ATI A&P HEART AND HEART DISEASE

mediastinum

central region of the thorax

apex

heart’s pointed, inferior portion directed towards the left

base

broad, superior portion directed towards the right; area of attachment for large vessels carrying blood in/out of the heart

endocardium

innermost layer of epithelial cells that lines the heart’s interior; provides a smooth surface for easy blood flow; covers the cusps of the heart valves

myocardium

heart muscle; thickest layer that pumps blood through the vessels

epicardium

serous membrane that forms the thin, outermost layer of the heart wall; considered the visceral layer of the pericardium

pericardium

sac that encloses the heart

fibrous pericardium

sac’s outermost/ heaviest layer; connective tissue membrane that anchors to diaphragm, sternum and other structures surrounding the heart (holds heart in place)

serous pericardium

outer, parietal layer that lines the fibrous pericardium and inner, visceral layer (epicardium); forms the inner layer of pericardium that reduces friction as the heart moves within the pericardium

intercalated disks

plasma membranes of adjacent cells that are tightly joined together by specialized membrane proteins

muscle fibers

branched fibers are interwoven so that the stimulation that causes the contraction of one fiber results in the contraction of the whole group

atria

blood-receiving chambers (upper)

ventricles

forceful pumps (lower chambers)

what structure has the thinnest walls and weakest contractions?

atria

which structure has the thickest wall?

left ventricular wall

right atrium

thin-walled chamber that receives blood returning from body tissues; low in O2

superior vena cava

brings blood from the head, chest, arms

inferior vena cava

delivers blood from trunk and legs

right ventricle

receives blood from right atrium and pumps it to the lungs

travels from right ventricle to large pulmonary trunk which divides into?

right and left pulmonary arteries; takes blood from the heart to the tissues; low in O2 which is unlike other arteries

left atrium

receives oxygen-rich blood as it returns from the lungs in pulmonary veins

pulmonary veins

carries blood high in O2 content unlike other veins

left ventricle

chamber with thickest wall, pumps highly oxygenated blood to all parts of the body; first travels to aorta

aorta

largest artery which branches out into the systemic arteries

interatrial septum

separates the two atria

interventricular septume

separates the two ventricles

septa consists of what?

myocardium

semilunar valves

each flap resembles a half-moon (exit valves)

atrioventricular valves

between the atria and ventricles (entrance valves)

when do atrioventricular valves open?

when the pressure is greater in the atria than in the ventricles

when do atrioventricular valves close?

when ventricular pressure exceeds atrial pressure, preventing flow

right atrioventricular valve is called?

tricuspid valves; has 3 cusps; blood flows from right atrium into right ventricle when open; closes when right ventricle contracts pushing the flow towards into the pulmonary trunk

left atrioventricular valve is called?

mitral valve; two cusps that permit blood flow from left atrium to left ventricle; ensures blood flows into aorta when closed

papillary muscles

AV valves have these thin fibrous threads that arise from the walls of the ventricles

chordae tendineae

the threads stabilize the valve flaps when the ventricles contract so that the blood’s force will not push valves up into the atria; helps prevent backflow

pulmonary valve

is a semilunar valve between the right ventricle and the pulmonary trunk

aortic valve

is a semilunar valve between the left ventricle and the aorta

coronary circulation

has right and left coronary arteries to provide oxygen and nourishment in the myocardium; first branches of the aorta; receives blood only when ventricles relax

left coronary artery

largest coronary artery and supplies blood to the left side of the heart; branches into left anterior descending artery and circumflex artery

right coronary artery

branches off into posterior descending artery; located inferior to the right atrium

coronary sinus

blood collects here; dilated vein that opens into the right atrium near the inferior vena cava

systole

active phase

diastole

resting phase

cardiac cycle

one complete sequence of heart contraction and relaxation

atrial diastole and ventricular systole begin?

at the same time; while ventricles are contracting forcing blood through the semilunar valves, the atria are relaxed and filling with blood

sinoatrial node (SA)

located in the upper wall of the right atrium in a sinus; initiates the heartbeats by generating action potential at regular intervals

pacemaker?

SA node is called this because it sets the rate of heart contractions

atrioventricular node (AV)

located in the interatrial septum at the bottom of the right atrium; delays signal

bundle of His

located at top of the interventricular septum; fibers travel down this in groups called the right and left bundle branches

purkinje fibers

smaller; travel in a branching network through the myocardium of the ventricles

sinus rhythm

normal heart rhythm originating at the SA node

cardiac output

the volume of blood pumped by each ventricle in one minute

stroke volume

the volume of blood ejected from the ventricle with each beat

heart rate

number of times the heart beats per minute

cardiac output formula

HR times SV= CO

average cardiac output for adult

5 L/min

increasing cardiac output ___ blood pressure?

increases

sympathetic fibers ___ heart rate by stimulating the SA and AV nodes?

increase

parasympathetic stimulation __ cardiac output by lowering heart rate?

decreases

vagus nerve (X)

parasympathetic nerve that supplies the heart; slows the heart rate by acting on the SA and AV nodes but does not influence stroke volume

beta adrenergic blocking agent

medication that reduces cardiac output by lowering sympathetic responses

newborn resting heart rate

120-140 bpm

resting heart rate in adults

60-80 bpm

bradycardia

relatively slow heart rate of less than 60 bpm

tachycardia

heart rate of more than 100 bpm

sinus arrhythmia

regular variation in heart rate caused by changes in rate/ deep breathing

premature ventricular contraction (PVC)

aka ventricular extrasystole; initiated by Purkinje fibers rather than SA node; can be experienced as a palpitation between normal heartbeats/ or as skipped beat

normal heart sounds

lub and dup

first heart sound

“lub”; low-pitched sound that occurs at start of ventricular systole; occurs due to the closure of AV valves

second heart sound

“dup” shorter and sharper sound; occurs at the beginning of ventricular relaxation; sudden closure of semilunar valves

murmur

abnormal sound; anything that disrupts smooth flow of blood through the heart

stenosis

narrowing of a valve opening

order in which electrical impulses travel through the heart

SA node, AV node, Bundle of His, Bundle Branches, Purkinje Fibers

functional murmur

normal sounds heard while heart is working

organic murmur

abnormal sound caused by any structural change in heart

cardiac output is always

L/min

stethoscope

instrument used to convey sounds from within patient’s body to an examiner’s ear

electrocardiograph

records electrical activity of the heart as it functions; corresponds to depolarization and repolarization during action potential

P wave

depolarization of the atria

QRS wave

depolarization of the ventricles; hides atrial repolarization

T wave

ventricular repolarization (diastole)

fluoroscope

instrument for examining deep structures with x rays

cardiac catherization

catheter passes through veins and into right side of the heart or passes through arteries to the left ventricle side of the heart

coronary angiography

contrast is injected into coronary arteries to map vascular damage

endocarditis

inflammation of the heart’s lining (inflammation of endocardium covering valves)

myocarditis

inflammation of the heart muscle

pericarditis

inflammation of the serous/ fibrous membrane surrounding the heart

arrhythmia

dysfunction anywhere within the heart’s conducting system that causes an abnormal rhythm of the heartbeat (aka dysrhythmia)

flutter

rapid, coordinated contractions

fibrillation

rapid, wild, uncoordinated contractions

defibrillator

device that generates a strong electrical current to discharge all the cardiac muscle cells at once

heart block

interruption of electrical impulses in the heart’s conduction system

rheumatic heart disease

originates with an attack of rheumatic fever in childhood or in youth; streptococcal infection that causes strep throat

congenital heart diseases

disease present at birth

foramen ovale

fetal heart has a small hole; opening allows some blood to flow directly from right atrium to left; bypasses lungs a

atherosclerosis

thickening and hardening of the vessels with a loss of elasticity

ischemia

lack of blood supply to the areas fed by those arteries

angina pectoris

discomfort in the region of the heart and in left arm and shoulder; feeling of suffocation; result of coronary artery disease

coronary thrombosis

thrombus formation in coronary artery

heart attack (myocardial infarction)

sudden occlusion/ closure of coronary vessel with complete obstruction of blood flow