Week 5: Blood Vessels Flashcards
What are the 3 layers of a blood vessel?
Tunica Interna
Tunica Media
Tunica Externa
Define an artery
Carries blood away from the heart to other organs
What does vasoconstriction mean?
A decrease in the diameter of the lumen of a blood vessel
What does vasodilation mean?
The increase in the lumen of the diameter
What is the function of the elastic arteries?
They help propel blood onward while the ventricles are relaxing. They include the aorta and pulmonary trunk. They are the biggest arteries.
What is the function of muscular arteries?
Medium sized. They distribute blood to each of the various organs. Eg: Brachial artery & radial artery.
What is the function of of arterioles?
The smallest.
They regulate the flow of blood into the capillary networks of the body’s tissues.
What is the relationship between anastamoses and collateral circulation?
Anastomoses is an alternative route of blood flow. The alternative route is know as collateral circulation.
What is the structure and function of capillaries?
Function: The change of substances between the blood and interstitial fluid.
Structure: Have a single layer of endothelial cells and a basement membrane.
Define auto regulation of capillary flow.
Adjusts blood flow through a capillary bed in response to physical and chemical changes in a tissue
What are 3 different types of capillaries?
Continuous - limited diffusion
Fenestrated - quick fluid, larger exchange
Sinusoids - large, incomplete basement membrane, quite leaky
What is capillary blood pressure?
Pushes fluids out of capillaries into interstitial fluid
What is colloid osmotic pressure?
Pulls fluid into the capillaries from interstitial fluid
Define venules
Are small vessels that collect blood from capillaries and drain into veins
Define veins
Have thinner tunica Interna and tunica media than arteries.
Why are valves necessary in veins?
To prevent back flow of blood.