Vascular System part 2 Veins & Lymphatics Flashcards
Endothelial Cells produce
vaso activated substances
What gets smooth muscle to relax?
nitric oxide and prostacyclin
prostacyclin
-prevents platelet adhesion and clumping (prevents clotting)
-gets smooth muscle to relax
Endothelin 1
potent vasoconstrictor peptide
topographic Permeability
venous end is more permeable than arterial end
What has the greatest permeability to leukocytes?
Postcapillary venules
What activates endothelium cells?
cytokines
What happen when endothelium cells are activated ?
go from flat to cuboidal
express cell adhesion for neutrophils
Weibel-Palade Bodies
storage granules
What do Weibel-Palade Bodies contain?
von Willebrand factor or P-section
Where do you not see Weibel-Palade Bodies
lymphatic capillaries
von Willebrand factor
essential for blood coagulation
binds with factor VIII (8) and leads to platelet adhesion
P-selectin
-increase permeability of endothelium
- facilitates leukocytes leaving the blood stream
What causes cells to lose attachment to one an other and retract?
Histamine
In the venous system you ______ see external elastic lamina
rarely
Veins have ______ in them
valves
What have valves?
veins and lymphatics
Postcapillary Venules
resemble capillaries but with wider lumen and more pericytes
What is the preferred site for migration of blood cells into the tissue?
postcapillary venules
Veins have relatively _______ ________ compared to arteries of the same size
thinner walls
Veins are often
collapsed (not a perfect circle)
Medium Muscular Viens
contain internal elastic lamina only
Serotonin and Histamine
vasoactive
act on venules
make more permeable
What causes Varicose Veins?
valves in the vein do not close properly
Embolus
part of a DBT that has broken off (circulating clot)
AV shunts
-direct connections between arterial and venous system (bypass capillary bed)
-common in the skin (thermoregulation)
Portal Vessels
vein or artery connect to capillary beds
What are examples of Portal Vessels?
hepatic portal vein and venous portal system
Vasculitis
-inflammation of your blood vessels (artery or veins)
-decreases lumen and blood flow
What can Vasculitis lead to?
changes in the blood vessels scarring, weakening, thickening, narrowing
Atherosclerosis
-thickening and hardening of the walls of the arteries
-caused by plaques, lipids, cells and connective tissue deposited int he tunica intima
Atherosclerosis is the cause of
myocardial infarction
stroke
ischemic gangrene