Exchange And Transport In Animals Flashcards
What exchanges take part in the body?
- aerobic respiration where cells take in oxygen and produce carbon dioxide which move between cells through diffusion
- water is taken up by osmosis and mineral ions are diffused within it
- urea diffuses from cells to the blood plasma to be removed from the body through the kidneys
What is the ease of exchange dependent on?
The surface area to volume ratio
-the larger an organism is the smaller its surface area to volume ratio is
Why do multicellular organisms need exchange surfaces?
- these organisms have a smaller surface area to their volume ratio
- this makes it difficult to exchange enough substances to supply their entire volume across their outside surface alone.
- this means they need some sort of exchange surface for efficient diffusion and a mass transport system
What do multicellular exchanges have to do?
-allow enough of the necessary substances to pass through hence they are adapted to maximise effectiveness
What do single cellular organisms need exchange surfaces less?
In these organisms gases and substances can diffuse directly in or out of the cell across the cell membrane
-this is due to large SA:V ratios so enough substances can be exchanged across the membrane to supply the volume of the cell
How are alveoli adapted for gas exchange to make diffusion quicker?
- moist lining to allow gases to dissolve
- good blood supply to maintain the concentration gradient of O2 and CO2
- very thin walls minimising the distance gases have to move
- enormous surface area due to folded walls and lots of them in lung
What and where are alveoli?
- small air sacs located in the lung
- blood arriving here has just returned to the lungs from the rest of the body so it contains lots of CO2 and little 02 to maximise the concentration gradient
What factors effect rate of diffusion?
- concentration gradient as substances diffuse faster if there is more particles to diffuse into a lesser area
- large surface area so more space for gases to diffuse
- thin walls to shorten the diffusion distance decreasing time taken (will double if halved)
What is fick’s law?
Rate of diffusion = surface area x concentration gradient/
Thickness of membrane
How are red blood cells (erthyhrocrotes) adapted to their function?
- carry oxygen from the lungs to all the cells in the body
- they have a biconcave disk shape giving them a larger surface area to absorb more oxygen
- no nucleus to allow more room to carry oxygen
- contain haemoglobin with iron in
What happens between oxygen and haemoglobin the red blood cells?
They bing
- oxygen + haemoglobin —oxyhemoglobin
- in body tissue this is reversed to release oxygen into cells
How are white blood cells adapted to their functions?
- phagocytes are white blood cells that can change shape to engulf microorganisms (phagocytosis)
- lymphocytes produce antibodies to destroy microorganism or so,e produce antitoxins to neutralise toxins from these organisms
- with infection these multiply to fight off infection so they are in high concentration
How is the structure of platelets related to its function?
- fragments of cells that have no nucleus
- they help blood to clot at a wound to stop us bleeding to death and to stop microorganisms getting in
- the platelets burst, react with fibrinogen in the plasma and turn it into a mesh of fibrin threads that harden
- lack of platelets can cause excessive bleeding and bruising
How is plasma adapted to its job?
- pale straw coloured liquid made of 90% water
- it carries almost everything in it
- nutrients like glucose and amino acids which are dissolved , carbon dioxide, urea, hormones and antibodies
How are arteries designed for their function?
- strong/thigh muscles and elastic tissue enabling it to flex to withstand and maintain high blood pressure
- lumen is relatively narrow to maintain high blood pressure
- pumps blood away from the heart at high pressures
What do capillaries do and how are they designed for their function?
- branch of arteries and are the smallest blood vessel, they supply food and oxygen and take away waste like CO2
- they have permeable and thin walls (one cell thick) so substances like red blood cells can diffuse in and out at a faster rate as this decreases the distance needed to travel
- very narrow to squeeze into gaps between cells to exchange with them
How are veins adapted to their role?
- transport blood back to the heart at low pressures
- the blood is at low pressure in the veins so walls are thinner with smooth muscle
- they have a bigger lumen as don’t need to maintain high pressure
- they have values to prevent the back flow of blood away from the heart and keep it travelling in the right direction
What respiratory system do mammals have?
- double circulatory system meaning oxygenated and deoxygenated blood is kept relatively separate
- it is made up of the heart, blood vessels and blood
What circulatory system do fish have?
A single circulatory system
- deoxygenated blood from the fish’s body travels to the heart which then pumps it right around the body again in a single circuit
- they only have two chambers
What two main chambers and blood vessels does deoxygenated blood travel through?
- the right atrium (C)of the heart receives deoxygenated blood from the body through the Vena Cava (V)
- the deoxygenated blood moves through the right ventricle(C) which pumps it to the lungs to the pulmonary artery (V)
What two main chambers and blood vessels does oxygenated blood travel through?
- the left atrium (C)receives oxygenated blood from the lungs through the pulmonary vein (V)
- the oxygenated blood then moves through to the left ventricle (C)which pumps it out round the whole body via the aorta (V)
Why is the left ventricle much thicker than the right?
It needs more muscle because it has to pump oxygenated blood around the whole body at high pressure. Whereas the right only has to pump it to the lungs
What is oxygenated, deoxygenated blood and values?
Oxygenated is enriched in oxygen
Deoxygenated is lacking oxygen
Valves prevent the back flow of blood in the heart keeping it travelling in the right direction
How can you calculate how much blood is pumped every minute?
- cardiac output is the total volume of blood pumped by a ventricle every minute, heart rate is number of beats per minute, stroke volume is the volume if blood pumped by one ventricle each time it contracts
- cardiac output = heart rate x stroke volume
What is respiration?
an exothermic reaction which occurs continuously in living cells to release energy for metabolic processes, including aerobic and anaerobic, contracting muscles and maintains temp
-energy is transferred through the breakdown of organic compound but some is transferred by heat to the environment
What is aerobic respiration?
- when there is enough oxygen available for respiration to take place
- it is the most efficient way to transfer energy from glucose
- glucose + 6oxygen — 6carbon dioxide + 6water
What is anaerobic respiration?
- occurs when there is a lack of oxygen present and transfers much less energy than aerobic so is less efficient
- the glucose is only particular broken down and lactic acid is also produced and builds up in the muscles (glucose —lactic acid + CO2)
- this can happen when you do vigorous exercise
What is anaerobic respiration in plants like?
-plants can respite without oxygen too but they produce ethanol and CO2 instead of lactic acid
Glucose — ethanol - carbon dioxide
Compare and contrast aerobic and anaerobic respiration?
- both release energy
- both are exothermic causing an increase in surrounding temp
- both require a source of glucose
- both happen all the time
- oxygen vs no oxygen
- anaerobic is less efficient so releases less energy and carbon dioxide is removed slower
