Chapter 19 Heart

pulmonary circuit

pulmonary circuit

carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated blood back to the heart

systemic circuit

carries oxygen-rich (oxygenated) blood returning from the lungs and back to the body tissues to supply oxygen. Left side of the heart. High pressure circulation.

pericardial sac

surrounds the heart

pericardial fluid

serous fluid between parietal & visceral pericardium; reduces friction when heart beats

visceral pericardium (epicardium)

serous membrane covering the heart

parietal pericardium

serous membrane that lines the fibrous pericardium

fibrous pericardium

tough, white fibrous connective tissue that is the outer layer of the pericardium

myocardium

thick middle muscle layer of the heart

endocardium

the simple squamous epithelium that lines the heart and is continuous with the endothelium of the great vessels

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.

semilunar valves

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

serous fluid

A clear, watery fluid secreted by the cells of a serous membrane.

mediastinum

area between the lungs containing the heart, aorta, venae cavae, esophagus, and trachea

sinoatrial (SA) node

A specialized area of cardiac tissue, located in the right atrium of the heart, which initiates the electrical impulses that determine the heart rate; often termed the pacemaker for the heart.

atrioventricular (AV) node

A small mass of specialized cardiac muscle fibers, located in the wall of the right atrium of the heart, that receives heartbeat impulses from the sinoatrial node and directs them to the walls of the ventricles.

interventricular septum

muscular wall between the right and left ventricles

interatrial septum

muscular wall between the right and left atria

superior vena cava

A vein that is the second largest vein in the human body and returns blood to the right atrium of the heart from the upper half of the body.

inferior vena cava

A vein that is the largest vein in the human body and returns blood to the right atrium of the heart from bodily parts below the diaphragm.

aorta

The largest artery in body; carries blood from the heart to be distributed by branch arteries through the body.

arteries

carry blood away from the heart

veins

carry blood to the heart

capillaries

microscopic blood vessels through which exchanges take place between the blood and cells of the body

pulmonary veins

carry oxygenated blood from the lungs to the heart

pulmonary arteries

carry deoxygenated blood out of the right ventricle and into the lungs

systemic arteries

carry oxygenated blood away from the heart

systemic veins

carry deoxygenated blood back to the heart

cardiac skeleton

crisscrossing, interlacing layer of connective tissue
-Anchors cardiac muscle fibers
-Supports great vessels and valves
-Limits spread of action potentials to specific paths

moderator band

muscular band of heart tissue that carries a portion of the right bundle branch to the papillary muscles in the right ventricle

trabeculae carneae

muscular ridges on the internal surface of the ventricles

pectinate muscles

internal ridges of myocardium in right atrium and both auricles

papillary muscles

anchor chordae tendineae

chordae tendinae

fibers attached to the tricuspid and bicuspid valves which pull it closed when papillary muscles contract, preventing backflow of blood

fossa ovalis

Oval shaped depression found in atria; interatrial septum between atria

foramen ovale

opening in the septal wall between the atria; normally present only in the fetus

coronary sinus

enlarged vein from junctions of coronary veins which empty into the right atrium

coronary arteries

supply oxygen-rich blood to the myocardium

coronary veins

blood vessels that transport deoxygenated blood from the heart toward the right atrium.

arteriosclerosis

hardening of the arteries due to loss of elasticity; resulting in narrowing of artery

atherosclerosis

condition in which fatty deposits called plaque build up on the inner walls of the arteries

atherosclerotic plaque

fatty deposit in wall of a coronary vessel

Electrocardiogram (ECG)

recording of the electrical changes that occur in the myocardium during a cardiac cycle

P wave

represents atrial depolarization

QRS wave

represents ventricular depolarization

T wave

represents repolarization of ventricles

intercalated discs

specialized connections between myocardial cells containing gap junctions and desmosomes

gap junctions

provide cytoplasmic channels between adjacent cells

diastole

relaxation of heart muscle

systole

contraction of hear muscle

End Diastolic Volume (EDV)

volume of blood in each ventricle at end of ventricular diastole

End Systolic Volume (ESV)

volume of blood remaining in each ventricle after ventricular systole

Stroke Volume (SV)

The volume of blood pumped forward with each ventricular contraction.

Heart rate

number of beats per minute

stenotic valve

a valve that cannot open fully; restricting flow of blood

incompetent valve

leaky valve that does not close properly and allows backflow of blood

cardioaceleratory center

within the medulla oblongata; controls sympathetic neurons that stimulate increased heart rate and force of contraction

cardioinhibitory center

within the medulla oblongata; controls parasympathetic neurons that stimulate decreased heart rate and force of contraction

preload

venous return that builds during diastole

afterload

resistance to left ventricular ejection

Starling's Law

The more the heart is filled during diastole the more forcefully it contracts

maximum heart rate

The heart's maximum working capacity. To find maximum heart rate = subtract age from 220 Examples: 220 - 14 = 206

cardiac reserve

difference between resting and maximal cardiac output

Cardiac Output (CO)

Amount of blood pumped in 1 minute (~5 L)

Bainbridge reflex

(also, called atrial reflex) autonomic reflex that responds to stretch receptors in the atria that send impulses to the cardioaccelerator area to increase HR when venous flow into the atria increases