Chapter 21 - Blood vessels, and hemodynamics Flashcards
Name the 3 layers of blood vessels
- Tunica Intima - innermost layers
- Tunica Media - middle layer
- Tunica Externa - outermost layer
Define angiogenesis
Formation of new blood vessels
Can be stimulated by some cancers
Define arteries
Carry blood away from the heart to other organs
Arterioles
small arteries that regulation the flow of blood to capillaries
blood capillaries
tiny vessels that allow the exchange of substances between the blood and body tissues
Venules
small veins that drain blood from capillaries
Veins
Blood vessels that carry blood from the tissues back to the heart
Why are the walls of arteries elastic?
allow them to absorb the pressure created by ventricles of the heart as they pump blood into the arteries
What does the smooth musclee in the tunica Media allow?
can regulation their diameter, allowing artiers to increase/decrease lumen size and to limit bleeding from wounds
Name and describe the 2 types of arteries
Elastic arteries (conducting arteries)
Large diameter
More elastic fibers, less smooth muscle
Walls function as pressure reservoirs
Muscular arteries (distributing arteries)
Medium diameter
More smooth muscle, fewer elastic fibers
Distribute blood to various parts of the body
Can contract (vasoconstriction) and relax
(vasodilation)
Define what are anastomoses?
they are the union of branches of 2 or more arteries supplying the same region of the body
What are arteries that do not form an anastomosis called?
“end arteries”
What can anastomoses also consist of
2 veins or a vein and an artery
That does vasoconstriction and vasodilation do?
Vasoconstriction decreases the size of the lumen of blood vessel, while vasodilation increases size of lumen
The smaller the vessel, the greater the __________
and the greater the resistance, more decreased flow and higher ____
resistance
BP
The blood flow through calipparies is called the ___________________
microcirculation
How are capillaries built?
they are composed of a single layer of cells and abasement membrane
where are capillaries present?
brain, liver kidney, muscle, nervous tissue
Where are capillaries absent?
cornea, lens of eye, cartilage, covering/lining epithelia
What are the 3 types of capllaries
Continuous cap.
Fenestrated cap.
sinusoids cap.
describe continuous capillaries
they are continuous and are found in CNS, lungs, muscle tissue, and the skin
Describe fenestrated capillaries
Found in kidneys, small intestine villi, choroid, plexuses of the brain, parts of the eyes and most endocrine glands
describe sinusoids
wider than other caps. found in red bone marrow, liver, spleen, anterior pituitary, parathyroid and suprarenal glands
What are venules?
they are small vessels formed by the union of several capillaries.
What’s the smallest venules types
smallest venules
What are muscular venules
they are distendible and serve as blood reservoirs
What is bulk flow
the passive process in which large numbers of ions, molecules or particles in a fluid move together in the same direction
The movement of water and dissolved substances(except proteins) through capillaries is dependent upon _________________ and _____________
hydrostatic
osmotic pressures
