33.2a Anatomy of the Heart

the heart and the peripheral blood vessels

The two major components of the cardiovascular system are (?).

anatomy and physiology of the cardiovascular system

Prehospital care of cardiovascular patients requires a sound knowledge of the (?).

an understanding of the heart and the peripheral blood vessels and how they work

Accurately assessing the patient, making a correct field diagnosis, and providing the best management possible depends on (?).

heart

The (?) is a muscular organ, approximately the size of an adult’s closed fist.

mediastinum

The heart is in the center of the chest in the (?), anterior to the spine and posterior to the sternum.

to the left of the midline, to the right

Approximately two-thirds of the heart’s mass is (?) with the remainder (?).

apex

The bottom of the heart, or (?), is just above the diaphragm, left of the midline.

base

The top of the heart, or (?), lies at approximately the level of the second rib.

great vessels

The (?) connect to the heart through the base.

trachea

#1 shows the (?)

left lung

#2 shows the (?)

right lung

#3 shows the (?)

base of the heart

#4 shows the (?)

apex of the heart

#5 shows the (?)

diaphragm

#6 shows the (?)

endocardium, myocardium, pericardium

The heart consists of three tissue layers: (?), (?), and (?).

endocardium

The (?) is the innermost layer. It lines the heart’s chambers and is bathed in blood.

myocardium

The (?) is the thick middle layer of the heart.

electrical properties

The myocardium's cells are unique in that they physically resemble skeletal muscle but have (?) similar to those of smooth muscle.

contract

Myocardial cells also contain specialized structures that help to rapidly conduct electrical impulses from one muscle cell to another, enabling the heart to (?).

pericardium

The (?) is a protective sac surrounding the heart.

visceral, parietal

The pericardium consists of two layers, (?) and (?).

visceral pericardium

The (?) , also called the epicardium, is the inner layer in contact with the heart muscle itself.

parietal pericardium

The (?) is the outer, fibrous layer of the pericardium.

pericardial fluid

In the pericardial cavity between these two layers is about 25 mL of (?) , a straw-colored lubricant that reduces friction as the heart beats and changes position.

compressing the heart and decreasing cardiac output

Certain disease processes and injuries can increase the amount of fluid in this sac, (?).

myocardium

#1

visceral pericardium

#2

pericardial cavity

#3

lung

#4

parietal pericardium

#5

pleural cavity

#6

pleura

#7

endocardium

#8

diaphragm

#9

four

The heart contains (?) chambers.

atria

The (?), the two superior chambers, receive incoming blood.

ventricles

The (?), the two larger, inferior chambers, pump blood out of the heart.

interatrial septum

The right and left atria are separated by the (?).

interventricular septum

The ventricles are separated by the (?).

fibrous connective tissue and contractile muscle

Both septa contain (?).

do not contribute significantly to the heart’s pumping action

The walls of the atria are much thinner than those of the ventricles and (?).

interatrial septum

#1

left atrium

#2

right atrium

#3

left ventricle

#4

right ventricle

#5

interventricular septum

#6

endocardial and connective tissue

The heart contains two pairs of valves, the atrioventricular valves and the semilunar valves, made of (?).

control blood flow

The atrioventricular valves (?) between the atria and the ventricles.

tricuspid valve

The right atrioventricular valve is called the (?) because it has three leaflets, or cusps.

mitral valve

The left atrioventricular valve, called the (?), has two leaflets.

papillary muscles

The tricuspid and mitral valves are connected to specialized (?) in the ventricles.

open the valves and allow blood flow between the two chambers

When relaxed, papillary muscles (?).

chordae tendineae

Specialized fibers called (?) connect the valves’ leaflets to the papillary muscles.

prolapsing into the atria and allowing backflow during ventricular contraction

The chordae tendineae prevent the valves from (?).

semilunar valves

The (?) regulate blood flow between the ventricles and the arteries into which they empty.

aortic valve

The left semilunar valve, or (?), connects the left ventricle to the aorta.

pulmonic valve

The right semilunar valve, or (?), connects the right ventricle to the pulmonary artery.

one-way movement of blood and prevent backflow

The semilunar valves permit (?).

left atrium

#1

aorta

#2

mitral valve (closed)

#3

papillary muscles (tensed)

#4

left ventricle (contracted)

#5

tricuspid valve (closed)

#6

mitral valve (closed)

#7

aortic valve (open)

#8

pulmonic valve (open)

#9

mitral valve (open)

#1

papillary muscles relaxed

#2

left ventricle (dilated)

#3

tricuspid valve (open)

#4

mitral valve (open)

#5

aortic valve (closed)

#6

pulmonic valve (closed)

#7

superior and inferior venae cavae

The right atrium receives deoxygenated blood from the body via the (?).

superior vena cava, inferior vena cava

The (?) receives deoxygenated blood from the head and upper extremities, the (?) from the areas below the heart.

through the tricuspid valve and into the right ventricle

The right atrium pumps this blood (?).

through the pulmonic valve to the pulmonary artery and on to the lungs

The right ventricle then pumps the deoxygenated blood (?).

pulmonary artery

The (?) is the only artery in the body that carries deoxygenated blood.

pulmonary veins

After the blood circulates through the lungs and becomes oxygenated, it returns to the left atrium via the (?).

oxygenated blood

The pulmonary veins are the only veins in the body that carry (?).

through the mitral valve and into the left ventricle

The left atrium sends this oxygenated blood (?).

through the aortic valve to the aorta

Finally, the left ventricle pumps the blood (?), which feeds the oxygenated blood to the rest of the body.

higher on the left than on the right

Intracardiac pressures are (?) because the lungs offer less resistance to blood flow than the systemic circulation.

thicker than the right

Because of the higher resistance to blood flow in systemic circulation, the left myocardium is (?).

aorta

The major vessels of the body all branch off of the (?), which has three main parts.

ascending aorta

The (?) comes directly from the heart.

thoracic aorta

The (?) curves inferiorly and goes through the chest (or thorax).

abdominal aorta

The (?) goes through the diaphragm and enters the abdomen.

superior vena cava

#1

aorta

#2

pulmonary trunk

#3

left pulmonary arteries

#4

left pulmonary veins

#5

left atrium

#6

pulmonic valve

#7

mitral valve

#8

left ventricle

#9