Nervous System VII

Question 1

What is the anatomy of CNS and what is it separated into?

Answer 1

Brain and spinal cord
Gray and white matter

Question 2

What does gray matter consist of?

Answer 2

Unmyelinated somas, dendrites, and axons
- butterfly shape inside spinal cord, outer of brain

Question 3

What does white matter consist of?

Answer 3

Mainly myelinated axons
- outer of spinal cord, inner of brain

Question 4

Why is brain and spinal cord different colours?

Answer 4

Different portions of neurons
- more or less myelin

Question 5

What are meninges and where are they located?

Answer 5

Pia mater(attached to brain spinal cord), arachnoid membrane (subarachnoid space), dura mater(most outer layer)
- 3 layers create protection around brain and spinal cord

Question 6

Where is cerebrospinal fluid?

Answer 6

In subarachnoid space between pia and dura

Question 7

What is the spinal cord?

Answer 7

Major pathways for info flowing back and forth between brain and skin, joints, organs, and muscles of the body
- brain to periphery, periphery to brain

Question 8

What are 5 regions further subdivided into 31 segments?

Answer 8

Cervical (8), thoracic (12), lumbar (5), sacral (5), coccygeal (1)

Question 9

What does each segment have?

Answer 9

Has bilateral pair of spinal nerves, each nerve splits into ventral and dorsal roots

Question 10

What kind of sensory info does dorsal root carry?

Answer 10

Afferent to CNS

Question 11

What type of info does ventral root carry?

Answer 11

Carries efferent info muscles and glands

Question 12

What does

Question 13

What is difference between nuclei and ganglia?

Answer 13

Nuclei: clusters of cell bodies in CNS
Ganglia: clusters of cell bodies in PNS

Question 14

What does gray matter in spinal cord consist of?

Answer 14

Sensory and motor nuclei

Question 15

What does white matter of spinal cord consist of?

Answer 15

Tracts of axons carrying info to and from brain

Question 16

What are ascending tracts?

Answer 16

Sensory tracts that carry sensory info to brain
- dorsal and external lateral

Question 17

What are descending tracts?

Answer 17

Efferent tracts that that carry commands to motor neurons
- ventral and interior lateral
- down regions of spinal cord

Question 18

What is a spinal reflex?

Answer 18

Spinal cord can act as integrating center to initiate response to a stimulus without receiving input from the brain
- rapid reflex
- sensory input comes into spinal cord and immediate output is sent

Question 19

What is the main difference between humans and lower organisms?

Answer 19

• cerebral cortex of humans has many folding in and out, increase surface area, increase neurons

Question 20

How many neurons in brain?

Answer 20

85 billion, containing thousands of synapses

Question 21

What are 6 major divisions of brain?

Answer 21

Cerebrum, cerebellum, diencephalon, midbrain, pons, medulla
- last 3 are brainstem

Question 22

What is the brainstem

Answer 22

Oldest and most primitive region of the brain

Question 23

What are 4 major regions of brainstem?

Answer 23

• midbrain, pons, medulla oblongata, reticular formation

Question 24

What does brainstem contain?

Answer 24

• ascending and descending tracts run through
• 11 of 12 cranial nerves (not olfactory)
• many nuclei

Question 25

What basic processes is brainstem involved in?

Answer 25

Arousal and sleep, muscle tone and stretch reflexes, coordination of breathing, blood pressure regulation and modulation of pain

Question 26

What does medulla contain?

Answer 26

White matter contain all ascending somatosensory tracts and descending corticospinal tracts
Nuclei

Question 27

Why does left side of brain control right side of body?

Answer 27

90% of corticospinal tracts crossover at pyramids of medulla

Question 28

What involuntary functions does nuclei of medulla control?

Answer 28

• cardiovascular center and respiratory center
• vomiting center
• swallowing center
• coughing, sneezing and hiccuping

Question 29

What does pons contain and do?

Answer 29

Contains nuclei and tracts
- relays info between cerebellum and cerebrum
- assists medulla in coordination of breathing

Question 30

What is the midbrain (mesencephalon)?

Answer 30

Junction between lower brainstem and diencephalon (nuclei and tracts)
- contains substantia Nigra

Question 31

What are functions of midbrain?

Answer 31

-primary is controlling eye movement
- relays auditory and visual reflexes (movement of body in response to stimuli)