Autonomics 2

Question 1

Primary neurotransmitter of the adrenergic system?

Answer 1

norepinephrine

Question 2

Are the levels of norepinephrine controlled by positive or negative feedback?

Answer 2

negative feedback

Question 3

What enzymes are able to breakdown norepinephrine? (2)

Answer 3

1. COMT (methylation in the synapse)
2. MAO (deamination in the presynaptic neuron)

Question 4

What adrenergic receptors are part of the sympathetic nervous system?

Answer 4

alpha-1, alpha-2, beta-1, beta-2, beta-3

Question 5

Which adreneric receptor (AR) is unique and why?

Answer 5

alpha-2 (a2), it is an autoreceptor on the presynaptic neuron

Question 6

What NTs are secreted from the adrenal medulla and in what ratio?

Answer 6

epinephrine (80%) and norepinephrine (20%)

Question 7

Can the adrenal medulla make epinephrine?

Answer 7

yes

Question 8

Two organs that are special cases in sympathetic signalling?

Answer 8

adrenal medulla and sweat glands

Question 9

Adrenal medulla

Answer 9

Ach release and binds to nicotinic receptors on the adrenal medulla which releases epi and NE into the bloodstream to travel and act on target organs

Question 10

Sweat Gland Special Case

Answer 10

ACh binds to nicotinic receptors on postganglionic fiber then those release ACh (NOT norepinephrine) and bind to muscarinic receptors on sweat glands

Question 11

Effect of Sympathetic System on Heart

Answer 11

increase heart rate and blood pressure

Question 12

Effect of Sympathetic System on Bronchioles

Answer 12

bronchial dilation

Question 13

Effect of Sympathetic System on Eyes

Answer 13

dilation of pupil by contracting the RADIAL muscles of the iris

Question 14

Effect of Sympathetic System on Blood Vessels

Answer 14

constricts blood vessels, increase blood pressure

Question 15

Effect of Sympathetic System on Stomach and Intestines

Answer 15

decrease GI motility by relaxing smooth muscle and contracting the sphincter

Question 16

Effect of Sympathetic System on Bladder

Answer 16

relax detrusor and contract sphincter

Question 17

Sympathetic Receptor in the Heart

Answer 17

beta-1 (b1)

Question 18

Sympathetic Receptor in the Eye

Answer 18

alpha-1 (a1)

Question 19

Sympathetic Receptor in the Lungs

Answer 19

beta-2 (b2)

Question 20

Sympathetic Receptor in Stomach and Intestines

Answer 20

beta-2 (b2) (and a1 to constrict the sphincters)

Question 21

Sympathetic Receptor of the Urinary Detrusor

Answer 21

beta-3 (b3)

Question 22

Sympathetic Receptor of Urinary Sphincters

Answer 22

alpha-1 (a1)

Question 23

Sympathetic Receptor of Salivary Glands

Answer 23

alpha-1

Question 24

Receptor of the Adrenal Medulla

Answer 24

Nicotinic (N)

Question 25

Main Sympathetic Receptor in Arteries and Veins

Answer 25

alpha-1 (also b2 to a smaller extent, as it is a vasodilator)

Question 26

Which sympathetic receptors are responsible for contraction/acceleration?

Answer 26

alpha-1 and beta-1 (a1 and b1)

Question 27

Which sympathetic receptors are responsible for relaxation?

Answer 27

beta-2 and beta-3 (b2 and b3)

Question 28

Phentolamine

Answer 28

alpha-1 blocker used to reverse epinephrine effetcs (prevents vasoconstriction so b2 takes over)

Question 29

Sympathomimetic

Answer 29

drugs that partially or completely mimic the actions of epinephrine or norepinephrine

Question 30

Is epinephrine selective?

Answer 30

no (non-selective) problem: wanting to iincrease blood pressure in an animal with cardiac disease

Question 31

Example of an a1 receptor agonist?

Answer 31

Phenylepinephrine

Question 32

Phenylepinephrine

Answer 32

can increase blood pressure without effects on the heart, not inactivated in the synapse by COMT (longer duration)

Question 33

Example of a b1 receptor agonist?

Answer 33

Dobutamine

Question 34

How do alpha-2 receptor agonists work?

Answer 34

activates the presynaptic receptor to decrease release of norepinephrine (negative feedback)

Question 35

Are alpha-2 receptor agonists sympathetomimetic?

Answer 35

no, because they do not activate adrenergic signals (only inhibitory G proteins)

Question 36

What type of G protein always activates?

Answer 36

S type

Question 37

Examples of b2 receptor agonists and their function

Answer 37

terbutaline and albuterol, used for coughing and bronchospasms

Question 38

Indirect acting sympathomimetics

Answer 38

stimulate release, prevent uptake, or prevent breakdown of norepinephrine

Question 39

Sympatholytic drug

Answer 39

inhibit the adrenergic signal