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Chapter 19 The Heart
pulmonary circuit
what circuit is on the right side of the heart
systemic circuit
what circuit is on the left side of the heart
pulmonary circuit
what circuit carries blood to lungs for gas exchange and back to heart
systemic circuit
supplies oxygenated blood to all tissues of the body and returns it to the heart; delivers oxygen and nutrients while removing waste products
mediastinum
space between lungs where the heart is located
pericardium
double-walled sac that encloses the heart
parietal pericardium
outer tough fibrous layer of connective tissue
visceral pericardium (epicardium)
inner, thin, smooth, serous membrane covering heart
pericardial cavity
space inside the pericardial sac falled with 4 to 30 mL of pericardial fluid
pericarditis
painful inflammation of the membranes
myocardium
middle muscle layer (cardiac muscle)
endocardium
lines inner heart; inner
right and left atria
receive blood returning to heart from the body and lungs, respectively.
auricles
enlarge chamber
right and left ventricles
pump blood into arteries
interatrial septum
wall that separates atria
pectinate muscles
internal ridges of myocardium in right atrium and both auricles
interventricular septum
muscular wall that separates ventricles
trabeculae carneae
internal muscular ridges; help chambers expand and refill more easily
coronary sulcus
separates atria above from ventricles below; encircles heart near base
anterior and posterior interventricular sulci
separate right and left ventricles
atrioventricular (AV) valves
control blood flow between atria and ventricles
right AV valve
tricuspid valve
left AV valve
mitral valve/bicuspid valve
chordae tendineae
strings of connective tissue that attach the AV valves cusps to papillary muscles on floor of ventricles
semilunar valves
control flow into great arteries; open and close because of blood flow pressure
pulmonary semilunar valve
in opening between right ventricle and pulmonary trunk
aortic semilunar valve
in opening between left ventricle and aorta
valvular insufficiency (incompetence)
any failure of a valve to prevent reflux (regurgitation), the backward flow of blood
valvular stenosis
cusps are stiffened and opening is constricted by scar tissue
mitral valve prolapse (MVP)
insufficiency in which one or both mitral valve cusps bulge into atria during ventricular contraction
coronary circulation
heart has its own supply of vessels to deliver blood to myocardium
angina pectoris (heart attack)
chest pain caused from partial obstruction of coronary blood flow
myocardial infarction
complete obstruction causes death of cardiac cells in affected area
cardiomyocytes
striated, short, thick branched cells, one central nucleus
mechanical junctions
tightly join cardiomyocytes
electrical junctions
gap junctions which form channels that allow ions to flow from the cytoplasm from one cell directly into the next
depolarization
exciting the cell
repolarization
relaxation (not systole)
SA (sinoatrial) node
modified cardiomyocytes
pacemaker
intitiates each heartbeat and determines heart rate
right and left bundle branches
Divisions of AV bundle that enter interventricular septum
purkinje fibers
Nerve-like processes spread throughout ventricular myocardium
systole
contraction
diastole
relaxation (of chamber or ventricles)
sinus rhythm
normal heartbeat triggered by SA node
70-80
adult at rest is typically _______ bpm
ectopic foci
region of spontaneous firing other than the SA node
electrocardiogram
Composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes (leads) on arms, legs, and chest
p wave
what wave is Atrial systole
pq segment
wave that represents time required for signals to pass from the SA node to the AV node
qrs complex
wave where Ventricular depolarization occurs
st segment
wave that represents ventricular systole
t wave
Ventricular repolarization and relaxation
cardiac cycle
One complete contraction and relaxation of all four chambers of the heart
s1
Louder and longer “lubb” occurs with closure of AV valves
s2
Softer and sharper “dupp” occurs with closure of semilunar valves
stroke volume
amount of blood ejected, 70 ml at rest
end systolic volume
amount of blood left in heart
congestive heart failure (CHF)
results from the failure of either ventricle to eject blood effectively
pulse
Surge of pressure produced by heart beat that can be felt by palpating a superficial artery (radial or carotid)
infants
who has HR of 120 bpm or more
young adult females
who average 72-80 bpm
young adult males
who average 64-72 bpm
tachycardia
Persistent, resting adult HR above 100 bpm
bradycardia
Persistent, resting adult HR < 60 bpm
cardioacceleratory center
Stimulates sympathetic cardiac nerves to SA node, AV node and myocardium
cardioinhibitory center
Stimulates vagus nerves
chemoreceptors
respiratory control
coronary artery disease (CAD)
A constriction of the coronary arteries
major risk factor for coronary artery disease (CAD)
excess of low-density lipoprotein (LDL) in the blood
Note 
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