Week 3; anatomy of the PNS and autonomic nervous system

Question 1

What do sensory nerves do?

Answer 1

afferent nerves carry information from sensory receptors to the CNS.

Question 2

What are the two body parts included in sensory division?

Answer 2

1. somatic (skin, muscles, joints)
2. visceral organs

Question 3

What do motor nerves do?

Answer 3

Efferent nerves carry information away from the CNS

Question 4

What are the two body parts included in motor division?

Answer 4

1. somatic nerves innervate skeletal muscles
2. autonomic nerves innervate glands, cardiac and smooth muscle

Question 5

3 key anatomical differences between sympathetic and parasympathetic division?

Answer 5

1. sites of origin
2. length of axons
3. location of ganglia

Question 6

2 types of nerves in the PNS:

Answer 6

1. cranial nerves
2. spinal nerves

Question 7

3 nerves classified on impulse and direction:

Answer 7

1. sensory
2. motor
3. mixed

Question 8

3 connective tissue in PNS

Answer 8

1. epineurium (surrounds peripheral nervous)
2. perineurium (surrounds fascicles)
3. endoneurium (surrounds individual nerve axons)

Question 9

2 different types of roots

Answer 9

1. dorsal root - sensory
2. ventral root - motor

Question 10

How many spinal cords are there ?

Answer 10

31 spinal cords
- 8 cervical
- 12 thoriac
- 5 lumbar
- 5 sacral
- 1 coccygeal

Question 11

What is ramus?

Answer 11

Ramus is the site where dorsal and ventral nerves meet and become mixed spinal nerves

Question 12

what is dorsal rami ?

Answer 12

provide motor and sensory innervation to the skin and back (smaller)

Question 13

What is ventral rami?

Answer 13

provide sensory and motor innervation to the trunk and rest of limbs (bigger)

Question 14

What are nerve plexuses ?

Answer 14

they are formed by ventral rami. Fibres from each rami project to periphery via many pathways. They are important incase a nerve is damaged, means the part still has nerves and functions and isn’t destroyed.

Question 15

4 types of nerve plexuses and their functions:

Answer 15

1. cervical - located under the sternocleidomastoid
2. brachial - neck and shoulder, innervates the arm
3. lumbar - located within the psoas muscle, innervates abdominal wall, anterior and medial thigh
4. sacral - posterior to lumbar, innervates buttocks, pelvis and lower limbs

Question 16

What ventral rami is the brachial plexus made from?

Answer 16

C5-C8 and T1

Question 17

What are the 4 parts of brachial plexuses?

Answer 17

1. 5 roots
2. 3 trunks
3. 3 cords
4. 5 peripheral nerves

Question 18

5 peripheral nerves in the brachial plexuses?

Answer 18

axillary, musculocutaneous, ulnar, radial, median

Question 19

How many cranial nerves are there and where are they attached?

Answer 19

12 cranial nerves
- CN1 attaches to cerebrum
- CN11 attaches to diencephalon
- CN111-CNXII attach to brainstem

Question 20

What does the ANS control?

Answer 20

glands, cardiac muscle, smooth muscle, adipose tissue

Question 21

What does the ANS maintain?

Answer 21

homeostatis, body temp, heart rate, blood pressure, water

Question 22

what are the target organs of the ANS?

Answer 22

thoracic and abdominopelvic cavities + the body wall

Question 23

definition of preganglionic neurons

Answer 23

found in the CNS, before reaching the ganglion, axons are called preganglionic fibers

Question 24

definition of postganglionic neurons

Answer 24

found in the PNS, cell bodies in the autonomic ganglia, axons are called postganglionic fibers

Question 25

Anatomy of sympathetic division

Answer 25

cell bodies of the preganglionic neurons are in the lateral horn of the spinal cord. preganglionic fibers leave the spinal cord at the ventral roots at the thoracic and superior lumbar segments
- synapse close to spinal cord, preganglionic fibers are short, post ganglionic fibers are long

Question 26

recite diagram from wall : division of sympathetic division

Answer 26

…..

Question 27

3 divisions of ganglia

Answer 27

1. sympathetic chain ganglia
2. collateral ganglia
3. adrenal medullae

Question 28

How does adrenal medullae supplement the sympathetic NS?

Answer 28

• increases metabolism. Lasts 5-10x longer than ANS. Reaches all tissues of the body and releases epinephrine and norepinephrine to 100% of the body

Question 29

Anatomy of parasympathetic division:

Answer 29

The cell bodies of parasympathetic division are in the brain stem and sacral segment of the spinal cord. They synapse with ganglia within close range to the target organ, preganglionic neurons are long and postganglionic neurons are short.

Question 30

What is the vagus nerve ?

Answer 30

provides 75% of all parasympathetic outflow

Question 31

What neurotransmitter does parasympathetic division produce?

Answer 31

ach - acetylcholine

Question 32

What neurotransmitter does sympathetic division produce?

Answer 32

norepinephrine / noradrenaline

Question 33

cholinergic receptors

Answer 33

all parasympathetic division - cells that respond to ach
1. nicotonic receptors:
all ganglionic neurons, release influx of na+ through cation channels
EXCITATORY
2. muscarnic receptors
all parasympathetic target organs e.g glands, cardiac, smooth muscle
EXCITATORY OR INHIBITORY

Question 34

adrenergic receptors

Answer 34

bind epinephrine and norepinephrine with differing affinities. found on sympathetic target organs, alpha and beta receptor types