Lecture 13: Neural Tissue 3

Question 1

Electrical Synapses

Answer 1

No neurotransmitter release,
Presynaptic and postsynaptic cell are linked at gap junctions,
Rare

Question 2

What Do Electrical Synapses Allow To Pass From Cell To Cell?

Answer 2

Ions and action potentials

Question 3

Chemical Synapses

Answer 3

Neurotransmitter release,

Release may or may not cause an action potential at postsynaptic cell

Question 4

Excitatory Neurotransmitters

Answer 4

Cause depolarization and promote action potentials on postsynaptic cell

Question 5

Inhibitory Neurotransmitters

Answer 5

Cause hyper polarization and suppress generation of action potentials

Question 6

What Determines The Type Of Neurotransmitter It Is At A Certain Location In Body?

Answer 6

Receptors

Question 7

Cholinergic Synapses

Answer 7

Common,
Neuron to neuron synapses in PNS,
Many CNS synapses,
Synapses in parasympathetic division of ANS

Question 8

Steps to Cholinergic Synapses (5)

Answer 8

1. Action potential arrives at synaptic knob
2. Opening of voltage-gated Ca++ channels in synaptic knob
3. Ca++ triggers exocytosis of Ach from vesicles
4. Ach diffuses across synaptic cleft and binds to receptors on postsynaptic cell causing depolarization of postsynaptic cell
5. Ach is broken down by AchE into acetate and choline

Question 9

Synaptic Delay

Answer 9

Delay between the arrival of the action potential at the synaptic knob and the effect at the postsynaptic membrane,
Due Ca++ influx and neurotransmitter release

Question 10

Why Does Faster Conduction Occur In Routes With Fewer Synapses?

Answer 10

Because there are less delays

Question 11

Common Neurotransmitters (5)

Answer 11

Acetylcholine
Norepinephrine
Dopamine
Serotonin
Gamma-aminobutyric Acid

Question 12

Neuromodulators

Answer 12

Chemicals that either alter the rate of neurotransmitter release at the presynaptic neuron or alter postsynaptic cell’s response to neurotransmitters

Question 13

Examples Of Neuromodulators

Answer 13

Opiods,
Endorphins,
Enkephalins

Question 14

Graded Potential

Answer 14

Local change in response to action potential

Question 15

Postsynaptic Potential

Answer 15

Graded potentials that develop on the postsynaptic neuron membrane in response to a neurotransmitter,
Excitatory or inhibitory

Question 16

EPSP

Answer 16

Excitatory postsynaptic potential,

Depolarization

Question 17

IPSP

Answer 17

Inhibitory postsynaptic potential,

Hyperpolarization

Question 18

Why Does EPSP Occur?

Answer 18

Results from the opening of chemically gated membrane channels that lead to depolarization,
Sodium Channels

Question 19

Why Does IPSP Occur?

Answer 19

Results from the opening of chemically gated membrane channels that lead to hyperpolarization,
Potassium Channels

Question 20

Summation

Answer 20

Combination of EPSPs and IPSPs and their effects on the postsynaptic neuron

Question 21

Temporal Summation

Answer 21

Doesn’t reach threshold,

Subsequent stimuli from one synapse within close time periods of each other

Question 22

Spatial Summation

Answer 22

Subsequent stimuli from 2 or more synapses that may reach threshold

Question 23

Neuromodulators can change ________ _________ to neurotransmitters

Answer 23

Membrane sensitivity

Question 24

Presynaptic Influences

Answer 24

Occurs at axoaxonic synapse

Question 25

Axoaxonic Synapses

Answer 25

Synapses on synaptic knob

Question 26

Presynaptic Inhibition

Answer 26

Inhibitory neuron releases neurotransmitter on presynaptic neuron axon and prevents Ca++ channels from opening,
GABA release

Question 27

Presynaptic Facilitation

Answer 27

Facilitory neuron releases neurotransmitters on presynaptic neuron axon and keeps Ca++ channels open longer,
Serotonin release

Question 28

Rate Of Action Potentials

Answer 28

Rate is highest if axon hillock has strong/sustained depolarizing stimuli