Cardiovascular System: Heart

cardiac muscle

myocardium, specialized involuntary striated muscle tissue on the walls of the heart

fiber

short branching fibers connecting 3-D network of heart muscle

nucleus

one or two centrally located per cell

intercalated discs

cellular junctions hold cells together with desmosomes and gap junctions located at the ends of adjacent cardiac muscle cells

apex

pointed, inferior tip of the heart formed by the inferolateral portion of the left ventricle

pericardium

double-layered membrane surrounding the heart and roots of the great vessels

epicardium

outer layer of the heart; visceral layer of the serous pericardium

myocardium

thick, muscular middle layer of the heart; pumps blood

endocardium

thins, smooth inner lining of the heart

auricles

small, ear-shaped muscular pouch attached to the outside of each upper heart chamber (atriums)

atria

the two upper chambers of the heart

right atrium

receives deoxygenated blood as it returns from the body cells; blood from superior and inferior vena cava

left atrium

receives oxygenated blood from the lungs; blood from pulmonary veins

ventricles

the two lower chambers of the heart

right ventricle

pumps deoxygenated blood to the lungs

left ventricle

pumps oxygenated blood to the body; thicker, stronger walls to pump blood at high pressure

interatrial septum

separates the two atria

interventricular septum

separates the two ventricles

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 (mitral) valve

valve between the left atrium and the left ventricle.

semilunar valves

pulmonary and aortic valves located between the right ventricle and the pulmonary artery and between the left ventricle and the aorta

pulmonary valve

valve positioned between the right ventricle and the pulmonary artery (lung artery)

aortic valve

heart valve between the left ventricle and the aorta (main body artery)

papillary muscles

responsible for pulling the atrioventricular valves closed by means of the chordae tendineae; left has 2, right has 3

chordae tendineae

thin bands of fibrous tissue that attach to the valves in the heart and prevent them from inverting

coronary arteries

blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle

cardiac veins

collects deoxygenated blood from heart muscle tissue empty into right atrium

aorta

the large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.

superior vena cava

second largest vein in the human body; returns blood to the right atrium of the heart from the upper half of the body.

inferior vena cava

largest vein in the human body; returns blood to the right atrium of the heart from bodily parts below the diaphragm.

pulmonary trunk

carries deoxygenated blood from right ventricle to pulmonary arteries

pulmonary arteries

bifurcations of pulmonary trunk; carry deoxygenated blood out of the right ventricle and into the respective lungs (left and right)

pulmonary veins

deliver oxygen rich blood from the lungs to the left atrium