Download Chapter 12 * the heart

Chapter 12 – the heart
4 chambers – which act as 2 pumps for
pulmonary circulation and systemic
circulation
 See diagrams pp. 324- 329
 Location – thoracic cavity between the
lungs, within the mediastinum
 Apex – most inferior portion
 Base – superior portion

Heart anatomy

diagram
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
all kinds of wonderful information on the
heart!
External anatomy
Coronary sulcus
 Superior and inferior vena cava
 Pulmonary veins
 Pulmonary trunk
 Aorta
 Membranes: pericardial cavity,
pericardium: fibrous, serous, parietal,
visceral, pericardial fluid

Blood supply to the heart
Coronary arteries (left and right)
 Cardiac veins
 Coronary sinus

Heart chambers
Atria – right and left
 Auricle
 Interatrial septum
 Ventricles – right and left
 Interventricular septum

Heart valves
Atrioventricular valves
 Tricuspid valve – between right atrium and
right ventricle
 Bicuspid (mitral) valve – between left
atrium and laft ventricle
 Papillary muscles
 Chordae tendineae
 Aortic and pulmonary semilunar valves

Blood flow through the heart
Both atria contract at the same time and
both ventricles contract at the same time
 Body vena cava  right atrium 
tricuspid valve  right ventricle 
pulmonary semilunar valve  pulmonary
arteries  lungs  pulmonary veins  left
atrium  bicuspid valve  left ventricle 
aortic semilunar valve aorta  body

Heart wall
Three layers:
 Epicardium
 Myocardium
 endocardium

Cardiac muscle
Striated
 Elongated, branching cells
 1 or 2 nuclei
 Rich in mitochondria
 ATP
 Intercalated disks

Conduction system of the heart
SA node
 AV node
 AV bundle
 Left and right bundle branches
 Purkinje fibers
 See diagram pg. 336
 Ectopic beat

electrocardiogram
P wave
 QRS complex
 T wave
 P-Q interval
 P-R interval
 Q-T interval

electrocardiogram
Cardiac cycle
Systole – atrial and ventricular –
contraction
 Diastole – atrial and ventricular –
relaxation
 Heart sounds – stethoscope
 Murmurs
 Incompetent valve
 Stenosed opening

Regulation of heart function
Cardiac output
 Stroke volume
 Heart rate
 Cardiac output = stroke volume x heart
rate

Intrinsic regulation
Regulation mechanisms contained within
the heart
 Venous return
 Preload
 Starling’s law of the heart
 afterload

Extrinsic regulation
Regulation by factors outside the heart –
nervous and hormonal regulation
 Baroreceptor reflex
 Medulla oblongata – cardioregulatory
center
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