12. Autonomics

Question 1

sympathetic vs parasympathetic:

where do they leave the CNS

Answer 1

s: thoracolumbar regions
ps: cranial and sacral regions

Question 2

sympathetic vs parasympathetic:

where do they synapse on postganglion fibers

Answer 2

s: sympathetic chain ganglia
ps: ganglia on or near target organ

Question 3

sympathetic vs parasympathetic:

preganglionic fibers release what NT onto what receptors

Answer 3

both Ach to nicotinic receptors

Question 4

sympathetic vs parasympathetic:

postganglionic fibers release what NT onto what receptors

Answer 4

s: NE onto alpha or beta adrenergic receptors
ps: Ach onto muscarinic cholinergic receptors

Question 5

preganglionic fibers of the sympathetic system that do not synapse at the sympathetic trunk do what

Answer 5

• → chromaffin cells of adrenal medulla
• release ACH onto nicotinic receptors
• influx of Na causes release of NE

Question 6

where are alpha 1 receptors found and what does their activation cause?

alpha 2?

Answer 6

Alpha 1: smooth muscle, causes contraction

Alpha 2: vascular smooth muscle, causes vasodilation

Question 7

where are beta 1 receptors found and what does their activation cause?

beta 2?

Answer 7

Beta 1: on cardiac myocytes

Beta 2: smooth muscle, cause relaxation

Question 8

what does activation of M1 ,M3, and M5 receptors cause?

M2, M4?

Answer 8

M1, M3, M5: IP3/DAG production and release of intracellular Ca

M2, M4: Gi proteins that lead to reduction in cAMP

Question 9

parasympathetic stimulation: SA node

• innervation via:
• receptors:
• effect:

Answer 9

• vagus
• muscarinic
• decreases rate of depolarization of pacemaker potential → slows HR

Question 10

sympathetic stimulation: SA node

• innervation via:
• receptors:
• effect:

Answer 10

• T1-5
• beta 1
• increases rate of depolarization of pacemaker potential → increases HR

Question 11

parasympathetic stimulation: AV Node and Ventricular Conducting Pathways (Bundle of His, Purkinjes)

• innervation via:
• receptors:
• effect:

Answer 11

• vagus
• muscarinic
• decreases slope of pacemaker potential; decreases depolarization rate during phase 0 of slow AP → decreased conduction velocity through AV node and ventricles

Question 12

sympathetic stimulation: AV Node and Ventricular Conducting Pathways (Bundle of His, Purkinjes)

• innervation via:
• receptors:
• effect:

Answer 12

• T1-5
• beta 1
• increases rate of depolarization during phase 0 and pacemaker potential
  → increased conduction velocity through AV node; increased ventricular rate if AV node is pacemaker

Question 13

parasympathetic stimulation: Cardiac Myocytes

• innervation via:
• receptors:
• effect:

Answer 13

• vagus (atria), debated for ventricles
• muscarinic
• decreased Ca entry into myocyte
  → decrease in atrial contractility, possible decrease in ventricular

Question 14

sympathetic stimulation: Cardiac Myocytes

• innervation via:
• receptors:
• effect:

Answer 14

• T1-5
• beta 1, beta 2 sometimes
• increases Ca conduction into myocytes
  → increase in contractility (muscle pumps stronger)

Question 15

sympathetic stimulation: Cerebral Vasculature

• innervation via:
• receptors:
• effect:

Answer 15

• local control (neuronal activity produces metabolites that vasodilate the local blood vessels in proportion to the metabolic need)
• alpha 1
• vasoconstriction

***only when systemic blood pressure becomes high enough that it might damage the cerebral capillaries; small arteries constrict to protect capillaries

Question 16

parasympathetic stimulation: Coronary Arteries

• innervation via:
• receptors:
• effect:

Answer 16

• vagus
• muscarinic
• vasodilation

Question 17

sympathetic stimulation: Coronary Arteries

• innervation via:
• receptors:
• effect:

Answer 17

• T1-T5
• alpha 1
• vasoconstriction

Question 18

sympathetic stimulation: Cutaneous Vasculature

• innervation via:
• receptors:
• effect:

Answer 18

• multiple sources
• alpha 1
• vasoconstriction

***except sweat glands, muscarinic receptors causing vasodilation

Question 19

parasympathetic stimulation: Skeletal Muscle Vasculature

• innervation via:
• receptors:
• effect:

Answer 19

• vagus
• muscarinic
• vasodilation

Question 20

sympathetic stimulation: Skeletal Muscle Vasculature

• innervation via:
• receptors: alpha 1 vs beta 2
• effect:

Answer 20

• multiple
• alpha 1: vasoconstriction
• beta 2: vasodilation

Question 21

sympathetic stimulation: Splanchnic Vessels

• innervation via:
• receptors:
• effect:

Answer 21

• T5-L2 (celiac, superior and inferior mesenteric ganglion)
• alpha 1
• vasoconstriction

***vasodilation occurs when sympathetic input stops

Question 22

sympathetic stimulation: Veins

• innervation via:
• receptors: alpha 1 vs alpha2/ beta2
• effect:

Answer 22

• alpha 1: contraction → increases blood return to heart
• alpha 2/ beta 2: relaxation → slowing blood return to heart

Question 23

parasympathetic stimulation: Pulmonary Vasculature

• innervation via:
• receptors:
• effect:

Answer 23

• vagus
• muscarinic
• vasodilation (via NO production and release)

Question 24

sympathetic stimulation: Pulmonary Vasculature

• innervation via:
• receptors: alpha 1 vs beta 1/2
• effect:

Answer 24

• first five thoracic ganglia
• alpha 1: vasoconstiction of large vessels
• beta 1/2: vasodilation of large vessels

Question 25

parasympathetic stimulation: Upper Airways - innervation via: - receptors: - effect:

Answer 25

- PS branches of trigeminal and sphenopalatine ganglion - muscarinic - vasodilation and increased mucus secretion

Question 26

sympathetic stimulation: Upper Airways - innervation via: - receptors: - effect:

Answer 26

- superior cervical ganglia (CN7) - alpha 1 - vasoconstriction and reduced mucus secretion

Question 27

parasympathetic stimulation: Lower Airways - innervation via: - receptors: - effect:

Answer 27

- vagus - muscarinic - bronchoconstriction and increased mucus synthesis/ secretion

Question 28

sympathetic stimulation: Lower Airways - innervation via: - receptors: - effect:

Answer 28

- T1-T5 - beta 2 - bronchodilation

Question 29

sympathetic stimulation: Renal Vasculature - receptors: - effect:

Answer 29

- alpha - vasoconstriction of renal artery and all arteries in kidney, afferent and efferent arteriole → decreased blood flow into kidney, decreased urine production, preservation of BP

Question 30

sympathetic stimulation: Juxtaglomerular Apparatus - innervation via: - receptors:

Answer 30

- beta 1 (granule cells of afferent arteriole) - increased release of renin → increased production of ANG → ANG2 → aldosterone → reabsorption of Na; release of ADH → water reabsorption → increase blood volume

Question 31

alpha 1 receptors are found where (5) and cause what

Answer 31

- cerebral, cutaneous, skeletal m, pulmonary vasculature - coronary a - splanchnic vessels - veins - upper airways CONSTRICTION

Question 32

alpha 2 receptors are found where and cause what

Answer 32

veins DILATION

Question 33

beta 1 receptors are found where (5) and cause what

Answer 33

- SA node (increase HR) - AV node (increase conduction) - cardiac myocytes (increase contractility via Ca) - pulmonary vasculature (dilation) - juxtaglomerular apparatus (increase blood volume via renin release) overall increases

Question 34

beta 2 receptors are found where and do what

Answer 34

- cardiac myocytes (increase contractility via Ca) - skeletal m vasculature (dilation) - veins (relaxation, decreased venous return) - pulmonary vasculature (dilation) - lower airways- dilation mostly dilation