Dr. Zachow - Lecture 2 - Intro to Phys

Question 1

What do each of these receptors do?

Answer 1

Alpha1 = vasoconstriction
Beta1 = inotropy and chronotropy
Beta2 = vascular smooth muscle such as the GI and bronchial smooth muscle.

Question 2

Adrenal Medulla’s role in the SNS?

Answer 2

The inner medulla, which is the innermost layer of the adrenal cortex, has preganglionic sympathetic fibers running into it to innervate. Then coming out of it are these Chrommafin cells, which act as modified postganglionics to spit out mostly epinephrine. It is supportive of the SNS, which can get things going but the adrenal medulla acts to ramp it up.

Question 3

What happens in flight or flight?

• epinephrine
• renal/cardiopulmonary
• gastrointestinal
• energy metabolism

Answer 3

When we get a stimulus that tells us to activate our SNS such as stress, pain, low BP, or exertion, there are signals sent to the SNS centers in the brain, which both send post-gangllionic fibers to secrete NorEpi at the effector organ.

• Epinephrine - After the pre-ganglionic fibers synapse, there are the chromaffin cells at the adrenal medulla, which secrete Epi throughout the body to kick it up a notch.
• Renal/Cardiopulm - vascular smooth muscle constriction (alpha1), inotropy and chronotropy (beta1), and bronchiolar dilation (beta2).
• GI - inhibition of GI motility (beta 2)
• energy metabolism - decreased insulin secretion from the pancreas, lipolysis, glycolysis and contractility (skeletal muscle - beta2), and gluconeogenesis and glycolysis (in the livier - beta2)

Question 4

What neurotransmitters are expressed in pre/postganglionic parasympathetics?

Answer 4

pre - acetylcholine

post- acetylcholine

Question 5

What type of receptors must be on the effector organ for it to respond to the acetylcholine coming from the postganglionic parasympathetic?

Answer 5

Cholinergic-muscarinic (CM)

Question 6

What is responsible for down-regulating the acetylcholine in the synapse between the postganglionic fiber and the effector organ?

Answer 6

cholinesterase

Question 7

What are the adrenergic and cholinergic agonists?

What are the adrenergic and cholinergic antagonists?

Answer 7

agonists - epi, norepi, and nicotine
antagonists - Beta blockers - propanolol, metoprolol, atenolol
- CM - atropine

Question 8

What is the mechanism for slowing down or speeding up heart rate based on pressure?

Answer 8

We have these baroreceptors. One is for low-pressure and is in the right atrium, the other is a high-pressure and is in the carotid sinus in the aortic arch. If pressure is too high/low then signals are sent to the medulla by way of the 9th and 10th cranial nerves (glossopharyngeal/vagus). The medulla has cardioacceleratory, cardioinhibitory, and vasomotor centers.

Question 9

What is the mechanism for slowing down or speeding up heart rate based on pressure?
- Part 2 - where does it go from the medulla? Parasympathetic/sympathetic

Answer 9

parasympathetic - it travels via the vagus nerve to synapse in the SA node, AV node, ventricle, atria.
Sympathetic - travels to the SA node, myocardium, atria, and vascular smooth muscle.

Question 10

normal vs orthostatic hypotension

Answer 10

normally when you get up there is a brief moment of a drop in venous return. Then your low pressure baroreceptors kick in and BP rises to correct for it.
When you have orthostatic hypotension, you have an increased BP at rest. When this happens, your low pressure baroreceptors translate this as you having too much volume so, when you stand up they don’t increase the blood pressure and you can have abnormally low BP. Also, your body might think that you have too much volume so you will be out water when in reality you just have high BP. This will lead you to be underperfused.

Question 11

What neurotransmitters to sympathetic pre/postganglionic fibers release?

Answer 11

Pre - Acetylcholine

Post - Norepinephrine