L9/L10 Flashcards
Force Forumla
Force = change in pressure/resistance
_ pressure = _ blood flow
increased pressure causes increased blood flow
_ resistance = _ blood flow
increased pressure causes decread blood flow
Resistance in blood vessels formula
R = [(blood viscosity)(blood vessel lenght)]/(raidus of of blood vessel)^4
total peripheral resistance (TPR) definition
systemic vascular resistance of blood cells
poiseuille’s law
Force =
[ (pi) (change in pressure) (radius of blood vessel)^4 ]
/
[ 8 (blood viscosity) (blood vessel lenght) ]
laminar blood flow vs turbulent blood flow
L: smooth, strealine manner
> parallel to axis of blood vessel
T: blood moves at various angles to the vessel axis
>creates sounds
>increased resistance
Hydrostatic Pressure (Blood Pressure)
the force exerted by the blood confined within blood vessels or heart chambers
pulse definition
pulse is caused blood being ejected from ventricles causing arteries to bulge and relax
pulse formula
pulse pressure = systolic - diastolic pressure
mean arterial pressure formula
MAP = diastolic pressure + 1/3 (systolic pressure - diastolic pressure)
cardiac output equation (flow)
cardiac output = mean aterial pressure
/
total peripheral resistance
Vascular Compliance Definition
ability of blood vessels to stretch
Vascular Compliance
>transmural pressure formula
pressure outside - pressure inside
Vascular compliance formula
compliance = change in volume
/
change in transmural pressure
*transmural pressure = Pin - Pout
Compliance in veins and arteries
veins can stretch a lot (high compliance)
arteries do not really stretch (low compliance)
velocity is ___ portional to _____
inversely & cross-sectional area
velocity formula
V= force
/
cross sectional area
Where is velocity slowest in vasculature
capillaries
where is velocity fastest in vasculature
aorta and venae cavae
circulation time
how much time it takes 1 drop of blood to:
right atrium -(pulmonary circulation)->left atrium -(systemic circulation)-> foot -(systemic circulation)-> right atrium
Factors that increase venous return
- venous valves
- respiratory pump
- venoconstrction
- skeletal muscle pump
- venous pressure gradient
factors that decrease venous return
-gravity
decreased venous return means
-increased right atrium/ventricle pressure
>causes: leaky triscup valve or increased gravity
Where does the blood go (cardiac output) after leaving the right ventricle
100 % go to the lungs
left Ventricle receiveing cardiac output
fraction go to organs (not lungs)
>task dependent
vascular tone definition
partial contraction/relaxation of arteriole setting a baseline
vascular tone function
principal method of regulating blood flow to different organs of the body
Intrinsic control definition
-mechanisms within an organ that regulate blood flow
intrinsic control mechanism
adjusts arteriole radii to meet specific metabolic demand
autoregulation
the ability to have constant blood flow with changing arterial pressures
physical changes related to intrinsic control
- vasodilation
- vasocontriction
- myogenic response
myogenic response function
- increases contraction when stretching
- decreases contraction when relaxation
myogenic mechanism for vasoconstriction
- increased arteriole pressure -> smooth muscle stretch (arteriolar wall) -> mecahnically-gated channels open (muscle membrane) -> Ca 2+ influx
- Ca 2+ + calmodulin -> complex -> activates enzyme myosin-light chain kinase -> phosphorylates myosin -> activated myosin
- activated myosin + actin -> smooth muscle contraction -> vasoconstriction -> negates inital stretch of arteriole -> constant blood flow
myogenic mechanism for vasodilation
decreased arterial blood pressure -> decreased stretching -> relaxation -> vasodilation
intrinsic control local mediators for vasodilation
paracrines (chemical mediators)
>vasodilators: Co2, K+, H+. adenosine and NO
-inflammation: body kinin, histamine and protacyclin
>increased oxygen
intrinsic control local mediators for vasoconstriction
paracrines (chemical mediators)
>vasoconstrictors: thromboxne A2, superoxide radicals, serotonin & endothelin
>decreased oxygen
vasodilation with adenosine mechanism
- adenosine + A2A purinergic receptor (sarcolemma smooth muscle of coronary arteriole) -> Gs activated - > stimulates adenylyl cyclase -> increase cAMP
- cAMP + protein kinsae ->K+ATP channeels phosphorylated (sarcolemma) -> opens -> K+ ion outflux -> hyperpolarization -> L-type voltage-gate Ca2+ channels close
- Ca2+ cannot enter cell -> relaxed smooth muscles -> vasodilation
Extrinsic Control definition
control from outside the organ
Extrinsic Control types
-nerves
>sympathetic and parasympathetic
-hormones
extrinsic control from sympathetic nerves
location (innervates): arterioles
> a1-adrenergic receptors: NE > E (vasoconstriction of kidneys & digestive tract)
> B2–adrenergic receptors:: NE < E (vasodilation of heart & skeletal muscle)
extrinsic control from parasympathetic nerves
> location: external genitalia
>Ach and NO
extrinsic control from hormones
NE & E from adrenal medulla
Cardiovascular center location
medulla oblongata
Cardiovascular center function
regulate mean arterial blood pressure via heart rate, contractility and blood vessel radius
cardiostimulatory center
increase heart rate
cardioinhibitory center
decrease heart rate
vasomotor center
regulate blood vessel radius
cardiovascular center gets input from:
> proprioceptors
baroreceptors (blood vessels, pressure and stretch)
chemoreceptors -(glossopharyneal X nerve)-> cerebral cortex -> limibic system -> hypothalamus -> cardiovascular center
cardiovascular center output from sympathetic nervous system
CV center -> spinal cord
1a. —(vasomotor nerve) —> blood vessel smooth muscle
1b. — (cardiac accelerator nerve) —> SA/AV node & ventricular myocardium
cardiovascular center output from parasympathetic nervous system
CV center -(vagus X) -> SA/AV node
Baroreceptor location in mean arteriole pressure
> aorta (internal carotid arteries)
large neck
chest arteries
How Baroreceptor report decreased mean arteriole pressure
to CV center (reflexes)
decreased blood pressure -> decreased stretching -> baroreceptors (carotid sinus) -> decrease action potential -(glossopharyngeal IX)-> CV center
How does the baroreceptor report increased mean arteriole pressure to the cv center (reflexes)
increased blood pressure -> increased stretching -> baroreceptors (carotid sinus) -> increased action potential -(glossopharyngeal IX)-> CV center
carotid sinus
regulates brain blood pressure via small widening of carotid artery
orthostatic (postural) hypotension
decreased systemic blood pressure when standing up
chemoreceptor locaation
> carotid/aortic bodies near aorta arch/carotid sinus
chemoreceptor function
detect blood levels: O2, Co2 and H+
chemoreceptors reflex
> sympathetic stimualtion when: decreased O2 or increased Co2/H+
NE role in cardiovascular system
- cardiac output
- total peripheral resistance
- increases vasoconstriction
- increase heart rate/contractility
- increase blood pressure
E role in cardiovascular system
- cardiac output
- total peripheral resistance
- increases vasoconstriction/dilation
- increase heart rate/contractility
- increase blood pressure
Angiorensin II is antagonistic to _ and _
Atrial natriureitc peptide and No
aldosterone is antagonistic to _
atrial natriuretic peptide
Shock definition
failure of cardiovascular system to deliver enough O2/nutrients to meet cellular metabolic needs
Shock types
- hypovolemic
- cardiogenic
- vascular
- obstructive
Hypovolemic shock
-decreased blood volume
>caused by hemorrhage, loss of body fluids and diabetes
cardiogenic shock
-decreased heart function
>causes: excessice preload or afterload, impaired contractility, myocardial infraction, ischemia, heart vavle issues and arrhythmia
vascular shock
-inappropriate vasodilations
>causes: decreased total peripheral resistance, anaphylatic/allergies, trauma to CV center, neurogenic and spetic
obstructive shock
-obstruction of blood flow
>causes: pulmoaru embolism -> clot in lung/blood vessel
Responses to shock
-renin- angiotensin-aldosterone system
-activation of renin- angiotensin-aldosterone system (triggered by decreased blood flow to kidneys)
>hormones increases Na+ reabsorption -> water reabosorption -> increased blood volume -> increases blood pressure
Responses to shock
-ADH
-triggered by decrease blood pressure
>ADH -> increases water reabsorption in kidneys -> conserves blood volume -> vasocontriction
Responses to shock
-ANS sympathetic
-ANS
>triggered by baroreceptors
>releases NE and E
>vasocontriction, icnreased heart rate and contractility
Reponses to shock
- local vasodilators
-relax precapillary spincters -> increases blood flow BUT decreases blood pressure (decreased total peripheral resistance)
Typically response to shock are _ feedback
negative
max amount of blood loss body can compensate for
10%
Shock symptoms decreases in:
-decreased: systolic blood pressure, pulse, skin temperature, urine, pH, digestive organ activity
Shock symptoms increases in:
-increased: resting heart rate, E/NE blood concentration, sweating, vasoconstriction, thrist, nausea
hyperemia
when blood flow to a tissue increases
active hyperemia
blood flow to a tissue increases in response to an increase in metabolic activity
reactive hyperemia
blood flow to a tissue increases in response to a temporary blockage of the blood supply to that area
Activation of the β2 receptors causes the arterioles to __
to vasodilate
Activation of the α1 receptors causes the arterioles to __
to vascoconstrict
Factor Influencing Blood Pressure
>Cardiac Output (neurotransmitters)
Norepinephrine Epinephrine
>Increased heart rate and contractility therefore increasing blood pressure
Factor Influencing Blood Pressure
>Total Peripheral Resistance (vasoconstriction)
Angiotensin II, Antidiuretic hormone (vasopressin) Norepinephrine* Epinephrine†
>increase blood pressure
Factor Influencing Blood Pressure
>Total Peripheral Resistance (vasodilation)
Atrial natriuretic peptide, Epinephrine†, Nitric oxide
>decrease blood pressure
Factor Influencing Blood Pressure
> Blood Volume (increase)
Aldosterone Antidiuretic hormone
>increases blood pressure
Factor Influencing Blood Pressure
> Blood Volume (decrease)
Atrial natriuretic peptide
>decreases blood pressure
