630 chapter 8

leaflets

flat, leaf-shaped structures that comprise the valves of the heart and prevent backflow of blood

lumen

tubular space or channel within an organ or structure of the body; space within an artery, vein, intestine, or tube

regurgitation

backflow or ejecting of contents through an opening

sphincters

circular muscles found in a tubular structure or hollow organ that constrict or dilate to regulate passage of substances through its opening

vasoconstriction

narrowing of the lumen of a blood vessel that limits blood flow, usually as a result of diseases, medications, or physiological processes

vasodilation

widening or relaxation of the lumen of a blood vessel associated with an increased blood flow that occurs in response to various physiological factors or medications

viscosity

thickness or a measure of how resistant a liquid is to flowing

tunica externa

outer coat of an artery

tunica media

middle layer of an artery; composed of smooth muscle

tunica intima

inner lining of the lumen of an artery; composed of endothelial cells

arterioles

small arteries

capillaries

microscopic vessels that join the arterial system with the venous system

venules

develop from the union of capilaries

veins

formed from venules

pulmonary circulation

the pathway where the right side of the heart pumps deoxygenated blood from the body to the lungs for oxygenation and release of carbon dioxide, then returns oxygenated blood to the left side of the heart to be pumped to the rest of the body through systemic circulation

systemic circulation

delivers the oxygen rich blood from the left side of the heart to the body tissues and organs, and returns deoxygenated blood back to the right side of the heart

pericardium

two-layer sac that protects the heart

fibrous pericardium

outer layer of the pericardium; structural support

serous pericardium

inner layer of the pericardium

pericardial cavity

located between the parietal layer and visceral layer (also called epicardium) of the serous pericardium

epicardium

covers the heart surface; outermost layer of the heart wall

myocardium

middle and thickest layer of the heart wall; composed of muscle tissue; responsible for the contractions that pump blood throughout the body

endocardium

innermost layer of the heart wall; serous membrane that lines the four chambers of the heart and its valves and is continuous with the endothelium of the arteries and veins

atriums

upper chambers of the heart; collects blood

ventricles

lower chambers of the heart; pumps blood for the heart

pulmonary circulation

when the right ventricle pumps deoxygenated blood to the lungs for oxygenation

systemic circulation

when the left ventricle pumps oxygenated blood to the entire body

superior vena cava

collects and carries blood from the upper body to the right atrium

inferior vena cava

collects and carries blood from the lower body to the right atrium

tricuspid valve

blood passes through it from the right atrium to the right ventricle; consists of three leaflets

pulmonic valve

prevents regurgitation of blood into the right ventricle from the pulmonary artery

pulmonary veins

carry oxygenated blood back to the heart via the left atrium

mitral (bicuspid) valve

blood passes through it from the left atrium to the right atrium; contains two leaflets

aorta

largest artery of the body

aortic semilunar valve (aortic valve)

permits blood to flow in only one direction - from the left ventricle to the aorta

right coronary artery

vascularizes the right side of the heart

left coronary artery

vascularized the left side of the heart

sinoatrial (SA) node

located in the upper portion of the right atrium; sets the basic pace for cardiac rate; commonly known as the pacemaker of the heart

atrioventricular (AV) node

each electrical impulse discharged by the SA node is transmitted to this causing the atria to contract; located at the base of the right atrium

bundle of His (or AV bundle)

a tract of conduction fibers, composed of a right and left branch, that relays the impulse to Purkinje fibers

Purkinje fibers

extend up the ventricle walls; transmit the impulse from the bundle of His to the right ventricles and left ventricles causing them to contract

P wave

depolarization (contraction) of the atria

QRS complex

depolarization (contraction) of the ventricles

ST segment

interval between ventricular depolarization and repolarization (recovery)

T wave

repolarization (recovery) of the ventricles

systole

contraction phase when the blood is forced out of the heart

diastole

relaxation phase when the ventricles are filling with blood

sphygmomanometer

measures blood pressure in millimeters of mercury (mm Hg)

systolic pressure

goes first in BP reading

diastolic pressure

goes last in BP reading

Normal BP

systolic <120 / diastolic <80

elevated BP

systolic 120-129 / diastolic <80

stage 1 hypertension

systolic 130-139 / diastolic 80-90

stage 2 hypertension

systolic >140 / diastolic >90

stage 3 hypertension

systolic >180 / diastolic >120

aneurysm/o

aneurysm

angi/o, vascul/o

vessel (usually blood or lymph)

aort/o

aorta

arteri/o

artery

arteriol/o

arteriole

atri/o

atrium

ather/o

fatty plaque

cardi/o, coron/o

heart

electr/o

electricity

embol/o

embolus (plug)

hemangi/o

blood vessel

my/o

muscle

phleb/o, ven/o

vein

scler/o

hardening; sclera (white of eye)

sept/o

septum

sphygm/o

pulse

sten/o

narrowing; stricture (CF)

thromb/o

blood clot (CF)

valv/o, valvul/o

valve

ventricul/o

ventricle (of the heart or brain)

-cardia

heart condition

-stenosis

narrowing, stricture

endo-

in, within

extra-

outside

peri-

around

trans-

across

aneurysm

localized abnormal dilation of a vessel, usually an artery

angina

chest pain or discomfort, caused by obstructions or spasms of the coronary arteries that decrease blood flow to the myocardium

arrhythmia

irregularity in the rate or rhythm of the heart; also called dysrhythmia

bradycardia

fewer than 60 bpm when resting

fibrilation

abnormally rapid, uncoordinated quivering of the myocardium that can affect the atria or ventricles

bruit

soft, blowing sound heard over a blood vessel on auscultation often associated with turbulent blood flow; it can indicate and underlying vascular issue, such as an obstruction or narrowing in the blood vessel

cardiomyopathy

group of diseases that affect the heart muscles and diminish cardiac function; can lead to heart failure, arrhythmias, or other complications

coarctation

narrowing of a vessel, especially the aorta

embolism

intravascular mass that dislodges from one part of the body and causes a blockage in another area, commonly leading to life-threatening situations

heart block

interference with the normal transmission of electrical impulses from the SA node to the Purkinje fibers

first-degree heart block

atrioventricular block in which the atrial electrical impulses are delayed by a fraction of a second before being conducted to the ventricles; shows as a prolonged PR interval

second-degree heart block

AV block in which occasional electrical impulses from the SA node fail to be conducted to the ventricles; QRS complexes are dropped periodically, usually every second, third, or fourth beat

third-degree heart block

AV block in which the electrical impulses from the atria fail to reach the ventricles; also called complete heart block; treatment consists of atropine or pacemaker

heart failure

inability of the heart to pump sufficient blood to meet the metabolic needs of the body

congestive heart failure (CHF)

blood returning to the heart backs up, causing fluid to accumulate in the lungs (pulmonary edema) and other parts of the body such as the liver, abdomen, and lower extremities

hyperlipidemia

excessive amounts of lipids (cholesterol, phospholipids, and triglycerides) in the blood

hypotension

persistently low blood pressure, generally less than 90/60 mm Hg

mitral valve prolapse (MVP)

structural defect in which the mitral valve leaflets prolapse into the LA during ventricular contraction (systole), resulting in incomplete closure and backflow of blood

murmur

abnormal heart sound heard with a stethoscope caused by turbulent blood flow through the heart