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

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