Actions of autonomic nervous system

Question 1

Eye (pupil diameter)
M3
B2
a1

Answer 1

M3 activation → iris circular muscle contraction → miosis
β2 activation → iris circular muscle relaxation → mydriasis (slight effect)
α1 activation → iris radial muscle contraction → mydriasis

Question 2

Eye (lens shape)
M3
B2

Answer 2

M3 activation → ciliary muscle contraction → relaxes ligament → accommodation for near vision
β2 activation → ciliary muscle relaxation → stretches ligament (slight effect)

Question 3

Eye (secretion)

M3

Answer 3

M3 activation → lacrimation

Question 4

Lung (bronchial smooth muscle)
M3
B2

Answer 4

M3 activation → muscle contraction → bronchoconstriction

β2 activation → muscle relaxation → bronchodilation

Question 5

Lung (bronchial glands)
M3
B2

Answer 5

M3 activation → mucous secretion

β2 activation → watery secretion via CFTR activation

Question 6

Heart
M2
B1, B2

Answer 6

M2 activation → bradycardia (SA node), ↓ AV node conductivity, ↓ atrial contractility

β1 and β2 activation → tachycardia (SA node), ↑ AV node automaticity and conductivity, ↑ His-Purkinje automaticity and conductivity, ↑ ventricular automaticity and contractility

Question 7

Vascular system 
M3
a1/a2
B2
D1

Answer 7

M3 activation (endothelial cells) → NO relaxation → ↓ blood pressure

α1 and α2 activation (smooth muscle cells) → constriction → ↑ blood pressure

β2 activation (liver and skeletal muscle) → relaxation → ↓ TPR → ↑ blood flow to these tissues

D1 activation → dilation of renal arteries and arterioles → ↑ renal blood flow

Question 8

Intestine
M3
a1/a2

Answer 8

M3 activation → contraction of circular and longitudinal muscles in intestinal walls → ↑ motility

α1 and β2 activation → relaxation→ ↓ motility

Question 9

Kidney and Bladder
D1
B1
M3
B2
a1

Answer 9

D1 activation → vasodilation → ↑ blood flow, GFR

β1 activation → stimulates renin release from kidney

M3 activation → contraction of bladder detrusor, relaxation of trigone and sphincter → promotes urination

β2 activation → relaxes detrusor → urinary retention

α1 activation → constricts trigone and sphincter → urinary retention

Question 10

Penis
M3
a1

Answer 10

M3 activation → relaxation of vessels → erection

α1 activation → contraction of seminal vesicles, prostatic capsule, vas deferens → ejaculation

Question 11

Uterus
B2
M3
a1
B2

Answer 11

Nonpregnant: β2 activation → relaxes uterus

Pregnant
M3 activation → contracts uterus
α1 activation → contracts uterus
β2 activation → relaxes uterus

Question 12

Secretions
M3
a1

Answer 12

M3 activation → stimulates watery secretions from salivary, nasopharyngeal, pulmonary, gastrointestinal, and eccrine sweat glands

α1 activation → stimulates secretion from apocrine sweat glands found in axillary and pubic regions; produces viscous salivary secretions

Question 13

Metabolism
a2
B2
B3

Answer 13

α2 activation → ↓ insulin release from pancreatic b cells

β2 activation → promotes glycogenolysis and gluconeogenesis in liver, glycogenolysis and K+ uptake in skeletal muscle, ↑ insulin release from pancreatic β cells (slight)

β3 activation → stimulates lipolysis in adipocytes