Card Set Information
veins arteries capillaries
veins, arteries, capillaries
What do the blood vessels of the body form?
closed circulatory system
What do blood vessels have the ability to do?
constrict or dilate and increase or decrease pressure
What is the job of arteries and veins?
Arteries carry blood away from heart & veins bring blood towards heart
What is Tunica Intima?
contains endothelium (simple squamous epithelium)
What is Tunica Media?
thickest layer composed of smooth muscle arranged in circular sheets & connective tissue. Controlled by sympathetic nervous system. Can have vasoconstriction or vasodilation
What does the sympathetic nervous system control?
smooth muscle activity
What is vasoconstriction and vasodilation?
vasoconstriction occurs when smooth muscle contacts decreasing flow of blood
vasodilation occurs when smooth muscle relaxes, increases diameter & thus the blood flow
What is Tunica externa?
outer most layer composed of connective tissue designed to protect, stretch, and anchor blood vessels
What is a Lumen?
cavity in the middle of the blood vessel filled with blood
How does the diameter of the luman change?
with vasoconstriction or vasodilation & can also be influenced by plaque build up
What happens when the artery gets closer to the heart and branches?
When artery gets closer to heart, the larger its diameter & the thicker its walls. When artery branches, it becomes smaller in diameter & thinner until it becomes a capillary
what do the arteries have the ability to do and why?
ability to change blood pressure because they have a thick muscle layer
What are elastic arteries?
2.5-1cm, largest, closer to heart, thick sheets of elastin in tunica media, able to withstand large fluctuations in blood pressure
What are muscular arteries?
1cm-0.33mm, distal to elastic arteries, reach organs, their tunica media is thicker in diameter than lumen
What are arterioles?
0.3mm-1um, smallest diameter, tunicas are considerably thinner but are still innervated to induce vasoconstriction or vasodilation
What do arterioles connect to?
What are capillaries?
smallest blood vessels (8-10um) forcing RBC to pass by in one after the other in line; where WBC exit the blood stream
What are capillary beds?
network or capillaries that is connected to a terminal arteriole & postcapillary venule
What are capillary permeability?
capillaries have thin walles so that molecules can quickly move in and out
Capillaries that have no pores & are not highly permeable are called what?
How does permeability happen?
dirrect diffusion, intercellular cleft, cytoplasmic vesicles (caveolae), fenestrations
What are continous capillaries?
Capillaries that have no pores & are not highly permeable
The capillaries that have lowest permeability are what?
those of the blood brain barrier (only permeable to lipid soluble substances & components such as H20 & CO2
What are Sinusoids?
wide leaky fenestrated capillaries in areas of extensive change & crossing or large materials
What are veins?
blood vessels that carry blood from capillaries to the heart
What happens to the veins as they move away from the capillaries?
increase in diameter
What is the blood pressure in veins?
less than in arteries & their walls are also thinner than arteries
What are venules?
8-100um, smallest & thinnest, closer to capillaries, become thicker as they approach the veins
What happens to the venules as they approach the veins?
What are vain valves?
assist in transport of blood back to heart & prevent back flow
Where are there no valves in the veins and why?
thoracic & abdominal cavities because they have a layer of smooth muscle
What do normal body movements produce when blood is being returned back to the heart from the veins?
produce muscle contractions that bring blood back to the heart
What do skeletal muscle contractions force?
force valves to open & propel blood towards heart
What is vascular anostomoses?
areas where several blood vessels unite or interconnect & may be arteries or veins
What can Anastomoses provide?
alternative routes for blood flow
What happens when blood flow blocage is in areas where there are no arterial anastomoses?
may result in severe tissue damage
What is vasa vasorum?
tiny arteries, capillaries, & veins in larger blood vessels to provide their own blood supply & nourishment for outer half of wall layers
What is the pulmonary circulation?
blood vessels that travel from heart to lungs, within the lungs, & back to heart
pulmonary circulation: What do arteries and veins carry?
arteries carry deoxygenated blood & veins carry oxygenated blood
pulmonary circulation: How does blood from the heart reach the lungs and once the blood is oxynated, what happens?
via the pulmonary arteries that carries deoxygenated blood
when oxynated, it is returned to heart via pulmonary veins
What is systemic circulation and what do the arteries and veins carry?
blood vessels that travel from heart throughout body & back to heart
arteries carry oxygenated blood & veins carry deoxygenated blood
What is arthrosclerosis?
hardening of artery due to fatty deposits (artery loses its flexibility)
What is aneurysm?
widening or out pocketing or an artery or vein increasing changes of vessel rupturing (may result from weaken walls)
What is deep vein thrombosis of lower limb?
formation of clots in lower legs (clot can detach, travel through body, & cause embolism or stroke)
What is venous disease?
inadequate drainage of lower limbs due to failure of valves & can possibly causing ulceration
What is microangiopathy of diabetes?
common long term diabetes mellitus complication
What is arteriovenous malformation?
congenital condition in which capillaries do not form & arteries connect directly into veins (usually occurs in cerebrum where veins becomes weaken & an aneurysm can occur)