Download The Heart

A&P Notes: The Heart
I. Heart Anatomy: Your Objectives:
 Determine the size & location of the heart.
 Determine the function/importance/description of each of the following
parts.
 Determine the location of the parts on a heart diagram
Heart location and size
 Weight in lbs and grams _______________________________________
 Location in chest (give landmarks to describe)
Heart Structures:
 Heart Wall & Pericardial Cavity
o Pericardial cavity
o Parietal pericardium
o Visceral pericardium
 (aka. Epicardium)
o Myocardium
o Endocardium
 Chambers & associated structures
o Atrium (atria = plural)
o Auricle
o Pectinate muscles
o Ventricles
o Trabeculae carnae
o Chordate tendinae & Papillary muscles
o Septum
 Valves and associated structures
o Atrioventricular valves
 Tricuspid

Bicuspid (aka. Mitral)
o Semilunar valves

Pulmonary SL

Aortic SL
o Know how valves open & close to prevent backflow of blood which is
important in keeping oxygenated & deoxygenated blood from mixing
and gets them to the right structures.
o What is the first heart sound caused by?
o What is the second heart sound caused by?
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 Blood vessels (major)
o Superior vena cava
o Inferior vena cava
o Pulmonary trunk
o Pulmonary arteries (right and left)
o Pulmonary veins (right and left)
o Aorta (ascending, descending, arch)
 Fetal structures – what is the purpose of these 2 structures in a fetal heart?
o Foramen ovale
o Ductus arteriosus
1. Why are the circulatory system organs lined with endothelium?
2. Which chamber has thickest most muscular walls and why?
3. What is the purpose of the 4 valves?
4. What do these fetal structures become in the adult heart? When does this
occur?
a. Foramen ovale
b. Ductus arteriosum
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Heart Diagram: Label the following parts on this diagram.
Aorta
Aorta
Aortic semilunar valve
Apex
Bicuspid valve
Descending Aorta
Inferior vena cava
Left Atrium
Left pulmonary artery
Left pulmonary veins
Left Ventricle
Pulmonary semilunar valve
Pulmonary trunk
Right Atrium
Right pulmonary artery
Right pulmonary veins
Right Ventricle
Septum
Superior vena cava
Tricuspid valve
Label the diagram directly on the part
without using leader lines: see
example
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Label the following:
 Trabeculae carnae
 Pectinate muscles
 Chordae tendinae
 Papillary muscles
II. Pathway of circulation: Your Objectives
 Differentiate between pulmonary circuit and systemic circuit: which side of
the heart is involved in each and what is the purpose of each?
 Determine the complete pathway a drop of blood would take beginning in
the superior and inferior vena cava
 Discuss the need for a separate cardiac circulation.
Diagram #2 – Trace the pathway of
blood flow
 Use blue arrows for deoxy
blood
 Use red arrows for oxy
blood
End of Quiz #1
Material – Includes
Diagrams
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Two events happen in a heart beat
1. electrical event which causes:
2. muscular event/contraction
Either event can have problems so doctors need the ability to check each one.
The Conduction system
I. Conduction System of the Heart - Know parts on diagram
Cardiac muscle needs organization/rhythm and speed control for
maximum efficiency- So two controlling/coordinating systems are needed:
A. autonomic nervous system divisions
1. sympathetic NS - increase rate & force
2. parasympathetic NS - decrease heart rate & force
B. Intrinsic conduction system
1. gap junctions 2. conduction system parts
a. sinoatrial (SA) node
b. atrioventricular (AV) node
c. AV bundle & bundle branches
d. Purkinje fibers
Muscular event – the Cardiac Cycle
I. alternate contraction and relaxation of heart
1. described in terms of ventricular events
2. systole - contraction
3. diastole - relaxation
II. Phases of cardiac cycle
A. mid to late diastole (heart is in complete relaxation) - ventricular filling
1. pressure in heart is low - blood flows passively into atria then ventricles
2. AV valves open - semilunar valves closed
3. 70% of ventricular filling occurs
4. atria begin to contract forcing remaining 30% of blood into ventricles
5. pressure in ventricles begins to close AV valves
B. ventricular systole
1. BP in ventricles rises sharply - closes AV valves
atrial begin filling again
2. isovolumetric contraction phase
a. while both sets of valves are closed - the muscle contracts which
builds pressure for a very short time period
3. BP exceeds BP in aorta & pulmonary trunk and forces SL valves open
4. ventricular ejection phase
a. blood expelled into aorta and pulmonary trunk
b. normal aorta pressure is 120 mm Hg
C. Early diastole / isovolumetric relaxation phase
1. ventricles relax and pressure drops
2. blood backflow closes semilunar valves
1. atrial pressure will then force open AV valves
D. Cardiac cycle = 0.8 secs
1. atria systole = 0.1 secs
2. vent systole = 0.3 secs
3. total heart relaxation (quiescent period) = 0.4 secs
only time heart gets to relax
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E. Important points
1. flow of blood is controlled by pressure changes
2. blood flows along pressure gradient through any available opening
3. An echocardiogram is a sonogram of the heart and is used to
visualize the opening/closing of valves and working of
muscles
Electrical Event
A. electrical events caused by conducting system are recorded as deflection waves
transmitted to entire body by means of electrolytes. The recording of heart
electrical waves is called an ECG or EKG - electrocardiogram
B. ECG has 3 kinds of deflection waves
1. P wave
a. atrial depolarization (electricity)
b. then atria contract
c. ventricles are relaxed
2. QRS complex
a. ventricular depolarization (electricity)
b. then ventricles contract
c. atria are in process of relaxing - repolarization is hidden by QRS
complex
3. T wave
a. ventricular repolarization (electricity)
C. healthy heart - consistant deflection waves
Be able to label the waves of an ECG and recognize normal and defective
patterns.
II. Frank-Starling law of the heart
A. degree of stretch determines SV - more stretch = more force of contraction
B. Important function: ensure equal ventricular output to distribute blood evenly
between systemic & pulmonary circuits. If one side of the heart starts pumping
more blood, the increase in venous return causes the other side of the heart to
stretch and increase its pumping power to an equal amount
End of Quiz #2 Material – Includes Diagrams
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Heart Disorders
angina pectoris
arteriosclerosis (atherosclerosis)
bradycardia
cardiac tamponade
congenital heart defects
1. patent ductus arteriosus
2. septal defect
3. tetralogy of Fallot
congestive heart failure
1. pulmonary congestion
2. peripheral congestion
cor pulmonale
decompensated heart
ectopic focus
extrasystole
fibrillation
heart block
heart murmur
heart palpitation
incompetent valve
mitral valve prolapse
myocardial infarction
myocarditis
pericarditis
tachycardia
valvular stenosis
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