Exam 2 Flashcards
Blood volume is directly proportional to?
pressure and flow
as volume decreases; pressure and flow rate…
DECREASE
as volume in creases; pressure and flow rate…
Increase
four main components of blood
RBC’s, WBC’s, Platelets, Plasma (fluid)
Blood viscosity is directly proportional to
resistance
Blood viscosity is inversely proportional to
flow
length of vessel is directly proportional to
resistance
diameter of the vessel is inversely proportional to
resistance
cross sectional area is inversely proportional to
linear velocity of flow (Q=VA)
velocity of flow is slowest in capillaries because?
greatest cross sectional area
velocity of flow is fastest in vessels
smallest cross sectional area
as diameter of a vessels in the body decrease, the cross sectional area
increases
caused by shear stress produced as blood flows past stationalry wall
streamlining
whorls, vortices, eddies
turbulent flow
if pressure in right atria or ventricle increases, venous return ____
decreases
two methods that help return blodo to right side of heart
- skeletal muscle pump
2. respiratory pump
standing on tiptoes compresses the vein causing
blood milking (further valve from heart closes and closer valve open)
milking of the thoracic cavity occurs on
exhalation
inhalation diphragm moves downward, causing a decrease in pressure of thoracic cavity, but an increase in abdominal cavity pressure resulting in….
abdominal veins compress and push more volume of blood through thoracid cavity towards heart
exhalation - diphragm moves upward causing increase in thoracic cavity pressure, but a decrease in the abdominal cavity pressure, resulting in….
valve close preventing backflow from thoracic veins into abdomen
blood pressure is deterimined by….
Cardiac output
Blood volume
Vascular Resistance
several INTERCONNECTED negative feedback systems control blood pressure by making adjustments in
heart rate
stroke volume
blood volume
systemic vascular resistance
cardiovascular control center located in?
helps to regulate?
Also controls neural, hormonal, and local negative feedback systems that help regulate BP
medulla oblongata
heart rate and stroke volume and blood vessel diameter
CV center regulates
heart rate, contractility, and blood vessel diameter
CV center three components
Cardio-stimulatory center
Cardio-inhibitory center
Vasomotor center (constrict or dialate)
does parasympathetic system control vascular tone?
NOOOOOOOPE
parasympathetic
vagal nerves decrease HR and contractility
sympathetic
cardiac accelerator nerves increase HR and contracility
vascular tone?
the continual sympathetic impulses sent to arteries and arterioles (reduction in rate reduces vascular tone)
BP is regulated by which two negative feedback loops?
Baroreceptor reflexes
Chemoreceptor reflexes
carotid SINUS
baroreceptor
carotid BODY
chemoreceptor
carotid SINUS is located…
innervated by?
on internal carotid artery
glossopharyngeal nerve
Two most important Baroreceptor reflexes
Carotid Sinus reflex
Aortic Reflex
helps regulate pressure in the brain
carotid sinus reflex
helps regulate systemic blood pressure (baroreceptor)
Aortic reflex
Aortic Reflex innervated by
vagal nerves
nerve impules sent at slower rate to CV center
CV center decreases parasympathetic stimulation through vagal nerves and increases sympathetic stimulation through cardiac accelerator nerves
why does this occur?
drop in BP at baroreceptors (stretched less)
increased epi and norepi
heart beats faster and more forcefully, increasing CO and systemic vascular resistance increase
systemic vascular resistance increases due to
decrease in BP (basically BP went down so arterioles constricted)
systemic vascular resistance decreases due to a
increase in BP regulated by Baroreceptors (i.e. vasomotor neurons cause vasodilation)
said differently BP went up so arterioles dialated
chemoreceptors detect changes in blood concentration of
O2, CO2, and H+
reduced plasma O2
hypoxia
increased H+ concentration
acidosis
increase in CO2 in plasma
hypercapnia
when chemoreceptors are stimulated this happens…
impulse to CV
CV increases sympathetic stimulation to arterioles adn veins causing vasoconstriction
vasoconstriction increases blood pressure
the only hormal regulator to LOWER BP by causing vasodilation (also the loss of salt and water in urine)
ANP/ANH Atrial Natriuretic peptide / hormone
RAA system stimulated by
decrease in blodo volume or flow to the kidneys causing an increase in BP by increasing water retention
released by hypothalamus
causes vasoconstriction
promotes water retention in kidneys
ADH
5 listed hormonal regulators of BP
RAA Epi/norepi ADH ADP/ANH EPO
increase CO by increasing HR and Force of contraction
causes vasoconstriction of arterioles in skin and abdominal organs
causes vasodilation of arterioles in cardiac and skeletal muscle
epi / norepi
causes vasoconstriction of arterioles in skin and abdominal organs
causes vasodilation of arterioles in cardiac and skeletal muscle
epi / nor epi
tissue changing blood flow based off metabolic demands i.e. local changes in capillary beds regulating Vasomotion
autoregulation
if O2 demand increases
vasomotion occurs where vasodilators dilate the arterioles and relax precapilllary sphincers allowing for more blood
OR
vasoconstrictors relax to allow more blood to bring O2
myogenic response
ateriole smooth muscle response
arteriole smooth muscle has a more forceful contraction when stretched more or less stressful contraction when stretched less due to what?
myogenic response or myotonic response
which types of cells alter blood-vessel diameter
WBC’s, platelets, smooth muscle fibers, macrophages, endothelial cells
vasodilating chemicals?
K+ H+ lactic acid adenosine NO kinins histamine
vasoconstricting chemicals
Thromboxane A2
Serotonin
Endothelins
What is different about Pulmonary vs Systemic Circulation in repone to low O2?
Pulmonary - constricts
Systemic - dialates
what helps creates your pulse?
expansion and recoil of elastic arteries
sounds heard when checking pulse with cuff (brachial artery)
Systolic - first sound
Diastolic -No longer hearing any
sounds heard during pulse check with cuff
Korotkoff sounds
how high above normal systolic BP to inflate cuff for BP check?
30mmHg above normal systolic
normal MAP?
70-110
MAP =
diastolic BP + (systolic - diastolic)/3
if MAP below 60 for extended time
hypoxia and ischemia (lack of perfusion)
Tissue perfusion ____ as someone transitions from rest, to exercise
increases
selective vasodilation occurs during exercise in ____
due to resistance decrease in these active tissues
also increased venous return (muscle and respiratory pump increase return) i.e. PRELOAD increasing contractility Frank Starling
skeletal muscles heart lungs liver skin
selective vasoconstriction occurs during exercise in ____
this allows more blood to be shunted to more metabolically demanding locations
kidneys, digestive system, reproductive system
