Neurophysiology

Question 1

3 Different types of Neurons are…

Answer 1

Sensory, Motor, and Interneurons

Question 2

Sensory Neurons

Answer 2

Receive sensory information (light, sounds, etc) “Afferent neurons

Question 3

Motor Neurons

Answer 3

Control the muscles, “efferent neurons”

Question 4

Interneurons

Answer 4

Lie between sensory and motor neurons (found only within the brain and spinal cord), “afferent and efferent”

Question 5

Soma

Answer 5

• Cell Body

- Contains all material needed for the life processes of the cell ( nucleus, mitochondria, etc)

Question 6

Dendrites

Answer 6

serve to receive incoming signals from other neurons

Question 7

Terminal Buttons

Answer 7

• site of neurotransmitter synthesis & release to other neurons
• communicates vis chemical means

Question 8

Axon

Answer 8

• transmits signal to another neuron

- covered in myelin sheath

Question 9

Multipolar neuron

Answer 9

neurons that have one axon and many dendrites

- most common neuron n the CNS

Question 10

Bipolar neuron

Answer 10

neurons that have 1 axon and 1 dendrite, usually at opposite ends of the soma

• usually sensory neurons
• found in the visual, olfactory and auditory systems

Question 11

Unipolar Neurons

Answer 11

Neurons that have 1 process that leaves the soma and then divides into 2 branches, one that receive information and the other transmits it

• cell body is separated
• associated with touch and pain
• usually sensory neurons
• found in the somatosensory system

Question 12

Glia Cells (supporting Cells) are…

Answer 12

1) Astrocytes
2) Oligodendrocytes
3) Microglia

Question 13

Astrocytes

Answer 13

• provides structural support and nutrients for neurons

- metabolizes sugars which allows them to provides energy for neurons

Question 14

Oligodendrocytes

Answer 14

provide structural support and myelin to axons

Question 15

Microglia

Answer 15

• recognize and remove foreign cells

- scavenge dead neurons

Question 16

Myelin Sheath

Answer 16

• produced as oligodendrocyte wraps itself around the axon

- not continuous

Question 17

Nodes of Ranvier

Answer 17

Gaps in the myelin sheath

Question 18

Neuron resting membrane potential

Answer 18

• (-70mV) voltage
• the neurons interior is polar
• maintained by two forces
  1) Force of Diffusion
  2) Electrostatic Force

Question 19

Force of Diffusion

Answer 19

between areas of different concentration; particles want to evenly distribute

Question 20

Electrostatic Force

Answer 20

between charged particles; differently charged particles are attracted to each other

Question 21

Membrane at Rest (Ions) location

Answer 21

K+ - more inside

Cl- - more outside

Na+ - more on outside

Question 22

K+ feel more pressure from…

Answer 22

force of diffusion

Question 23

Cl- feels more pressure from

Answer 23

force of diffusion

Question 24

Na+ feels pressure from…

Answer 24

electrostatic force and force of diffusion

Question 25

At rest voltage gated channels are...

Answer 25

innactive

Question 26

At rest leaky channels are

Answer 26

slightly permeable

Question 27

With the depolarization of neuron the membrane potential becomes

Answer 27

less negative

Question 28

Decremental Potentials

Answer 28

short lived depolarizations | - as it spreads down the axon it gets weaker

Question 29

Threshold of excitation

Answer 29

-60mV

Question 30

Which channels open at -60mV

Answer 30

Sodium voltage gated channel opens | -Na+ is coming into the cell

Question 31

Which channel opens at -45mV

Answer 31

Potassium voltage gated channels | - leaving the cell

Question 32

Action potential

Answer 32

+40MV - large depolarization - membrane potential reverses itself

Question 33

Which channel become refractory at action potential

Answer 33

sodium ion channels

Question 34

What allows the membrane to re-polarize

Answer 34

- K+ channels staying open longer then Na+ | - sodium/potassium pumps taking Na+ out of cell and K+ into cell

Question 35

Action Potential obeys...

Answer 35

All or none law - runs down entire length of axon - does not decline in strength

Question 36

Saltatory Conduction

Answer 36

The jumping of the AP from one Node of Ranvier to the next

Question 37

At each node of ranvier ...

Answer 37

The AP is regenerated

Question 38

Why is the AP regenerated at each node?

Answer 38

There is a high density of sodium channels at each node

Question 39

The two advantages of saltatory conduction

Answer 39

1) Na+/K+ pumps only have to work at the nodes, reduces energy 2) Decremental conduction under myelin is very fast

Question 40

Refractory Na+ channels allow the AP...

Answer 40

to move in one direction

Question 41

AP is conducted along the axon membrane to the...

Answer 41

axon terminals

Question 42

Presynaptic Neuron

Answer 42

Neuron that send the signal

Question 43

Postsynaptic Neuron

Answer 43

neuron that receives signal

Question 44

At the axon terminal there are _____ that contain________

Answer 44

synaptic vesicles, neurotransmitters

Question 45

Neurotransmitters

Answer 45

Chemical messengers released by the neuron

Question 46

Neurotransmitters are released into the ____ and bind with ______

Answer 46

synapse, specialized receptors

Question 47

Types of synapse

Answer 47

``` Axosomatic synapse Axodendritic synapse (most common) ```

Question 48

Arrival of AP to axon terminal causes ___ to open

Answer 48

Opens Ca+ ion channels

Question 49

Ca+ channels opening cause____ to move to release zone

Answer 49

synaptic vesicles

Question 50

_____ binds to the presynaptic membrane to form a ____ shape to release _____

Answer 50

Synaptic vesicle; omega; neurotransmitters

Question 51

NT interaction with receptors causes.....

Answer 51

change in membrane potential ( Transient Change )

Question 52

EPSPS

Answer 52

Depolarize, make inside more negative, more likely to reach threshold

Question 53

IPSPS

Answer 53

hyperpolarize, make inside more negative, less likely to reach threshold

Question 54

EPSPS and IPSPS are ....

Answer 54

decremental conduction ( loose strength over time and distance)

Question 55

if Na+ comes inside the neuron

Answer 55

EPSPS

Question 56

if K+ leaves neuron

Answer 56

IPSPS

Question 57

if Cl- enters neuron

Answer 57

IPSP

Question 58

Excititory Connections

Answer 58

release of NT for presynaptic neuron to postsynaptic neuron makes it more likely to reach threshold

Question 59

Inhibitory Connections

Answer 59

release of NT from presynaptic neuron to postsynaptic neuron makes it less likely to reach threshold

Question 60

Effects of neurotransmitters must be ____ quickly

Answer 60

terminated

Question 61

Neurotransmitter reuptake

Answer 61

We remove NT from the synapse back to presynaptic terminal to be recycled - requires transporter molecules - most NT go through this

Question 62

Enzyme degredation

Answer 62

Enzymes degrade NT into their smaller parts

Question 63

When a neuron is sufficiently stimulated...

Answer 63

it will fires a volley of action potentials

Question 64

Neural Integration

Answer 64

At the axon hillock if the sum of EPSPS and IPSPS are above the threshold an action potential will occur, if not, then no action potential