Blood Vessels Flashcards
Tunica intima
thin, endothelial, internal elastic lamina
inner most layer
Tunica media
smooth muscle
Elastic and reticular fibers
external elastic lamina
Tunica adventitia
- collagen I, elastic fibers
- prevents too much stretch
- protective
- contains vasa vasorum
Which part of the vascular system really controls blood flow?
arterioles
vasa vasorum
small blood vessels that feed the bigger blood vessels
difference between large elastic artery and medium muscular artery
- large elastic artery
- thick tunica media layer
- lots of elastic
- medium muscular
- much thinner tunica media
- more smooth muscle, less elastic
Continuous capillary
- most common
- tight, occluding juctions
- minimal fluid leakage
- everything must cross the cells by diffusion
- basement membrane intact
Fenestrated capillary
- have tight junctions with perforations (fenestrations) that allow greater exchange through the endothelium
- continuous basement membrane
- Found in organs where molecular exchange with the blood is important
- endocrine organs
- intestine walls
- choroid plexus
Sinusoid
- discontinuous capillaries
- discontinuities between the endothelial cells; large fenestrations
- Partial, discontinuous basement membrane
- Found where exchange of macromolecules and cells occurs readily
- bone marrow
- liver
- spleen (RBC in the obstacle course)
How do precapillary sphinctors affect blood flow?
- sense changes in chemistry (ex. AMP) and will open in response, increasing blood flow rate through arteriole
How do arterioles affect blood flow?
Arterioles can sense increas in blood flows (after precapillary sphinctors have opened) and will know to allow more blood through and will dilate.
This higher blood flow will “wash away” the AMP that the precapillary sphinctors were sensing
what happens when veins constrict?
big decrease in volume, no appreciable increase in resistance
Which blood vessels have tunica adventitia?
all except capillaries
Three ways of blood pressure regulation
- autoregulation (local response)
- sphincto control in capillary beds
- shear stress induced vasodilation
- myogenic response
- Neural regulation
- cardiovascular centers of the medulla oblongata
- vascular tone
- baroreceptors
- chemoreceptor
- cardiovascular centers of the medulla oblongata
- Hormonal regulation (slower)
- RAAS
- ANP
Increased HR
causes increased CO and BP
increased contractility causes
increased ejection fraction which causes increased CO and BP
increased SVR causes
decreased CO but increased BP
Increased CVP causes
increased LVEDV which causes increased SV which causes increased CO and BP
Effector organs of ANG II
- blood vessels- vasoconstriction
- Heart- increased CO
- Adrenal cortex- aldosterone release
- increase Na reabsorption by kidney
- hypothalamus- minor increase in ADH release
- increase H2o absorption by kidney
Effects of ANP
- increased Na and water excretion
- vascular smooth muscle relaxation
- blocking ADH, aldosterone, and NE
difference btw ANP and BNP
same as bnp but released from ventricles
supra Medullary regulation
- hypothalamus and cortex connext the cardiovascular control center to alther its activity
- drives to increase CO and respirations before you need it
- ADH is also released during exercise
hepatic portal system
brings the blood from stomach/intestine to liver to be cleaned
hepatic artery
brings blood to the liver for its own nutrient/o2 requirements
splanchnic circulation and SNS stimulation
lots of blood chillin in the liver. When needed elsewhere, SNS activity will cause vasoconstriction and blood will be shunted out of liver
