Lecture 4 - Neural/Humoral Control of Circulation and BP

Question 1

Baroreceptors are _______ receptors that respond to the stretch of blood vessels. They are typically located at _____ points and in the aortic arch.

Answer 1

Mechanoreceptors

Bifurcation

Question 2

Baroreceptors in the Carotid sinus respond to pressures in the range of ____mmHg - ____mmHg. How do the barorecptors in the Aortic arch compare?

Answer 2

60mmHG - 180mmHg

The baroreceptors in the Aortic arch are less sensitive, with a threshold about 30mmHg higher than carotid barorreceptors. So basically they respond at pressures too high for the carotid barorecptors to respond.

Question 3

The ____ nerve innervates the Carotid sinus barorecptors, and it joins the glossopharyngeal nerve (CN ___). The ______ nerve innervates the Aortic arch barorecptors, and it joins the Vagus nerve (CN ___). Both of these CNs travel to the Nucleus of the Tractus Solitarius in the _____ of the brain. From the NTS, the signal propagates to the Cardiovascular centers in the _____ of the brain.

Answer 3

Sinus

CN IX

Aortic

CN X

Medulla

Medulla

Question 4

There are Vasoconstrictor, Cardiac Accelerator, and Cardiac decelerator centers in the Brain Stem. Which are under Sympathetic and which are under Parasympathetic control?

Answer 4

Vasoconstricor and Cardiac Accelerator centers are under SYMPATHETIC.

Cardiac Decelerator is under PARASYMPTATHETIC.

Question 5

The barroreceptor is NOT important for the ____-term regulation of MAP. It is mostly involved in response to changes in posture. Remember that ________ hypotension indicates an abnormality in the baroreceptor reflex.

Answer 5

Long-term

Orthostatic hypotension

Question 6

The control center for long-term control of MAP is the _____ via RAAS.

Answer 6

Kidneys

Question 7

What effect does EPO have on blood volume, and what does that mean for MAP?

Answer 7

It increases the production of RBCs, so it inreases blood volume –> that in turn increases MAP

Question 8

ADH acts on the _____ _____ in the nephron. It also acts on V1 receptor on vasculature, which increases intracellular [___] in the VSMCs via the IP3 pathway.

Answer 8

Collecting Duct

Ca++

Question 9

Where in the body is ACE produced?

Answer 9

In the lungs

Question 10

Angiotensin II stimulates the production of ______ in the Cortex of the Adrenal glands, which increases Na+ reabsorption in the DCT and in the Collecting Duct.

Answer 10

Aldosterone

Question 11

ANP is synthesized and stored in in atrial myocytes. It is a potent ______ (vasoconstrictor or dilator?) that is released in response to atrial wall stretch/distension due to blood volume expansion. It acts on the kidney to inhibit secretion of ______.

Answer 11

Vasodilator

Renin