Lecture 9 - Spinal cord

Question 1

End-point of the spinal cord

Answer 1

Conus medullaris

Question 2

Within the spinal cord are 2 enlargements

Answer 2

Cervical and lumbar enlargement

Question 3

Cervical enlargement

Answer 3

From which the brachial plexus is formed

Innervates the upper extremities (C5-T1)

Question 4

Lumbar enlargement

Answer 4

From which the lumbar plexus is formed

Innervates the lower extremities (L1-S4)

Question 5

The spinal cord is practically divided into R/L halves by depressions called the:

Answer 5

Anterior (ventral) median fissure

Posterior (dorsal) median sulcus

Question 6

Center of grey matter

Answer 6

Central canal

Question 7

Central canal (3 things)

Answer 7

Continuous the length of the spinal cord
Continuous with the 4th ventricle of the brain
Filled with CSF

Question 8

surrounding the H-form on all sides are areas of ___ matter

Answer 8

White

Question 9

Equivalent of schwann cells of the PNS in the CNS

Answer 9

Oligodendrocytes

Question 10

Tracts (2)

Answer 10

Ascending tracts

Descending tracts

Question 11

Ascending tracts

Answer 11

Sensory facts/afferent

Relay impulses from the periphery or spinal levels to the brain

Question 12

Descending tracts

Answer 12

Motor tracts/efferent

Relay impulses from the brain to different spinal levels and the periphery

Question 13

the grey commissure (H) has a pair of horns, name them

Answer 13

2 anterior (ventral) horns
2 posterior (dorsal) horns

Question 14

Only found in T-spine and upper L-spine

Answer 14

Lateral horns

Question 15

The group of nerve fibers which enter the Dorsal Horn are called + content

Answer 15

Dorsal roots
Sensory information (no disregard from location)

Question 16

The group of nerve fibers which enter the Ventral horn are called + content

Answer 16

Ventral roots

Motor information

Question 17

Contains sensory neurons

Their cell bodies lie outside the s.c. in the intervertebral foramen and are called ?

Answer 17

Dorsal roots

? = dorsal root ganglia or spinal ganglia

Question 18

Contains axons of motor neurons

Cell bodies are contained within the anterior and lateral horns

Answer 18

Ventral roots

Question 19

The dorsal and ventral roots come together to form what?

Answer 19

The spinal nerve

Question 20

Spinal nerve exits where?

Answer 20

Through the intervertebral foramen

Question 21

The spinal nerve divides into

Answer 21

Dorsal and ventral rami

Question 22

Supplies the deep vertebral muscles and skin of the back

Answer 22

Dorsal rami

Question 23

Supplies all the ventral and lateral musculature

Answer 23

Ventral rami

Question 24

Spinal nerves are mixed, only sensory, or only motor

Answer 24

Mixed

Question 25

There are __ pairs of nerves + elaborate

Answer 25

31 | 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Question 26

Role of meninges

Answer 26

- Protect the brain and spinal cord - Form the supporting framework for arteries, veins and venous sinuses - Encloses the subarachnoid space for the circulation of CSF

Question 27

3 layers of meninges

Answer 27

Pia mater Arachnoid Dura mater

Question 28

Dura mater

Answer 28

Diaphragm Sellae

Question 29

Arachnoid

Answer 29

Subarachnoid space contains CSF

Question 30

Pia mater

Answer 30

Denticulate ligaments

Question 31

All three layers cover the spinal nerves until they exit through the _____ _____

Answer 31

Intervertebral foramina

Question 32

Specialized nerve endings

Answer 32

Free nerve endings (bare dendrites) | Encapsulated sensory endings (enclosed dendrites)

Question 33

- They branch between epithelial cells, connective cells, muscle cells, etc. - Are thought to act primarily as pain receptors of the body - Also act as tickle, itch and thermal, and touch receptors

Answer 33

Free nerve endings

Question 34

- They are surrounded by connective tissue capsules | - There are 6 in total

Answer 34

Encapsulated sensory endings

Question 35

Types of encapsulated sensory endings

Answer 35

``` Meissner corpuscles Pacinian corpuscles End bulbs of Krause Ruffini corpuscles Muscle spindles Golgi tendon organs ```

Question 36

Surrounds spinal ending of a dendrite Sensitive to light touch, pressure, and slow vibrations Rapidly adapting Found in the skin, mucous membrane of the tongue, and other sensitive regions of the body

Answer 36

Meissner corpuscles - very superficially located

Question 37

Located in the dermis and subcutaneous tissue, submucosa, joints, periosteum, and some viscera Adapt rapidly Stimulated by heavy pressure, fast vibrations, tickling

Answer 37

Pacinian corpuscles (located deeper)

Question 38

Located in the mucous of the lips, tongue, conjunctiva, external genitalia Common throughout the body (dermis of skin) Serve as cold receptors

Answer 38

End-bulbs of Krause

Question 39

Located in subcutaneous tissue, ligaments, tendons Slow adapting Respond to stretching of the skin (joint positioning, balance, posture, equilibrium, proprioception)

Answer 39

Ruffini corpuscles

Question 40

Location of muscle spindles

Answer 40

Skeletal muscle

Question 41

React to change in length

Answer 41

Muscle spindles

Question 42

Response to stretching of the muscles by the muscles spindles

Answer 42

Stimulation of the efferent (motor) neurons to the same muscle that contracts it (stretch is reflexively resisted)/

Question 43

Composition of golgi tendon organs

Answer 43

Dendrites that have many branches on the muscle tendon junction

Question 44

React to muscle tension

Answer 44

Golgi tendon organs

Question 45

Response of the golgi tendon orgnas

Answer 45

Stimulus will go back to the s.c. where the motor neurons to the same muscles are inhibited, thus relaxing the muscle

Question 46

All spinal nerves are CUTANEOUS except ___ (innervate the skin)

Answer 46

C1

Question 47

Dermatomes (3 things)

Answer 47

Important diagnostic technique Each spinal nerve innervates a segmental field of skin Generally there is a specific area for each of dermatomes (but considerable overlap)

Question 48

Reflexes (3)

Answer 48

Cranial reflexes Somatic reflexes Autonomic reflexes

Question 49

Reflex arc

Answer 49

``` Sensory receptor Sensory neuron Integrating center Motor neuron Effector ```