-H+ pump

  • Na+ glucose transport

  • Na/Ca pump

Explanation

Question 51 of 60

1

Mitochondria:

Select one of the following:

  • 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

Explanation

Question 52 of 60

1

The endoplasmic reticulum:

Select one of the following:

  • 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

Explanation

Question 53 of 60

1

The mammalian cell membrane:

Select one of the following:

  • 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

Explanation

Question 54 of 60

1

Membrane ion channels:

Select one of the following:

  • 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

Explanation

Question 55 of 60

1

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

Select one of the following:

  • 1,3, 5 and 4

  • 1, 2 and 3

  • 3 and 1

  • 3 and 2

  • 4, 2 and 1

Explanation

Question 56 of 60

1

The junction between one neuron and the next, or between a neuron and an effector is called:

Select one of the following:

  • a synapse

  • a dendrite

  • a neurotransmitter

  • a ventricle

  • none of the above

Explanation

Question 57 of 60

1

Which of the following blocks acetylcholine receptor sites causing muscle relaxation?

Select one of the following:

  • novocain

  • curare

  • nicotine

  • nerve gases

  • carbon monoxide

Explanation

Question 58 of 60

1

Transmission across a synapse is dependent on the release of?

Select one of the following:

  • neurotransmitters

  • synaptic vesicle

  • neurons

  • receptor proteins

  • hormones

Explanation

Question 59 of 60

1

Saltatory conduction:

Select one of the following:

  • 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

Explanation

Question 60 of 60

1

An action potential in a nerve fibre:

Select one of the following:

  • 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

Explanation

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