Lecture 16

Question 1

• Spinal enlargement:
• Where are the two enlargements of the spinal cord?

Answer 1

• widened regions of spinal cord to accommodate for innervation of the upper and lower limbs
• cervical and lumbar regions

Question 2

Conus medullaris=
Cauda equine=
Filum terminale=

Answer 2

• the lower end of the spinal cord
• “horse tail”–> bundle of spinal nerves
• fibrous strand anchoring the spinal cord to the coccyx (NON-functional, no nerve tissue)

Question 3

_________: opening in occipital bone for spinal cord

Answer 3

foramen magnum

Question 4

Where does the spinal cord end?

Answer 4

At L1-L2 level
(lumbar 1-2 region)

Question 5

3 layers of membranes protect the brain and spinal cord= meninges
1.
2.
3.

• the spinal cord resides within the ________ _______

Answer 5

1. Dura mater
2. Arachnoid mater
3. Pia mater
   - vertebral column

Question 6

H-shaped GREY matter=
WHITE matter=

Answer 6

• somas of neurons (cell bodies)
• myelinated axons

Question 7

Dorsal root= ______ signals
Ventral root= ______ signals
Ganglion=

Answer 7

sensory
motor
cluster of neurosomas in the PNS (somas of SENSORY neurons)

Question 8

_________: cluster of neurosomas in the CNS
found in ______ matter

Answer 8

nuclei
gray

Question 9

Organization of the gray matter in the spinal cord:
- ______ horn=
- ______ horn=
- ______ horn=

Answer 9

• dorsal or posterior= interneurons
• lateral= visceral (autonomic motor neurons)
• ventral or anterior= somatic motor neurons

Question 10

The spinal cord is a ____-way impulse conduction pathway and a ______ center

Answer 10

two; reflex

Question 11

The _____ matter is composed primarily of myelinated axons, organized in _______, each of which contains ascending or descending axon ______ related to specific functions

Answer 11

white; columns; tracts

Question 12

Tracts:

Answer 12

bundles of CNS axons that share a common origin, destination, and function

Question 13

• ascending tracts contains _______ information which is sent to the _____
• descending tracts contains _______ information that comes from the __________ of the brain and sends it to __________ cord

Answer 13

• sensory; brain
• motor; cerebral cortex; spinal

Question 14

3 main types of ascending tracts

1.
2.
3.

Answer 14

1. Spinothalamic tract
2. Dorsal column-medial lemniscus system
3. Spinocerebellar pathway

Question 15

Two pathways of spinothalamic tract:

1. __________: temperature and pain
2. __________: pressure and crude touch
   - both finish in _______

Answer 15

1. lateral
2. anterior
   - thalamus

Question 16

Fasciculus

Answer 16

bundle of axons

Question 17

____________: the ability to sense position (posture) and perform movements

Answer 17

proprioception

Question 18

Dorsal column-medial lemniscus system
- fasciculus gracilis (medial):
- fasiculus cuneatus (lateral):

-what type of info do these both carry?

Answer 18

• info from lower body
• info from upper body
• conscious proprioception, vibration, tactile sensation, and two point discrimination

Question 19

Spinocerebellar pathway
- Golgi tendon organs, muscle spindles, joint capsules –> __________
- doesn’t ascend to cerebral cortex
- ___________ proprioception

Answer 19

• cerebellum
• unconscious

Question 20

Types of neurons in spinothalamic tract
1.
2.
3.

Answer 20

1. First order neuron
2. Second order neurons
3. Third order neurons

Question 21

First order neuron
- location of cell bodies:
- where they end:

Answer 21

• dorsal nerve root ganglion
• substantia gelatinosa in dorsal horn (synapse to second order neurons)

Question 22

Second order neurons:
- location of cell bodies:
- where they end:
- their fibers form the ________ tracts

Answer 22

• dorsal horn
• thalamus
• ascending

Question 23

Third order neurons
- location of cell bodies:
- where they end:

Answer 23

• thalamus
• cerebral cortex of the brain

Question 24

Spinothalamic pathways ________ which means they cross to the other side within the spinal cord

Answer 24

decussate

Question 25

spinal nerve

Answer 25

a bundle of axons in the PNS that contain sensory and motor nerve fibers

Question 26

The _______ (sensory) and ________(motor) roots fuse to form a spinal nerve

Answer 26

dorsal; ventral

Question 27

Nerves have many _______ (bundles of axons) which are wrapped around _______

Answer 27

fascicles; perineurium

Question 28

3 connective tissue layers of nerve 1. 2. 3.

Answer 28

1. Epineurium: covering the peripheral nerve 2. Perineurium: around 1 fascicle 3. Endoneurium: inside fascicle; between axons

Question 29

2 major group of nerves: -_____ pairs of cranial nerves: some are sensory or motor, most are mixed - _____ pairs of spinal nerves: all are mixed

Answer 29

12 31

Question 30

__________= areas of sensation located in the skin a ___________ is a digram of the cutaneous (skin) regions innervated by each spinal nerve

Answer 30

dermatomes dermatome map

Question 31

following a traumatic injury, the clinician can test dermatomes to determine the presence and the extent of a ______ ____________ ______

Answer 31

spinal cord lesion

Question 32

nerve plexus:

Answer 32

a branching network of intersecting nerves; located in the spinal cord

Question 33

5 spinal nerve plexuses 1. 2. 3. 4. 5.

Answer 33

1. Cervical plexus 2. Brachial plexus 3. Lumbar plexus 4. Sacra plexus 5. Coccygeal plexus

Question 34

reflexes are: - ______: involve few, if any, interneurons and minimum synaptic delay - _______: occur without intent and are difficult to suppress - _______ : occur essentially the same way every time (automatic) reactions of ________ or _______ to stimulation

Answer 34

quick involuntary stereotyped glands; muscles

Question 35

Visceral reflexes:

Answer 35

involve a glandular or non-skeletal muscular response carried out in internal organs such as heart, blood vessels, or structures of the GI tract

Question 36

Somatic reflexes:

Answer 36

reflexes involving the somatic nervous system innervating skeletal muscle

Question 37

Spinal reflex:

Answer 37

somatic reflexes mediated by the spinal cord

Question 38

reflex arc:

Answer 38

the neural "wiring" pathway of a single reflex

Question 39

A reflex arc 1. stimulus activates _________ 2. Nerve impulse travels through sensory neuron to _______ 3. Nerve impulse is processed in the integration center by __________ 4. Motor neuron transmits nerve impulse to _______ 5. ________ responds to impulse from motor neuron

Answer 39

- receptor - spinal cord - interneuron - effector - effector

Question 40

Poly= Mono=

Answer 40

- multiple synapses - only one synapse

Question 41

polysynaptic reflexes contain __________, while monosynaptic reflexes DO NOT

Answer 41

interneurons

Question 42

The Stretch Reflex (aka _________) - type of reflex= - regulates skeletal muscle ________ - stretching of muscle detected by ________ ________

Answer 42

myotactic - monosynaptic reflex - length - muscle spindles

Question 43

Stretch reflex example - Patellar (Knee-jerk) reflex the stimulus (the tap on the patellar ligament stretches the quadriceps femoris muscle and initiates ________ of the muscle, thereby extending the knee joint

Answer 43

contraction

Question 44

The Golgi Tendon Reflex - reflex type: - it is a response to...... - it protects the muscle from excessively _______ loads by causing the muscle to relax and drop the load - tension is detected by....

Answer 44

- polysynaptic since inhibitory interneurons participate - excessive tension on the tendon - heavy - Golgi tendon receptors

Question 45

Alpha motor neurons (also called lower motor neurons):

Answer 45

innervate skeletal muscle and cause the muscle contractions that generate movement

Question 46

The flexor (________) reflex - the quick _______ of flexor muscles resulting in the withdrawal of a limb from an injurious stimulus - initiated by a ______ stimulus - flexor muscle= ________ - extensor muscle= _______

Answer 46

withdrawal - contraction - painful or noxious - contracts - relaxes

Question 47

The crossed extension reflex - _________ and _______ that limb and enables you to keep your balance - flexors= _________ (motor neurons _______) - extensors= ________ (motor neurons ________)

Answer 47

- extends and stiffens - relaxes; inhibited - contraction; activated

Question 48

For the crossed extension reflex to exist the _______ reflex must coexist (occur)

Answer 48

flexor (withdrawal) reflex