Lec 14- Cardiac System I Flashcards
Pulmonary
Closed loop circulation to the lung.
Systemic
Circuit of vessels carrying blood between the heart abd the other body systems.
Atria
Upper cambers of the heart that receive blood returning to the heart and deliver it to the lower chambers.
Ventricle
Pump blood away from the heart.
Septum
Separates the two halves of the heart.
Myocardium
middle layer of the heart.
Aorta
Carries oxygenated blood away from the heart to the body.
Pulmonary artery
Carries partially deoxygenated blood from the heart to the lungs.
Pulmonary vein
Returns oxygenated blood to the left atrium of the heart.
AV valves
Valves between the atrium and ventricles.
Tricuspid
Right AV valve.
Bicuspid/mitral
Left AV valve.
Semilunar valves
Aortic and pulmonary.
Each have 3 cusps resembling a shallow half-moon-shaped pocket.
CO - cardiac output
volume of blood pumped by each ventricle per minute.
SA (sinolatrial) node
A small, specialized region in the right atrial wall.
Fastest autorhythmicity at 70 to 80 AP’s per minute.
Is the pacemaker of the heart.
Internodal pathway
extends from the SA node to the AV node.
Ensure sequential contraction of the ventricles following atrial contraction.
AV (atrioventricular) node
Located at the base of the right atrium.
Only form of communication between the atria and ventricles.
Bundle of His
A tract that starts from the AV node and travels through the septum out through the ventricles facing back to atrium
Purkinje fibers
small fibers that extend form the bundle of his and spread throughout the ventricular myocardium.
HCN - hyperpolarization activated cyclic-nucleotide gated.
aka funny channels.
spontaneous depolarization is caused by Na+ flwoing through channel that opens when hyperpolarized.
These unusual channels open when the potential becomes more negative (hyperpolarizes) at the end of repolarization from the previous AP.
Absolute refractory period
Cannot be stimulated again, will not produce an AP.
Plateau phase (Ca++)
Results from balance between slow Ca2+ influx and K+ efflux.
SV - stroke volume
The amount of blood pumped out of each ventricle with each contraction.
EDV - end diastolic volume
volume of blood in the ventricle at the end of diastole.
Ejection Fraction
SV/EDV.
Normally is 60%; useful clinical diagnostic tool.
Frank-Starling law of the heart
states that strength of ventricular contraction varies directly with EDV.
Chronotropic effect
Influence heart rate
Inotropic
Alters force of muscle contraction/strength.
Intrinsic
Frank-Starling law of the heart is an intrinsic property of the myocardium.
Extrinsic
FIND
Skeletal Muscle Pump
Contraction of the skeletal muscle around the veins help push blood back up to the heart.
Venous return
Venous return requires help from skeletal muscle pumps and one-way valves.
Capacitance vessels
Veins hold 70% of blood in the body.
Have thin walls and stretch easily to accommodate more blood without increased pressure.
Compliance
Veins have thin walls and stretch easily to accommodate more blood without increased pressure. Have higher compliance.
Isovolumetric contraction
When all valves are closed, pressure builds up until it exceeds aortic pressure.
Isovolumetric relaxation
All valves closed again.
Waiting for AV to open.
Heart murmurs
Abnormal heart sounds produced by abnormal patterns of blood flow in the heart.
Rheumatic fever
Secondary damage of this can cause mitral stenosis.
Mitral Stenosis
Mitral valve is thickened and calcified. Vavle will not open fully.
TPR - total peripheral resistance
impedance to blood flow in the arteries.
