The Circulatory System
the heart- which is the muscular pump that keeps the blood moving around the body
theblood- which carries the substances around the body
thearteries- which carry blood away from the heart
theveins- which return blood to the heart
thecapillaries- which are tiny blood vessels that are close to the body’s cells where exchanges can happen
Hmans have a double circulatory system (one for the lungs and one for the rest of the body)
- The organ responsible for pumping blood around the circulatory system
- Walls of the heart are made from muscle tissue which can contract to put blood under pressure, forcing its movement
- Consists of two seperate sides (double circulation) the blood doesnt mix between the two
- The right side recieves deoxygenateed blood from the body and pumps it to the lungs.
- The left side recieves the freshly oxygenated blood and pumps it to the rest of the body, It has thicker walls than the right ventricle because it has to pump blood further
- Each pump has 2 chambers
- Each side has an atrium at the top that recieves blood from a vien
- They also have a ventricle at the bottom that pushes blood out of the heart through an artery
The Passage of blood through the heart
Deoxygenated blood arrives at the left-hand side of the heart:
- It enters the heart through the vena cava.
Blood flows into the right atrium.
Blood is pumped into the right ventricle.
Blood is pumped out of the heart, along the pulmonary artery, to the lungs.
Oxygenated blood arrives at the right-hand side of the heart:
The coronary blood vessels
The heart tissue needs a constant supply of oxygen and glucose to keep working
These are carried to the heart tissue by the conorary arteries
Wastes such as carbon dioxide are carried away in the conorary veins
If these blood vessels develop fatty deposits, they are less efficent and may become blocked, this could lead to a heart attack.
Artificial Vs Real Hearts
Artifical Heart Real Donated Heart
Advantages -Doesnt needs to take any drugs -Longer lasting
-No need to wait for a real heart
Disadvantages - Can cause clotting problems -Need immunosupressant drugs (stops
-Short lifespan for device body from rejecting heart
Arteries and Veins
Blood flows from the heart to the bodies organs through the artieries
In the organs the arteries branch of into smaller blood vessels called capileries
These then branch together again to form veins which carry the blood back to the heart
Arteries- Carry blood Away from the heart
VeINs- Carry blood INto the heart
- Blood is under high pressure generated from the heart
- Thick walls - to resist the high pressure from the blood
- Thick layer of elastic fibres - allow the artery to stretch when a surge of blood goes through it then recoil in between heart beats to maintain blood pressure
- Thick layer of muscle in the wall - to allow blood to get to where it needs to be in the body
Arteries and Veins 2
- Blood is underless pressure
- Thin walls
- One way valves - to prevent blood flowing back in opposite direction
Smallest time of blood vessel. Adapted to allow the exchange of substances between the blood and tissues of the body