21 Flashcards
Tunica interna (intima
– inner layer
* Has simple squamous
* Slick lining- no stick
* Selectively permeable barrier
artieries are called resistence vessles bc
withstand high BP
capavitance vessles
veins
contain most of our blood
capillaries
micro vessles connecting small arteries to small veins
Tunica media –
middle layer
* Thick layer
smooth muscle, collagen, maybe elastin
* vasoconstriction and vasodilation (close and open)
Tunica externa (adventitia) –
outer layer
* Loose connective tissue
* Anchors vessel to its surroundings
vaso vasorum
Large vessels have their own network of small vessels
dsitributing artieries have
elastic lamina
tunica interna
little valve in vein to prevent backflow of blood to feet
Conducting (elastic) arteries
– biggest
arteries
* Ex: aorta
Distributing (muscular) arteries –
midsized
* Ex: femoral a.
Resistance arteries
– smallest arteries
* Less than 0.1 mm in diameter
* Arterioles are smallest examples
Metarterioles
– short vessels linking
arterioles and capillaries
baroreceptor
Send signals to the vasomotor and cardiac center (medulla o) of the brain
changes diamter of vessles/heart rate
Chemoreceptor
Send signals to the respiratory centers of the brain (pons or med o)
monitors blood comp
alts respiratory rate
shit monitored in blood
PH, CO2, O2
Baroreceptors
aortic sinus
carotid sinuses
Aortic sinus
- Innervated by vagus nerve
to heart
Carotid sinuses
to brain
* Innervated by glossopharyngeal
nerve
Chemoreceptors
– Carotid bodies
– Aortic bodies
– Carotid bodies
- Innervated by glossopharyngeal
nerve
– Aortic bodies
- Innervated by vagus nerve
Arterial Pressure Points
high pressure in aorta
low pressure in veins
Continuous capillary –
endothelial cells joined by
tight junctions,
some intercellular clefts present (space bn cells)