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BE320 - Exam 2
Sherwood Ch. 9
115
Physiology
Undergraduate 3
01/10/2012

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Term
circulatory system
Definition
body's transport system
Term
heart
Definition
serves as the pump; establishes the pressure gradient needed for blood to flow to the tissues; hollow, muscular organ
Term
blood vessels
Definition
serve as the passageways through which blood is directed and distributed from the heart to all parts of the body and then returned to the heart
Term
blood
Definition
transport medium within which materials being transported long distances are dissolved or suspended
Term
pulmonary circulation
Definition
consists of a closed loop of vessels carrying blood between the heart and lungs
Term
systemic circulation
Definition
circuit of vessels carrying blood between the heart and other body systems
Term
thoracic cavity
Definition
location of heart
Term
sternum
Definition
breastbone
Term
vertebrae
Definition
backbone
Term
base
Definition
broad region of heart located proximal to head
Term
apex
Definition
pointed tip of heart located distal to head
Term
cardiopulmonary resuscitation (CPR)
Definition
emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest
Term
atria
Definition
upper chambers of heart, receive blood returning to the heart
Term
ventricles
Definition
lower chambers of heart, pump blood from the heart
Term
veins
Definition
vessels that carry blood from the tissues back to the atria
Term
arteries
Definition
vessels that carry blood away from the ventricles to the tissues
Term
septum
Definition
separates the two halves of the heart, continuous muscular partition that prevents mixture of blood fromt eh two sides of the heart
Term
venae cavae
Definition
two large veins through which blood returning from the systemic circulation enter into the right atrium
Term
pulmonary artery
Definition
artery through which the right ventricle pumps blood, branches into two veins that feed into a lung each
Term
pulmonary veins
Definition
veins through which blood is returned to the left ventricle from the lungs
Term
aorta
Definition
artery into which the left ventricle pumps blood to be sent through the systemic circulation
Term
right and left atrioventricular (AV) valves
Definition
positioned between the atrium and the ventricle, let blood flow from the atria into the ventricles during ventricular filling but prevent backflow in the opposite direction
Term
tricuspid valve
Definition
consists of three cusps or leaflets, right AV valve
Term
bicuspid valve (mitral valve)
Definition
two cusps, resembles a mitre (bishop's hate), left AV valve
Term
chordae tendineae
Definition
tough, thin, fibrous cords of tendinous-type tissue along the edges of AV valve leaflets that prevent valves from being everted (opening the wrong direction)
Term
papillary muscles
Definition
protrude from the inner surface of the ventricular walls and connect to each cusp of AV vales, pull down the chordae tendineae during ventricular contraction
Term
aortic and pulmonary valves
Definition
lie where the major arteries leave the ventricles
Term
semilunar valves
Definition
three cusps that each resemble a half-moon-shaped pocket; forced open when ventricle pressure exceeds arterial pressure, closer reults when the vnetricles relax and pressure drops below atrial pressure; aortic and pulmonary valves
Term
fibrous skeleton
Definition
four interconnecting rings of dense conncective tissue; provides firm base for attachment of heart valves; separates the atria from the ventricles and also provides a fairly frigid structure fro attachment of the cardiac muscle
Term
endothelium
Definition
thin inner layer of the heart wall, unique epithelial tissue that lines entire circulatory system
Term
myocardium
Definition
middle layer of heart wall; composed of cardiac muscle and constitutes bulk of heart wall
Term
epicardium
Definition
thin external layer of heart wall that covers the heart
Term
pericarial sac
Definition
encloses heart; consists of two layers -- tough, fibrous covering and secretory lining
Term
pericardial fluid
Definition
secreted by pericardial lining and provides lubrication to prevent friction between the pericardial layers as they glide over each other with every beat of the heart
Term
pericarditis
Definition
an inflammation of the pericardial sac that results in a painful friction rub between the two pericardial layers
Term
authorhythmicity
Definition
heart contracts rhythmically as a result of action potentials that it generates by itself
Term
contractile cells
Definition
99% of cardiac muscle cells; do the mechanical work of pumping; normally do not initiate APs
Term
autorhythmic cells
Definition
1% of cardiac muscle cells; do not contract but specialize in initiating and conducting the APs responsible for contraction of the working cells
Term
pacemaker potential
Definition
slow drift to threshold by an autorhythmic cell membrane
Term
T-type Ca2+ channel
Definition
opens during second half of pacemaker potential; transient channel that causes a brief influx of Ca2+ that brings membrane to threshold in pacemaker cells
Term
L-type Ca2+ channels
Definition
voltage-gated Ca2+ channel that causes a large influx of Ca2+ causes rising phase of AP in a pacemaker cell
Term
sinoatrial (SA) node
Definition
noncontractile caridiac cell; small, specialized region in the right atrial wall near the opening of the superior vena cava
Term
atrioventricular (AV) node
Definition
noncontractile cardiac cell; small bundle of cells loaced at the base of the right atrium near the septum
Term
bundle of His
Definition
noncontractile cardiac cells; tract of cell that originates at the AV node an enters the interventricular septum; divides for form right and left bundles that go down septum and around ventricular tip back toward atria along the outer walls
Term
Purkinje fibers
Definition
terminal fibers that extend from the bundle of His and spread throughout the ventricular myocardium
Term
pacemaker
Definition
fastest rate of autorhythmicity drives the rest of the heart at this rate; usually the SA node at 70-80 bpm
Term
latent pacemakers
Definition
slower pacemakers that take over if the normal fails
Term
complete heart block
Definition
when the conducting tissue between the atria and ventricles is damaged and becomes nonfunctional; pt becomes comatose
Term
artificial pacemaker
Definition
implanted device rhythmically generates impulses that spread throughout the heart to drive both the atria and ventricles at the typical rate of 70 bpm
Term
ectopic focus
Definition
abnormally excitable area that initiates a premature AP that spreads throughout the rest of the heart before the SA node can initiate a normal AP
Term
premature ventricular contraction (PVC)
Definition
abnormal impulse froma ventricular ectopic focus; seen with organic heart disease, in response to anxiety, lack of sleep, or excess caffeine, nicotine or alcohol consumption
Term
fibrillation
Definition
random, uncoordinated excitation and contraction of the cardiac cells; in ventricles is more serious than in atria because blood isn't pumped into arteries with this
Term
electrical defibrillation
Definition
very strong electrical current is applied on the chest wall to correct fibrillation
Term
interatrial pathway
Definition
extends fromt eh SA node within the right atrium to the left atrium; spreads excitation so that left and right are exciting at same time
Term
internodal pathway
Definition
extends from the SA node to the AV node; only way AP can be spread from atria to ventricles is through AV node
Term
AV nodal delay
Definition
AP is conducted relatively slowly through the AV node; allows time for complete ventricular filling
Term
Ca2+ induced Ca2+ release
Definition
Ca2+ diffues into the cytosol from the ECF across the T tubule membrane during cardiac AP, triggers the opening of nearby Ca2+ release channels in the adjacent lateral sacs of the sacroplasmic reticulum
Term
electrocardiogram (ECG)
Definition
small part of the electrical signals generated by the cardiac muscle that is conducted through body fluids and is detected by recording electrodes
Term
lead
Definition
specific arrangement of electrodes between two points on the body
Term
P wave
Definition
represents atrial depolarization, corresponds to the atrial contraction
Term
QRS complex
Definition
represents ventricular depolarization, corresponds to ventricular contraction
Term
T wave
Definition
represents ventricular repolarization, corresponds to ventricle contraction (emptying)
Term
PR segment
Definition
time between end of P wave and onset of QRS segment; corresponds to atrial contraction
Term
ST segment
Definition
when the ventricles are completely depolarized and cardiac contractile cells are undergoing the plateau; corresponds to ventricular contraction and ejecting
Term
TP interval
Definition
when the heart muscle is completely repolarized and at rest and ventricular filling is taking place
Term
tachycardia
Definition
rapid heart rate of more than 100 bpm
Term
bradycardia
Definition
slow heart rate of fewer than 60 bpm
Term
arrhythmia
Definition
any variation from the regularity or spacing of the ECG waves
Term
atrial flutter
Definition
characterized by rapid but regular sequence of atrial depolarizationsat rates between 200 and 380 bpm; AV node does not follow this pattern, so ventricles are unaffected
Term
atrial fibrillation
Definition
characterized by rapid, irregular, uncoordinated depolarizations of the atria with no definite P waves; atria contractions are chaotic and asynchronized; ventricle rhythm is also very irregular
Term
pulse deficit
Definition
when heart rate exceeds pulse rate
Term
ventricular fibrillation
Definition
rhythmic abnormality in which the ventricular musculature exhibits uncoordinated, chaotic contractions; ventricles are ineffective pumps; if not fixed in 4 minutes, irreversible brain damage occurs
Term
heart block
Definition
arises from defects in the cardiac conducting system; atria beat regularly but ventricles fail to be stimulated and thus do not contract following atrial contraction
Term
cardiac myopathies
Definition
damage of the heart muscle
Term
mycardial ischemia
Definition
inadequate delivery of oxygenated blood to the heart tissue; necrosis occurs if heart block or ruptured vessel
Term
necrosis
Definition
death of a tissue
Term
acute myocardial infarction (heart attack)
Definition
when heart tissue becomes necrotic; produces abnormal ECG signals
Term
systole
Definition
contraction and emptying
Term
diastole
Definition
relaxation and filling
Term
isometric ventricular contraction
Definition
all valves to/from ventricle are closed, ventricle pressure continues to increase during this time
Term
stroke volume (SV)
Definition
amount of blood pumped out of each ventricle with each contraction
Term
end-systolic volume (ESV)
Definition
amount of blood left in the ventricle at the end of systole when ejection is compolete
Term
dicrotic notch
Definition
when aortic valve closes and produces a disturbance or notch on the aortic pressure curve
Term
isovolumetric ventricle relaxation
Definition
after aortic valve closes; constant volume and decreasing pressure in ventricle
Term
first heart sound
Definition
low-pitched, soft, relatively long, "lub"; corresponds to vibrations caused by closure of AV valves; signals onset of ventricular systole
Term
second heart sound
Definition
higher pitch and shorter and sharper; "dup"; corresponds to vibrations caused by closure of semilunar valves; signals onset of ventricular relaxation
Term
murmurs
Definition
abnormal heart sounds associated with cardiac disease
Term
functional murmurs
Definition
murmurs not involving heart pathology, more common in young people
Term
stenotic valve
Definition
stiff narrowed valve that does not open completely; causes abnormal whistling sound (murmur)
Term
insufficient (incomplete) valve
leaky valve
Definition
valve that cannot close completely; backwards flow causes swishing or gurgling murmur
Term
regurgitation
Definition
backflow through an incomplete valve
Term
rheumatic fever
Definition
an autoimmune disease triggered by a streptococcus bacterial infection; often causes valvular stenosis and leakiness
Term
systolic murmur
Definition
a murmur between the first and second heart sounds
Term
diastolic murmur
Definition
murmur occurs between the second and first heart sounds
Term
cardiac output (CO)
Definition
volume of blood pumped by each ventricle per minute
Term
cardiac reserve
Definition
difference between the CO at rest and maximum volume of blood that the heart can pump per minute
Term
vagus nerve
Definition
parasympathetic nerve to the heart, primarily supplies the atrium, especially SA and AV nodes
Term
intrinsic control (cardiac)
Definition
heart's inherent ability to vary stroke volume, depends on direct correlation between end-diastolic volume and stroke volume; depends on length-tension relationship of cardiac muscle
Term
Frank-Starling law of the heart
Definition
the heart normal pumps out during systole the volume of blood returned to it during diastole; increased venous return results in increased stroke volume
Term
preload
Definition
extent of filling, workload imposed on the heart before contraction begins
Term
extrinsic control (cardiac)
Definition
factors originating outside the heart; most important are from the sympathetic nerves and epinephrine
Term
contractility
Definition
strength of contraction at any given EDV, sympathetic stimulation and epinephrine enhance
Term
afterload
Definition
aterial blood pressure, workload imposed on the heart after contraction has begun
Term
heart failure
Definition
the inability of the cardiac output to keep pace with the body's demands for supplies and removal of wastes
Term
congestive heart failure
Definition
backward failure; blood that cannot enter and be pumped out by the heart continues to dam up in the venous system due to heart's failure to pump an adequate am of blood to the tissues
Term
coronary circulation
Definition
coronary arteries branch from the aorta and coronary veins empty into right atrium; supply blood to the heart muscle
Term
coronary artery disease (CAD)
Definition
pathological changes within the coronary artery walls that diminish blood flow through these vessels
Term
vascular spasm
Definition
abnormal spastic constriction that transiently narrows the coronary vessels; associated with early stages of CAD; reversible and usually doesn't last long enough to damage cardiac muscle
Term
atherosclerosis
Definition
progressive, degenerative arterial disease that leads to occlusion of affected vessels, reduding blood flow through them;
Term
atherosclerotic plaque
Definition
plaques forming beneath the vessel lining within arterial walls; consists of a lipid-rich core covered by an abnormal overgrowth of smooth muscle cells topped off by a collagen-rich connective tissue cap; bulges into vessel lumen
Term
angina pectoris
Definition
pain associated with myocardial ishcema; felt beneath the sternum and appears to come from left shoulder and down left arm
Term
thrombus
Definition
abnormal clot attached to vessel wall
Term
embolus
Definition
freely floating clot
Term
thromboembolism
Definition
formation of thrombus and emboli
Term
collaterla circulation
Definition
exists when small terminal branches from adjacent blood vessels nourish the same area
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