Integrated Cardiovascular Function

Question 1

The animal can withstand a loss of ____% of its blood without death.

Answer 1

40%

Question 2

A person loses ____% of its blood during blood donation

Answer 2

10%

Question 3

How does a decrease in blood volume lead to a decrease in Pa?

Answer 3

1. decrease in venous return
2. decrease EDV
3. decreased preload (pressure during EDV)
4. decreased CO

Question 4

What is the central venous pressure?

Answer 4

hydrostatic pressure in the anterior vena cava

Question 5

What does a high CVP suggest?

Answer 5

1. increased venous return
2. fluid overload
3. heart failure

Question 6

What does a low CVP suggest?

Answer 6

1. hypovolemia
2. dehydration
3. severe blood loss (hemorrhage)

Question 7

Contraction of the veins ___________ the unstressed volume and __________ venous return

Answer 7

decreases; increases

Question 8

Responses to hemmorage

Answer 8

1. baroreceptor response and atrial volume receptor reflex (RAAS, ADH)
2. capillary reabsorption of water
3. chemoreceptors sense decrease in PO2 (vasoconstriction)

Question 9

How long does it take for the body to restore blood volume, pressure, proteins, and blood cells?

Answer 9

Pressure: a few seconds
Volume: minutes to hours
Proteins: days (liver)
Blood cells: weeks (bone marrow)

Question 10

During severe hemorrhage, you can see contraction of the muscular capsule of what organ? Why?

Answer 10

spleen, it mobilizes rbc’s

Question 11

Hemorrhage causes a _________ in MAP and thus __________ filtration in the capillaries

Answer 11

decreased; increased

Question 12

Spleen contraction in the dog and horse can mobilize ____% of the total blood volume

Answer 12

10%

Question 13

What is hypoxemia?

Answer 13

decreased arterial PO2 below normal (<95 mmHg)

Question 14

What senses hypoxemia? Where?

Answer 14

1. peripheral chemoreceptors in carotid and aortic bodies (sense increased CO2, pH, decreased O2)
2. central chemoreceptors in medulla (sense elevated arterial CO2)

Question 15

What is the response of hypoxemia?

Answer 15

increasing sympathetic outflow to the blood vessels (vasoconstriction)

Question 16

Do Starling forces favor filtration or reabsorption during hemorrage?

Answer 16

reabsorption

Question 17

What limits reabsorption of ISF during hemorrage?

Answer 17

increased tissue oncotic pressure

Question 18

What secretes renin and when?

Answer 18

Juxtaglomerular cells (in the kidney) secrete renin when Pa decreases

Question 19

What does angiotensin II do?

Answer 19

1. vasoconstriction (increased TPR, Pa, decreased Pc, filtration)
2. secretion of aldosterone by adrenal cortex
3. hypothalamus

Question 20

What is another name for ADH?

Answer 20

vasopressin

Question 21

ADH causes arteriolar vasoconstriction via ____ receptors

Answer 21

V1 receptors