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Cardiovascular Physiology

Terms in this set (53)

coronary circulation
supplies blood to the muscle tissue of the heart
Atrioventricular valves
Valves located between the atrial and ventricular chambers on each side of the heart, prevent backflow into the atria when the ventricles are contracting
tricuspid valve
valve between the right atrium and the right ventricle
bicuspid valve
valve between the left atrium and the left ventricle.
semilunar valves
located between the ventricles and arteries leaving the heart, prevent backflow
pulmonary valve
valve positioned between the right ventricle and the pulmonary artery
aortic valve
valve positioned between the left ventricle and the aorta
"lub"
(1st sound) produced by closing of AV valves
"dub"
(2nd sound) produced by semilunar valves closing
conducting system
controls and coordinates heartbeat
contractile cells
produce contractions that propel blood
SA node
pacemaker of the heart
electrocardiogram
record of the electrical activity of the heart
P wave
atrial depolarization
QRS complex
prior to ventricular contraction, atrial repolarization
T wave
ventricular repolarization
systole
Contraction of the heart
diastole
Relaxation of the heart
cardiac cycle
A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles
end diastolic volume
volume of blood in each ventricle at end of ventricular diastole (relaxation/filling)
end systolic volume
volume of blood remaining in each ventricle after systole (contraction)
cardiac output
heart rate x stroke volume
stroke volume
The amount of blood ejected from the heart in one contraction.
Automaticity
The ability of the heart to generate and conduct electrical impulses on its own.
Preload
The precontraction pressure in the heart as the volume of blood builds up.
Afterload
The force or resistance against which the heart pumps.
contractility
ability to shorten forcibly when stimulated
total peripheral resistance
the resistance of the entire cardiovascular system, alters after load
venous return
The amount of blood returned to the heart by the veins
Ejection Fraction (EF)
percentage of blood volume in the ventricles at the end of diastole that is ejected during systole; a measurement of contractility
baroreceptor reflex
Sudden changes in arterial BP initiate reflex that evokes an inverse change in HR
chemoreceptor reflexes
respond to changes in chemical composition, particularly pH and dissolved gases
What are some intrinsic regulators of myocardial performance and blood pressure?
frank starling mechanism, output of both ventricles
What are some extrinsic regulators of myocardial performance and blood pressure?
autonomic nervous system, chemical control
Frank-Starling Law
As end diastolic volume (preload) increases, stroke volume increases (decreases end systolic volume)
microcirculation
Circulation through smallest vessels of body
Arterioles, capillaries, venules, and lymphatics
How does net filtration pressure affect the exchange of fluid between capillaries and tissues?
total pressure that promotes filtration
How does hydrostatic pressure affect the exchange of fluid between capillaries and tissues?
promotes the exchange of fluids, with increase in pressure there is increase in filtration
How does oncotic pressure affect the exchange of fluid between capillaries and tissues?
stops fluid exchange, with increase in pressure there is decrease in filtration
How do starling forces affect the exchange of fluid between capillaries and tissues?
there is a balance that when reached, promotes fluid movement in or out
Anti-diuretic hormone (ADH)
released by the pituitary gland, elevates blood pressure by reducing water loss in kidneys
Aldosterone
responds to fall in renal pressure
Renin-Angiotensin-Aldosterone System
a hormone cascade pathway that helps regulate blood pressure and blood volume
Atrial Natriuretic Peptide (ANP)
hormone secreted from atrial cells of the heart in response to atrial stretching and an increase in circulating blood volume.
What is the role of pressure in blood flow?
blood flows from an area of high pressure to low pressure
What is the role of resistance in blood flow?
a decrease in vessel diameter increases resistance, with decreased blood flow
How is blood flow regulated at the local level?
microcirculation
Coronary circulation
flow of blood to and from the tissues of the heart, Controlled by local metabolites, myocardial metabolic activity
Cutaneous circulation
involves stimulating the skin through massage, vibration, heat, or cold to reduce the intensity of pain, Controlled by sympathetic innervation
Skeletal muscle circulation
sympathetic and metabolic factors
-sympathetics at rest
---alpha 1 = vasoconstrict
---beta 2 = vasodilate

lactate, adenosine, K
Cerebral circulation
supplies the brain, Controlled by local metabolites
Pulmonary circulation
flow of blood from the heart to the lungs and back to the heart, controlled by oxygen
Fetal circulation
the system of blood vessels and structures through which blood moves in a fetus,
Ductus venosus: bypasses liver, as 50% of placental blood already to liver
Foramen ovale: bypasses developing fetal pulmonary circulation
Ductus arteriosus: blood from pulmonary trunk to aorta, bypasses fetal pulmonary circulation
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