Human Circulatory System and blood cells - Systems in the Human Body Flashcards
How do humans have a double circulatory system?
Circulatory system is made up of the heart, blood vessels and blood.
A double circulatory system is two circuits joined together;
In the first circuit, the heart pumps deoxygenated blood to the lungs. Blood picks up oxygen in the lungs.
Oxygenated blood then returns to the heart
In the second circuit, the heart pumps oxygenated blood around the other organs of the body - which delivers oxygen to the body cells.
Deoxygenated blood returns to the heart to be pumped out to the lungs again.
What is the circulatory system made up of?
Heart, blood vessels and blood.
What does the heart do? and what are the parts of it?
Heart had four chambers - with walls mostly made up of muscle tissue which pumps blood around the body.
1. Blood flows into the two atria from the vena carbs and the pulmonary vein.
2. The atria pumps the blood into the ventricles
3. The ventricles pump the blood out of the heart
Blood from the right ventricle (bottom right) goes through the pulmonary artery to the lungs.
Blood from the left ventricle (bottom left) goes through the aorta to the rest of the body.
The blood then flows to the organs through the arteries, and returns thriigu the veins.
Atria fills again, and cycle restarts.
(Search up heart diagram)
What do the valves in the heart do? Where does the heart get oxygenated blood from?
Stops blood flowing backwards
Heart also needs supply of oxygenated blood from the coronary arteries which branch off of the aorta and surround the heart.
How does the heart have a pacemaker?
Your resting heart rate is controlled by a group of cells in the right atrium (top right) wall.
Cells act as a pacemaker - tell heart when to pump blood.
A pacemaker that doesn’t work properly causes an irregular heartbeat.
An artificial pacemaker can be used to keep the heart beating.
What do the arteries do?
Carry blood away from the heart
Heart pumps the blood out at high pressure
So artery walls are strong and elastic
They have thick layers of muscle to make them strong
They have elastic fibers to allow them to stretch and spring back
Walls are thick compared to the size of the hole in the middle (lumen)
What are capillaries? What do they do?
Arteries branch into capillaries.
Capillaries are really tiny- too small to see
They carry the blood really close to every cell in the body to exchange substances with them.
They have gaps in their walls so substances can diffuse in and out.
Supply food and oxygen and take away waste like co2.
Walls are usually only one cell thick. This means diffusion is very fast as there is only a short distance for molecules to travel.
What do veins do?
Take blood back to heart.
Capillaries join to form veins.
The blood is at a lower pressure in the veins, thus means the walls don’t need to be as thick as artery walls.
Veins have a bigger lumen than arteries which helps the blood flow despite the lower pressure.
Also have valves which keep blood flow in the right direction.
