The Heart Flashcards
describe the function of the heart
helps maintain homeostasis of blood pressure
trace the flow of blood through the heart and pulmonary circuit
deoxygenated blood is pumped to the lungs by the right side of the heart; gas exchange occurs between ait in the alveoli and blood in the pulmonary capillaries; oxygenated blood is returned to the left side of the heart
describe the structure of the heart
chambers = left & right atrium and left & right ventricles
great vessels = veins (vena cava and pulmonary veins) and arteries (aorta and pulmonary trunk)
valves = tricuspid, bicuspid, pulmonary, and aortic
describe the structure and function of the coronary arteries and cardiac veins
coronary arteries = right & left coronary arteries and ascending aorta
cardiac veins = great, small, and middle cardiac veins
receive blood from veins?
atria
pump blood into ventricles?
atria
pump blood into ventricles through…
valves
close when ventricles contract to keep blood from moving backward
flaps on valves
eject blood into arteries?
ventricles
bring blood to and away from heart
great vessels
drains deoxygenated blood from veins superior to diaphragm
superior vena cava
drains deoxygenated blood from veins inferior to diaphragm
inferior vena cava
receives deoxygenated blood pumped from right ventricle
pulmonary trunk
bring deoxygenated blood to right and left lungs
pulmonary arteries
supplies entire systemic circuit with oxygenated blood
aorta
returns oxygenated blood in pulmonary capillaries to heart
pulmonary veins
pulmonary circuit =
deoxygenated blood
systemic circuit =
oxygenated blood
two valves that prevent blood backflow into atria
tricuspid and bicuspid valves
two valves that prevent blood backflow into ventricles
pulmonary and aortic valves
the big picture
blood in systemic capillaries delivers oxygen to body cells; systemic veins return deoxygenated blood to the right atrium; blood passes from the right atrium through the tricuspid valve to the right ventricle; the right ventricle pumps blood through the pulmonary valve to the pulmonary trunk; the pulmonary trunk delivers blood to the pulmonary capillaries of the left and right lungs; the aorta delivers blood to the systemic capillaries; the left ventricle pumps blood through the aortic valve to the aorta; blood passes from the left atrium through the mitral valve to the left ventricle; the blood becomes oxygenated in the pulmonary capillaries and the pulmonary veins return oxygenated blood to the left atrium
how you get blood flow to the tissues of the heart
coronary circulation
systems of channels formed between blood vessels; bypass; used for blockage of a coronary artery so we put a blood vessel around it so blood can still get down to the heart tissue
anastomoses
pathway of coronary circulation
the coronary arteries come off from the ascending aorta, so as the heart contracts, blood is pushed out through the aorta and its oxygenated; the oxygenated blood then goes to the coronary arteries that takes the blood to the myocardium of the heart; the coronary veins drain blood into the coronary sinus which is what is going to connect to the vena cava and drain the blood from the three great veins into the right atrium
comes off the aorta and takes blood to the heart muscle
coronary arteries
cardiac electrical activity is coordinated by very small, unique population of cardiac muscle cells that start their own action potential
pacemaker cells
these cells rhythmically and spontaneously generate action potentials and spread to other types of cardiac muscle cells that are propagated from pacemaker cells
contractile cells
cardiac conduction system
the SA node generates an action potential, which spreads to atrial cells and the AV node; after the AV node delay, the action potential is conducted to the AV bundle and then to the right and left bundle branches; the action potential spreads from the bundle branches along the Purkinje fibers to the contractile cells of the ventricles
represents atria depolarization
P wave
represents ventricular depolarization
QRS complex
represents ventricular repolarization
T wave
heart sounds
under normal conditions, blood flow through open AV and semilunar valves is relatively quiet; sounds ONLY occur when valves CLOSE; sounds are likely a result from VIBRATIONS of ventricular and blood vessel walls
S1 =
“lub” when AV valves CLOSE
S2 =
“dub” when SEMILUNAR valves CLOSE
occurs when blood flow through heart is turbulent and caused by defective valves
heart murmur
average heart rate
60-80 beats per minute
amount of blood pumped into pulmonary and systemic circuits in 1 minute
cardiac output
resting stroke volume =
70ml
normal adult blood volume =
5 liters
factors that influence stroke volume
preload, heart contractility, and afterload
refers to length or degree of stretch of sarcomeres in ventricular cells before they contract
preload
heart’s intrinsic pumping ability
contractility
refers to force that right and left ventricles must overcome in order to eject blood into their respective arteries
afterload
how changes in preload, contractility, and afterload affect stroke volume
high preload leads to high EDV = increased contractility = low afterload = high stroke volume and low ESV
low preload leads to low EDV = weakened contractility = high afterload = low stroke volume and high ESV
factors that influence heart rate
chronotropic agents
anything that increases rate at which SA node fires; includes sympathetic nervous system, hormones, and elevated body temp
positive chronotropic agents
anything that decreases rate at which SA node fires; includes parasympathetic nervous system and decreased body temp
negative chronotropic agents
