Membrane potentials - Synaptic integration

Question 1

What doe s a monovalent cation channel allow into the cell?

Answer 1

sodium

depolarise

little bit of potassium our of the cell

Question 2

Why does A create a bigger depolarisation compared to A? (closer to threshold)

Answer 2

A = is farther away from the axon

B = closer to the axon

graded potentials only cause AP over a short distance

closer to the initial segment will have a bigger effect on the graded potential

Question 3

What is detrimental to the cell reaching threshold?

Answer 3

the initial segment

Question 4

What are ways graded potential can reach an AP?

Answer 4

1. Stimulate an input twice in quick succession - temporal summation
2. stimulate 2 different input at one time - spatial summation

Question 5

What are ways inhibitory channels can stop AP?

Answer 5

e.g. chloride channels - hypopolarisation

e.g. inhibit the amount of neurotransmitter released from the exitory terminal
= smaller EPSP

Question 6

What s a common sequence of IPSP and EPSP?

Answer 6

first an exitory AP, followed quickly by an inhibitory AP

Question 7

Name the types of synaptic integration A-D

Answer 7

A = axo-dendritic synapse

B = axo-somatic synapse - inhibitory

C = initial segment (axon hillock)

D = axo-axonic synapse - inhibitory