structure and function of circulation Flashcards
what structures are in all blood vessels?
lumen, tunica intima , and media (all but capillaries) , and tunica externa (all but capillaries)
what is tunica intima?
layer of endothelial cells on basement membrane
what does tunica media contain?
elastic tissue + muscle (composition vaires)
what can tunica externa contain?
collagen (strength)
nerves (large vein and arteries)
vasa vorium (large artery+vein)
lymphatics (larger vessels)
what is vasa vorium?
network of blood vessels in outer layer of large arteries and veins
what is medial layer in aorta/elastic arteries like?
smooth muscle in medial layer is replaced by many layers of ELASTIC TISSUE (cope with ejection pressures——
windkessel effect)
what is composition of media in muscular arteries?
thick layer of smooth muscle
what is ateriosclerosis?
thickening/toughening of arterial walls
involves ca depositation
aging disease diabetes
what is athersclerosis?
lipid + monocyte deposition in tunica media
high LDLs, low Apoe
cholesterol
what are arterioles?
smaller than arteries within tissues.
have 3 or less layers of smooth muscle (control)
what do ACE inhibitors do?
reduce BP (ramipril, perindopril)
what does angiotensin II do?
cause vasoconstriction (raise BP)
responds to drops in BP
can effect hypothalamus
how many amino acids does AngiotensinII have?
8
what are capillaries?
endothelial cells on basement membrane.
what are fenestrations?
pores in capillaries
if large fenestrations -is discontinuous
compare venules to arterioles
small vein
venules are less muscular than arterioles- more prone to collapse.
compare veins to arteries
veins are less muscular but can open up more (more distensible ) . and veins can store blood
what is structure of large veins?
have bundles of smooth muscle, (more muscular than venules)
contain pocket valves
what are pocket valves?
folds in tunica intima - stop blood flowing in wrong direction.
what are varacous veins form by?
poor valves (build up of blood)
what is lympahtic system?
diffuse system that delivers excess tissue fluid to CVS.
central venous system
what is caused by impaired flow in lympahtics?
oedema
give some properties of lymphatics
blind ended, freely permeable, flap valves
how do lymphatic system and CVS link?
via lymphatic ducts
