Lecture 5: Synaptic Transmission

Question 1

3 structures a neuron may terminate on

Answer 1

-another neuron
-muscle
-a gland

Question 2

When a neuron terminates on another neuron, this is called a

Answer 2

Synapse

Question 3

When a neuron terminates on a muscle, this is called

Answer 3

Neuromuscular junction

Question 4

When a neuron terminates in a muscle or gland, the neuron __________ the structure

Answer 4

Innervates

Question 5

Motorneurons

Answer 5

Nerves that innervate muscle fibers

Question 6

Ventral horn of spinal cord

Answer 6

Contains gray matter
-cell bodies of motor neurons that send axons of spinal nerves to terminate on muscles
-motor neuron

Question 7

Synapse definition

Answer 7

Junction between a presynaptic neuron and postsynaptic neuron

Question 8

2 types of synaptic transmission

Answer 8

Electrical
Chemical

Question 9

Are gap junctions electrical or chemical

Answer 9

Electrical

Question 10

Directionality of chemical synaptic transmission

Answer 10

Unidirectional

Question 11

Directionality of electrical synaptic transmission

Answer 11

Bidirectional

Question 12

Gap junction definition

Answer 12

Gap between 2 adjacent cells linked by small connecting tunnels formed by connexons

Question 13

Where are gap junctions abundant

Answer 13

Cardiac and smooth muscle

Question 14

Function of gap junctions in non-muscle tissues

Answer 14

Permit unrestricted passage of small nutrient molecules between cells

Question 15

What does synaptic knob contain

Answer 15

Synaptic vesicles

Question 16

What synaptic vesicles store

Answer 16

Neurotransmitter

Question 17

Synaptic delay definition

Answer 17

Time needed for conversion of electrical signal from presynaptic neuron to electric signal in postsynaptic neuron by chemical means/neurotransmitter
-about 0.5 to 1 msec

Question 18

5 steps of excitation-secretion coupling in chemical synapses

Answer 18

-action potential reaches axon terminal of presynaptic neuron (depolarization)
-calcium entrees synaptic knob via concentration gradient (opens voltage gated calcium channels and calcium enters cell)
-neurotransmitter released by exocytosis into synaptic cleft
-neurotransmitter diffuses across synaptic clef and binds to receptor on postsynaptic cell
-neurotransmitter binding to receptor opens channel

Question 19

Kinds of receptors at post synaptic membrane (2)

Answer 19

-ligand gated ion channels
-g protein coupled receptors

Question 20

Ligand gated ion channels vs G protein coupled receptors (speed of transmission)

Answer 20

Ligand = fastest
G protein = slower

Question 21

What ends the signal

Answer 21

Removal of neurotransmitter

Question 22

3 ways neurotransmitter is removed

Answer 22

-diffusion
-enzymatic degradation
-reuptake

Question 23

Removing a neurotransmitter through diffusion

Answer 23

Movement away from synaptic cleft

Question 24

Removing neurotransmitter through enzymatic degradation

Answer 24

Inactivation by specific enzymes within synaptic cleft

Question 25

Removing neurotransmitter through reuptake

Answer 25

-actively taken back up into presynaptic axon terminal
-recycled (Stores and released another time)
-destroyed by enzymes within synaptic knob

Question 26

Neurotransmitter in cholinergic synapse

Answer 26

Acetylcholine

Question 27

Excitatory adrenergic synapse neurotransmitter

Answer 27

Norepinephrine

Question 28

Norepinephrine aka

Answer 28

Noradrenaline