PNS-efferent system (mostly ANS)

Question 1

describe somatic nervous system (type of control, acts on what?).

Answer 1

• voluntary control
• involves skeletal muscle

Question 2

describe autonomic nervous system (type of control, acts on what?).

Answer 2

• involuntary control
• involves heart, smooth muscles, glands

Question 3

There are no ganglia formed in the somatic nervous system. T or F.

Answer 3

T

Question 4

What is a ganglion?

Answer 4

Collection of cell bodies where neurons will synapse

Question 5

In the somatic n.s the end result is always excitation while in the ans, the end result may be inhibition or excitation, depending on which system is activated. T or F.

Answer 5

T

Question 6

Describe preganglionic fibres (type of fibres, releases what?).

Answer 6

• are made of type B fibres
• releases Ach

Question 7

Describe postganglionic fibres (type of receptors, type of fibres, releases what?).

Answer 7

• have nicotinic type II receptors (Ach from the preganglionic fibres bind to)
• are made of type C fibres
• releases Ach or NE/NA

Question 8

NE released from the postganglionic fibres will bind to which receptors on the effector tissue?

Answer 8

alpha or beta adrenergic receptors

Question 9

Ach released from the postganglionic fibres will bind to which receptors on the effector tissue?

Answer 9

muscarinic receptors not nicotinic receptors

Question 10

d-tubocurarine will block nicotinic receptors on ganglion. T or F.

Answer 10

F- d-tubocurarine will block nicotinic receptors in the somatic n.s.

Question 11

which drug will block nicotinic receptors on the ganglion?

Answer 11

Hexamethonium (so does Trimethaphan)

Question 12

Adrenal medulla releases what into peripheral blood?

Answer 12

NE and E

Question 13

NA synthesis?

Answer 13

Phenylalanine to tyrosine to DOPA to Dopamine to NA
note: formation of DOPA is the rate limiting step

Question 14

NA is metabolized by?

Answer 14

Monoamine oxidase (MOA) and Catechal-O-methyltransferase (COMT)

Question 15

Storage of dopamine in vesicles requires what?

Answer 15

• ATP and chromagranins
• note: Reserpine and guanethedine interferes with the storage

Question 16

ANS is modulated by which part of the brain?

Answer 16

hypothalamus, cerebral cortex and limbic system

Question 17

Parasympathetic NS is the cranio-sacral division of the ANS. T or F.

Answer 17

T

Question 18

Sympathetic NS is the thoraco-lumbar division of the ANS. T or F.

Answer 18

T

Question 19

ANS arises from what?

Answer 19

neural crest cells

Question 20

Post-ganglionic fibres never releases adrenaline. T or F.

Answer 20

T- only Ach or NE; adrenaline is a central neurotransmitter

Question 21

Whats the rate limiting step of NA synthesis?

Answer 21

formation of DOPA

Question 22

What are the cholinergic sympathetic fibres?

Answer 22

eccrine sweat glands and special blood vessels that supply skeletal muscles

Question 23

When is a fast EPSP formed?

Answer 23

when pre-ganglionic fibres release Ach which then binds to the nicotinic receptors

Question 24

Small intensely fluorescent cells release what?

Answer 24

catecholamines

Question 25

When is a slow EPSP formed?

Answer 25

when pre-ganglionic fibres release Ach which then binds to the SIF cells

Question 26

When is a slow IPSP formed?

Answer 26

When the SIF cells release dopamine which then binds to the d2 receptors note: regulatory effect to prevent an overwhelming summation

Question 27

When is a late slow EPSP formed?

Answer 27

When GnRH is released from the pre-ganglionic fibres

Question 28

What does the brain stem control in the ANS?

Answer 28

controls reflexes that are vital- HR, BP, respiration, swallowing, tears, vomiting, lens accommodation.

Question 29

What does the hypothalamus control in the ANS?

Answer 29

global and interdependent functions like control of thermal and nutritive economies

Question 30

What does limbic system control in ANS?

Answer 30

emotional experience and expression

Question 31

Where is the vasomotor located?

Answer 31

medulla note: its the control centre for sympathetic preganglionic neurons that control specific functions eg BP and HR

Question 32

Where is the hunger centre and what does it do?

Answer 32

- in the lateral hypothalamus - stimulates salivary glands

Question 33

Where is the satiety centre and what does it do?

Answer 33

- in the ventromedial nucleus in the hypothalamus - inhibits the hunger centre

Question 34

damage to what causes horner's syndrome?

Answer 34

- central nerve fibres synapsing on preganglionic neurons (level 1) - preganglionic sympathetic fibres from T1 (level 2) - superior cervical ganglion or its efferent flow (level 3)

Question 35

Effects of horner's?

Answer 35

- miosis - anhydrosis - ptosis - others include: anoscoria, vasodilation, enophthalmosis

Question 36

Causes of horner's syndrome?

Answer 36

- brainstem lesion like stroke - thoracic nerve root lesions like cancer - cervical paravertebral ganglion lesion like surgical trauma, metastatic cancer - arterial injury to neck like direct trauma