Chapter 18 Flashcards
Lumen
an area filled with blood
How many tunics do blood vessels have
3, tunica interna, tunica media, tunica externa
Tunica interna
inner layer, made of simple squamous epithelium, with areolar connective tissue deep
Tunica media
middle layer, made of smooth muscle and connective tissue (elastic and collagen fibers)
Tunica externa
outer layer, made of collagen connective tissue
What is the pressure and direction of arteries
high pressure, away from heart
What tunic do arteries have
thick tunica media with increasing elastic tissue
Lumen size of arteries
small
How many types of arteries are there
3
1.) large, elastic, and conducting arteries
2.) medium, muscular, distributing arteries
3.) small, resistance arteries
Describe large, elastic, and conducting arteries
large amounts of elastic tissue creates balloon-like shape to maintain pressure, the aorta and its major branches
Describe medium, muscular, distributing arteries
higher percent of smooth muscle in tunica media, inner/outer elastic lamina on either side of smooth muscle, have ability to constrict allows blood to flow to different places
Describe small, resistance arteries
no names, contains small arterioles that lead into capillaries
What tunic do capillaries have
tunica internia
Describe size of capillaries
short - 1mm in length, narrow - 1 rbc in diameter
Pericyte
stem cell that repairs capillaries
How many types of capillaries are there
3
continuous, fenestrated, discontinuous/sinusoidal
Describe continuous capillaries, location, permeability
solid layer of closely connected endothelial cells, all over the body, least permeable
Describe fenestrated capillaries, location, permeability
contains windows, found in intestines and kidneys, slightly permeable because of the small windows
Describe discontinuous/sinusoidal capillaries, location, permeability
have gaps in endothelial cells, rare but found in spleen, bone marrow, liver, high permeability due to large spaces for cells to move in and out
Pressure and direction of veins
low pressure, returning blood to heart
Describe the walls and lumen of veins
thin, large
How much blood do veins store
60%
How many types of veins are there
3
post-capillary venule(s), small veins, large veins
Post-capillary venule(s)
have gaps in walls where WBCs leave the blood
Small veins
no names, some have valves
Large veins
have names and valves
