Kim - Regulation Of Vasculature

Question 1

________ do not play a significant role in the regulation of systemic vascular resistance and arterial blood pressure

Answer 1

Parasympathetic nerves

It does, however, play a role in the regulation of the heart

Question 2

In blood vessels, ___——- released by sympatheic adrenergic nerves preferentially binds to α1-adrenoceptors to cause smooth muscle contraction and vasoconstrictionn

Answer 2

Norepinephrine

Question 3

Norepinephrine binding to Beta-2 receptors in blood vessels causes?

Answer 3

Vasodilation

Question 4

Explain vasomotor tone:

Answer 4

The vasoconstrictor area of the vasomotor center in the brain sends constant signals that tell the blood vessels to hold a baseline “sympathetic vasoconstrictor tone”, which maintain a partial state of contraction.

Sudden removal of sympathetic tone produces significant hypotension and vasodilation

Question 5

What does standing with. Venous poolin in the legs do ?

Answer 5

Decreases venous return, central venous pressure, ventricular preload.

This leads to a decrease in cardiac output and in arterial blood pressure.

Question 6

Stretch receptors in the heart are located at the _______ junctions and respond to atrial filling and contraction. An increase in firing of these, will lead to increased sympathetic activity. A decrease in central venous pressure will lead to a decrease in firing.

Answer 6

Venoatrial junctions

Question 7

Antidiuretic hormone is released by the ?

Answer 7

Posterior pituitary

Question 8

Specialized cells w/in the medulla and on arteries that monitor blood PO2, PCO2, or pH

Answer 8

Chemoreceptors

Question 9

What causes an increase in firing of the chemoreceptor cells that are located in the aortic arch and the carotid sinus?

Answer 9

Hypoxia, hypercapnia (high CO2), or high H ion concentration (acidosis)

Question 10

Examples of catecholamines

Answer 10

Epinephrine

Norepinephrine

Question 11

During activation of the sympathetic nervous system, ________ are released from the adrenal medulla into the blood stream

Answer 11

Catecholamines

Question 12

Moderately low levels of circulation epinephrine can cause vasodilation, but higher levels of circulating epinephrine will cause vasoconstriction. Why is this?

Answer 12

There are some B-2 receptors in the arterioles of a few specific organs which are more sensitive to epinephrine and promote vasodilation. With enough epinephrine, though, alpha 1 receptors become activated and cause vasoconstriction to take over.

Question 13

The relative distribution of blood flow to the organs is regulated by the vascular resistance of the individual organs, which is influenced by ____ and ____ mechanisms

Answer 13

Neurohormonal

Local regulatory

Question 14

A _______ in the availability of oxygen to the tissues increases blood flow

Answer 14

Decrease

Question 15

A ______ in metabolism increases blood flow to the tissues

Answer 15

Increase

Question 16

Vasodilator substances

Answer 16

Adenosine, carbon dioxide, potassium ions, hydrogen ions

Question 17

The transient increase in organ blood flow that occurs following a brief period of ischemia, usually produced by temporary arterial occlusion

Answer 17

Reactive hyperemia

Question 18

The increase in organ blood flow that is associated with increased metabolic activity of an organ or tissue

Answer 18

Active hyperemia

Question 19

Releases in every tissue in the body if the tissue becomes damaged or inflamed.

Has vasodilator effect on the arterioles and ability to increase capillary permeability

Answer 19

Histamine

Question 20

Formed in the blood and tissue fluids of some organs w/ tissue inflammation or by other similar chemical or physical effects on the blood or tissue

Causes both arteriolar dilation and increased capillary permeability

Normal role to help regulate blood flow to skin, salivary, and GI glands

Answer 20

Bradykinin

Question 21

The vascular endothelium serves as an important ________ role in the regulation of smooth muscle tone and organ blood flow.

Answer 21

Paracrine

Question 22

The intrinsic ability of an organ to maintain a constant blood flow despite changes in perfusion pressure

Answer 22

Autoregulation

Question 23

Organs with a high degree of autoregulation:

Answer 23

Coronary circulation, cerebral circulation, renal circulation

Question 24

Organs with a moderate degree of autoregulation of blood flow

Answer 24

Skeletal muscle circulation, gastrointestinal circulation

Question 25

Type of tissue with virtually no autoregulation:

Answer 25

Cutaneous circulation