Class 11 Flashcards
When does an artery tend to collapse?
1) Elastic property of the elastic and collagen fibers enclosing the artery
2) Active tension by vascular smooth muscle cells
What is critical closing pressure?
For a given blood vessel is the blood pressure at or below which the blood vessel will collapse, causing cessation of blood flow through that section of blood vessel
What does the constant force/pressure in blood vessels do?
Keeps the blood vessels open
If blood vessels were ever to close, can you open them?
NO
Critical closing pressure increases with an increase in what?
Vascular tone
When is there zero blood flow?
At critical closing pressure
When does critical closing pressure increase?
When vascular tone is increased through higher intensity of sympathetic activation
When do blood vessels collapse? At what mmHg?
6-7 mmHg
What can be defined as the blood volume within the vasculature that can be utilized to perfuse the organ systems within the body?
Effective circulating volume
Effective circulating volume is related to what aspect of blood vessels?
The fullness of them
What is defined as the force exerted by blood against a vessel wall?
Blood pressure
What can blood pressure be influenced by? (2)
1) Physiological
2) Physical
What are the physiological factors of blood pressure? (4)
- HR
- SV
- CO (HR x SV)
- Peripheral resistance
What are the physical factors influencing bp?
- effective circulating blood volume
- elastic characteristics
What contributes the majority of the resistance to flow in the body?
Arteries and arterioles
