Cardiovascular

Question 1

Define blood pressure

Answer 1

• the pressure that keeps the blood moving in the circulation (high on arterial side, low on venous side)
• the pressure exerted by the blood on the blood vessel wall

Question 2

What is the equation for mean arterial blood pressure?

Answer 2

MABP = diastolic pressure + 1/3(systolic pressure - diastolic pressure)

Question 3

How does ANP effect blood pressure?

Answer 3

decreases blood pressure by increasing urination, decreasing cardiac output, suppressing thirst, and vasodilation

Question 4

What stimulates the release of ANP?

Answer 4

release from myocardial cells stimulated by atrial stretching due to increase venous return

Question 5

How does ADH effect blood pressure?

Answer 5

increases blood pressure by decreasing urination, increasing cardiac output, and vasoconstriction

Question 6

What stimulates the release of ADH?

Answer 6

decreased blood volume or blood pressure

Question 7

How does Aldosterone effect blood pressure?

Answer 7

increases sodium retention by the kidneys, so increases blood volume and blood pressure

Question 8

How does Angiotensin II effect blood pressure?

Answer 8

vasoconstriction, so enhances venous return, and increases blood pressure

Question 9

If the radius of the vessel decreases, what happens to TPR?
What happens to blood pressure?

Answer 9

TPR will increase, and blood pressure will therefore increase

Question 10

Explain the baroreceptor reflex when blood pressure is increased

Answer 10

• baroreceptor firing increases
• parasymp. stimulation increases: decreased heart rate
• symp. stimulation decreases: decreased contractility and decreased vasoconstriction

Question 11

Explain the baroreceptor reflex when blood pressure is decreased

Answer 11

• baroreceptor firing decreases
• symp. stimulation increases: increased contractility and vasoconstriction
• parasymp. decreases: increased heart rate

Question 12

Describe what happens when an animal goes from a lying position to a standing position

Answer 12

• gravity causes blood to pool in lower extremities (expanded veins)
• decreased venous return to heart, so decrease EDV, SV, and CO
• decrease in blood pressure
• baroreceptor firing decreases: symp. increases, parasymp. decreases

Question 13

What is the starling equation?

What does each variable stand for?

Answer 13

Kf [(Pc + πi) - (πc + Pi)]
Kf - hydraulic conductance
Pc - capillary hydrostatic pressure
πi - interstitial osmotic pressure
πc - capillary osmotic pressure
Pi - interstitial hydrostatic pressure

Question 14

What happens when muscle tissue becomes more active?

Answer 14

• more pre-capillary sphincters relax, leading to more open capillary beds
• arteriolar vasodilation occurs, leading to more blood flow into the capillaries
• this leads to increased surface area and total volume, so diffusion and bulk flow increase

Question 15

What factors effect lymph flow?

Answer 15

• myogenic effect of smooth muscle
• skeletal muscle pump
• one-way valves
• respiratory pump

Question 16

What are the causes of edema?

Answer 16

• increase in capillary hydrostatic pressure
• decrease in capillary osmotic pressure
• increase in hydraulic conductance
  impaired lymphatic drainage

Question 17

What factors influence venous return?

Answer 17

• venous capacity
• bulk flow across capillary walls
• renin-angiotensin-aldosterone system
• sympathetic nervous system
• gravity
• skeletal muscle pump
• one-way valves
• respiratory pump
• cardiac suction

Question 18

What is circulatory shock?

Answer 18

when blood pressure falls so low, that adequate blood flow to the tissues can no longer be maintained

Question 19

What are the parameters and effects of Hypovolemic shock?

Answer 19

• hemorrhage, burns, surgery and trauma, and severe diarrhea and vomiting
• all lead to loss in blood volume

Question 20

What are the parameters and effects of Vasogenic shock?

Answer 20

septic shock: endotoxin release by invading bacteria stimulate nitric oxide release from macrophages
- overproduction leads to vasodilation, decreasing TPR
anaphylatic shock: release of histamine
- vasodilation and increased permeability of capillaries

Question 21

What are the parameters and effects of Cardiogenic shock?

Answer 21

heart failure, weakened heart muscles, decreases cardiac output

Question 22

What are the parameters and effects of Neurogenic shock?

Answer 22

• decreased symp. activity leading to loss of vascular tone

- vasodilation which decreases TPR

Question 23

What are the immediate compensatory measures for hemorrhage?

Answer 23

• vasoconstriction, venoconstriction, and increased heart rate
• due to increased symp. tone, angiotensin II, vasopressin, and epinephrine

Question 24

What are the medium term compensatory measures for hemorrhage?

Answer 24

• movement of interstitial fluid into vasculature

- due to reduced capillary pressure, and increased interstitial fluid osmolarity

Question 25

What are the long term compensatory measures for hemorrhage?

Answer 25

• recovery of fluid volume, plasma protein synthesis, erythropoiesis
• due to reduced urine output, increased fluid uptake, protein synthesis in liver, and erythropoietin production in kidneys

Question 26

Describe the Renin-Angiotensin-Aldosterone System

Answer 26

• decrease blood pressure leads to decreased amount of O2 to kidneys
• stimulates release of Renin by kidneys, which converts angiotensinogen to angiotensin I
• angiotensin I is converted to angiotensin II
• angiotensin II goes to the adrenal cortex and stimulates the release of aldosterone, which increases sodium reabsorption in the kidney, increasing blood volume
• angiotensin II also causes vasocontriction in the blood vessels