B3.2 Transport Systems in Animals and Plants Flashcards
What is the main function of the circulatory system?
To get food and oxygen to every cell in the body, and to also remove any waste products to places where they can be removed completely from the body
What type of circulatory system do humans have?
Double circulatory systems
What does the first circuit do in a human’s circulatory system?
The first circuit pumps deoxygenated blood to the lungs to take in oxygen - I then returns to the heart
What does the second circuit do in a human’s circulatory system?
Pumps oxygenated blood around all the other organs of the body - the blood gives up its oxygen at the cells and it is then sent back to the heart where it is pumped out the lungs again
What are the walls of the heart mostly made up of?
Muscle tissue which contracts to pump the blood
What the four chambers of the heart?
The left and right atrium and the left and right ventricle
How do you label the structure of the heart?
As if it was in you e.g. left is right and right is left
What are the main blood vessels leading into the heart? (4)
The vena cava, the pulmonary artery, aorta and pulmonary vein
What do the valves in the heart do?
They make sure that the blood is flowing in the right direction
Can you describe the process of the heart pumping out blood?
- blood flows into the 2 atria through the vena cava and the pulmonary vein
- The atria contract, pushing blood into the ventricles
- The ventricles contract forcing the blood into the pulmonary artery and the aorta, and out the hear
- the blood then flows to the organs through arteries and back to the heart through veins
- The process starts over
What are arteries?
A blood vessel which carry blood away from the heart (A for artery is A for away) and towards organs
What is the structure of an artery and why?
They have walls which contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back - this is because blood is pumped through arteries at a very high pressure
What is the whole down the middle of an artery called, and what is the size of this hole compared to the thickness of the walls?
The lumen, is small compared to the thickness of the walls
What do arteries branch into?
Capillaries
What are capillaries involved in?
The exchange of materials at the tissue
What do capillaries supply to cells?
They carry blood really close to cells and supply food and oxygen, they also remove any waste products like carbon dioxide
What is the structure of a capillary? How does this help them carry out their job? (4)
They are really small, they have permeable walls to allow substances to diffuse in and out, their walls are one cell thick which increases the rate of diffusion by decreasing the distance over which it occurs, and they are very narrow giving them a large surface to volume ration which increase the rate of diffusion
What do capillaries join up to form?
Veins - they carry blood to the heart
Why aren’t the walls in veins as thick as the walls in arteries?
Because the blood is at a lower pressure in the veins
What is the size of the lumen in veins compared to the size of the lumen in arteries?
The lumen in veins are much larger to help blood flow despite the lower blood pressure
Why do veins have valves?
To help keep blood flowing in the right direction
What is blood?
A tissue
What is the function of blood?
To carry substances around the body
What is the blood made up of?
Red blood cells, white blood cells, and platelets which are all suspended in a liquid called plasma
What is the job of the red blood cell?
To carry oxygen around the body
How do red blood cells carry oxygen?
They contain a red pigment called haemoglobin which carries the oxygen