membrane models and measurement - ionic balance

Question 1

what is electrophysilogy

Answer 1

study of electrical properties of biological cells and tissues.
It involves measurements of voltage changes or electric current of ion channels or whole organs

Question 2

how do the nernst and GHK equation compare

Answer 2

way of measuring equilibrium potential of a single ion,or multiple ions

compares the electron gradient (+/-) with the actual concentation gradient and considers the NET FLUX OF IONS ACROSS A CELL MEMBRANE

Question 3

what is the nernst equations

Answer 3

at 37 degrees

61 log 10 (conc ion outside cell / conc inside cell

Question 4

which phase of an action potential does TTX prevent?
A depolarization
B polarization
C refractory period
D stimulus
E hyperpolarisation

Answer 4

OPTION A
TTX blocks Na+ channels so there will be no sodium influx into cell so cell cannot depolarise

> naturally foun in pufferfish and can result in respiratory paralysis so prevents depolarisation

Question 5

what are the effects of neurotoxin TEA+?
A Blocks sodium channels
B blocks calcium channels
C inhibits acetylcholine esterase
D blocks potassium channels
E competes with acetylcholine

Answer 5

OPTION D

this prevents repolarisation so there is no relaxation of tissue, its under tonic stimulation