The Heart Flashcards
The heart is no more than
a transport system pump.
Blood vessels are
the delivery routes for the heart
right side of the heart receives
oxygen-poor blood and pumps it to the lungs to get oxygen.
The left side of the heart receives
the oxygenated blood returning from the lungs and pumps this blood out to the rest of the body.
The heart has two receiving chambers
right atrium and left atrium
The heart has two main pumping chamgers
right ventricle and left ventricle
The medial cavity of the thorax that encloses the heart
the mediastinum
Apex of the heart is located where and does what
apex is the most inferior portion of the heart and can be felt beating in the chest.
Pericardium
A double walled sac that encloses around the heart.
endocardium
third layer of the heart wall. It is white sheet of endothelium which is a layer of simple squamous epithelial cells.
Atria
3 vessels that bring deoxygenated blood back to the heart and into the right atrium
Superior Vena Cava
one of the three vessels that bring deoxygenated blood back to the heart. it drains the head and neck
inferior vena cava
one of the three veins that bring deoxygenated blood back to the heart. It drains the lower body.
Coronary sinus
one of the three vessels that bring deoxygenated blood back to the heart. drains the heart muscle itself
Most superior portion of the heart
the base
The role of All valves
To prevent backflow.
the way that valves open and close are due to
pressure
chrodae tendinae
Heart strings. they anchor the valve
cardiac muscle cells are always in ABSOLUTE refractory, why?
it cannot respond to a second stimulus until the first actions potential is completely done.
if the heart is contracting and it was hit with a second stimulus and didn’t let the cells relax, it wouldn’t be able to fill for the next cycle. Need to be able to receive as well as pump. To prevent Teutonic contraction
The P wave represents
depolarization of the atria and is followed by atrial contraction (systole)
The QRS complex on the surface ECG represents
ventricular depolarization. Contraction (systole) begins after an approximately 50 ms delay and results in closure of the mitral valve.
Diastole
Period of the cardiac cycle when either the ventricles or the atria are relaxing.
systole
Period when either the ventricles or the atria are contracting.
Cardiac Cycle
all events associated with the blood flow through the heart during one complete heart beat. atrial systale and diastole followed by ventricular systole and diastole.
stroke volume
How much blood comes out of the left ventricle in one beat and goes to the AORTA.
cardiac output
the amount of blood pumped out by each ventricle in 1 minute.
end diastolic volume
the amount of blood that collects in a ventricle during diastole
end systolic volume
the volume of blood remaining in a ventricle after it has contracted
How is the stroke volume determined?
The difference between EDV and ESV
SV=EDV−ESV=120mlbeat−50mlbeat=70mlbeat