Organisation and Transport in Plants + Animals Flashcards
catchy
What is blood
A tissue consisting of plasma, platelets, red blood cells and white blood cells
Plasma
Yellow liquid that transports all blood cells and other substances (glucose, antibodies, hormones) around the body
e.g Carbon dioxide to the lungs, urea to the kidneys from the liver, small soluble products of digestion from the small intestine to your cells
Red blood cells
Contains haemoglobin which binds to oxygen to transport it from lungs to tissues and cells, which need it for respiration.
oxygen and haemoglobin word equation
oxygen + haemoglobin <-> oxyhaemoglobin (reversible)
White blood cells
Bigger than red blood cells, wbc are part of the body’s defence system against harmful microorganisms
● Some produce antibodies
● Some form antitoxins
● Some ingest and digest bacteria and viruses
Platelets
Small fragments of cells which recognise damaged blood vessels and trigger blood clotting to prevent too much bleeding
How are red blood cells adapted to their function
● Biconcave disc shape – increased sa:v ratio which increases diffusion of oxygen
● Very small, can fit through tiny capillaries
● No nucleus – more space for haemoglobin.
● Packed with haemoglobin
Arteries
Take blood from heart to organs
Have thick walls made from muscle and elastic fibres
Small lumen
Veins
Take blood from organs to heart
Thinner walls and valves to prevent backflow
Large lumen
Capillaries
Allow substances needed by cells to pass out of the blood
Allow substances produced by the cells to pass into the blood
Allow exchange of oxygen, co2, hormones etc
Narrow, very thin walls a single cell layer thick, narrow lumen
Diffusion distances are short
Why is a transport system needed
To circulate chemicals around the body - oxygen and glucose are needed for respiration by every cell and cells need to get rid of waste products e.g carbon dioxide and urea
Double circulation system process
Oxygenated blood is pumped by the heart to the rest of the body
Oxygen leaves the blood in the body and the blood returns to the heart
Deoxygenated blood is pumped from the heart to the lungs
At the lungs, the blood receives oxygen and is pumped back to the heart
Pacemaker cells
Regulate natural resting heart rate, found in right atrium
Coronary heart disease
Layers of fatty material build up in coronary arteries and narrow them, reducing blood flow to the heart
Reduces supply of oxygen to the heart muscle, resulting in pain, heart attacks, even death
How do stents work
Small cut in thigh, tube carrying a balloon inserted
When in place, balloon will inflate to expand the stent
Balloon deflates, stent is in place, artery is widened
Stents pros and cons
Increases blood flow
Cheap
No general anaesthetic
Patients will recover well
Will not work on very blocked arteries
How do statins work
Prescribed tablets that reduce blood cholesterol levels, thin blood
Statins pros and cons
Slows down the rate of fatty material deposit
Non invasive
No surgery risk - no concern
Have to take for life
Side effects
Patients may forget/od
How does a bypass operation work
Vein is taken from thigh and attached to the heart
Vein placed underneath the blockage, making an alternative route for blood flow
Pros and cons of bypass operation
Effective if the blockage is severe
General anaesthetic involved (risky)
Expensive