PHARM A29: Introduction to Autonomics

Question 1

What is the myelination status of autonomic nervous system nerves?

Answer 1

The preganglionic fiber is myelinated, while the postganglionic fiber is not

Question 2

What is the sole criteria for distinguishing the sympathetic from the parasympathetic nervous system?

Answer 2

Location of the preganglionic cell body: SNS cell bodies are located in the thoracolumbar region and PSNS bodies are located in the cranial and sacral regions

Question 3

What is the myelination status of motor nerves?

Answer 3

Myelinated

Question 4

Are the preganglionic or postganglionic nerves longer in the SNS? In the PSNS?

Answer 4

In the SNS the postganglionic fibers are longer; in the PSNS the preganglionic fibers are longer

Question 5

True or False: Sympathetic preganglionic fibers can activate multiple postganglionic fibers to create a diffuse response

Answer 5

True

Question 6

Through what structure do sympathetic nerve fibers reach the sympathetic chain?

Answer 6

White rami

Question 7

Following the entry of a SNS fiber into the sympathetic chain, what are the three routes that can be taken?

Answer 7

The fiber can 1) synapse at the same spinal cord level 2) ove up or down the chain to synapse at another spinal cord level or 3) exit the chain without synapsing and synapse on prevertebral ganglia

Question 8

Through what structure can preganglionic SNS fibers exit the sympathetic chain?

Answer 8

Grey rami

Question 9

What is the relative affinity of ACh for the nicotinic and muscarinic receptors?

Answer 9

Equal

Question 10

Where are nicotinic cholinergic receptors found? Muscarinic?

Answer 10

At autonomic ganglia on postganglionic cell bodies and skeletal muscle ; some end/ target organs

Question 11

What is the relative affinity of norepinephrine to alpha 1 and 2 and beta 1 adrenergic receptors? What is the relative threshold for activation by NE among the three?

Answer 11

Equal; B1 has a lower threshold than A1 and 2

Question 12

What neurotransmitters are used at SNS and PSNS synapses?

Answer 12

PSNS- both synapses use ACh; SNS- preganglionic fiber is cholinergic, and post is adrenergic (except cholinergic going to sweat glands)

Question 13

What is the difference between a junctional and extrajunctional receptor?

Answer 13

Junctional receptors are located very near nerve terminals, while extrajunctional receptors are not and so they require greater concentrations of release or a circulating substance

Question 14

What branch of the autonomic nervous system generally sets the predominant tone for dual innervated organs?

Answer 14

PSNS

Question 15

What is miosis? What is the opposite?

Answer 15

Miosis is the parasympathetically stimulated pupillary constriction; Opposed by SNS stimulated mydriasis

Question 16

What is the response of vasculature to muscarinic stimulation?

Answer 16

Vasodilation

Question 17

What is the effect of stimulating a B2 adrenergic receptor?

Answer 17

Vasodilation

Question 18

What is the effect of stimulating a B1 receptor?

Answer 18

Increased contractile force of the heart and heart rate

Question 19

What is the effect of stimulating A1 or A2 adrenergic receptors?

Answer 19

Vasoconstriction

Question 20

Which organs do not have dual intervention and what branch of the ANS does innervate them

Answer 20

Blood vessels- only SNS; Sweat glands- only sympathetic cholinergic; adrenal glands- only sympathetic; pili arrector mm.- SNS only; Bronchioles- PSNS only