Autonomic Nervous System I

Question 1

Describe the organisation of the nervous system

Answer 1

CNS, Peripheral nervous system
PNS > Somatic NS, Autonomic NS
ANS > PSNS, SNS

Question 2

Describe the autonomic nervous system

Answer 2

Subdivision of the peripheral nervous system

Regulates body function not under conscious control

Question 3

Describe the physiological principles of ANS

Answer 3

Associated with rapid coordinated responses
No cognitive evaluation
Has a short latency
Endocrine control too slow for rapid readjustment of physiological function

Question 4

Describe the PSNS

Answer 4

Active during rest/digest
Anabolic - Building up
D-division: Digestion, Defecation, Diuresis

Question 5

Describe the SNS

Answer 5

Activity increases in stress (Fight or flight)
Catabolic - Breaking down stores
E-division: Excitation, Exercise, Emergency, Embarrassment

Question 6

What are the 2 types of outflow in the PSNS?

Answer 6

Cranial outflow, Sacral outflow

Question 7

Describe cranial outflow in the PSNS

Answer 7

Most vital, Vagus nerve (10th cranial nerve) which innervates (organ/etc with nerves) the viscera including heart, lungs and gut

Question 8

Describe the sacral outflow in the PSNS

Answer 8

Forms pelvic splanchnic nerves and innervates lower gut and pelvic genitourinary organs

Question 9

Describe the SNS around the body

Answer 9

Aka thoracolumbar system, all neurons in lateral horn (T1-L1)
Innervates every organ in body
Causes sweating, bp rises (vasoconstriction), dry mouth, pupils dilate, inc heart/respiratory rate to inc O2 to skeletal muscle

Question 10

What are the target tissues of the ANS?

Answer 10

Smooth muscle - Vascular, Visceral (gut/reproductive organs)
Exocrine glands - Lacrimal, salivary, sweat
Heart - Rate/force of contraction
Liver - Glucose utilisation

Question 11

Describe the main effects of the ANS on the body for SNS

Answer 11

Heart: Inc rate/force of contraction
Blood vessels: Constriction
Bronchi: No innvervation, affected by circulating adrenaline
Viscera: Dec activity
Eye: Dilation
Skin (sweat glands): Secretion
Salivary glands: Secretion

Question 12

Describe the main effects of the ANS on the body for PSNS

Answer 12

Heart: Dec rate/force of contraction
Blood vessels: No effect
Bronchi: Constriction
Viscera: Inc activity
Eye: Constriction
Skin: No effect
Salivary glands: Secretion

Question 13

What type of pathway is the ANS?

Answer 13

An efferent pathway consisting of 2 neuron chains (made up pre/postganglionic fibers from CNS to effector

Question 14

Describe the fibres of the PSNS

Answer 14

Long preganglionic fiber - Thinly myelinated

Short postganglionic fibre -Unmyelinated

Question 15

Describe the fibres of the SNS

Answer 15

Short preganglionic fibre - Thinly myelinated

Long postganglionic fibre - Unmyelinated

Question 16

Summarise the origin, neuron structure and ganglia location of the SNS

Answer 16

O: Thoracic/lumbar region of spinal cord
NS: Short pre, Long post
GL: CLose to spinal bord (paravertebral and collateral ganglia)

Question 17

Summarise the origin, neuron structure and ganglia location of the PSNS

Answer 17

O: Cranial/Sacral region of spinal cord
NS: Long pre, Short post
GL: Close to/in target organ