Chapter 21 [ EXAM #3] Flashcards
what blood vessel carries blood from the fetus to the placenta
umbilical arteries (2)
what blood vessel carries blood from the placenta to fetus
umbilical vein (1)
what blood vessel contains an increased amount of O2 and nutrients in placental blood supply
unbilical vein
identify two structures present in the fetus but not the infant that allows blood to flow through pulmonary circuit
where are they located
foramen ovale = right → left atrium
ductus arteriorsus = pulmonary trunk → aorta
why is blood routed away from pulmonary circuit in fetus
fetal lungs are collapsed and filled with fluid
Once a baby takes their first breath, what happens to the foramen ovale and ductus arteriorsus
foramen ovale seals off by 1 week
ductus arteriosus seals off by 3 months
what does the fossa ovale and and ductus arteriorsus become in the adult heart
fossa ovale → fossa ovalis
ductus arteriorsus → ligamentum arteriorsum
what is the heart defect that results when the ductus arteriosus fails to close
patent ductus arteriosus
location and function of foramen ovale
blood flow from right to left atrium
bypasses pulmonary circuit
location and function of ductus arteriosus
from pulmonary trunk to aorta
bypasses pulmonary circuit
what is the heart defect that results when blood recirculates through pulmonary circuit
patent foramen ovale
meaning of patent
hole remains open
what are the four defects of tetralogy of Fallot
too narrow pulmonary trunk
right ventricle hypertrophy
ventricular septum defect
aorta opens from both ventricles
what is the result of ventricular septal defect
blood mix between the two ventricles
heart and lungs work harder
function of arteries
carry blood away from heart to organs
function of arterioles
small arterial branches, regulate blood flow
function of capillaries
tiny vessels off of arterioles in tissues
exchangers between blood and interstitial fluid
function of venules
small veins formed after capillaries reunite
function of veins
carry blood from tissues back to heart
what are the three layers of blood vessel wall
tunica intima
tunica media
tunica externa
what’s the thickest layer in blood vessel wall
tunica media in arteries
tunica externa in veins
describe tunica intima
most inner layer of blood vessel wall
smooth endothelium
describe tunica media
middle layer of blood vessel wall
thick in arteries and thin in veins
sympathetic NS controls vaso-constriction/dilation
tunica externa
most external wall of blood vessel
collagen and elastic fibers protect reinforce and anchor
thickest in veins
purpose of elasticity in arteries
stretch to accommodate blood
recoil to propel blood
purpose of contractility in arteries
critical in vascular spasm when vessel is damaged
3 types of arteries from heart to tissue
elastic arteries
muscular arteries
arterioles
what are pressure reservoirs and their function
abundant elastic fibers in tunics
prevent large changes in pressure and maintain stable blood flow
muscular arteries are also called…
distributing arteries
distributing arteries are also called…
muscular arteries
function of muscular arteries
distribute blood to body organs/regions
MOST ABUNDANT
what is arteriosclerosis
thickening/toughening of arterial walls
what is atherosclerosis
lipid/cholesterol plaques deposit on vessel wall narrowing lumen
what is angioplasty
flatten plaque with balloon catheter
what is aneurysm
arterial walls thins and balloons out, may rupture
what is vasomotor tone
small muscle partially constricted regulated by brainstem vasomotor center
what is vasoconstriction/dilation site
blood pressure regulation
dimeter affected by sympathetic, endocrine chemical influences
what are the two subdivisions of cardiovascular center
cardiac center
vasomotor center
what are three types of capillaries
continuous
fenestrated
sinusoidal
what are three types of arteries
elastic
muscular
arteriole
where are elastic arteries
large arteries near heart
function of elastic arteries
conduct blood to muscular arteries
what is the most common capillary
continuous capillaries are most common
where can you find continuous capillaries
skin and muscles
continuous capillaries openings are called…
intercellular clefts
what is trapped in and what can get out of continuous capillaries
trapped in: large proteins, cells
get out: water and small solutes
where can you find fenestrated capillaries
small intestines and endocrine glands
fenestrated capillary openings are called…
fenestrations
what are fenestrations
small pores in endothelial plasma membranes within capillaries
describe exchange in fenestrated capillaries
rapid exchange possible, absorption and secretion
describe exchange in sinusoidal capillaries
what can get in and out
very leaky with large fenestrations
blood cells
plasma proteins
where can you find sinusoidal capillaries
liver spleen bone marrow
what is microcirculation
flow of blood in capillaries between arterioles and venules
what is metarteriole
feeds blood into capillary bed
what is vascular shunt in capillary beds
direct connection between arteriole and venule
metarteriole and thoroughfare channel
what are true capillaries
exchange vessels
what are precapillary sphincters
smooth muscle regulates blood flow into true capillaries
contract to close, relax to open
what is perfusion
specific amount of blood entering capillaries/time
what does a local decrease in oxygen result in
relaxation of smooth muscle and increased bloodflow (exercise)
what NS regulates capillary beds
sympathetic NS ONLY
[veins] what are blood reservoirs
veins and venules hold 60+% of total blood
[veins] what are capacitance vessels
stretch easily to hold blood
[veins] venoconstriction is a response to…
hemorrhaging
[veins] venous reserve
redirection of venous reserve to vital organs
[veins] are veins a high or low pressure blood vessel
veins are a low pressure blood vessel
[veins] function of valves in veins
valves in veins prevent backflow of blood
what is arterial anastomoses
interconnected arteries, blocked arteries don’t interrupt blood flow
what is venous anastomoses
interconnected veins, blocked veins don’t interrupt blood flow
what is blood flow
volume of blood that flows through vessel/organ in period of time (ml/min)
what is autoregulation
local decrease in O2 = relaxation of smooth muscle → increase blood flow
what is blood pressure
force of blood on blood vessel wall
does an increased pressure gradient increase or decrease blood flow
increased pressure gradient increased blood flow
what is resistance
opposition to blood flow
what’s the formula for blood flow, pressure, and resistance
F = change in P / R
what is peripheral resistance
resistance in peripheral blood vessels
what influences peripheral resistance
blood viscosity increases peripheral resistance
blood vessel length increases peripheral resistance
what has the biggest significance to blood flow
vessel diameter
what has the biggest significance to resistance
vessel diameter
as resistance increases, the demand for blood pressure increases/decreases
as resistance increases, the demand for blood pressure increases
what is arterial blood pressure
ratio of systolic : diastolic pressure
what is average arterial blood pressure
120 / 80
systolic / diastolic
what is hypertension
abnormally high blood pressure
what is pulse pressure
additional pressure placed on arteries when heart is going from resting to contracting
what is mean arterial pressure (MAP)
average blood pressure in arteries (93mHg)
what is transcytosis
one side to other side of cell
pinocytosis → exocytosis
what is hydrostatic pressure
blood pushing against vessel wall
what does CHP stand for
capillary hydrostatic pressure
what does CHP promote
CHP promotes filtration: forcing fluid out of blood into interstitial tissue
what is colloid osmotic pressure
opposes filtration and favors reabsorption (water pulled into blood)
what is blood colloid osmotic pressure (BCOP)
BCOP draws water back into blood via osmosis
hydrostatic pressure ______ and osmotic pressure ______
hydrostatic pressure pushes and osmotic pressure sucks
what is a colloid
large solute that’s trapped
what is the formula for net filtration pressure
CHP - BCOP = net filtration pressure
If HP > OP → ______ ( _ )
If OP > HP → ______ ( _ )
If HP > OP → filtration ( + )
If OP > HP → reabsorption ( - )
what is hemorrhage
excessive blood loss
what is the respiratory pump in venous blood pressure
inhale squeezes veins
exhale sends blood to heart
what is neural regulation
regulation of blood pressure by sympathetic and parasympathetic
what is endocrine regulation
regulation of blood pressure by hormones
when are neural and end endocrine regulation activated
when autoregulation is not sufficient
what are some vasodilators
low O2 or high CO2
low pH
NO
high temperature
pre-capillary sphincters contract in response to
vasoconstrictors, reducing bloodflow
where are the cardiac and vasomotor centers
medulla oblongata
the cardiac centers affect…
HEART:
sympathetic cardioaccelatory center
parasympathetic cardioinhibitory center
the vasomotor center affects
[SYMPATHETIC ONLY] BLOOD VESSELS:
vasoconstriction
vasodilation
what is vasomotor tone
arterioles partially constricted
cardiovascular center is modified by what
baroreceptor and chemoreceptor reflexes
what are baroreceptors
monitor blood pressure by stretch in BV or heart wall
how can a physician use their knowledge to decrease the heart rate of a patient with tachycardia
doctor can do internal carotid massage
baroreceptors become stimulated, know are stretched, help drop heart rate
what are chemoreceptors
respond to chemical changes in blood
what is hypoxia
low oxygen levels
what is acidosis
low pH levels
what is hypercaphia
high carbon dioxide
what is renin-angiotensin system activated in response to
decrease in blood pressure / volume
function of aldosterone
water reabsorbed
decreased urination
function of ADH
increased thirst
what is hypovolemic shock
blood volume too low to meet tissues need
what is angina pectoris
chest pain due to increased workload and inability to meet demands
what is myocardial infarction
heart attack
death of tissue due to lack of blood supply
what is special about pulmonary vessels in how they contract
if high O2 content: dilate to absorb
if low O2 content: constrict to not bother
