Vascular Anatomy Flashcards
Tunica Adventitia
- outter connective tissue made of collagen fibers
- protect vessel and hold to surrounding tissues
3 Vessel Layers
- tunica intima
- tunica media
- tunica adventitia
Tunica Media
- circular smooth muscle with elastin and proteoglycans
- allow constriction/dilation of vessels
- deparated from adventitia by external elastic laminae
Thickest Artery Layers
- tunica media
- due to increased pressure
Primary Elastin Arteries
- Aorta
- branches closest to heart
Primary Muscular Arteries
-arteries other than aorta
Diastolic Pressure
- pressure in Aa during ventricular relaxation
- reflect peripheral resistance or ability of blood to flow from Aa to capillaries
Diastolic pressure reflects:
peripheral resistance
ability of blood to flow from Aa to capillaries
Arterioles
- “resistance vessels”
- Primarily smooth muscle
- can act as control valves
- no pulse
2 artery types
- primarily elastin
- primarily muscular
systolic pressure
- pressure within Aa during ventricular contraction
- reflects work of heart and strain of Aa
Systolic pressure reflects
work of heart and strain of Aa
Precapillary sphincters
- between metarterioles and capillaries to control blood flow locally
- during exercise to increase blood flow to muscles and decrease to organs
Precapillary Sphincters Open in response to
- Increased: CO2, H+, Lactate
- Decreased: pH, O2
Histamines and Capillary Pores
- histamines cause cell tightening and pore widening
- allows large proteins to escape that normally can’t
Veins
- reservoir/store blood
- get blood back to heart
- @ rest they hold about 64% of blood
- primarily made of adventitia with little elastin
Capillaries
- separated from metarterioles by precapillary sphincters
- exchange nutrients and waste and fluids
- single cell layer
Venules
-collect blood from capillaries
Tunica Intima
- single layer of squamous endothelial cells
- impermiable to large proteins (small proteins can pass through)
- separated from media by internal elastic lamina
MAP
- mean arterial pressure
- average pressure at which blood flows
- reflects ability of blood to perfuse tissue
Normal MAP
70-110mmHg
-<60mmHg=inadequate tissue perfusion
MAP=
MAP=DBP + 1/3 (SBP-DBP)
Diffusion in Capillaries
- through cells or pores between cells
- lipid soluble stuff goes through cells
- glucose, amino acids, ions go through pores
- large proteins confined to plams
