The size of a person fist

A sac that encloses the heart

Loosely fitting superficial layer: helps protect the heart and anchors it to the soroudings structures, such as the diaphragm and sternum.

Slippery

Lines the interior with the fibrous pericardium attaches to the large arteries superiorly leaving the heary and then makes a U turn and continues inferiorly over the geart surfaceas the visceral layer

part of the heart wall; innermost layer

is produced by the serous pericardial membranes and collects in the pericardial cavity between serous layers

Heart walls are composed of three layers

Consist of thick bundlea of cardiac muscle

A thin glistening sheet of endothelium thats lines the heart chambers

guards the bases of the two large arteries leaving the ventricular chambers

Each have 3 cusps that fit tightly together when the valves are closed During ventricular contraction and forcing blood out of the heart, the cusps are forced open the arteries by the tremendous force of rushing blood During ventricular relaxation blood begins to flow backward towards the heart and the cusps fill with blood like a parachute filling with air, dosing the valves

Are open during ventricular relaxation and closed during ventricular contraction

are closed during ventricular relaxation and dosed during ventricular contraction

branch from the base of the aorta and encircle the heart in the coronary sulcus (atrioventricular groove) at the junction of the atria and ventricles

Originates on the left side of the aorta

Lies on the interventricular sulcus

Extends around the coronary sulcus on the left to the posterior surface of the heart

extends inferiorly along the lateral wall of the left ventricle from circumflex artery

Drains blood from the cardiac muscle to the coronary sinus to the right atrium

Drains directly to the right atrium

results from the opening of the voltage-gates Na channels, which increases the permeability of the cell membrane to Na. Na ions then diffuse into the cell causing depolarization

is primarily the result of the opening of voltage regulated Ca channels. The slow diffusionof Ca into the cells is the reason cardiac muscle fiber action potential lasts longer.

a group of specialized cardiac muscle cells in the interventricular septum. L

• 3. The AV bundle then divides into two branches of conducting tissue, called the __________. Action potentials pass down the bundle branches toward the apex of the heart

pass to the apex of the heart and then extend to the cardiac muscle of the ventricle walls

the pacemaker of the heart, but other cells of the conduction system are also capable of producing action potentials spontaneously.

if the SA node us unable to funcyiom , another area such as the ___ , becomes the pacemaker.

When action potential originate in an area of the heart other than the SA node, the result is called.

Ectopic beats may cause very small portions of the heart to contract rapidly and independently of all other areas. This condition, called____, reduces the output of the heart to only a few milliliters of blood per minute when it occurs in the ventricles.

A process that stops fibrillation

Inflammation of the endocardium; affects the valves more severely than other areas of the endocardium; may lead to scarring, causing stenosed or incompetent valves

Disease cause or occurring secondarily to other disease; results in weakened cardiac muscle, causing all chambers of the heart to enlarge; may eventually lead to congestive heart failure

Results from a streptococcal infection in young people; toxin produced by the bacteria can cause RF several weeks after the infection that can result in rheumatic endocarditis

Hole in the septum between the left and right sides of the heart, allowing blood to flow from one side of the heart to the other and greatly reducing the heart's pumping effectiveness

Ductus arteriosus fails to close after birth, allowing blood to flow from the aorta to the Dulmonary trunk under a higher pressure, which damages the ungs also, the left ventricle must work harder to maintain dequate systemic pressure

results from the hearts normal functional characteristics and does not depend on either neural or hormonal regulation.

Involves neural and hormonal control

Results from sympathetic and parasympathetic reflexes

From epinephrine and norepinephrine secreted by the adrenal medulla

- transport blood from the right ventricle thru the lungs back to the left strium

transport blood from the left ventricle through all parts of the body and back to the right atrium

refers to contraction of the two atria

refers to the contraction of the two ventricles

refers to the relaxation of the two atria

refers to the relaxation of of the two ventricles