The Cardiovascular System
Cont.
Chapters 19, 20, 21
III. Heart
•
•
Cardiac muscle tissue
Four chambers
• Right atrium
• Right ventricle
• Left atrium
• Left ventricle
•
Atria are upper, less
muscular chambers
Heart Valves
• Prevent blood
from flowing back
• Atrioventricular
– Tricuspid
– Bicuspid or mitral
• Semilunar
– Aortic
– Pulmonary
Functions of the Heart
•
•
•
•
Generating blood pressure
Routing blood
Ensuring one-way blood flow
Regulating blood supply
– Changes in contraction rate and force respond
to changing metabolic needs
Cardiac Cycle
• Repetitive contraction (systole) and
relaxation (diastole) of heart chambers
• Normal blood pressure <120/80
• Measured by sphygmomanometer
• High blood pressure = hypertension
Circuits
Pulmonary circuit
Between the right side of the
heart, to the lungs, and back
to the left side of the heart
Systemic circuit
Between the left and right
sides of the heart and the rest
of the body
Common Disorders of the Circulatory System
• Anemia - lack of iron in the blood, low RBC count
• Leukemia - cancer; white blood cells proliferate wildly
• Hemophilia - bleeder’s disease due to lack of fibrinogen
in thrombocytes
• Heart murmur - abnormal heart beat caused by valve
problems
• Heart attack - death of heart muscle; happens when
supply of blood to an area of heart muscle is blocked,
usually by a clot in a coronary artery