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
How are red blood cells adapted for their job? (2)
They have a biconcave shape which gives them a larger surface area for absorbing oxygen, and they don’t have a nucleus so there’s more space for haemoglobin and more space to carry oxygen
Why do body cells require oxygen?
For respiration which releases energy
How does oxygen get into the blood?
The blood is taken to lungs where oxygen diffuses into the blood and combines with the haemoglobin to become oxyhaemoglobin
How does oxygen get into cells?
Blood is taken to body tissues, the oxyhaemoglobin then breaks up into haemoglobin and oxygen, to release oxygen to the cells
How do white blood cells defend against microorganisms? (3)
They can engulf and digest them, they can produce antibodies to fight microorganisms, and they can produce antitoxins to neutralise any toxins produced by the microorganisms
How do white blood cells differ from red blood cells?
White blood cells contain a nucleus
What are platelets?
Small fragments of cells
Do platelets have a nucleus?
No
What do the platelets help the blood to do? Why does this help?
To clot at a wound, this seals the wound stopping you from losing too much blood, and stops microorganisms from getting into the wound
What can a lack of platelets cause?
Excessive bleeding and bruising
What is plasma?
A pale straw-coloured liquid which carries pretty much everything in the blood
What does the plasma in blood carry? (9)
Red and white blood cells, platelets, nutrients, carbon dioxide, urea, hormones and antibodies and antitoxins
What are artificial hearts?
Mechanical devices that are put into a person to pump blood if their own heart fails
Are artificial hearts permanent or temporary?
Both, sometimes they are temporary whilst a donor heart is found, but they can be a permanent fix
What are the advantages of artificial hearts? (2)
They extend the life of patients and they are less likely to be rejected by the body’s immune system than a donor heart
What are the disadvantages of artificial hearts? (4)
The surgery putting in the heart can lead to bleeding and infection, they don’t work as well as healthy hearts (parts of the heart can wear out or the electrical motor could fail, blood doesn’t flow as smoothly through a’hearts than it would with a real heart which can cause blood clots and strokes and it can be uncomfortable for the patient
What do patients with artificial hearts receive in order to prevent blood clots?
Drugs which thin the blood - but this can cause problems with bleeding because their blood doesn’t clot as well as it normally would
What problems are there if artificial heat valves?
Although the procedure to replace a valve is a much less drastic procedure than a whole heart transplant - fitting an artificial valve can still result in infection and there can be problems with blood clots
What are stents?
Wire mesh tubes that can be inserted inside arteries to widen them and keep them open
When are stents used?
When a person has coronary heart disease
What is coronary heart disease and what can it cause?
It is when the coronary arteries get blocked by fatty deposits, which causes the arteries to become narrow and can lead to a heart attack
What are the pros of stents?
They are a way of lowering the risk of heart attack in people with coronary heart disease
What are the cons of stents? (2)
Over time the artery can narrow again as stents irritate the artery and make scar tissue grow and there’s risk of blood clotting so the patient has to take drugs to think their blood
What is artificial blood?
A blood substitute which can be used to keep people alive in an emergency where they have lost a lot of blood
What is done with donated blood?
It is usually separated into its components e.g. the red blood cells are give to those who have had a major surgery
What problems are there with donated blood? (4)
Blood products can’t be stored for very long, only 4% of the population donate blood so there isn’t always enough blood available, infection and problems with rejection
What are volume expanders?
An artificial blood product which can be used to replace the lost volume of blood (e.g. from an accident)
What does volume expanders allow a patient who has lost a lot of blood do?
They can keep people alive even if they lose 2/3 of their red blood cells, which may even give the patient enough time to produce new blood cells (if not, they need a blood transfusion)
What would the ideal artificial blood product be?
An oxygen-carrying substitute - a product which replaces the function of the red blood cell so there is no need for a blood transfusion
What are the transport tissues in plants called?
The phloem and xylem
What do the transport tissues in plants form?
Tubes
What are phloem tubes made up of?
Living cells with small holes in the end to allow substances to flow through
What do phloem tubes transport?
Food substances made in the leaves to growing regions and the storage organs of the plant
In what direction does the food substances travel in phloem tubes?
In both direction - from the leaves down to the roots and from the roots to the leaves
What are xylem tubes made up of?
Dead cells joined end to end with no end walls between them and a hole down the middle
What do xylem tubes carry? And in what direction?
Water and minerals up the plant - from the roots to the stem and leaves
What are substances moved through in the xylem?
The transpiration stream
What is transpiration?
The loss of water from a plant
What is the transpiration stream?
The movement of water through a plant from the roots to the leaves
How does the transpiration stream work? (3)
- Water from inside a leaf evaporates and diffuses out of the leaf, mainly through the stomata
- This creates a shortage of water in the leaf, so water is drawn from the roots through the xylem to replace it
- This means that there is then a shortage of water in the roots so there is a constant transpiration stream of water through the plant
Why does transpiration occur?
Leaves need stomata to allow gases like carbon dioxide in for photo’, but when the stomata are open, there is more water inside the plant than there is out so water diffuses out
