vessels & their structure
what are the three types of blood vessels (+ what do they do)
•Arteries: carry blood away from heart; oxygenated except for pulmonary circulation and umbilical vessels of fetus
•Capillaries: direct contact with tissue cells; directly serve cellular needs
•Veins: carry blood toward heart; deoxygenated except for pulmonary circulation and umbilical vessels of fetus
what are the three types of arteries
–Elastic arteries
–Muscular arteries
–Arterioles
this type of capillary forms the blood-brain barrier
continusous capillaries
what is pulse pressure
PP = SBP - DSP
what are the hormones involved in hormonal controls
Adrenal medulla hormones
~Epinephrine and norepinephrine from adrenal gland increase C O and vasoconstriction
Angiotensin II - stimulates vasoconstriction
ADH - high levels can cause vasoconstriction
ANP - decreases B P by antagonizing aldosterone, causing decreased blood volume
what are the three layers of the blood vessel wall (not in capillaries)
1.Tunica intima
2.Tunica media
3.Tunica externa
this type of artery is also called a resistance artery + why
arterioles
- b/c changing diameters change resistance to blood flow
these vessels have a large lumen and thin walls that allow for storage
veins
this is directly proportional to blood pressure gradient
- blood flow
~ F = P/R
what are the components of the cardiovascular center
-Cardiac centers: cardioinhibitory and cardioacceleratory centers
-Vasomotor center: sends steady impulses via sympathetic efferents called vasomotor fibers to blood vessels
what surrounds capillaries
endothelium w/ sparse basal lamina
this type of artery has elastin in all three layers of the BV wall
elastic arteries
- elastin found in all three layers - mostly tunica media
Venous valves
~Prevent backflow of blood
~Most abundant in veins of limbs
Venous sinuses
~Flattened veins with extremely thin walls
~Composed only of endothelium
~Examples: coronary sinus of the heart and dural sinuses of the brain
what is the equation for resistance & what do the variables stand for
▪R=8nl/πr4
~Blood viscosity (n)
~Total blood vessel length (l)
~Blood vessel diameter (2r)
what are the components in the neural reflex arc
–Cardiovascular center of medulla oblongata
–Baroreceptors
–Chemoreceptors
Higher brain centers
which layer of the BV is responsible for vasoconstriction and vasodilation
tunica media
- smooth muscle and sheets of elastin
- bulkiest layer responsible for maintaining blood flow and blood pressure
which vessel has the thickest tunica media (+ what is it composed of)
muscular arteries (aka distributing arteries)
- have the thickest tunica media with more smooth muscle, but less elastic tissue
these form tight juntions and are found in the liver, bone marrow, spleen, and adrenal medulla
sinusodial capillaries
what are the equations for MAP
MAP = DBP + 1/3 (SBP-DBP)
= 1/3 SBP+2/3 DBP
MAP = SV x HR x R
how to chemoreceptors increase BP
▪Signaling cardioacceleratory center to increase CO
▪Signaling vasomotor center to increase vasoconstriction
collagen fibers are found in which layer of the blood vessel wall
tunica externa (also called the tunica adventitia)
- collagen fibers that protect and reinforce wall & anchor to surrounding structures
this artery acts as pressure reservoirs that expands/recoils as blood is pumped from the heart
elastic arteries
these are found in areas of active filtration (kidneys), absorption (intestines), or endocrine hormone secretion
fenestrated capillarys
what vessel has the steepest drop in systemic pressure
- arterioles
where are chemoreceptor reflexes found
–Aortic arch and large arteries of neck detect increase in C O2, or drop in p H or O2