Chapter 20 Vessels Flashcards
What are arteries?
What are capillaries?
What are veins?
Describe the structures of a blood vessel
What are the three types of a arteries?
How are different capillaries distinguished?
by their premeability
What are the three types of capillaries and their premability?
In capillary bed most control of flow involves constriction of ____ that are upstream from the capillaries
arterioles
Within the capillary bed, ____ controls flow
precapillary sphincters
What happens within the capillaries when sphincters are relaxed?
capillaries are well prefused with blood
What happens in capillaries whne sphincters contract?
they constrict the entry to the capillaries and blood bypass the capillary
What happens in capillaries when sphincters are open vs closed?
What are functions of veins?
What are the adaptations of veins?
Blood supply to a tissue can be expressed by?
flow and perfusion
the amount of blood flowing through an organ, tissue, or blood vessel in a given time
blood flow
the flow per given volume or mass of tissue in a given time
perfusion
At rest, total flow is constant and is _ to the Cardiac output
equal
How is systemic blood flow calculated?
What is hypertension?
What is hypotension?
stiffening of arteries due to deterioration elastic tissues of artery walls
arteriosclerosis
build up of lipid deposits that become plaques
atherosclerosis
How does distance affect blood pressure?
What determins blood pressure?
What is resistance influenced by?
The most important blood in the body in the ____
capillaries
two way movement of fluid across capillary walls
capillary exchange
How do materials get from the blood into the surrounding tissue?
capillary exchange
The flow of blood back to the heart
venous return
Explain venous return
What are the four mechanisms of venous return?
mechanism of contracting muscle squeezes blood out of the compressed part of the vein
skeletal muscle pump (most important)
mechanism that allows blood to flow faster with inhalation
thoracic (respiratory) pump
