B4: Organising Animals and Plants Flashcards
What does the circulatory system do?
The circulatory system is made up of blood, blood vessels and the heart and carries oxygen and nutrients to every cell in the body as well as removing waste products.
What is plasma and what does it do?
• It is a yellow liquid that transports blood cells and other substances around the body.
E.g:
- Waste carbon dioxide produced by the cells is carried to the lungs.
- Urea formed in the liver from breakdown of proteins is carried to kidneys to be removed from the blood by urine.
- Small, soluble products of digestion pass into plasma from the small intestine.
What are red blood cells and what do they do?
• They carry oxygen to cells where it is needed.
- They have a biconcave shape to increase surface area for diffusion.
- Haemoglobin binds to oxygen and has no nucleus to make more space.
What do white blood cells do?
They form part of the body’s defence system against harmful microorganisms. Some produce antibodies and antitoxins and some engulf and digest bacteria/viruses (phagocytosis)
What are platelets?
They are fragments of cells that clot blood and form scabs. Protects new skin as it grows and stop bacteria from easily entering through the wound.
What do arteries do and what is their structure?
They carry blood away from the heart to the organs of your body (usually oxygenated).
They have strong muscular and elastic walls to help them stretch and withstand high pressure. They have a narrow lumen.
What do veins do and what is their structure?
They carry blood into the heart (usually deoxygenated).
They have valves to prevent the back flow of blood.
Thin walls and wide lumen so more low pressure blood can flow through.
What do capillaries do?
It is where gaseous exchange takes place and link arteries and the veins.
Only one cell thick so diffusion of substances like glucose and oxygen and waste products such as carbon dioxide is very quick and easy.
Substances pass into the blood through the capillaries.
What is a double circulatory system?
One transport system carries blood from your heart to the lungs and the other from your heart to the rest of your body. This makes the circulatory system more efficient as more areas of your body receive fully oxygenated blood quickly.
What is the path of oxygenated blood?
Pulmonary Vein - Left Atrium - Left Ventricle - Aorta - Rest of your Body
What is the path of deoxygenated blood?
Vena Cava - Right Atrium - Right Ventricle - Pulmonary Artery - Lungs
What do ventricles do?
They contract to pump blood out of the heart. The left one is stronger so it can pump more blood to the rest of the body.
What is coronary heart disease?
It is when the coronary arteries that supply oxygenated blood to the heart muscle become narrow, usually caused by the build up of fatty deposits. The supply of oxygen to the heart is reduced, which can lead to heart attacks/death.
What are stents and what are the advantages and disadvantages of them?
• Stents are a metal mesh placed in the coronary artery to widen the vessel and allow more blood to flow through, keeping their heart beating.
Advantages: Effective in lowering the risk of heart attacks, the recovery time is quick.
Disadvantages: Risk of heart attack or infection during the procedure, chance of blood clots near the stent (thrombosis).
What are statins and what are the advantages and disadvantages of them?
• Statins are drugs taken to reduce ‘bad’ cholesterol levels to slow down the build up of fatty deposits in the coronary arteries.
Advantages: Reduces the risk of coronary heart disease, strokes and heart attacks. Increase the levels of good cholesterol.
Disadvantages: Long term drug that needs to be taken continuously so someone might forget. Takes time for it to have an effect. Possible side effects which may be serious e.g. liver damage.
How can leaky valves be treated?
They can be replaced with mechanical or biological valves.
Mechanical: Last for long time but constant medication needed to stop blood clotting around it.
Biological: Works very well but only lasts 12-15 years.
What are pacemakers and how could it be treated?
Pacemaker is found in the right atrium and controls the heart beat. Can use an artificial pacemaker if problems. This would be used to correct irregularities, by sending electrical signals to the heart to stimulate to beat properly.
How can heart failure be treated?
It can be treated by using an artificial heart or a donor heart transplant.
Artificial hearts are less likely to be rejected however there is a risk of infection or blood clots and it may fail.
What is the job of the respiratory system?
It is to move air into and out of the lungs, brought about the contraction and relaxation of the intercostal muscles.
How does gas move when breathing in and out?
- When you breathe in, oxygen moves into the lungs and diffuses into the bloodstream.
- Breathing out removes carbon dioxide from your lungs to maintain concentration gradient for carbon dioxide to diffuse out of bloodstream into the lungs.
How does gas exchange occur during inhalation?
During inhalation the alveoli fill with oxygen. Blood in capillaries surrounding the alveoli is deoxygenated so oxygen diffuses into the capillary bloodstream and carbon dioxide diffuses from the blood to the alveoli, where it will be lost from the lungs during exhalation.
What are the adaptations of alveoli?
Small and very thin for a short diffusion path. Have a large surface area for a quicker rate of diffusion. Capillaries provide a large blood supply to maintain the concentration gradient.
What are the functions of different parts of the plant?
Epidermal - cover surface and protect, often secrete waxy substance over surface of the leaf.
Palisade Mesophyll - contains lots of chloroplasts for photosynthesis.
Spongy Mesophyll - contains chloroplasts and has air spaces and large surface area for diffusion.
Xylem/Phloem - both are transport tissues, xylem carries water and dissolved mineral ions from roots to the leaves. Phloem carries dissolved sugars from leaves around the plant.
Meristem - contains stem cells that can grow and differentiate into other types of cells.
What is translocation?
- It is the movement of dissolved sugars from leaves to the rest of the plant.
- It is needed for making new cells, as an energy stored and for respiration.
- Mineral ions are needed for the production of proteins and molecules.
What do guard cells do?
They control gas exchange and water loss by opening the stomata to allow air into the leaves and water out. Carbon dioxide diffuses in and oxygen diffuses out.
What is transpiration and how is it increased?
Transpiration is the loss of water vapour through the leaf.
It is increased by temperature, light intensity, high amounts of wind and a high carbon dioxide concentration. It is decreased by humidity as the concentration gradient isn’t as steep.
How can water loss be reduced?
Waxy, waterproof layer around the stomata protects it and prevents too much water loss.
Wilting prevents water loss as it reduced surface area.
