The Heart Biology 120 Section WW2 By: OluwatosinOwasanoye
The Heart is a strong muscular pump a little larger than a fist.
It pumps blood continuously through the circulatory system.
Each day the average heart ‘beats’ (or expands and contracts)100,000 times and pumps about 2,000 gallons of blood.
In a 70 year life time, an average human heart beats more than 2.5 billion times.
The structure of the Heart
The Heart has four chambers through which blood is pumped :
The upper two are the right and left atria
The lower two, the right and left ventricles. Four valves open and close to let blood flow in one direction when the heart beats:
The tricuspid valve, located between the right atrium and right ventricle.
The pulmonary or pulmonic valve, between the right ventricle and pulmonary artery.
The mitral valve, between the left atrium and left ventricle.
The aortic valve, between left ventricle and the right aorta.
THE CIRCULATORY SYSTEM This is a network of elastic tubes that allows blood to flow throughout the body and it includes : The Heart Lungs Arteries Arterioles(small intestines) Capillaries(minute blood vessels)
How does the Heart pump blood? The Heart pumps blood to the lungs and to all the body tissues by a highly organized sequence of contractions of its four chambers. There are two phases of the Cardiac cycle: The diastole phase: The heart ventricle relax and the heart fills with blood. The systole phase : The ventricles contract and pump blood into the arteries.
Effects of Ageing on the Heart
Hypertrophy of the ventricle is a common age -related condition.
The maximum heart rate declines so that, by age 85, the cardiac out put may be decreased by 30-60%.
There is an increase tendency for valves to function abnormally and for arrhythmias to occur.
Because increased oxygen consumption is required to pump the same amount of blood, age-related coronary artery disease is more severe.
Exercise improves the functional capacity of the heart at all ages.
Medical Terminology, Fourth Edition ,F. Fremgen and S. Frucht.
Seely’sAnatomy and Physiology, Ninth Edition. VANPUTTE, REGAN, RUSSO.