20-1
The Cardiovascular System
The Heart
FUNCTIONS OF THE HEART
Generating blood pressure
Routing blood
• Heart separates pulmonary and systemic
circulations
Ensuring one-way blood flow
• Heart valves ensure one-way flow
Regulating blood supply
20-2
• Changes in contraction rate and force match blood
delivery to changing metabolic needs
SIZE, SHAPE, LOCATION
OF THE HEART
Size of a closed fist
Shape
• Apex: Blunt rounded
point of cone
• Base: Flat part at
opposite of end of cone
20-3
Located in thoracic
cavity
20-4
HEART CROSS SECTION
HEART WALL
Three layers of tissue
• Epicardium: This serous membrane of smooth outer
surface of heart
• Myocardium: Middle layer composed of cardiac
muscle cell and responsibility for heart contracting
20-5
• Endocardium: Smooth inner surface of heart
chambers
20-6
HEART WALL LAYERS
20-7
HEART WALL LAYERS
EXTERNAL ANATOMY
Four chambers
• 2 atria
• 2 ventricles
Auricles
• a small, muscular pouch
at the upper corner of the
atrium
Major veins
• Superior vena cava
• Pulmonary veins
Major arteries
20-8
• Aorta
• Pulmonary trunk
20-9
EXTERNAL ANATOMY
HEART VALVES
Atrioventricular
• Tricuspid
• Bicuspid or mitral
Semilunar
• Aortic
• Pulmonary
20-10
Prevent blood from
flowing back
20-11
HEART VALVES
20-12
FUNCTION OF THE HEART VALVES
20-13
BLOOD FLOW THROUGH HEART
INTERACTIVE HEART
Go to:
http://www.innerbody.com/image_card02/card51-new.html
And use the inteactive explorer to practice your knowledge of
the heart.