Intro to nervous system (lec 2)

Question 1

the two major components of the nervous system

Answer 1

• Central nervous system (CNS)
• Peripheral nervous system (PNS

Question 2

function of the nervous system

Answer 2

(1) receive and process information
(stimuli) from the environment
(internal/external)
(2) Coordinate and carry out an
appropriate action to respond to
those stimuli

Question 3

components of the CNS

Answer 3

brain and
spinal cord

Question 4

components of the PNS

Answer 4

all nerves
outside of CNS

Question 5

functional divisions of the PNS

Answer 5

• Somatic Nervous System
• Visceral (a.k.a., autonomic)
  Nervous System

Question 6

stimuli of the somatic nervous system

Answer 6

largely external
e.g., touch, vibration,
external forces due to
gravity, etc.

Question 7

responses of the somatic nervous system

Answer 7

Responses voluntary
E.g., motor control over
skeletal muscles

Question 8

stimuli of the visceral nervous system

Answer 8

primarily internal
e.g., body temp, heart rate

Question 9

responses of the visceral nervous system

Answer 9

vinvoluntary
E.g., control over smooth
muscle, visceral organs and
their functions (heart rate,
digestion, arousal, etc.)

Question 10

messengers

Answer 10

Basic cellular units of the nervous system

Question 11

how neurons communicate

Answer 11

Neurons communicate through chain-like connections

Question 12

the movement og the info travelling neurons

Answer 12

unidirectional

Question 13

dendrite

Answer 13

Receives info,
generally short

Question 14

cell body

Answer 14

Processes information

Question 15

axon

Answer 15

Relays information in
the form of electricity,
can be very long!

Question 16

myelin

Answer 16

increases speed
of electrical impulses

Question 17

synapse

Answer 17

Passes info onto other
nerves or effector organ
chemically

Question 18

the 2 neuron types in the somatic PNS

Answer 18

1) multipolar motor/efferent
2) pseudo-unipolar sensory/afferent

Question 19

Spinal Nerve

Answer 19

bundle of
sensory and motor neurons
(i.e., ‘mixed’) that emerge
from the spinal cord (CNS)
at regular intervals to
modulate sensory and
motor information from
the body’s periphery

Question 20

Ventral horn of spinal cord:

Answer 20

contains motor neuron cell
bodies for that spinal nerve

Question 21

Posterior root ganglion:

Answer 21

contains sensory neuron cell
bodies for that spinal nerve

Question 22

nerve

Answer 22

bundle of sensory
and motor axons
All parts in periphery are
mixed

Question 23

posterior root ganglion

Answer 23

group of cell bodies for
the sensory neurons

Question 24

ventral horn

Answer 24

group of
cell bodies for the motor
neurons

Question 25

Rootlets:

Answer 25

axon bundles from
sensory neurons (post.) and motor
neurons (ant.), closest to spinal
cord

Question 26

roots

Answer 26

convergence of the rootlets.
Posterior root contains cell bodies of sensory neurons! (post. root ganglion)

Question 27

spinal nerve

Answer 27

convergence of the
roots, emerges from vert. column

Question 28

rami

Answer 28

(sing. = ramus, ‘branch’): first
split of the spinal nerve into: posterior ramus and anterior ramus

Question 29

Posterior ramus

Answer 29

(to intrinsic back
muscles and associated skin

Question 30

anterior ramus

Answer 30

everything else

Question 31

motor units

Answer 31

-Often work in groups
* Can innervate a varying
number of muscle fibers

Question 32

why the muscles fibers are stimulated

Answer 32

Skeletal muscle fibers (myofibers) are stimulated to contract by the somatic nervous
system

Question 33

how motor neurons are form

Answer 33

This stimulation or innervation of myofibers occurs via motor neurons.

Question 34

Spinal cord

Answer 34

Part of the CNS from which the
spinal nerves emerge at regular
intervals from superior (closest to
brain) to inferior (closest to coccyx)

Question 35

how the spinal nerve pairs are named

Answer 35

Spinal (a.k.a., segmental) nerve
pairs are named in relation to the
vertebrae:
* Thoracic (12), lumbar (5), sacral (5)
and coccygeal nerves: superior vert
* Cervical nerves (8): inferior vert.
* Exception!  spinal n. C8

Question 36

what the cervical and lumbar enlargement correspond with plexuses

Answer 36

involved in
providing innervation to
the limbs.

Question 37

cauda equina

Answer 37

axons of inferior
spinal nerves

Question 38

conus medularris

Answer 38

end of the cord

Question 39

growth of the spinal cord

Answer 39

1- In the Embryo:
Spinal cord fills the
length of vertebral
column
2- At Birth:
Spinal Cord ends at L3
3- Spinal Cord
ends at L1/L2

Question 40

number of pairs of spinal nerve

Answer 40

31 but many more
structures to innervate,
especially in the limbs!

Question 41

peripheral nerves

Answer 41

Spinal nerves coalesce,
cross over, and branch
again to form named
peripheral nerves that
innervate multiple
structures (e.g., sciatic,
L4-S3 spinal nerve roots)

Question 42

dermatome

Answer 42

area/region of skin innervated by a
single spinal nerve

Question 43

myotome

Answer 43

group of muscles innervated by a
single spinal nerve

Question 44

Relationship of spinal nerves to cord

Answer 44

Each spinal nerve will
have a discrete area of
sensory innervation, and
will innervate a specific
set of muscles