Nervous System: Motor and Sensory Pathways

Question 1

Three protective coverings of brain

Answer 1

skull
CSF
meninges

Question 2

Three layers of meninges from outer to inner

Answer 2

dura mater (2 layers, periosteal and meningeal, loose covering of brain)
arachnoid mater (projections that penetrate into dura, CSF reabsorption, blood vessels)
pia mater (adheres to surface of brain)

Question 3

What is CSF and what does it do? What is it produced by? How much is produced? (10)

Answer 3

clear and colourless fluid
bathes brain and spinal cord
mechanical protection (shock, cushioning)
nourishment (oxygen and glucose)
circulation (exchange of nutrients and wastes, communication)
produced by ependymal cells
500 mL each day
entire volume replaced in 8 hours
80-150 mL circulating at one time
moves through ventricles into spinal cord

Question 4

Three layers of meninges covering spinal cord

Answer 4

dura mater
arachnoid mater
pia mater

Question 5

Is dorsal root input/output and afferent/efferent? Where is it located?

Answer 5

sensory input
afferent

back

Question 6

Is ventral root input/output and afferent/efferent? Where is it located?

Answer 6

motor output
efferent

front

Question 7

What is a fascicle?

Answer 7

bundle of axons

Question 8

What are the layers of CT protecting nerves called and what do they cover?

Answer 8

endoneurium (surrounds myelin of axon)
perineurium (surrounds fascicle)
epineurium (surrounds entire nerve)

Question 9

What are the two types of nerves? Where do they exit from, how many pairs and what do they innervate?

Answer 9

cranial: exit via brain, 12 pairs, primarily innervate head and neck
spinal: exit via spinal cord, 31 pairs, mixed nerves (sensory, somatic, autonomic), innervate rest of body

Question 10

What are the types of sensory receptors and what do they detect?

Answer 10

thermo-receptors (temp.)
mechanoreceptors (touch, pressure, vibration)
chemoreceptors (chemical stimuli)
photo-receptors (light)
nocireceptors (pain)

Question 11

Where are chemoreceptors present?

Answer 11

medulla oblongata, carotid bodies, aortic bodies

Question 12

What do mechanoreceptors do and where are they found?

Answer 12

regulate visceral function

found in digestive tract, bladder, sinus, lung, colon

Question 13

Three types of somatic-sensory pathway and their purpose

Answer 13

Dorsal column pathway (pain, temp., fine sensation)
Spinothalamic tract (localized touch, crude sensation)
Spinocerebellar pathway (proprioceptive touch)

Question 14

What is proprioception and where are proprioceptors located?

Answer 14

sense relative position of body parts

found in muscles, tendons and joints

Question 15

What are visceral sensations caused by?

Answer 15

communication between viscera (internal organs) and CNS

disruption to homeostasis

Question 16

What do reflexes do? Are they fast? Where do they go via and what gets left out?

Answer 16

protection
rapid
via spinal cord, excluding brain

Question 17

How can reflexes be classified?

Answer 17

development (innate, acquired)
motor response (visceral, somatic)
complexity of circuit (monosynaptic, polysynaptic)
processing site (spinal, intersegmental, cranial)