1-6

Question 1

resting potential

Answer 1

sustained voltage across the membrane. acts as a battery in neurons - immediately available energy. Movement of K+ ions is the key of maintaining the resting potential; 65mV

Question 2

Key work done for recording resting potential

Answer 2

Hodgkin and Huxley - squid giant axon

Question 3

sensory receptors

Answer 3

cells specialised to receive a particular form of envi stimulus - such as light energy, mechanical movement, or chemical molecules in an odour - and to respond with an electrical signal.

Question 4

proprioceptors

Answer 4

sensory receptors providing info about positions or movements of an animal’s body part

Question 5

motor neuron

Answer 5

a nerve cell that connects with and controls muscle fibres

Question 6

gradient potential

Answer 6

much smaller voltage signals than spikes. They are not fixed in amplitude, and can be summed together, allowing neurons to combine signals in time and space. Gradient potentials originate at synaptic junctions between neurons, or within sensory receptor cells, and they are responsible for controlling spike production.

Question 7

receptor potential

Answer 7

also known as a generator potential, a type of graded potential, is the transmembrane potential difference produced by activation of a sensory receptor. A receptor potential is often produced by sensory transduction. It is generally a depolarizing event resulting from inward current flow.

Question 8

rapidly adapting receptors

Answer 8

phasic - respond briskly (ojiveno) but briefly to any increased strech

Question 9

slowly (sustainable) adapting response

Answer 9

tonic - provide over time a more accurate measure of stretch

Question 10

Postsynaptic potentials (PSP)

Answer 10

changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic potentials are graded potentials, and should not be confused with action potentials although their function is to initiate or inhibit action potentials.

Question 11

refractory period

Answer 11

a moment after the production of a spike when the membrane is unable to be immediately excited again, so that spikes remain discrete and do not fuse into each other.

Question 12

action pottential

Answer 12

carry signals in axons over distance without getting smaller because it constantly regenerate across the axon. the action potential is a regenerative, positive-
feedback cycle.

Question 13

electroplaques

Answer 13

in strongly electric fish, stacks of modified muscle cells. They are surrounded by lipids (for isolation) and connect to the surface through openings - pores

Question 14

frog nerve muscle experiment: line of evidence

Answer 14

Kratz et.al.

1. Delay – therefore not direct current flow
2. Drug – curare – therefore chemical involved (Ach), able to see the shape
3. Calcium – reduced [Ca2+] in saline – reduced PSP therefore Ca2+ needed
4. Miniature PSPs – vesicles contain packets of transmitter (quanta)
5. E.M. (Heuser) – after AP, vesicles fuse and release content; freeze slamming and freeze fracture.

Question 15

equilibrium potential

Answer 15

a voltage at which the chemical force (concentration gradient) acting on the ion is equal and opposite to the
electrical force(charge gradient) acting on the ion.

Question 16

conductance

Answer 16

the ability of an electrical circuit to carry

current.