Cardiac Output, Blood Flow, BP #1 Flashcards
cardiac output is
volume of blood pumped per minute by left or right ventricle
The product of what equals the cardiac output
stroke volume X cardiac rate
Pulmonary has ___ resistance, ___ pressure and ___ blood flow compared to systemic circulation
low, low, high
____ ventricle pumps the equivalent of the total blood volume each minute
each
The automatic rhythm of the haeart is a result of what?
HCN channels that depolarize pacemaker cells of the SA node`
`The total blood volume
5.5 Liters
_____ from sympathetic axons and _____ from the adrenal medulla bind to ______ receptors in the heart to stimulate the production of _______
norepinephrine, epinephrine, beta adrenergic receptors, cyclic AMP
Cyclic AMP actons on what channels to stimulate faster production of action potentials in the heart
Hyperpolarization cyclic nucleotide channels and calcium (DHP) channels
Mechanisms that increase the cardiac rate have a
positive chronotropic effect
Resting bradycardia of endurance athletes is largely due to
high vagus nerve activity
The autonomic innervation of the heart is coordinated by
the cardiac control center
The end diastolic volume is sometimes called
preload
Total peripheral resitance is sometime called
the afterload
Greater peripheral resistance leads to
lower stroke volume
Ejection fraction is typically
60%
As the ventricles fill with blood, the myocardium ____ and has what effect?
stretches, increases interactions between actin and myosin and increases sensitivty of RYR2 channels
What is anrep effect?
when the force of myocardial contraction gradually increases over 10-15 minutes following the initial rapid increase when ventricles are stretched
Frank Starling Law of the heart
strength of ventricular contraction varies directly with end diastolic volume
What intrinsic mechanisms show that increase of end diastolic volume produces increase in contraction strength and stroke volume
Anrep effect, increased sensitivity of ryanodine RYR2 receptors, Frank Starling mechanism
Why do veins have higher compliance than arteries?
They have thinner less muscular walls, so they expand more and can hold more blood
What are capacitance vessels
veins
Where is osmotic pressure greatest and where is blood pressure greatest?
venules, arterioles
What is net filtration pressure?
the hydrostatic pressure of blood in capillaries minus the hydrostatic pressure of tissue fluid outside capillaries
The osmotic pressure exerted by plasma proteins
colloid osmotic pressure
The difference between colloid osmotic pressure of plasma and of interstitial fluid
oncotic pressure
The opposing forces taht affect the distribution of flid across the capillary
starling forces
Starling forces favor the filtration of fluid out the capillary at the
arterial end
Where is most of the filtrate returned in the vascular system?
90% to blood capillaries, 10% to lymphatic
High arterial blood pressure that causes excessive filtration leads to
edema
proteins in the urine indicate
kidney disease
worms in lymphatic drainage
elephantiasis
Sucking insects that spread parasitic nematode worm
filariasis
What hormones have the greatest effect on BP
ADH and aldosterone
Dilution of the blood ____ the release of ADH
inhibits
salt retaining hormone
aldosterone
Difference between adh and aldosterone
aldosterone promotes the reabsorption of salt and water but adh promotes only water reabsorption
What secretes the enzyme renin
juxtaglomerular apparatus
How does angiotension 2 promote a rise in blood volume
stimulating the thirst center and the adrenal cortex to secrete aldosterone
Drugs that prevent the conversion of angiotension 1 to 2
angiotension converting enzyme inhibitors
inhibits the binding of angiotension 2 to its receoptors
angiotension receptor blockers
What does the brain rely on to maintain the constancy of blood flow
intrinsic myogenic regulation
When metabolic product accumulate in an area and then cause vasodilation
reactive hyperemia
Chest pain caused by sudden and severe spasm of coronary artery that obstructs blood flow
variant angina (prinzmetal’s)
