Cardiovascular Physiology 26

Question 1

What are Local Controls?

Answer 1

Mechanisms that are independent of nerves or hormones that allow an organ or tissue to alter its own arteriolar resistance thereby regulating its own blood flow

Question 2

What is Active Hyperemia?

Answer 2

A local control which acts to increase blood flow when the metabolic activity of an organ or tissue increases

Question 3

What is Arteriole smooth muscle sensitive to?

Answer 3

Local chemical changes in the extracellular fluid surrounding the arterioles ie. changes in oxygen, carbon dioxide and pH

Question 4

What do changes in Oxygen, carbon dioxide and pH result from?

Answer 4

Changes in metabolic activity in the cells near the arterioles

Question 5

How do metabolic changes act on smooth muscle in the arterioles?

Answer 5

They cause vasodilation and increased blood flow

Question 6

How is Active Hyperemia induced?

Answer 6

Increases metabolic activity decreases oxygen in the cells and increases metabolites like carbon dioxide. This causes arteriolar dilation and brings blood flow to the organ back to normal conditions

Question 7

Where is Active Hyperemia most developed?

Answer 7

Skeletal Muscle, Cardiac Muscle and Glands

Question 8

When can locally mediated changes in Arteriolar resistance occur?

Answer 8

When a tissue or organ experiences a change in its blood supply resulting from a change in blood pressure

Question 9

How does an increase in arterial pressure affect blood flow to an organ?

Answer 9

It increases blood flow to an organ

Question 10

How does a decrease in arterial pressure affect blood flow to an organ?

Answer 10

It decreases blood flow to an organ

Question 11

What does altered blood flow do to the concentration of local chemicals?

Answer 11

It changes the concentration of local chemicals ie. Oxygen, carbon dioxide and hydrogen ions

Question 12

What does the change in concentration of local chemicals do to blood vessels?

Answer 12

Alters their state of constriction and ultimately altering blood flow to bring the state of local chemical back to normal

Question 13

How does Flow Autoregulation work if there Arterial low blood pressure?

Answer 13

Low blood pressure causes low blood flow to the organ which cause low oxygen and increased metabolites. Arteriolar dilation occurs and restores blood flow back to normal in organ and reestablishing metabolites

Question 14

What is the initial event that causes Active Hyperemia?

Answer 14

A change in metabolic activity

Question 15

When does Flow Autoregulation occur?

Answer 15

During constant metabolic activity and is the result of a change in pressure in an organ and as a result blood flow

Question 16

How does Flow Autoregulation work when there is an increase in Arterial Pressure?

Answer 16

An increase in arterial pressure increases blood flow to an organ which increases oxygen and decreases metabolites. This leads to arteriolar constriction and restoration of blood flow back to normal

Question 17

What kind of controls are Active Hyperemia and Autoregulation?

Answer 17

Local controls

Question 18

What activates Flow Autoregulation and Active Hyperemia?

Answer 18

A change in local chemicals due to either change in pressure or change in metabolic activity

Question 19

What is the Myogenic Response?

Answer 19

The direct response of arteriolar smooth muscle to stretch

Question 20

What are the two ways that Flow Autoregulation is mediated?

Answer 20

• The myogenic response

* Changes in local chemical

Question 21

How does Flow Regulation work when there is increases vessel wall stretch in organ?

Answer 21

When arterial pressure increases, there is increased blood flow to an organ causing the vessel wall to stretch. Flow autoregulation causes arteriolar constriction to restore blood flow toward normal in the organ

Question 22

What does Flow Autoregulation occur in the absence of?

Answer 22

Changes in metabolic activity