Cardiovascular / Circulatory System (Blood (Red blood cell (contains…
Cardiovascular / Circulatory System
•Receive blood from the heart.
• Arteries have walls which are thick, muscular and elastic to withstand the pressure of the blood that is forced out of the heart.
• Blood pressure in the veins is much lower than the blood pressure in the arteries.
• Blood flows slowly and smoothly thus does not need the walls to be thick and muscular.
• However most veins have internal valves to prevent backflow of blood
Heart ➡Aorta ➡Arterioles ➡ Capillaries ➡ Venules➡ Vein➡ Vena Cava
Red blood cell
contains haemoglobin that combines reversibly with oxygen
Circular, biconcave shaoe. This increases the cell's surface area to volume ratio, thus allows the cell to absorb and release oxygen at a faster rate.
It does not contain any nucleus, enabling it to carry mote haemoglobin thus more oxygen.
White blood cell
destroy foreign particles that enter the blood
engulfs the bacteria by flowing over them and enclosing them.
Protective function of blood
Production of antibodies
In double circulation, the blood passes through the heart twice in one complete circuit
• blood flows from the body ( deoxygenated blood) back to the heart then to the lungs to receive gas exchange.
The blood will be pumped back to the heart again before being pumped to the other parts of the body.
Heart ➡ pulmonary arteries carry the deoxygenated blood ➡ Lungs
Oxygenated blood will be pumped back to the heart by the pulmonary veins
• Oxygenated blood leaves the left side of the heart is distributed to all parts of the body except the lungs through the arteries.
• Veins carry the blood from all parts of the body back to the right side of the heart.
Structure of the heart
• deoxygenated blood from the body returned to the right atrium.
• Blood from the upper body parts will return to the right atrium through the superior vena cava.
• Blood from the lower parts of the body except for tje lungs is brought back through the inferior vena cava
• When the right atrium contracts , blood flows into the right ventricle.
• tricuspid valve is in between the right atrium and the right ventricle. It will open when the blood pressure in the right atrium is higher than the right ventricle