Past Paper Flashcards
Concerning Skeletal Muscle
1. Neuromuscular Transmission
The neurotransmitter released from motor nerves is
2. On arrival of a single action potential, motor nerves release a number of quanta of
transmitter approximately equal to
3. Transmitter release can be blocked by
4. Depolarization block of neuromuscular transmission is caused by
5. Neuromuscular block caused by a competitive antagonist can be overcome using
acetylcholine
100
botulinum toxin
suxamethonium
neostigmine
Concerning cardiac ventricular action potentials
1. The upstroke of the action potential is primarily determined by
2. Repolarization of the action potential is primarily determined by
3. L-type Voltage-gated Ca2+ channels are blocked by
4. Voltage-gated K+ channels are blocked by
5. Voltage-gated Na+ channels are blocked by
Voltage gated Na+ Channels
Voltage gated K+ channels
Verapamil
Amiodarone
Tetodotoxin
Concerning contraction and relaxation of smooth muscle
Contraction of vascular smooth muscle is caused primarily by activation of the
following receptors on the smooth muscle membrane
alpha adrenoceptors
Relaxation of vascular smooth muscle is caused by activation of the following
receptors on the smooth muscle membrane
. beta adrenoceptors
Relaxation of vascular smooth muscle is caused by release of the following from
endothelial cells
NO
Relaxation of gut smooth muscle is caused by activation of the following receptors
on the smooth muscle membrane
. alpha adrenoceptors
Relaxation of smooth muscle results from
activation of adenylyl cyclase producing cAMP
Concerning membrane transport mechanisms and membrane
permeability
The sodium-potassium ATP-ase transports the following number of sodium ions out
of the cell during each cycle of activity
3
At the same time the sodium-potassium ATP-ase transports the following number of
potassium ions into the cell
2
The sodium-calcium exchange transports the following number of calcium ions out
of the cell during each cycle
1
The sodium-calcium exchange transports the following number of sodium ions into
the cell during each cycle
3
Most cells in the body have a negative resting potential determined by a dominant
permeability to the following ion
K+
Concerning the concentrations of ions
The extracellular concentration of potassium ions (mM) is approximately
4
The extracellular concentration of sodium ions (mM) is approximately
140
The free concentration of calcium ions (M) in the cytosol is usually approximately
10-7
The extracellular bicarbonate concentration (mM) is approximately
25
The intracellular concentration of potassium ions (mM) is approximately
140
Concerning contraction of skeletal muscle
During contraction of skeletal muscle (figure above) the band which does not
shorten is the
A band
The band that contains most myosin is the
A band
The actin filaments are attached to
the Z lines
Contraction is activated primarily by
a voltage-gated mechanism involving interaction between proteins in the
transverse tubule and ryanodine receptor calcium release channels in the
sarcoplasmic reticulum
Contraction is activated by calcium binding to
Troponin C
Concerning the action potential and the effect of drugs
Select one factor that can increase conduction velocity
Decrease membrane resistance
Myelination increases conduction velocity because it
decreases membrane capacitance
