Chapter 11: The Nervous System

Question 1

how many pairs of spinal nerves do humans have?

Answer 1

31 pairs

Question 2

cervical nerves

Answer 2

8 (C1-C8)

Question 3

thoracic nerves

Answer 3

12 (T1-T12)

Question 4

lumbar nerves

Answer 4

5 (L1-L5)

Question 5

sacral nerves

Answer 5

5 (S1-S5)

Question 6

coccygeal nerves

Answer 6

1 (Co)

Question 7

cauda equina

Answer 7

formed by descending roots of lumbar, sacral, and coccygeal nerves

Question 8

what type of nerves are spinal nerves?

Answer 8

mixed, except first pair (motor)

Question 9

how does each spinal nerve split?

Answer 9

into a dorsal & ventral root inside the vertebral column

Question 10

posterior (dorsal) root

Answer 10

• sensory
• posterior root ganglion

Question 11

posterior root ganglion

Answer 11

contains cell bodies of sensory neurons whose axons conduct impulses from peripheral body parts into spinal cord

Question 12

anterior (ventral) root

Answer 12

• motor
• axons of motor neurons whose cell bodies are in the spinal cord

Question 13

spinal nerve

Answer 13

• union of anterior & posterior roots
• mixed
• 4 branches

Question 14

4 spinal nerve branches (outside spinal cord)

Answer 14

1. meningeal
2. posterior branch/ramus
3. anterior branch/ramus
4. visceral (only thoracic & lumbar)

Question 15

nerve plexuses

Answer 15

complex network forms by anterior rami (branches) of spinal nerves

Question 16

where are nerve plexuses NOT located?

Answer 16

T1-T12; instead the anterior rami become intercostal nerves

Question 17

3 nerve plexuses

Answer 17

1. cervical
2. brachial
3. lumbosacral

Question 18

cervical plexus

Answer 18

• formed by anterior rami of C1-C4 spinal nerves
• deep in neck
• supply muscles & skin of neck
• C3-C5 contribute to phrenic nerves, which transmit motor impulses to diaphragm

Question 19

why are C3, C4, & C5 nerves important?

Answer 19

they contribute to phrenic nerves, which transmit motor impulses to diaphragm

Question 20

brachial plexus

Answer 20

• formed by anterior branches C5-T1
• deep in shoulders
• 5 branches

Question 21

5 branches of brachial plexus

Answer 21

1. musculocutaneous
2. ulnar
3. median
4. radial
5. axillary

Question 22

musculocutaneous

Answer 22

supply muscles of anterior arms & skin of forearms

Question 23

ulnar & median

Answer 23

supply muscles of forearms & hands, skin of hands

Question 24

radial

Answer 24

supply posterior muscles of arms & skin of forearms & hands

Question 25

axillary

Answer 25

supply muscles & skin of anterior, lateral, & posterior arms

Question 26

lumbosacral plexus

Answer 26

- formed by anterior branches of L1-S4 roots - lumbar=abdomen, sacral=pelvic - contain obturator, femoral, & sciatic

Question 27

obturator

Answer 27

motor impulses to adductors of thighs

Question 28

femoral

Answer 28

motor impulses to muscles of anterior thigh & sensory impulses from skin of thighs & legs

Question 29

sciatic

Answer 29

supply muscles & skin of thighs, legs, & feet; largest & longest nerve of the body

Question 30

ANS

Answer 30

autonomic nervous system

Question 31

ANS characteristics

Answer 31

- part of PNS - functions w/o conscious effort - controls visceral activities - homeostasis - regulates smooth & cardiac muscles, glands - helps respond to stress - prepares body for exercise

Question 32

how to sensory nerve fibers transmit signals?

Answer 32

from viscera & skin to neural centers in CNS

Question 33

how to motor impulses travel?

Answer 33

along 2 efferent nerve fibers which synapse in ganglia outside CNS

Question 34

how do muscles & glands respond to these signals & impulses?

Answer 34

contracting, secreting, or being inhibited

Question 35

2 divisions of ANS

Answer 35

parasympathetic & sympathetic

Question 36

sympathetic

Answer 36

fight or flight

Question 37

parasympathetic

Answer 37

rest & digest

Question 38

autonomic nerve fibers

Answer 38

- all of the neurons are motor - somatic motor paths link the CNS & skeletal muscle fibers via 1 neuron - autonomic motor paths contain 2 neurons

Question 39

2 neurons associated with autonomic motor pathways

Answer 39

preganglionic & postganglionic

Question 40

preganglionic fibers

Answer 40

- axons of preganglionic neurons - neuron cell bodies in CNS

Question 41

postganglionic fibers

Answer 41

- axons of postanglionic neurons - neuron cell bodies in ganglia - extend to visceral effector

Question 42

sympathetic division is also called..

Answer 42

thoracolumbar (T1-L2)

Question 43

where do preganglionic fibers originate? (sympathetic)

Answer 43

in spinal cord, leave via ventral roots, leave spinal nerves through white rami, & enter sympathetic chain (paravertebral) ganglia

Question 44

what makes up sympahetic trunk?

Answer 44

sympathetic chain ganglia & fibers that conenct

Question 45

where do sympathetic chain ganglia lie? (sympathetic)

Answer 45

some close to viscera & some further away from viscera

Question 46

parasympathetic division is also called...

Answer 46

craniosacral

Question 47

where do preganglionic neurons originate? (para)

Answer 47

brainstem & S2-S4 spinal nerves

Question 48

where do preganglionic fibers extend from? (para)

Answer 48

cranial or sacral nerves to terminal ganglia (near or in visceral organs)

Question 49

where are preganglionic fibers in head also included?

Answer 49

- oculomotor - facial - glossopharyngeal

Question 50

where are preganglionic fibers in thorax & abdomen also included?

Answer 50

vagus nerve, which contains 75% of all parasympathetic fibers

Question 51

what is the job of preganglionic fibers of sacral region?

Answer 51

carry impulses to pelvic viscera