Action potential of neurons is mainly a result of
Na and K
Na and Mg
Ca and K
Strength of ion currents during action potential is related to
Duration of hyperpolarisation action potential phase
Equilibrium potentials of ions
Distance from point of stimulation
During action potential which quantity is altered
Permeability of membrane for diffusion types of ions
Diametric permeability of membrane
None
Membrane potential operated channels are on
active fixed value
permanently active
active in certain range in membrane potential
Mark correct
all the ion channels
all the ion channels let pass
ion flow depends on ion type and membrane potential
Ion channel blockers
Universal
Specific to given channels
Chemical substances attached to the channel during action potential
Ion channels are filled with
water
air
lipid
Action potential is
alteration of electric polarity of the membrane when cell moves
membrane response to over-threshold irritation
nonelectric quantity with chemical nature
At physiological condition cell membrane is
solid structure
gas
liquid-crystal structure
Membrane hyperpolarization leads to
elevation of the membrane potential
decrease of the membranes potential
alteration of membrane charge sign
Membrane depolarization leads to
Elevation of membrane potential
Decrease of membrane potential
Noe
Resting potential of cell membrane is measured in
Megavolts
Volts (v)
Millavolts (mv)
Action potential duration ten times of
seconds
milliseconds
nanoseconds
Which term is not related to action potential
Overshoot
Entropy
Depolarisation
Threshold
During the action potential
cation currents from intercellular to extracellular
cation currents from extracellular to intercellular
none of above
The first law or principle of thermodynamics(TD) is defined for
covered TD system
closed TD system
opened TD system
The ionophores are
ions used in medicine
transport molecules
ions after the ion polarisation
Blocking of Na/K pump working non-electrogenous in stage
make depolarization of cell membrane
make hyperpolarisation of cell membrane
make no alteration of cell membrane
The administration of the blocker tetradotoxin led to alteration of following stage of action potential
repolarisation phase
shape and type of trace potentials
depolarisation phase
Electrochemical potential is measured by
direct method with non polarized electrodes
by the disperse phase velocity in constant electric field
direct method- electrophoresis with constant electric field
In Boltzmann equation
entropy is directly proportional to the temperature
entropy logarithmically depends on the thermodynamic probability
entropy is directly proportional to the thermodynamical probability
The filaments of muscles are based on
actin fibers
troponin globules
myosin fibers
In cell membranes are present
hydrophobic interactions omly
hydrophilic interactions only
both types
The basic condition for arising of membrane potential
difference of ion concentration on the two sides of them
difference of temperature concentration on two sides of the membranes
"one way" permeability of the membrane
The classic electrophoresis is performed by
a constant current
alternated current
magnetic field
Smooth muscles are two types
phasic and tonic
tonic and synergic
phasic and antagonistic
In smooth muscle
Only phosphorylated myosin can bind to actin
Ca2+ calmodulin causes phosphorylation of myosin light chain kinase(MLCK)
Phosphorylated MLCK causes phosphorylation of myosin
A, B and C
None of the above
Each globular head group (often called a crossbridge) of a myosin molecule of skeletal muscle contains:
A binding site for the attachment of troponin
A binding site for the attachment of tropomyosin
An actin binding site and a myosin ATPase site
One site which binds troponin and another which binds tropomyosin
A site which is phosphorylated by protein kinase A(PKA), thereby allowing interaction with actin
In order to make ATP (adenosine triphophate) in muscles, creatine phosphate (CP) transfers ________________ to adenosine diphosphate (ADP)
Oxygen
Phosphate
Adenosine
A sacromere is part of a
Myofibril
Myofilament
Endomysium
Perimysium
Differences between striated (skeletal, cardiac) muscle and unstriated (smooth) muscle include:
only unstriated muscle is innervated by autonomic nervous system
only striated muscle exhibits pacemaker activity
striated muscle can contract in the absence of extracellular Ca2+, but unstriated muscle cannot
only unstratied muscle has gap junctions
none of the above are true
As a skeletal muscle contracts
The A bands become shorter
The I band become shorter
Adjacent Z lines become farther apart
The H zones don't change in size
The M lines become shorter
The period of contraction of a typical ventricular muscle fiber is
about the same as that of a typical slow skeletal muscle fiber
shorter than that of a typical atrial muscle fiber
slightly longer in duration than the action potential in the ventricular fiber
slightly shorter in duration than the action potential in the ventricular fiber
longer in duration than contraction in any smooth muscle cell
The transverse tubular system of skeletal muscle
has a very small lumenal volume and large surface area relative to the cytoplasmic volume and surface area of the fiber
propogates action potentials at about the same speed as the surface membrane
forms gap junctions with the sacroplasmic reticulum (SR)
never comes closer than about 1 micron from the SR membrane
does not contain voltage-gated Na+ channels
During the plateau (phase 2) of the ventricular action potential
Na+ channels remain open causing the continued depolarization
Ca2+ channels are mostly closed
K+ permeability of the membrane is greater than when the membrane is at rest
Both Ca2+ and K+ permeability of the membrane is lower than when the membrane is at rest
none of these
Contractility (or inotropic state) of cardiac muscle is increased by
increased stretch of cardiac muscle (e.g increased filling of the heart)
increased myoplasmic Ca2+ during systole
Ca2+ channel blockers
Decreased coronary blood supply
Both A and B will increase contractility
The sequence for smooth muscle contraction is....
increased cytosolic calcium, which binds to troponin, complex binds with myosin light-chain kinase which uses ATP to phosphorylate myosin cross-bridges, which bind to actin filaments, resulting in contraction
increased cytosolic calcium, which binds to calmodulin in cytosol, which binds with myosin cross-bridges resulting in contraction
increased cytosolic calcium, which binds to calmodulin in cytosol, which moves tromyosin from blocking active sites on actin filament, which binds with myosin cross-bridges, resulting in contraction
increase cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active actin filament, which binds with myosin cross-bridges resulting to contraction
The neuron action potential starts with
Na+ influx
Na+ eflux
N+ influx
The membrane potential after accessing its maximal valve by constant condition
Remain stable in time
Decrease exponentially
Slowly close resting membrane potential
The trans-membrane proteins in difference with peripheral
do transversal diffusion
have hydrophilic and hydrophobic parts
possess mainly enzymes activity
The most punctual definition of membrane potential valve is defined with the equation of
Goldman
Nernst
Bernstein
Sodium-potassium pump in electrogenic condition
depolarized cell membrane
repolarized cell membrane
hyperpolarized cell membrane
TTX tetrodoxin is a blocker of
potassium channels
sodium channels
calcium channels
The contraction of striated muscle
faster than smooth muscle
slower than smooth muscle
equal to smooth muscle
Thin filaments of muscle
Actin fibers
Troponin
Myosin fibers
Striated muscles are characterized
perodically alter
equal to zero membrane potential
stable resting
Source of calcium needed for contraction striated muscle (rapid transition)
Extracellular
Endoplasmic Reticulum
Motor Neurons
Hyperpolarisation phase of striated muscles
Preliminary to the stiulus
Repeats twice after each action potential occurs
Is missing
Mark the correct expression
all ion channels let pass ions from extra to intra cellular compartment
all ion channels let pass ions from intra to intra cellular compartment
The membrane theory of excitation is based on the idea that stimulation of the surface membrane of an excitable cell causes a molecular restructuring that alters the membrane’s permeability and gives rise to transmembranous ion currents
Source of calcium needed for contraction striated muscle tissue (rapid transition) is
Contraction of smooth muscle is _____________ than that of skeletal muscle
slower
faster
equal
The trans-membrane transport (transdiffusion) is similar to
A filtration
A passive membrane transport
An active membrane transport
Smooth muscle's slow wave is defined by
Concentration of Na+, K+ and Ca2+
Concentrations of Na+, K+ and Ca2+ pump
Concentrations of Na+, K+ and Na/K pump
Order the polarizations according to their time of appearing
Ionic, Dipolar, Macrostructural
Surface, Dipolar, Ionic
Surface, Macrostructural, Dipolar
The membrane potential after reaching maximum value
Remains constant in time
Is altered slowly to submaximal value
Decreases to zero
The membrane lipids are
amphiphilic
formed glycocalcs
have many transport function
The lipids are
transmembrane
membrane receptor
organized in layers
The plateau phase of myocardial cells is determined by
Concentrations of Ca2+ and Na+
Concentrations of Ca2+ and K+
Concentrations of Na
Membrane potential depends on
temparature of the thermodynamic system
viscosity of the medium
medium's protein/lipid ration
