The Cardiovascular System
The cardiovascular system is composed of the heart, blood vessels and blood.
Its main functions are:
1- Delivery O2 fuel and nutrients to the body and remove CO2 and waste from
tissues
2- Thermoregulation -Maintenance of constant body temperature
3- Immune function – prevention of infection
The Heart
The heart is made up of special muscle tissue call myocardium.
The heart is the size of a closed fist, and is divided into two halves that work
together as a double pump.
The right side pumps in deoxygenated ( dark and blue in colour reality dark red)
blood which has returned from the body to the lungs this is called pulmonary
circulation
The left side pumps oxygenated blood ( bright red, which has returned from the
lungs to the rest of the body, this is called systemic circulation.
Layers of the heart
Pericardium: A protective sac around the heart
Epicardium: outer layer of the heart
Myocardium : muscle of the heart under the epicardium
Endocardium: tissue that lines the inside of the heart
Chambers and valves of the Heart:
There are 4 chambers of the heart.
2 upper chambers called atria and 2 lower called ventricles.
The atria and ventricles are separated by atrioventricular values that only allow
blood flow in one direction.
The right side: tricuspid value – 3 flaps
The left side: bicuspid value – 2 flaps
The values are attached to muscular extensions called papillary muscles by special
tissues call chordae tendinae. These help prevent the value from turning inside
out.
Pulmonary semilunar valve: prevents blood flowing back from the pulmonary
arteries into the right ventricle
Aortic semilunar valve: separates the aorta and the left ventricle
Path of blood through the Heart
1. Superior / Inferior Vena Cava
2. Right Atrium
3. Tricuspid valve
4. Right ventricle
5. Pulmonary semi lunar valve
6. Pulmonary arties
7. Lungs
8. Pulmonary veins
9. Left atrium
10.Bicuspid valve
11.Aortic semilunar valve
12.Aorta
13.Systemic circulation
14.Superior/Inferior Vena Cava
Arteries: vessels that carry blood away from the heart
Veins: vessels that carry blood toward the heart.
Systemic circulation: arteries carry oxygenated blood from the heart to
body tissues and the veins carry the deoxygenated blood back from the
body tissues.
Pulmonary circulation: carries deoxygenated blood from the heart to the lungs to
get oxygenated and returned back to the heart to be then pumped into the
systemic circulation