Lecture 11: Controlling Regional Blood flow Flashcards
What is the first reason for a large pressure difference between arteries and veins?
To give unidirectional flow
What is the second reason for a large pressure difference between arteries and veins?
To control the flow of blood through the system
What does a low blood pressure result in?
Lack of blood flow control
What does a high arteriole blood pressure result in?
Full blood flow control
How much blood flow is there through the systemic/pulmonary circuits?
Equal blood flow
How is the systemic circuit described?
A bunch of circuits in parallel to each other
What is a result of the parallel design of the systemic circuit?
Cardiac output is distributed to all organs
What does continual branching of the arterial network do?
It divides blood flow among the regional circulations
What does the total blood flow in parallel circuits of the systemic circuit equal?
The total blood in/out flow through the circuit
What happens to cardiac output during exercise?
It increases
During exercise where does blood flow increase?
3
- Muscle
- Heart
- Skin
During exercise where does blood flow decrease?
2
- GI tract
- Kidneys
Where in the body is blood flow constant even during exercise?
Brain
What happens to cardiac output during exercise?
Increases
What happens to mean arterial blood pressure during exercise?
It remains constant
What happens to total peripheral resistance during exercise?
Decreases
What organs do resistance increase in during exercise?
3
- Kidneys
- Intestines
- Spleen
What organs does resistance decrease in during exercise?
3
- Muscle
- Heart
- Skin
What controls organ resistance?
Arterioles
Why are arterioles referred to as resistance vessels?
They control our peripheral resistance
How do you calculate the resistance of blood flow in a vessel?
Resistance = 1/r^4
What is the relationship of radius to resistance in blood vessels?
Inversely proportional
What does the rule of 16 mean?
If diameter doubles or halves then flow responds so proportionally by a factor of 16
