circulation Flashcards
pulse
wave of pressure you can feel anywhere there is an artery close to skin surface
beats/min
blood pressure
how much pressure is being pushed
sphygmomanometer used to measure
how does sphygmomanometer work
cuff goes around arm and squeezes radial artery when it inflates
when it deflates, artery opens
we here Karatkaff sounds
blood perfusion
blood flow to different tissues in out body
perfusion matches need
tissue perfusion
delivers O2 and nutrients to tissues
removes wastes from tissues
exchanges gases in lungs
forms urine in kidneys
blood velocity is ___ related to cross sectional area of vessels
inversely
higher blood vessel area means ___ speed
lower
how is blood velocity locally regualted
by modifying diameter of arterioles
we have more ___ than any other vessels
capillaries
regulation of blood flow mechanisms
- decreased levels of nutrients or O2 causes vasodilation and relaxation of precapillary sphincters
- change in stretch of vessels causes response in smooth muscle of vessel
- angiogenesis increases number and size of vessels
metabolic mechanism of auto regulation of blood flow
decreased levels of nutrients or O2 causes vasodilation and relaxation of precapillary sphincters (delivers more blood!)
myogenic mechanism of auto regulation of blood flow
change in stretch of vessels causes response in smooth muscle of vessel to contract
angiogenic mechanism of auto regulation of blood flow
angiogenesis increases number and size of blood vessels
angiogenesis = production of new blood vessles
how do respiratory gases and lipid soluble molecules pass through capillary?
direct diffusion
passes directly through capillary cells
how do water soluble solutes (small things dissolved in plasma) pass through capillary?
intercellular clefts and fenestrations
how do large molecules pass through capillaries?
caveoli
caveoli
clathrin-coated vesicles that grab/move things in/out of cell through exo- or endo-cytosis
how do fluids pass through capillary?
pinocytic vesicles
capillary fluid dynamics
fluid forced out though clefts at arterial end; most returns at venous end
capillary fluid flow regulated by:
hydrostatic pressure and colloid osmotic pressure (gradient)
hydrostatic pressure
force exerted by fluid pressing against wall of capillary
capillary hydrostatic pressure ____ along length of capillary bed
decreases
colloid osmotic pressure
force created by presence of large, nondiffusible molecules (proteins)
functions in opposition to hydrostatic pressure- wants to draw fluid back in
colloid osmotic pressure ____ along length of capillary bed
does not vary
net filtration pressure
interaction between hydrostatic pressure and colloid osmotic pressure
determines if there is a net gain or loss of fluid from capillaries
portal systems
capillary bed that exists between venules
tissues in our body may need extra blood supply, so we put extra capillary bed in them
(serves specific regional tissue needs)
artery –> cap –> venule –> cap –> venule –> vein
portal system
circulatory shock
any conditions where we cannot properly circulate blood
hypovolemic, cardiogenic, or vascular
hypovolemic shock
shock due to hemorrhage, losing too much blood
blood volume so low we cannot circulate it properly
vascular shock
shock caused by steep drop in blood pressure (infection, sunburn, anaphylaxis)
vasodilation reduces bp and blood won’t flow correctly
cardiogenic shock
pump not working correctly
after heart attack
embryological development of blood vessels
- mesoderm cells form endothelial lining of blood vessels all over embryo
- these collect as blood islands
- these connect to form vascular tubes
- PDGF signals mesenchymal cells to form muscular and fibrous coats
T/F embryological development of blood vessels starts from heart
false! it starts all over and connects to heart
age related blood vessel changes
atherosclerosis
hypertension
T/F estrogen prevents atherosclerosis in women
true
hypertension can cause:
stroke vision loss heart failure sexual dysfunction heart attack kidney failure/dx
