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52 terms

A&P 2: Chapter 20

Anatomy & Physiology 2 Lamar University Lecture-Armacost
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Heart
is located in the thoracic cavity, above the diaphragm, near the midline, slightly towards the left
Pericardium
is the serous membrane surrounding the heart, it anchors the heart while allowing it movement.
Fibrous Pericadium
first layer of the pericardium
Parietal Pericardium
second layer of the pericardium
Visceral
third layer of the pericardium (epicardium)
Pericardial Cavity
is located between the parietal and visceral layers, and is filled with pericardial fluid
Heart Wall
is composed of 3 layers: epicardium, myocardium, and endocardium
Epicardium
heart wall layer: is considered both part of the percardium and the heart wall
Myocardium
heart wall layer: is composed of cardiac muscle tissue, is striated, and is mainly under involuntary control
Endocardium
heart wall layer: is an epithelial lining
Heart Chambers
Include atria, the first 2 chambers, and ventricles, the last 2 chambers
Atria
first 2 chambers of the heart, are small, and include a right and a left
Ventricles
last 2 chambers of the heart, are large, and include a right and a left
Atria (thickness/function)
have thin walls and they pump blood to adjacent ventricles
Ventricles (thickness/function)
has thick walls and they pump blood to lungs (rt. ventricle) or to body (lf. ventricle)
Left/Right
____ ventricle has thicker walls than ____ ventricle
Heart Valves (function)
includes preventing the backflow of blood
Atrioventricular Valves
heart valve set including Tricuspid Valve and Bicuspid Valve
Tricuspid Valve
is the right AV valve, and is located between the right atrium and ventricle
Bicuspid Valve
is the left AV valve, and is lovated between the left atrium and ventricle
Open
AV valve is ____ when papillary muscles are relaxed, chordae tendineae are slack, and valve cusps project into ventricle
Closed
AV valve is ____ when papillary muscles contract, chordae tendinaea become taut, and prevention of vavle cusps from everting
Semilunar Valves
heart valve set including Pulmonary Valve and Aortic Valve
Pulmonary Valve
a semilunar valve, located between the right ventricle and pulmonary trunk
Aortic Valve
a semilunar valve, located between the left ventricle and aorta
Convex
semilunar valves contain 3 crescent moon-shaped cusps with ____ outer margins
Closed Circuits
the heart pumps blood in 2 ____ ____
Pulmonary Circuit
closed circuit at the right side of the heart, that received deoxygenated blood from body, and sends deoxygenated blood to the lungs
Systemic Circuit
closed circuit at the left side of the heart, that receives oxygenated blood from the lungs, and that sends oxygenated blood to body
Coronary Circulation
includes input from the coronary arteries and the coronary veins
Coronary Arteries
these surround the heart like a crown, contains many anastomoses, and carrys oxygenated blood to cardiac muscle
Coronary Veins
these return deoxygenated blood to the right atrium
Myocardial Ischemia
includes a reduced blood flow to myocardium caused by obstruction in a coronary artery
Myocardial Infarction
includes complete obstruction of blood flow leading to the death of cardiac muscle cells, causing decreased efficiency of heart or death
Cardiac Muscles
include: Contractile fibers and Autorhythmic fibers
Contractile Fibers
a cardiac muscle: similar to skeletal muscle (in structure and function), contract in response to action potentials, and joined by intercalated discs (desmosomes connect cells and gap junctions allow direct transmission of muscle action potentials btwn muscle fibers)
Autorhythmic Fibers
a cardiac muscle: generates action potentials (do not require a stimulus from the nervous system), and conducts action potential throughout the heart
Cardiac Cycle (establishment)
coordinates contraction of cardiac muscle in different parts of the heart (cardiac muscle in different parts of the heart contract at different times), includes systole and diastole
Cardiac Cycle 1
artia contract- atrial systole and ventricles in diastole
Cardiac Cycle 2
ventriles contract- ventricular systole and atria in diastole
Electrocardiogram (ECG/EKG)
composite of action potentials produced by all cardiac fibers, during contraction. includes 3 recognizable waves- p wave, qrs complex, and t wave
P Wave
small peak associated with atrial depolarization, atrial systole
QRS Complex
dip, strong peak, and second dip associated with ventricular depolarization, ventricular systole
T Wave
small peak associated with ventricular repolarization, ventricular diastole
Cardiac Output (CO)
volume of blood ejected from ventricle per minute
Stroke Volume (SV)
volume of blood ejected from ventricle per contraction
Heart Rate (HR)
number of heartbeats/contractions per minute
CO = SV x HR
CO = __ x __
Cardiac Output (regulation)
varies depending on metabolic demands both intrinsic and extrinsic factors can influence this, and it can be regulated by changing stroke volume or heart rate
Stroke Volume (intrinsic regulation)
frank-starling law of the heart states that as a heart chamber fills with blood cardiac muscle in heart wall are strecth, and the more they are stretched during diastole, the more forcefully they contract during systole, it equalizes input and output
Stroke Volume (extrinsic regulation)
stimulation by sympathetic division of ANS increases the strength of contraction by releasing epineprine and norepinephrine, which are neurotransmitters and hormones
Heart Rate (extrinsic regulation)
stimuation by sympathetic division of ANS increases HR by releasing norepinephrine, and stimulation by parasympathetic division of ANS decreases HR by releasing acetylcholine