Neurons And Neural Teansmission

Question 0

Name the two types of cells that communicate

Answer 0

Muscle fibers and neurons (excitable cells)

Question 1

What is an action potential?

Answer 1

The ability to move an electrical signal down a membrane

Question 2

What are the sections of an action potential?

Answer 2

Depolarizing, re polarizing, hyper polarizing, threshold

Question 3

What is the path for sodum?

Answer 3

Sodium rushes in which causes depolarization and it’s channels are closed at the peak of depolarization.

Question 4

What is the path for potassium

Answer 4

Has a slow respond and slow recovery. Potassium moves out of the cell..

Question 5

Describe the molecular mechanism of an action potential

Answer 5

See your notes..

Question 6

What happens at threshold to sodium?

Answer 6

There is a influx of sodium that continues to build as more channels open (positive feedback cycle)

Question 7

Describe activation gates and inactivation gates

Answer 7

Activation gates open rapidly at threshold also at threshold the inactivation Gates start closing slowly.. Membrane repolarizes (while inactivation gate is closed) once membrane is repolarized the gate resets.

Question 8

Describe the 4 zones of a neuron

Answer 8

Input zone

Output zone

Conducting zone
Trigger zone

Question 9

What is the point of the myelin sheath

Answer 9

Produces faster conduction.

Question 10

What do glial cells do?

Answer 10

Support neurons

Question 11

What is an afferent neuron?

Answer 11

Sensory towards the Cns

Question 12

What is a efferent neuron?

Answer 12

From Cns towards muscles and glands

Question 13

What are the events at the synapse?

Answer 13

See notes if you have forgotten

Question 14

What are neutotransmitters?

Answer 14

Chemical messengers that bridge the gap between the presynaptic cleft and post synaptic membrane

Question 15

What are graded potentials? Name the two types

Answer 15

Signals coming from receptors on the membrane that add together to create an action potential (some are for an action potential some are against)

Spatial summation
-when Two different neurons fire at the same time

Temporal summation
When a neuron fires rapidly twice it more times in a row.

Question 16

What are epsps and ipsps

Answer 16

Graded potentials
Excitatory post synaptic potentials
Inhibitory post synaptic potentials

Question 17

Describe how action potentials are propagated across a membrane

Answer 17

See book for details

Question 18

What is the difference between an absolute refractory period and a relative refractory period.

Answer 18

Absolute is immediately following the action potential

Relative follows the absolute refractory period

Question 19

Describe saltatory conduction

Answer 19

See notes for more details

Question 20

How do activation/ inactivation gates help with the refractory period?

Answer 20

During action potential activation gate/ inactivation gates are active.. In activation gate is closed until reaching resting membrane potential and isn’t reset until then.

Question 21

What are Neurotransmitters?

Answer 21

Chemicals that are released by synaptic vesicles to send chemical messages from cell to cell through synaptic clefts

Question 22

Name the four examples of Neurotransmitters

Answer 22

Acetylcholine
Biogenetic amines
Amino acids
Neuropeptides

Question 23

What are acetylcholines receptors

Answer 23

Nicotinic receptors and muscarinic

Question 24

What are the two types of biogenetic amines receptors (also known as adrenergic receptors)?

Answer 24

Alpha and beta receptors

Question 25

What are Neurotransmitters and what do they do?

Answer 25

They are chemical messengers that send information from one membrane to another

Question 26

What are the receptors on the post synaptic membrane?

Answer 26

Acetylcholine -Nicotinic receptors and muscarinic

Norepinephrine- beta 1, alpha one or alpha 2

Epinephrine - beta 2

Question 27

What are ligand gated channels?

Answer 27

Channels that require an ion or molecule to attach to it for it to open

Question 28

Please describe in detail the molecular mechanism of a single action potential

Answer 28

Sodium channels open allowing sodium to rush into the cell causing it to reach threshold which causes more sodium channels to open

While the sodium channels are opening and the cell membrane begins to depolarize to +30 mV potassium channels begin opening aswell but they open slowly.. This allows potassium to escape out.
Once the membrane is sufficiently depolarized the sodium channels should be in an inactivation state (closed) meanwhile potassium gates are closing slowly.. The membrane begins to hyper polarize and the sodium potassium pump restores the resting membrane potential

Question 29

Please explain the events that occur at the synapse..

Answer 29

When an action potential reaches a presynaptic button calcium is released into that button which causes vesicles of Neurotransmitters to move towards the membrane for Exocytosis.. The contents are then released into the synaptic cleft.

Question 30

How is an action potential propagated down a nerve cell axon

Answer 30

Described in book if you must check