A And P 2 Quiz 2

Front 1

pulmonary circuit

Back 1

carries blood between the heart and lungs for gas exchange. Systemic circuit carries blood between heart and organ systems.

Front 2

Position

Back 2

the heart lies in the mediastinum, the cavity between the lungs. It leans to the left side of the thoracic cavity and is about the size of a fist.

Front 3

Pericardium

Back 3

double-walled sac enclosing the heart to separate it from the other organs, lubricate it and allow appropriate expansion. 2 layers.

Front 4

Parietal pericardium

Back 4

has an outer layer of dense irregular fibrous connective tissue and an inner layer of serous membrane that secretes serous lubricating fluid.

Front 5

Visceral pericardium

Back 5

the serous layer of the parietal pericardium folds inwards to cover the surface of the heart. This creates the pericardial cavity filled with pericardial fluid

Front 6

Heart wall- 3 layers of tissue

Back 6

1. Epicardium (= visceral pericardium)- overlies thin areolar tissue and has thick deposits of fat that fill heart grooves and cover coronary vessels.
2. Myocardium- thickest layer of tissue, composed of cardiac muscle surrounding a fibrous skeleton of collagen and elastic fibers. Functions of the fibrous skeleton:
a. Structural support for the heart, valves and vessel openings.
b. Framework for cardiac muscle to pull against.
c. Non-conductive barrier to prevent electrical impulses from travelling directly from atria to ventricles.
3. Endocardium- simple squamous epithelium overlying thin layer of areolar tissue that lines the chambers and valves of the heart.

Front 7

Auricles

Back 7

ear-like extensions off of the atria that increase volume.

Front 8

Pectinate muscles

Back 8

ridges of myocardium in the atria.

Front 9

Trabeculae carnae

Back 9

ridges of myocardium in the ventricles

Front 10

Atrioventricular valves

Back 10

separate the atria from the ventricles. Composed of cusps of fibrous tissue attached to tendon-like chordae tendonae anchored to papillary muscles inside the ventricles. 3 cusps on the right AV valve (tricuspid) and 2 cusps on the left AV valve (bicuspid).

Front 11

Semilunar valves

Back 11

separate the ventricles from their major arteries (pulmonary and aortic). Composed of 3 loose cusps of fibrous connective tissue that open like parachutes when blood flows the wrong way.

Front 12

Coronary circulation

Back 12

feeds blood to the heart tissue by left and right coronary arteries that branch off of the aorta. The great cardiac vein (anterior) and middle cardiac vein (posterior) collect venous blood from the heart and deposit it in the right atrium through the coronary sinus.

Front 13

Cardiac muscle and cardiac conduction

Back 13

all the muscle cells of the heart (cardiocytes) contract in sequence without neuromuscular junctions at each cell.

Front 14

Cardiocytes

Back 14

short, branched muscle cells with a central nucleus. Adjacent cells are joined by intercalated discs.

Front 15

Intercalated discs

Back 15

interdigitating folds where the plasma membrane of both cells interlock and increase surface area of cell contact.
2. Discs possess fascia adherens where actin filaments from one cell anchor to the plasma membrane and, through transmembrane proteins, to the actin filaments of the next cell. Desmosomes fill the gaps between these links.
3. Discs also have gap junctions where ions can flow freely between adjacent cells and carry an electrical impulse from one cell to the next.

Front 16

Heart muscle relies almost entirely on aerobic or anaerobic respiration

Back 16

C. Heart muscle relies almost entirely on aerobic respiration and the cardiocytes have large mitochondria and more myoglobin than skeletal muscle.

Front 17

Right and left bundle branches

Back 17

divisions of the AV bundle that descend towards the apex of the heart down the interventricular septum.

Front 18

Purkinje fibers

Back 18

branch from the bundle branches at the apex to carry the electrical exitation upwards through both ventricles.

Front 19

Sinus rhythm

Back 19

triggered by SA node, this is the normal means of maintaining heart rhythm. Any abnormal rhythm is an arrhythmia.

Front 20

Ectopic focus

Back 20

any point of spontaneous firing other than the SA node.