Nervous System

Question 1

Axon

Answer 1

Transmits electrical signal (action potential) from the soma to the synaptic knob.

Question 2

The axon hillock

Answer 2

Integrates excitatory and inhibitory signals from the dendrites and fires an action potential if the excitatory signals are strong enough to reach threshold

Question 3

Dendrites

Answer 3

Receive incoming signals and carry them to the soma

Question 4

Myelin sheth

Answer 4

Acts as an insulation around the axon and speeds conduction

Question 5

Soma

Answer 5

Cell body, contains nucleus, endoplasmic reticulum, ribosomes

Question 6

Synaptic bouton

Answer 6

Lies at the end of the axon and releases neurotransmitters

Question 7

Collection of cell bodies in the CNS

Answer 7

Nucleus

Question 8

Collection of cell bodies in the PNS

Answer 8

ganglion

Question 9

Astrocytes

Answer 9

Nourish neurons and form the blood-brain barrier which controls the transmission of solutes from the bloodstream into the Nervous system

Question 10

Ependymal Cells

Answer 10

Lines the ventricles of the brain and produces cerebrospinal fluid, which physically support the brain and serves as a shock absorber

Question 11

Microglia

Answer 11

Are phagocytic cells that ingest and break down waste products and pathogens in the central nervous system

Question 12

Oligodendrocytes (CNS) and Schwann Cells (PNS)

Answer 12

Produce mylenin around the axons

Question 13

What neural structure initiates the action potential?

Answer 13

Axon Hillock

Question 14

What maintains the resting potential? what is the resting potential

Answer 14

The Na+/K+ ATPase at about -70mV

Question 15

Temporal Summation

Answer 15

Integration of multiple signals close to each other in time

Question 16

Spacial Summation

Answer 16

Integration of multiple signals that are close to each other in space/location

Question 17

During action potential which ion channel open first? how is it regulate? What effect does it have on the polarization of the cell?

Answer 17

The sodium channel opens first at threshold -50mv.
Regulated by inactivation, which occurs at +35nV. Inactivation can only be reversed by repolarization of the cell. Opening of sodium channel causes depolarization.

Question 18

During action potential what channel opens second, how is it regulated and what effect does it have on the polarization of cell?

Answer 18

Potassium (K) channel opens second at around +35mV. it is regulated by closing at low potential (below -70mV). Opening of potassium channel results in repolarization and eventually hyperpolarization.

Question 19

Absolute refractory Period

Answer 19

The cell is unable to fire an action potential regardless of the intensity of a stimulus

Question 20

Relative refractory period

Answer 20

Cell can fire an action potential only with a stimulus that is stronger than normal

Question 21

What ion is responsible for the fusion of neurotransmitter containing vesicles with nerve terminal membrane?

Answer 21

Calcium

Question 22

3 methods by which a neurotransmitter’s action can be stopped?

Answer 22

1. Enzyme degradation
2. Re uptake
3. Diffusion

Question 23

What parts of the nervous system is the PNS

Answer 23

Cranial and spinal nerves and sensors

Question 24

Monosynaptic reflex

Answer 24

a sensory (afferent, presynaptic) neuron fires directly onto a motor (efferent, post synaptic) neuron.

Question 25

polysynaptic reflex,

Answer 25

A sensory neuron may fire directly onto a motor neuron, but interneurons are used as well. Interneurons fire onto other motor neurons

Question 26

Which is he neurotransmitter used in both ganglia of of both SNS and PNS?

Answer 26

acetylcholine released by preganglionic neuron in both SNS and PNS postganglionic neuron in SNS: norepinephrine postganglionic neuron in PNS: acetylcholine

Question 27

Dorsal root ganglion

Answer 27

Contains all the cell bodies of sensory neuron

Question 28

Primary different between somatic and automatic nervous systems in the PNS?

Answer 28

``` Somatic= one motor neuron Automatic= 2 neurons that work in series ( preganglionic and poatganglionic) ```