Question
|
Answer
|
What is the typical concentration of intracellular K+?
|
140mM
|
What is the typical concentration of intracellular Na+?
|
15mM
|
At rest, is the normal cell membrane more permeable to Na+ or K+?
|
more permeable to K+
|
What is the stoichiometry and direction of Na+ and K+ movements powered by the Na+/K+ATPase in a resting cell?
|
3Na+ out and 2K+ in
|
A drug that will block the Na+/K+ ATPase.
|
ouabain
|
An action potential in a myelinated fibre is conducted at 50 m/s and lasts 2 ms. Calculate the distance one action potential occupies.
|
10cm
|
Select one factor that can increase conduction velocity
|
increase membrane resistance
|
Myelination increases conduction velocity because it
|
decreases membrane capacitance
|
Select a drug that can suppress the generation of a neuronal action potential by blocking
voltage-gated Na+ channels
|
lignocaine
|
A clinical use of a voltage-gated Na+ channel blocker is
|
local anaesthetic
|
The extracellular calcium concentration
|
2mM
|
One mechanism that releases the ion from the endoplasmic (or sarcoplasmic) reticulum
|
IP3
|
A calcium binding protein that mediates the effects of calcium
|
calmodulin
|
A calcium-activated enzyme that stimulates smooth muscle contraction
|
myosin light chain kinase
|
An inhibitor of a voltage-operated Ca2+ channel
|
verapamil
|
Beta-2 adrenoceptor agonist
|
asthma
|
Cholinesterase inhibitors
|
myasthenia gravis
|
Inhibitor of angiotensin converting enzyme
|
hypertension
|
Na+ channel blocker
|
cardiac dysrhythmia
|
Cyclooxygenase inhibitor
|
pain killer
|
atropine
|
cardiac acetylcholine receptor
|
nicotine
|
ganglionic acetylcholine receptors
|
noradrenaline
|
alpha-adrenoceptors
|
isoprenaline
|
beta-2-adrenoceptor
|
trimetaphan
|
ganglion blocker
|
What cells in the stomach secrete gastric acid?
|
parietal cells
|
What hormone stimulates acid production?
|
gastrin
|
What hormone inhibits acid generation?
|
cholecystokinin
|
What drug blocks acid secretion?
|
omeprazole
|
What does omeprazole target?
|
H+/K+ATPase
|
Where does the bulk of sodium reabsorption occur?
|
proximal tubule
|
Where does the rest of sodium reabsorption occur?
|
distal collecting tubules
|
What is hormone stimulates sodium reabsorption?
|
aldosterone
|
Sodium ions leave the lumen to enter cells by crossing the apical membrane. How does this transport occur?
|
epithelial sodium channels (ENaC)
|
What drug can block the epithelial sodium channels?
|
amiloride
|
What type of capillary is found in skeletal muscle?
|
continuous
|
What type of capillary is found in the kidney?
|
fenestrated
|
What type of capillary is found in the liver
|
sinusoidal
|
What is the main force driving fluid out of capillaries?
|
capillary hydrostatic pressure
|
What is the main force driving fluid reabsorption?
|
plasma colloid osmotic pressure
|
K+ through a K+ selective channel
|
-90mV
|
Na+ through a Na+-selective channel
|
+60mV
|
Ca2+ through a Ca2+-selective channel
|
+100mV
|
K+ through a non-selective cation channel that is equally permeable to Na+ and K+ but which excludes Ca2+
|
-15mV
|
What would happen to the reversal potential for K+ if the extracellular K+ concentration increased?
|
it would become more depolarised
|