Cell Physiology and General Physiology of Excitable Tissues

The concept of homeostasis refers to

a) unwavering control of a physiological set point
b) the "all or none" law
c) the regulation of body temperature
d) maintaining a stable external environment
e) maintaining physiological functions in a stable state

e) maintaining physiological functions in a stable state

Utilisation time is:

a) the maximal time period for which a threshold stimulus should act, in order for an AP to occur
b) the duration of the depolarisation phase of the AP
c) the duration of the AP
d) the duration of the absolute refractory period
e) the minimal period of time for which a threshold stimulus should act, in order for an AP to occur

e) the minimal period of time for which a threshold stimulus should act, in order for an AP to occur

The highest lability has

a) muscle cells
b) nerve cells
c) epithelial cells
d) glial cells
e) glandular cells

b) nerve cells

Hormones:

a) are only with lipid structure
b) may be secreted by exocrine glands
c) may be secreted by nerve cells
d) are only used in synapses
e) are only with peptide structure

c) may be secreted by nerve cells

For an action potential to occur

a) the cell membrane must be in the absolutely refractory period
b) K+ influx must exceed Na+ efflux
c) the cell membrane must be out of the relative refractory period
d) the stimulus must reach or exceed threshold
e) Cl- influx must exceed K+ efflux

d) the stimulus must reach or exceed threshold

During the rising phase of the action potential

a) voltage gated K+ channels close
b) voltage gated K+ channels open
c) voltage gated Na+ channels close
d) voltage gated Na+ channels open
e) voltage gated Cl- channels open

d) voltage gated Na+ channels open

The plasma membrane:

a) is permeable to lipophilic molecules
b) is permeable to hydrophilic molecules
c) may burst in hypertonic extracellular solutions
d) cannot generate action potentials in excitable cells
e) can generate action potentials in non-excitable cells

a) is permeable to lipophilic molecules

Overcooling the nerve will cause:

a) increase of the threshold;
b) increase of the liability;
c) increase of the excitability;
d) decrease of the threshold;
e) increased release of neurotransmitters.

a) increase of the threshold;

The properties of local response:

a) "all or none" law
b) transmission with energy consumption
c) summation
d) transmission without energy consumption
e) excitability is decreased

c) summation

the property of the living systems to react to changes of the external or internal environment is called:

a) excitation
b) excitability
c) irritability
d) action potential
e) resting potential

c) irritability

A less negative membrane potential means:

a) it is "less positive" than the resting potential
b) it is closer to +20 mV
c) the resting membrane potential is closer to the sodium equilibrium
d) slight repolarisation
e) the cell cannot generate an action potential

c) the resting membrane potential is closer to the sodium equilibrium

The membrane of a typical resting neuron is largely impermeable to:

a) Cl-
b) K+
c) Na+
d) Ca2+
e) Fe2+

c) Na+

The ion with the lowest intracellular concentration is:

a) Ca2+
b) HCO3-
c) Na+
d) Mg2+
e) K+

a) Ca2+

The blockers of the calcium ion channels are called:

a) calcium agonists
b) calcium binding proteins
c) calcium receptors
d) calcium antagonists
e) calcium binding lipids

d) calcium antagonists

Which of the following requires energy:

a) diffusion
b) osmosis
c) facilitated diffusion
d) active transport
e) filtration

d) active transport

The most common intracellular cation is:

a) calcium
b) sodium
c) magnesium
d) phosphorus
e) potassium

e) potassium

Most appropriate solution for intravenous infusion is:

a) hypertonic NaCl soln
b) hypotonic NaCl soln
c) isotonic NaCl soln
d) distilled water
e) ionised water

c) isotonic NaCl soln

What is the normal pH value of the body fluids:

a) 7.35 - 7.45
b) 7.15 - 7.25
c) 7.55 - 7.65
d) 7.00 - 7.35
e) 6.5 - 7.5

a) 7.35 - 7.45

which of the following is not found in the cell membrane:

a) galactose
b) phospholipids
c) proteins
d) cholesterol
e) nucleic acids

e) nucleic acids

the main structural elements in the cell membrane are:

a) proteins
b) phospholipids, cholesterol and proteins
c) carbohydrates
d) cholesterol
e) nucleic acids

b) phospholipids, cholesterol and proteins

the local response is a potential that is generation as a result of the action of a:

a) subthreshold stimulus and propagated along the nerve cell membrane
b) subthreshold stimulus and could be registered only at irritation site
c) super-threshold stimulus and propagated along nerve cell membrane
d) postsynaptic membrane as a result of neurotransmitter actions
e) super-threshold stimulus and could be registered only at irritation site

b) subthreshold stimulus and could be registered only at irritation site

Norepinephrine is a neurotransmitter with the highest affinity to:

a) N-cholinergic receptors
b) beta adrenergic receptors
c) alpha and beta adrenergic receptors
d) alpha adrenergic receptors
e) M-cholinergic receptors

d) alpha adrenergic receptors

the oculocardiac reflex is an example of

a) somato-somatic reflex
b) viscero-somtic reflex
c) somato-visceral reflex
d) visero-visceral reflex
e) integrated conditioned reflex

c) somato-visceral reflex

the parasympathetic postganglionic neurons of the ANS secrete:

a) norepinephrine (98%) and epinephrine (2%)
b)epinephrine (80%) and norepinephrine (20%)
c) L-DOPA
d) norepinephrine (2%) and epinephrine (98%)
e) acetylcholine

e) acetylcholine

A structure that permits an excitable cell to pass an electrical or chemical signal to another cell with excitatory or inhibitory effects is called:

a) juxtaglomerular apparatus
b) synapse
c) intercalated disc
d) Golgi apparatus
e) modulator

b) synapse

The critical level of depolarisation is:

a) level of AP at which depolarisation goes into repolarisation
b) level of AP at which repolarisation goes into depolarisation
c) a degree of depolarisation of the post synaptic membrane, at which further action of the neurotransmitter is abolished
d) a degree of depolarisation of the excitable membrane at which its intensity does not depend on irritant action
e) a degree of depolarisation of the nerve cell membrane at which its source of energy are completely exhausted

d) a degree of depolarisation of the excitable membrane at which its intensity does not depend on irritant action

H1- receptors are situated on the smooth muscle cell membrane of the:

a) gastrointestinal tract
b) bronchi
c) urinary tract
d) uterus
e) blood vessels

b) bronchi

The Horveg-Weiss curve represents:

a) the intenstiy/duration relationship of the threshold stimulus
b) the phases of the AP
c) the conduction of the excitation through myelinated nerve fibers
d) the intensity/duration relationship of the subthreshold stimulus
e) the conduction of the excitation through unmyelinated nerve fibers

a) the intenstiy/duration relationship of the threshold stimulus

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

a) M-choline receptors
b) alpha 1 receptors
c) beta 1 receptors
d) alpha 2 receptors
e) beta 2 receptors

c) beta 1 receptors

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

a) Cs-Th1
b) S2-S4
c) Th10 - Th8
d) L2-L4

b) S2-S4

Facilitated diffusion is a mechanism:

a) that works with the help of a carrier in the membrane
b) for transporting substances against their concentration gradient
c) connected with membrane polarity
d) associated with loss of energy
e) for transporting lipid soluble substances through the membrane

a) that works with the help of a carrier in the membrane

The diffusion through the phospholipid layer of the cellular membrane is possible for:

a) lipophilic substances
b) only for oxygen and carbon dioxide
c) hydrophilic substances
d) lipophobic substances
e) only for water

a) lipophilic substances

A distinguishing feature of the membrane potential at rest is:

a) high permeability for K+ ions
b) low permeability for Na+ ions and high for K+ ions
c) low permeability for Cl- ions
d) the small difference between the equilibrium potentials for Na+ and K+ ions
e) low permeability for Na+

b) low permeability for Na+ ions and high for K+ ions

The common expression of excitation is:

a) membrane transport
b) muscle cell contraction
c) nerve cell conduction and excitation
d) glandular secretion
e) the action potential

e) the action potential

Acetylcholine is a neurotransmitter which has:

a) always an excitatory effect on the postsynaptic membrane
b) always an inhibitory effect on the postsynaptic membrane
c) excitatory or inhibitory effect depending on the amount released
d) excitatory or inhibitory effect on the postsynaptic membrane depending on the type of receptors
e) no effect on the post synaptic membrane

d) excitatory or inhibitory effect on the postsynaptic membrane depending on the type of receptors

An example of a ligand dependent membrane is:

a) the axon membrane
b) the postsynaptic membrane
c) the nodes of Ranvier
d) the skeletal muscle T-tubule membrane
e) the axon hillock

b) the postsynaptic membrane

Crurare is a substance that blocks:

a) M-cholinergic receptors
b) alpha adrenergic receptors
c) N-cholinergic receptors in neuromuscular synapses
d) beta adrenergic receptors
e) all types of cholinergic receptors

c) N-cholinergic receptors in neuromuscular synapses

Which statements for the electrical synapses is true:

a) they are unidirectional
b) the information is transmitted bidirectionally
c) the synaptic cleft is bigger than in chemical synapses
d) the transmission of the information is slower
e) they can be controlled

b) the information is transmitted bidirectionally

Throughout the relative refractory period:

a) the excitability becomes equal to zero;
b) the excitability is equal to that at rest;
c) the excitability is higher than that at rest;
d) accommodation occurs;
e) the excitability is lower than that at rest.

d) accommodation occurs;

Na/K pump is called electrogenic because:

a) exports equal amount of Na+ and K+
b) imports equal amount of Na- and K+
c) exchanges equal amount of Na+ and K+
d) imports Na+ and exports K+
e) the exchanged amount of Na+ and K+ is not equal

e) the exchanged amount of Na+ and K+ is not equal

The conditioned reflexes are:

a) formed on the basis of unconditioned reflexes
b) inborn
c) permanent
d) typical of the species
e) not individual

a) formed on the basis of unconditioned reflexes

Excitability is a property of:

a) nerve, muscle and some endocrine cells
b) all cells in the body
c) only nerve cells
d) only muscle cells
e) only endocrine cells

a) nerve, muscle and some endocrine cells

Which of the statements is not true:

a) at the chemical synapse, transmission of excitation is one way
b) the velocity of transmission of excitation is higher at the chemical synapses that at the electrical ones
c) at most of the electrical synapses transmission is two way
d) the velocity of transmission of excitation is greater at the electrical synapses that at the chemical ones
e) when there is continuous excitation at a synapse, fatigue occurs

b) the velocity of transmission of excitation is higher at the chemical synapses that at the electrical ones

Which is the basic inhibitory neurotransmitter in the CNS:

a) glutamate
b) GABA
c) neuropeptide Y
d) substance P
e) nitric oxide

b) GABA

Which of the following transmitters does not bind with a membrane receptor to fulfil its effect:

a) glutamate
b) serotonin
c) dopamine
d) histamine
e) nitric oxide

e) nitric oxide

the basic factor for the ion symmetry on both sides of the excitable membrane is:

a) Ca2+ pump and the low permeability for Na+
b) Na+ pump and the low permeability for Na+
c) iodine pump
d) K+ pump and the high permeability for Na+
e) Na+/K+ pump and the low permeability for Na+

e) Na+/K+ pump and the low permeability for Na+

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

a) the strength of irritation
b) the cross sectional area of the axon
c) the duration of irritation
d) the direction of propagation
e) the threshold

b) the cross sectional area of the axon

saltatory conduction:

a) occurs only in myelinated fibers
b) has faster velocity in cold than in warm conditions
c) is slower than non-saltatory conduction in nerve fibers with diameters around 10 micrometers
d) transmits impulses with a velocity proportional to fibers length
e) occurs only in non-myelinated fibers

a) occurs only in myelinated fibers

The result of activated α1 - adrenergic receptors is:

a) relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters
b) increased heart rate
c) constriction of the vessels smooth muscle
d) dilation of the vessels smooth muscle and relaxation of the uterus
e) constriction of the bronchi smooth muscles

c) constriction of the vessels smooth muscle

Intracellular depot for Ca2+ ions is:

a) mitochondria
b) endoplasmic reticulum
c) microtubules
d) Golgi apparatus
e) nucleus

b) endoplasmic reticulum

The result of activated α2 - adrenergic receptors is:

a) increased heart rate
b) constriction of the vessels smooth muscle
c) relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters
d) dilation of the vessels smooth muscle and relaxation of the uterus
e) constriction of the bronchi smooth muscles

c) relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters

secretion of more than one transmitter by a neuron is called:

a) habituation
b) cotransmisson
c) sensitisation
d) perception
e) inhibition

b) cotransmisson

protein synthesis occurs at the:

a) ribosomes
b) lysosomes
c) within the nucleus
d) mitochondria
e) vacuoles

a) ribosomes

during repolarisation of the cell membrane:

a) Na+ move inside the cell
b) Na+ move outside of the cell
c) K+ move outside of the cell
d) K+ move inside of the cell
e) Cl- move outside of the cell

c) K+ move outside of the cell

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

a) osmosis
b) facilitated diffusion
c) filtration
d) simple diffusion
e) active transport

c) filtration

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

a) uses facilitated diffusion
b) requires cellular energy
c) is passive transport
d) requires both cellular energy and facilitated diffusion
e) uses its conc gradient to move

b) requires cellular energy

cell membranes:

a) are formed entirely by protein molecules
b) are impermeable to fat soluble substances
c) are not changed throughout life
d) in some tissues permit transport of glucose at a greater rate in the presence of insulin
e) are permeable to water soluble substances

d) in some tissues permit transport of glucose at a greater rate in the presence of insulin

the substance acetylcholine is released from synaptic vesicles by the process of:

a) phagocytosis
b) simple diffusion
c) passive transport
d) endocytosis
e) exocytosis

e) exocytosis

inhibitory postsynaptic potential (IPSP) can be generated by:

a) opening of calcium channels
b) closing of potassium channels
c) opening of sodium channels
d) opening of chlorine channels
e) closing of chlorine channels

d) opening of chlorine channels

proteins that are secreted by cells are generally:

a) not synthesised on ribosomes that are bound to endoplasmic reticulum
b) packed in the golgi apparatus
c) synthesised in the mitochondria
d) across the cell membrane by endocytosis
e) synthesised in the lysosomes

b) packed in the golgi apparatus

transmission across a synapse is dependant on the release of:

a) hormones
b) synaptic vesicle
c) neurons
d) receptor proteins
e) neurotransmitters

e) neurotransmitters

the unique feature in mitochondria is:

a) myosin
b) DNA
c) actin
d) prothrombin
e) haemoglobin

b) DNA

An example of co-transport is:

a) Na+ glucose transport
b) Ca++ pump;
c) Na+- H+ pump;
d) Na+-K+ pump;
e) Na/Ca pump.

a) Na+ glucose transport

the resting membrane potential of a cell

a) is equal to the equilibrium potential of Na+
b) falls to zero if Na+/K+ ATP-ase in the membrane is inhibited
c) is equal to the equilibrium potential for K+
d) is dependant on the permeability of the cell membrane to K+ being greater to Na+
e) is equal to the equilibrium potential of Cl-

d) is dependant on the permeability of the cell membrane to K+ being greater to Na+

Mitochondria:

a) are the chief site of lipid synthesis
b) are the chief site of protein synthesis
c) are more numerous in white than in brown fat cells
d) are the chief sites for ATP generation
e) are absent near the membranes of actively secreting cells

d) are the chief sites for ATP generation

For the endoplasmic reticulum it is not true that:

a) it is a complex system of intracellular tubules
b) it has a membrane structure similar to the cell membrane
c) it is associated with ribonucleoprotein
d) it is well developed in secretory cells
e) it stores sodium ions

e) it stores sodium ions

the mammalian cell membrane:

a) is seen as an optically dense line using light microscopy
b) consists mainly of proteins
c) contains enzymes DNA
d) is more permeable to fat than to water soluble particles
e) contains the receptors for steroid hormones

d) is more permeable to fat than to water soluble particles

Which of the following is an example for active transport

a) filtration
b) osmosis
c) simple diffusion
d) ATP binding cassette
e) facilitated diffusion

d) ATP binding cassette

an action potential is a nerve fiber:

a) occurs when its membrane potential is hyperpolarised to a critical level
b) is associated with a transient decrease in membrane permeability to postassium
c) is associated with a transient increase in membrane permeability to sodium
d)induces local response
e) has an amplitude which varies directly with strength of stimulus

c) is associated with a transient increase in membrane permeability to sodium

which of the following receptors controls the ion permeability of the postsynaptic membrane by a direct pathway:

a) beta-adrenergic receptors
b) N-cholinergic receptors
c) receptors for serotonin
d) alpha-adrenergic receptors
e) M-cholinergic receptors

b) N-cholinergic receptors

EPSP can be generated by:

a) closing of sodium-potassium channels
b) closing of sodium channels
c) opening of chlorine channels
d) closing of potassium channels
e) closing of sodium-potassium-calcium channels

d) closing of potassium channels

the conduction velocity of a nerve impulse can be determined by which of the following factors:

a) temperature, stimulus frequency, myelin sheath, stimulus strength
b) temperature, diameter of axon, stimulus frequency
c) temperature, stimulus frequency
d) temperature, diameter of axon, myelin sheath
e) diameter of axon, stimulus frequency

d) temperature, diameter of axon, myelin sheath

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

a) dendrite
b) synapse
c) neurotransmitter
d) ventricle
e) none of the above

b) synapse

the vesicular transport from the cell to the extracellular environment id called:

a) endocytosis
b) exocytosis
c) pinocytosis
d) phagocytosis
e) apoptosis

b) exocytosis

which of the following blocks acetylcholine receptor sites causing muscle relaxation:

a) novocaine
b) nicotine
c) curare
d) nerve gases
e) carbon monoxide

c) curare

The nerve center of the pharyngeal reflex, manifested with urge to vomit, is located in:

a) the midbrain
b) the spinal cord
c) the medulla oblongata
d) the limbic system
e) the cerebral cortex

c) the medulla oblongata

the elements of the reflex arc do not include:

a) receptor
b) conducting pathways
c) nerve center
d) effector
e) stimulus

e) stimulus

the most important element of the reflex arc is:

a) receptor
b) conducting pathways
c) nerve center
d) effector
e) all are equally important

e) all are equally important

electroneurography (ENG) is:

a) the method for recording the bioelectrical activity of the brain
b) the method for recording the bioelectrical activity of the peripheral nerve fivers
c) the method for recording the bioelectrical activity of the myocardial cells
d) the method for recording the bioelectrical activity of the glial signals
e) the method for recording the bioelectrical activity of the spinal cord

b) the method for recording the bioelectrical activity of the peripheral nerve fivers

the innervation of the adrenal medulla is carried out by:

a) postganglionic cholinergic fibers
b) preganglionic cholinergic fibers
c) preganglionic adrenergic fibers
d) postganglionic adrenergic fibers
e) preganglionic dopaminergic fibers

b) preganglionic cholinergic fibers

the ability to generate action potential without external irritation is called:

a) automaticity
b) accommodation
c) acclimatisation
d) absolute refractory period
e) ambivalent period

a) automaticity

the minimum time required for a stimulus with the strength of two rheobases to generate an action potential is called:

a) utilisation time
b) rheobase
c) chronaxie
d) threshold of irritation
e) time constant

c) chronaxie

which of the following types of nerve fibers has the slowest conduction velocity:

a) A-alpha
b)A-beta
c) C
d) B
e) A-sigma

c) C

the main mechanism involved in the formation of short term memory is:

a) convergence
b) divergence
c) the formation of reverberating circles in the brain
d) generalisation
e) encephalisation

c) the formation of reverberating circles in the brain

general manifestation of the excitation is:

a) contraction of the muscle cell
b) action potential
c) conduction through nerve cells
d) secretion by glandular cells
e) motion

b) action potential

secondary messengers are:

a) substances that bind to membrane receptors
b) substances that mediate the intracellular response
c) hormones that are formed in the cell in response to its stimulatios
d) substances which are outside the cell and modulate the strength of the cellular response
e) substances which create new cellular functions

b) substances that mediate the intracellular response

the cellular response is not determined by:

a) the type of receptors on the cell membrane
b) the location of the synapse in the body
c) the number of the second messenger molecules
d) the number of the activated intracellular kinases
e) the number of the receptors on the cell membrane

b) the location of the synapse in the body

which is not an element of the chemical synapse:

a) presynaptic membrane
b) connexon
c) postsynaptic membrane
d) synaptic cleft
e) vesicles with neurotransmitters

b) connexon

which statement is not true for electrical synapses:

a) the transmission of the information is faster in comparison with chemical synapses
b) the transmission of the information is facilitated by neurotransmitters
c) the transmission of information is bidirectional
d) the transmission of the information happens through a connexon
e) they are also called gap junctions

b) the transmission of the information is facilitated by neurotransmitters

Which of the following types of nerve fibers has the fastest conduction velocity:

a) A-alpha
b) A-beta
c) C
d) B
e) A-sigma

a) A-alpha