Physiology: Lecture 4

Question 1

Synapse arrangement that has one pre-synaptic to one post-synaptic; NMJ; Conveys information

Answer 1

One-to-one synapse

Question 2

Synapse that has one presynaptic to more than one post-synaptic; motorneurons in the spinal cord; used to amplify a signal

Answer 2

One-to-many synapse

Question 3

Synapse arrangement that has more than one pre-synaptic to on post-synaptic; very common; allows for integration of many signals. “Decides” the proper response; puts a lot of info into one cell

Answer 3

Many-to-one synapse

Question 4

What changes when a neurotransmitter binds to the post-synaptic membrane?

Answer 4

• It changes the post-synaptic membrane potential (aka post-synaptic potentials) = can generalize neurotransmitters based on their usual effect
• can be excitatory or inhibitory

Question 5

Examples of inhibitory neurotransmitters

Answer 5

Glycine and GABA (most of the time)

Question 6

Example of excitatory neurotransmitter

Answer 6

Ach

Question 7

Membrane potentials that depolarize the cell towards threshold

Answer 7

Excitatory post-synaptic potentials (EPSPs)

Question 8

What are EPSPs usually the result of? Give 2 examples.

Answer 8

• Opening Na channels

- Glutamate, Acetylcholine (at nAchR)

Question 9

What does the EPSP look like on the graph?

Answer 9

Sensory nerve fires first; then the motor neuron bumps up a little bit

Question 10

Membrane potential that hyperpolarizes the cell away from threshold

Answer 10

Inhibitory post-synaptic potentials (IPSPs)

Question 11

What are IPSPs usually the result of? Give 2 examples

Answer 11

Opening of Cl channels

GABA and glycine

Question 12

What does IPSP look like on a graph?

Answer 12

Sensory near fires first; motor nerve dips down a little bit

Question 13

How do the numerous pre-synaptic cells integrate their signals to the single post-synaptic cell? Through what does this process occur?

Answer 13

• Signals have to be integrated - combined together and a decision made
• Occurs through temporal and spatial summation

Question 14

Time aspect of synaptic integration of PSPs; can be from one or more pre-synaptic; inputs overlap, membrane does not completely depolarize between; later impulses further depolarize towards threshold

Answer 14

Temporal summation

Question 15

What happens to the inputs when the impulses become faster?

Answer 15

Increases sensation = more neurotransmitters are released

Question 16

Synaptic integration of PSPs where there are multiple inputs at the same time; multiple pre-synaptics provide input at the same time; impulses add together

Answer 16

Spatial summation

Question 17

Rapid stimulation of pre-synaptic increases response in post-synaptic; Increased Ca2 in pre-synaptic, leads to more neurotransmitter (NT) release; Short-term modulation

Answer 17

Facilitation = augmentation = potentiation

*all three terms mean the same thing..just depends on where you are to what term or use.

Question 18

Modulation that uses repeated stimulation to expend the stored neurotransmitter (NT); eventually run out of neurotransmitter and signal will just stop

Answer 18

Short-term depression

Question 19

What does long-term modulation require?

Answer 19

Transcriptional changes; altering the receptor concentration on the post-synaptic cell; altering the amount of neurotransmitter stored in the pre-synaptic cell

Question 20

QUESTION:
Consider a cell at RMP, opening of which ion channel would result in an EPSP?
A) Chloride
B) Potassium
C) Water
D) Calcium

Answer 20

D) Calcium

[A) Inhibitory; B) Inhibitory; C) Nothing; D) Excitatory]

Question 21

QUESTION:
Consider a cell at RMP, opening of which ion channel would result in an IPSP?
A) Potassium
B) Calcium
C) Water
D) Sodium

Answer 21

A) Potassium

[A) Inhibitory; B) Excitatory; C) Nothing; D) Excitatory]