Chapter 4.4 Flashcards
1
Q
Describe why it is difficult to use the continuity equation for the circulatory system
A
- because there is nonconstant flow in the circulatory system
- > it is a closed system but has a noncostant flow rate
- > due to valves, gravity, etc
2
Q
Describe the individual resistance of vessels away from the heart and then describe the total resistance of the system away from the heart
A
- individual vessels
- > each vessel has progressively higher resistance until the capillaries
- total resistance
- > total resistance of the system decreases
- > because the increased number of vessels are in parallel with each other
3
Q
How does blood get back to the heart. Think about the expansion of the heart and the contraction of the skeletal muscles.
A
- the heart expands
- > decreases
- > this decreases the pressure
- the skeletal muscles contract
- > this increases the pressure in the limbs
- > pushes the blood back up to the heart
-high to low pressure pushes the blood into the heart
4
Q
Describe the pressure gradient in the respiratory system
A
- during inspiration
- > there is negative pressure gradient
- > moves air into the lungs
- during expiration
- > the gradient reverses
- note the total resistance increases as air leaves the alveoli
- > because the body has parallel pathways which decrease the resistance
