Nervous System

Question 1

What is the Nervous System made up of?

Answer 1

Neurons + glial cells

Question 2

1) What is the neuron?
2) What are the glial cells and what are they involved in?

Answer 2

1) functional cell of NS
2) supporting cells - they wrap axons in myelin

Question 3

What 3 actions is the neuron involved in?

Answer 3

1) receives excitation (at a synapse or receptor) or becomes excited
2) conducts excitation along an axxon
3) transmits excitation (via release of chemical at synapse)

Question 4

What is a multipolar neuron?

Answer 4

the cell body is located where input excitation occurs (in center of receptor region)

Question 5

What is a unipolar neuron?

Answer 5

the cell body is located along the axon (in a spinal ganglion)

Question 6

Are most neurons multipolar or unipolar?

Answer 6

multipolar

Question 7

1. Label which neuron is mutlipolar and unipolar
2. Label all the structures of each neuron.

Answer 7

Answers:

1. Multipolar
2. unipolar
3. dendrites
4. cell body
5. axon
6. synapse
7. receptor
8. axon
9. cell body
10. synapse

Question 8

True or False:

Sensory neurons are multipolar.

Answer 8

False

Sensory neurons are unipolar

Question 9

Answer 9

Question 10

Excitable cell =

Answer 10

polarized plasma membrane

Question 11

Define excitation

Answer 11

flow of ions across plasma membrane (membrane breaks down to allow ion flow)

Question 12

What drives the flow of ions?

Answer 12

electrical gradient and ionic mileu

Question 13

In unipolar neurons…

1) what does the receptor act as?
2) what triggers excitability

Answer 13

1) conducer
2) environmental energy

Question 14

What are neurons dependent on?

Answer 14

local environment of ions

Question 15

Define these terms:

1) nerve
2) root
3) ganglion

Answer 15

1) bundle of axons ensheathed by supporting cells adn enveloped by connective tissue
2) nerve that is adjacent to the CNS adn eveloped by meninges
3) localized site where a nerve is enlarged due to a collection of cell bodies

Question 16

1) Name the two types of ganglia
2) Name which type of cell body each contain

Answer 16

1) spinal ganglia:

unipolar cell bodies

2) autonomic ganglia:

mutlipolar cell bodies

Question 17

True of False:

Autonomic ganglia have synapses on them

Answer 17

True

they contain multipolar cell bodies which are located next to synapses

Question 18

Where are spinal ganglia located?

Answer 18

on dorsal roots of cell bodies

Question 19

What do autonomic ganglia innervate?

Answer 19

viscera

Question 20

What are roots made up of and are they part of the PNS or CNS?

Answer 20

made up of rootlets and they are part of the PNS

Question 21

Are unipolar neurons part of the CNS or PNS?

Answer 21

CNS

Question 22

1) What are the two divisions of the NS?
2) Name the structures of each division

Answer 22

1) Central (CNS) and Peripheral (PNS)
2) CNS: brain and spinal cord

PNS: 12 pairs of cranial nerves (attached to brain)

36 pairs of spinal nerves (attached to spinal cord

8 cervial, 13 thoracic, 7 lumbar, 3 sacral, 5 caudal

Question 23

What happens when info is urgent and needs to be transnmitted quickly?

Answer 23

the axons are wrapped in myelin

Question 24

True or False:

Most axons are myelinated

Answer 24

False

Most axons are non-myelinated

Question 25

Where is the spinal cord (CNS) and spinal roots (PNS) located?

Answer 25

within the vertebral canal of vertebral column

Question 26

What is a spinal nerve made up of?

Answer 26

dorsal and ventral spinal roots united on each side

Question 27

True or False: dorsal rootlets contain unipolar neurons.

Answer 27

True dorsal rootlets and ventral rootlets (which make up dorsal and ventral roots) unite to form spinal ganglion which is where the cell bodies are located within the unipolar neuron

Question 28

1) where is the spinal nerve found? 2) What are the three layers of CT involved with eveloping spinal nerves?

Answer 28

1) in the intervertebral foramen (adjacent vertebrae combine to form this) 2) epineurium, perineurium and endoneurium

Question 29

1) Where is each layer of CT located within the spinal nerve?

Answer 29

1) Endoneurium surrounds the whole nerve 2) Perineuron surrounds each fascicle within the nerve 3) Endoneurieum surrounds the axons within each fascicle

Question 30

Describe some characteristics of spinal nerves

Answer 30

1) short 2) located at an intervertebral foramen 3) connected to the spinal cord by two roots 4) divides into 4 primary branches

Question 31

What two roots connect the spinal nerve to the spinal cord and what are they composed of?

Answer 31

1) Dorsal root - composed of Afferent (sensory) axons where spinal ganglion is located 2) composed of Efferent axons that innervate muscle and gland

Question 32

Describe the 4 primary branches of the spinal nerve

Answer 32

1) Meningeal branch - small, sensory to meninges 2) ramus communicans - cnonects to sympathetic trunk and innervates viscera (ANS) 3) ventral branch - largest branch, innervates hypaxial muscles and muscles of limb and branches into lateral and ventral cutaneous nerves 4) dorsal branch - branches into medial and lateral branches; innervates epaxial muscles and further branches into dorsal cutaneous nerves

Question 33

Label the numbered structures

Answer 33

1) Epineurium 2) Perineurium 3) Endoneurium

Question 34

Label the numbered structures

Answer 34

1. dorsal root 2. spinal ganglion 3. ventral root 4. dorsal branch 5. medial branch 6. lateral branch 7. ventral branch 8. sympathetic trunk 9. ramus communicans 10. meningeal branch

Question 35

Define fiber types

Answer 35

types of nerve fibers found in a spinal nerve and its branches

Question 36

Name the two types of fiber and describe them

Answer 36

1) Afferent (sensory) - axons associated with receptors and unipolar cell bodies in spinal ganglia 2) Efferent (motor) - axons that innervate muscle and gland; cell bodies are located in the spinal cord

Question 37

Name the two different divisions of afferent axons and where are they located?

Answer 37

1) General Somatic Afferent (GSA) receptors in skin and muscles, tendons, joints 2) General Visceral Afferent (GVA) receptors in viscera

Question 38

Name the two divisions of efferent axons adn what they innervate

Answer 38

1) Somatic Efferent (SE) innervates skeletal muscle 2) Visceral Efferent (VE) innervates cardiac and smooth muscle and glands

Question 39

What is unique about the VE pathway from the ANS?

Answer 39

it is composed of two multipolar neurons whereas the other pathways only have one.

Question 40

1) where is the first neuron of VE located? 2) Where is the second neuron of VE located?

Answer 40

1) First neuron's cell body is in the CNS (brain or spinal cord) 2) cell body of second nueron is located within autonomic ganglion in PNS

Question 41

Name the 5 regions of cutaneous innervations and their branches

Answer 41

1) Neck - dorsal and ventral cutaneous 2) Thorax - dorsal, lateral and ventral cutaneous 3) Abdomen - dorsal and lateral cutaneous 4) Limbs - individually named cutaneous branches of regional nerves that originate from nerve plexuses (brachial or lumbosacral) to the limbs 5) Face - named cutaneous branches of cranial nerves

Question 42

Where does Great Auricular nerve come from?

Answer 42

C-2 ventral branch

Question 43

True or False: C1 is not cutaneous

Answer 43

True

Question 44

1) What does the brachial nerve plexus innervate? 2) What does the lumbosacral nerve plexus innervate?

Answer 44

1) thoracic limb 2) pelvic limb

Question 45

What do nerve plexuses innervate?

Answer 45

limbs

Question 46

What are individual muscles composed of?

Answer 46

multiple mmyotomes that overlap in forming the muscles

Question 47

1) Describe innervation of trunk muscles. 2) Describe innervation of limb muscles.

Answer 47

1) multiple dorsal or ventral branches of spinal nerves serially innervate each individual muscle. Innervations overlap within the muscle because of myotome overlap 2) each muscle is innervated by the branch of a single regional nerve. Because of multiple myotomes per muscle, the regional nerves must contain axons from ventral branches of multiple spinal nerves. Exchange of axons among ventral branches as they forrm regional nerves produces a nerve plexus for each limb

Question 48

What does myelin do?

Answer 48

increases rate of transmittance along the axon

Question 49

Answer 49