Chapter 14 - Spinal Cord and Spinal Nerves Flashcards Preview

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Flashcards in Chapter 14 - Spinal Cord and Spinal Nerves Deck (47):
1

What is the spinal cord?

-part of the central nervous system that extends from the brain

2

What type of information does the spinal cord convey?

-sensory input up the cord
-motor input down the cord
-reflex arcs

3

Where does the spinal cord begin and end?

Begins as a continuation of the medulla oblongata extending from the foramen magnum of the occipital bone to its termination as the conus medullaris between L1 - L2.

4

what is the Cauda Equina of the spinal cord?

the roots of the lower spinal nerves (AKA horse tail)

5

name and describe the 3 layers of meninges.

1) Dura Mater
-thick fibrous layer which forms a sac that encloses the cord
2) Arachnoid Mater
-located against dura mater
3) Pia Mater
- against spinal cord
-supplies cord with nutrients

6

what is located between the layers of meninges mater?

spaces.
1) epidural space
-outside dura mater
2)subdural space
-btw dura and arachnoid mater
3)subarachnoid space
-btw arachnoid and pia mater
-circulates cerebral spinal fluid

7

explain the process of lumbar puncture.

-A needle inserted into the subarachnoid space for the purpose of withdrawing Cerebral Spinal Fluid
-BTW L3 and L4

8

explain the process of Epidurals

-An anesthetic is injected into the epidural space
-Numb sensory neurons unless put too much then can numb motor neurons

9

what is White matter of the brain and spinal cord?

-formed by groups of myelinated axons (make white)

10

what is Grey matter of the brain and spinal cord?

formed by neuronal cell bodied and dendrites.

11

what structure do somatic motor cell bodies form?

Anterior (ventral) gray horns
-inside spinal cord

12

describe the structure white matter within the spinal cord.

divided into anterior, posterior, and lateral columns

13

what is a bundle of neuronal axons called? and where is this located?

Tract (spinal pathway)
-located in a specific area of the cord, and are all traveling to the same place

14

Describe the posterior spinal pathway.

-afferent tract
-Convey nerve impulses for discriminative touch, light pressure, vibration and conscious proprioception (awareness of your body in space) --> to cerebral cortex

15

describe the anterolateral pathway

-composed of afferent spinothalamic tracts
-Detect crude touch and pressure, pain, temp, itch, tickle
-go from spine to thalamus

16

describe the spinocerebellar tracts

carry signals from proprioception to the cerebellum.

17

Where do Motor Spinal Cord pathways convey information ?

convey nerve impulses from the brain stem
-Lateral and anterior cortico-spinal (from cerebellum to spine)
-Voluntary movement of skeletal muscles
Other: coordinate visual stimuli with body movements, maintain posture

18

what do spinal nerves do?

connect the CNS to muscles, glands, and receptors.

19

describe spinal nerves.

-Axons are surrounded by endoneurium, then bundled into fascicles and surrounded by perineurium.
-Multiple fascicles are bundled into nerves and surrounded by epineurium

20

Explain the arrangement of spinal nerves.

31 left-right pairs of spinal nerves emerge from the cord at regular intervals (called segments).
- leave from the intervertebral foramen between adjoining vertebrae
*Cervical – 8 pairs, C1-C8
*Thoracic – 12 pairs, T1-T12
*Lumbar – 5 pairs, L1-L5
*Sacral - 5 pairs, S1-S5
*Coccygeal – 1 nerve pair

21

How are spinal nerves connected to the spinal cord?

Two bundles of axons, called roots, connect each spinal nerve to the cord by rootlets.
*posterior root - sensory axon
*anterior root - motor axons

22

what is a dermatome?

A dermatome is an area of skin that is innervated by a single spinal nerve, indicated by the letters and number of a particular segmental nerve.

23

What part of the body is innervated by the dermatomes C6/C7?

thumb and index finger ("six Shooter")

24

What part of the body is innervated by the dermatome T4

nipple line

25

What part of the body is innervated by the dermatome T10

umbilicus

26

What part of the body is innervated by the dermatomes L1-L5

lower extremities

27

what are peripheral nerves?

nerve pluses
-a network of interweaving nerves
-anterior rami of spinal nerves

28

describe cervical pluxus.

-Formed by anterior rami of C1-C5
-Serves head, neck, and diaphragm

29

describe the phrenic nerve

-emerges from cervical pluxus
-Supplies diaphragm
“C345 keep the diaphragm alive”

30

describe brachial pluxus

Anterior rami
C5-C8+T1

31

what 5 major nerves emerge from the brachial pluxus

1) Musculocutaneous nerve
-Biceps brachii and brachioradialis
2) axillary nerve
-Serves deltoid and shoulder
3) radial nerve
-Tricepts brachii, proximal and middle phlanges
4)median nerve
-Flexors of the forearm, lateral aspect of palm and fingers
5)ulnar nerve
-Medial side of hand
-Little finger

32

describe lumbar pluxus

-L1-L4
-Supplies absominal wall, external genitalia, part of the lower limbs

33

what 2 nerves emerge from the lumbar pluxus?

Femoral nerve
– hip joints, extensor of knee, medial side of leg and foot
Obturator nerve
– adductor of hip and medial thigh

34

describe the sacral pluxus

L4-L5 + S1-S4
-Supplies buttocks, perineum, part of the lower limbs
-gives rise to sciatic nerve
-Skin of leg, muscles of back of thigh, leg and foot

35

what is a reflex?

fast involuntary response to a stimulus

36

what is a reflex arc?

pathway that a nerve impulse follows to produce a reflex.

37

what is a reflex arc composed of?

sensory receptor
sensory neuron
an integrating center inside the cord
an exiting motor neuron
an effector

38

describe the stretch reflex

causes contraction of a skeletal muscle in response to over stretching
monosynaptic reflex arc
*look at diagram

39

what is the tendon reflex?

controls muscle tension
-causes muscles to relax before tendons are torn
(polysynaptic)

40

crossed-extensor reflex

help maintain balance

41

flexor reflex

withdraw limb

42

what is the consequence of a completely severed spinal cord?

no motor or sensory function

43

what is the consequence of an incomplete injury of the spinal cord?

preservation of motor OR sensory function

44

what functions are lost in anterior cord syndrome?

motor, pain, temp, sensations are lost
touch, proprioception, and vibration are okay

45

Explain spinal reflexes

in a spinal reflex integration takes place in the spinal cord, not the brain.
-either monosynaptic or polysynaptic

46

withdrawal reflex

causes you to withdraw limb (often due to pain)

47

cross extensor reflex

maintain balance