Week 4 - Mean Arterial Pressure

Question 1

What is the equation for mean arterial pressure?

Answer 1

MAP = Cardiac Output (CO) x Total Peripheral Resistance (TPR)

Question 2

Why is the velocity relatively low in the arteries despite the high blood pressure?

Answer 2

• next vessel (arteriole) constrains blood
• not enough space for blood to be received
• time required for the blood to flow out first

Question 3

How is flow controlled in the arteriole?

Answer 3

• radius is controlled
• controls resistance
• vasoconstriction / dilation
• R(esistance) ∝ 1/r(adius)⁴

Question 4

What body-wide factors regulate radius of the arterioles?

Answer 4

hormonal
- norepinephrine
- epinephrine
- vasopressin
- angiotensin II
neural
- sympathetic control
- releases norepinephrine

Question 5

What local factors regulate radius of the arterioles?

Answer 5

• metabolite changes in the endothelial cells
• oxygen constricts
• locally secreted chemicals
• vasoactive substances
• temperature
• cold constricts

Question 6

What is the equation for cardiac output?

Answer 6

CO = Heart Rate (HR) x Stroke Volume (SV)