ch 15 Flashcards
five major types of blood vessels
Arteries, Arterioles, capillaries, venules, veins
arteries act as a
pressure reservoir
what kind of layers do arteries have
thick layers of vascular smooth muscles
what are arteries made of
lots of elastic and fibrous connective tissue
arterioles
site of variable resistance
what are arterioles a part of
microcirculation
what is the ratio in arterioles
less elastic and more muscular
what are metarterioles
branches of arterioles
what kind of tissue makes up metarterioles(think about how its related to arterioles)
partial smooth muscle layer
precapillary sphincters
open and close to direct blood flow to capillaries or venous circulation
capillaries
primary exchange site between blood and interstitial fluid
what are pericytes
contractile cells associated with capillaries
what do pericytes contribute to
capillary impermeability
what do pericytes secrete
paracrine factors that promote vascular growth and differentiation
venules
receive blood from capillaries
what kind of epithelium for venules
thin exchange
what takes blood back to the heart
veins
volume reservoir(think opposite to pressure reservoir)
veins
one way valves
in veins prevent backward flow
are arteries or veins more numerous
veins
where is blood pressure highest
arteries
where is blood pressure lowest
veins
pulse pressure
pressure wave produced by ventricular contraction
pulse pressure equation
systolic -diastolic
how does friction affect blood pressure
causes it to decrease
what aids venous return
valves, skeletal muscle pump, respiratory pump
arterial blood pressure
reflects the driving pressure for blood flow
mean arterial pressure
the driving pressure
MAP equation
diastolic pressure + .3(sys-dia)
hypotension
lower than normal MAP
hypertension
greater than normal MAP
spygmomanometer
measures blood pressure
when does blood flow
when there is a pressure gradient
what opposes blood flow
resistance of the system
three factors of resistance
blood vessel radius
blood vessel length
blood viscosity
primary determinant of velocity
total cross sectional area of vessel
blood flow into aorta
cardiac output of left ventricle
if flow in exceeds flow out
blood volume increases and MAP increases
if flow out exceeds flow in
blood volume decreases and MAP decreases
how does blood volume fluctuate through the day
relatively constant
4 factors of MAP
blood volume
cardiac output
resistance
distribution of blood
what influences arteriolar resistance
local and systemic control mechanisms
3 things that directly alter arteriolar resistance
local control
sympathetic reflexes
hormones
myogenic autoregulation
adjusts blood flow
what regulates its own contraction
vascular smooth muscles
major paracrine control molecules
nitrous oxide
histamine
neural and hormonal signals that control BP
ANP and angiotensin II
what controls most systemic arterioles
sympathetic innervation
whats the exception to systemic arterioles
penis and clitoris
adrenal medulla
releases epinephrine into blood
just take the time to
learn figure 15.11 b
what does blood dist vary with
metabolic needs of individual tissues
what governs blood dist
local control mechanisms, homeostatic reflex
individual arterioles
regulate own flow
cerebral flow
stays nearly constant
what do bareceptors control
blood pressure
where are baroreceptors concentrated
carotid artery
activated baroreceptors produce
continuous action potential to brainstem
change in pressure is reflected in
changes in frequency of action potential
orthostatic hypotension
triggers the baroreceptor reflex
arterial chemoreceptors are activated by
low O2
what do activated arterial chemoreceptors cause
increased cardiac output
adaptive integration is between
respiratory and cardiovascular systems
what brain structures modulate blood pressure
hypothalamus and cerebral cortex
vasovagal syncope
a common type of fainting that occurs when the body overreacts to certain triggers
what is related to the metabolic activity of cells
capillary density
two types of capillaries
continuous and fenestrated
sinusoids
modified capillary vessel
where do sinusoids reside
bone marrow, liver and spleen
when is velocity higher
in smaller diameter tubes
primary determinant of velocity
total cross-sectional area of all capillaries
how does exchange between plasma and interstitial fluid occur
paracellular pathway, endothelial transport
bulk flow
mass movement as a result of hydrostatic or osmotic pressure gradients
filtration
fluid movement out of capillaries
absorption
fluid movement into capillaries
what causes filtration
hydrostatic pressure
what caused absorption
colloid osmotic pressure
what does the lymphatic system do
return fluids and proteins to circulatory system
what can the lymphatic system do
pick up and transfer fat from digestive to circulatory
what can the lymphatic system filter
pathogen
one way or two way movement of interstitial fluid ?
one way in the circulatory system
are lymph capillaries continuous or blind ended
blind ended
edema
accumulation of fluid in the interstitial space
risk factors for CVD
smoking and obesity
what can’t be controlled for in CVD
sex, age, family history
diabetic mellitus
metabolic disorder that contributes to development of atherosclerosis
atherosclerosis
inflammatory process
what is atherosclerosis
increased blood cholesterol and triglycerides
what is heart failure
the inability of the CO to keep with the demands of the body for blood supply
diastolic Heart Failure
heart has trouble filling up with blood
systolic Heart failure
heart has difficulty pumping blood out, may result from a heart attack
diastolic dysfunction
Ventricular compliance may decrease but contractility is normal. Hypertrophy of the left ventricle working against increased arterial pressure (afterload) may make the ventricle less compliant, and stiff.
pulmonary edema
fluid in the lungs
