Chapter 14 - Spinal Cord and Spinal Nerves

Question 1

Spinal Cord Functions

Answer 1

1. Conduction
2. Neural Integration
3. Locomotion
4. Reflexes

Question 2

Spinal Meninges

Answer 2

1. Dura Mater
2. Arachnoid Mater
3. Pia Mater

Question 3

Dura Mater

Answer 3

• meninge
• tough, outer layer
• dense collagen fibers
• within epidural space

Question 4

Arachnoid Mater

Answer 4

• meninge
• middle layer
• subarachnoid space with CSF
• shock absorber & diffusion medium

Question 5

Pia Mater

Answer 5

• meninge
• delicate, inner layer
• elastic and collagen fibers

Question 6

Nerve

Answer 6

several axons wrapped by connective tissue

Question 7

Endoneurium

Answer 7

wraps one axon

Question 8

Perineurium

Answer 8

wraps a fascicle of axons

Question 9

Epineurium

Answer 9

wraps entire nerve

Question 10

Afferent Nerve Fibers

Answer 10

carry sensory signals from receptors to CNS

Question 11

Efferent Nerve Fibers

Answer 11

carry motor signals from CNS to effectors

Question 12

Somatic Nerve Fibers

Answer 12

innervate skin, skeletal muscles, bones, and joints

Question 13

Visceral Nerve Fibers

Answer 13

innervate blood vessels, glands, and viscera

Question 14

General Nerve Fibers

Answer 14

innervate widespread organs such as muscles, skin, glands, viscera, and blood vessels

Question 15

Special Nerve Fibers

Answer 15

innervate more localized organs in the head, including the eyes, ears, olfactory and taste receptors, and muscles of chewing, swallowing, and facial expression

Question 16

How many spinal nerves?

Answer 16

31 pairs

• C1-C8
• T1-T12
• L1-L5
• S1-S5
• Co1

Question 17

Proximal Branches of Spinal Nerves

Answer 17

• occur as it passes through the intervertebral space
• dorsal root (w/ dorsal root ganglion)
• ventral root

Question 18

Distal Branches of Spinal Nerves

Answer 18

• posterior ramus (innervates muscles and joints in the region of the spine and skin of the back)
• anterior ramus (innervated the anterior and lateral skin and muscles of the back and gives rise to the nerves of the limbs)
• meningeal branch (reenters vertebral canal and innervates the meninges, vertebrae, and spinal ligaments)

Question 19

Ganglion

Answer 19

cluster of cell bodies outside the CNS that contains sensory neurons

Question 20

Plexuses

Answer 20

anterior rami branch and merge repeatedly to give rise to 5 web-like nerve plexuses or peripheral nerves

1. Cervical plexus (neck)
2. Brachial plexus (shoudler)
3. Lumbar plexus (lower back)
4. Sacral plexus (below lumbar)
5. Coccygeal plexus (lower sacrum and coccyx)

Question 21

Cervical Plexus

Answer 21

• C1-C5
• innervates:
  
  • muscles of the neck
  • diaphragm (**phrenic nerve)
  • skin of neck & superior part of chest

Question 22

Brachial Plexus

Answer 22

• C5-T1 (C4 & T2)
• innervates:
  
  • pectoral girdle
  • upper limbs (**ulnar nerve)

Question 23

Lumbar Plexus

Answer 23

• T12-L4
• Innervates:
  
  • pelvic girdle
  • lower limbs

Question 24

Sacral & Coccygeal Plexuses

Answer 24

• L4-S4

* *sciatic nerve

Question 25

Properties of a Reflex

Answer 25

1. Requires stimulation 2. Quick 3. Involuntary 4. Stereotyped 5. Big role in homeostasis

Question 26

Reflex Arc

Answer 26

Route followed by nerve impulse 1. arrival of stimulus & activation of receptor 2. sensory neuron activated (to posterior horn of grey) 3. information processing in CNS 4. motor neuron activated (from anterior horn of grey) 5. peripheral effector responds

Question 27

Visceral (Autonomic) Reflex

Answer 27

- glands, cardiac muscle, smooth muscle * heart rate, respiration, digestion, urination - controlled by autonomic nervous system * sympathetic NS = fight or flight * parasympathetic NS = rest and digest

Question 28

Somatic Reflex

Answer 28

- involuntary control of skeletal muscles - controlled by somatic nervous system * stretch reflex = pateller reflex * tendon reflex = skeletal muscle can't break tendon * withdrawal (flexor) reflex = pain * plantar reflex = corticospinal tracts working

Question 29

Spinal Shock

Answer 29

syndrome of paralysis and absence of reflexes after transection of cord

Question 30

Neurogenic Shock

Answer 30

dangerous drop in blood pressure due to lack of sympathetic nervous system activity

Question 31

Paraplegia

Answer 31

paralysis of both lower limbs due to lesions from T1-L1

Question 32

Quadriplegia

Answer 32

paralysis of all four limbs due to lesions above C5

Question 33

Hemiplegia

Answer 33

paralysis on one side of the body usually due to stroke or brain lesions