Hormones:
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
For an action potential to occur
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
During the rising phase of the action potential
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
The concept of homeostasis
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
The plasma membrane
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
Overcooling the nerve will cause
decrease of the threshold
increase of the liability
increase of the excitability
increase of the threshold
increased release of neurotransmitters
The properties of local response:
'all-or-none’ law
transmission with energy consumption
without energy consumption
summation
excitability is decreased
A “less negative" membrane potential means:
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
The membrane of a typical resting neuron is largely impermeable to
Na+
K+
Cl-
Ca2+
none of the above
The ion with the lowest intracellular concentration is:
HCO3
Mg2+
The most common intracellular cation is:
calcium
sodium
potassium
phosphorus
magnesium
What is the normal pH value of body fluid?
7.15-7.25
7.35-7.45
7.55-7.65
7.00-7.35
6.5-7.5
Which of the following requires energy?
Diffusion
Osmosis
Active transport
Facilitated diffusion
Filtration
Which of the following is not found in the cell membrane?
Cholestrol
Phospholipids
Proteins
Galactose
Nucleic acids
The local response is:
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
The oculocardiac reflex is an example of:
soma-somatic reflex
soma-visceral reflex
viscera-somatic reflex
viscera-visceral reflex
integrated conditioned reflex
Norepinephrine is a neurotransmitter with the highest affinity to:
α-adrenergic receptors
β-adrenergic receptors
α- and β-adrenergic receptors
N-choline receptors
M-choline receptors
The parasympathetic post-ganglionic neurons of the ANS secrete
Nor-epinephrine (98%) and epinephrine (2%)
Acetylcholine
L-DOPA
Nor-epinephrine (2%) and epinephrine (98%)
Epinephrine (80%) and nor-epinephrine (20%)
The critical (firing) level of depolarization is
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
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:
synapse
juxtaglomerular apparatus
intercalated disc
Golgi apparatus
modulator
H1 receptors are situated an the smooth muscle cell membrane of the:
gastrointestinal tract
urinary tract
bronchi
uterus
blood vessels
The adrenergic effect an the cardiac conduction system and working myocardium is exercised by affecting:
α1 receptors
α2 receptors
β1 receptors
β2 receptors
The parasympathetic spinal centers, regulating the reservoir functions, are situated in the following
C8-Th1
Th1-Th8
Th10-L2
S2-S4
L2-L4
Facilitated diffusion is a mechanism:
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
A distinguishing feature of the membrane potential at rest is:
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+
Acetylcholine is a neurotransmitter which has:
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
The common expression of excitation is:
the action potential
muscle cell contraction
nerve cell conduction and excitation
glandular cell secretion
membrane transport
Curare is a substance that blocks
N-choline receptors in neuromuscular synapses
all types of cholinoreceptors
An example of a ligand dependent membrane is
the postsynaptic membrane
the axon membrane
the nodes of Ranvier
the skeletal muscle cell membrane
the axon hillock
Throughout the relative refractory period:
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
Na/K pump is called electrogenic, because:
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
The conditioned reflexes are:
typical of the species
inborn
permanent
formed on the basis of unconditioned reflexes
Which of the statements is not true:
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
Which is the basic inhibitory neurotransmitter in CNS:
Glutamate
Substance P
Neuropeptide 4
GABA
Nitric Oxide
The basic factor for the ion asymmetry on both sides of the excitable membrane is
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
The velocity of AP propagation along the axon membrane depends on:
the strength of irritation
the duration of irritation
the cross sectional area of the axon
the direction of its propagation
the threshold
The sympathetic postganglionic neurons secrete:
norepinephrine (98%) and epinephrine (2%)
acetylcholine
norepinephrine (2%) and epinephrine (98%)
epinephrine (20%) and norepinephrine (80%)
The result of activated α1-adrenergic receptors is:
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
The result of activated α2-adrenergic receptors is:
Protein synthesis occurs at the
mitochondria
lysosomes
within the nucleus
ribosomes
vacuoles
During repolarization of the cell membrane:
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
In a cell, movement of molecules from an area of low concentration to an area of high concentration:
uses facilitated diffusion
requires cellular energy
is passive transport
requires both cellular energy and facilitated diffusion
uses its concentration gradient to move
Movement of solvent and dissolved substances across a cell membrane by hydrostatic pressure is:
filtration
facilitated diffusion
osmosis
simple diffusion
active transport
The substance acetylcholine (ACh) is released from synaptic vesicles by the process of:
phagocytosis
passive transport
exocytosis
endocytosis
Cell membranes
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
Proteins that are secreted by cells are generally:
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
The unique feature in mitochondria is:
myosin
actin
DNA
prothrombin
haemoglobin
The resting membrane potential of a cell:
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-
Many substances are removed from the cell to the outside by:
pinocytosis
chemotaxis
An example of co-transport is:
Na+-K+ pump
Ca++ pump
Na+-H+ pump
Na+ glucose transport
Na/Ca pump
Mitochondria:
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
The endoplasmic reticulum:
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
The mammalian cell membrane:
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
Membrane ion channels:
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
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
1,3, 5 and 4
1, 2 and 3
3 and 1
3 and 2
4, 2 and 1
The junction between one neuron and the next, or between a neuron and an effector is called:
a synapse
a dendrite
a neurotransmitter
a ventricle
Which of the following blocks acetylcholine receptor sites causing muscle relaxation?
novocain
curare
nicotine
nerve gases
carbon monoxide
Transmission across a synapse is dependent on the release of?
neurotransmitters
synaptic vesicle
neurons
receptor proteins
hormones
Saltatory conduction:
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
An action potential in a nerve fibre:
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
