Exchange and Transport in Animals Flashcards
How does oxygen and carbon dioxide move between cells?
By diffusion.
How is water taken up by the cells?
By osmosis.
What organisms diffuse along with water?
Dissolved food molecules and Mineral ions.
What is Urea?
A waste product produced by animals from proteins which diffuses from cells to the blood plasma for removal from the body by the kidneys.
What is the surface area to volume ratio (SA : V)?
How big its surface area is compared to its volume.
The larger an organism is…
the smaller its surface area is compared to its volume.
How do you calculate surface area to volume ratio?
Calculate the surface area
Calculate the volume
Divide both the surface area and the volume by number of the volume to get N : 1.
What does it mean if an organism has a high surface area to volume ratio? (Single-celled organisms)
It is tiny, can rely on diffusion across their surface to exchange everything they need.
What does it mean if an organism has a low surface area to volume ratio? (Multicellular organisms)
It is big, can’t rely on diffusion. So they need Specialised exchange surfaces to increase their surface area to volume ratio.
What happens to the distance that molecules would have to diffuse to get from the outside of their body to the inside of their body?
Increases massively. Meaning diffusion will be slower
Exchange systems…
get substances in and out of their bodies.
Transport systems…
transport those substances to the parts of their bodies that need them.
What is the job of the lungs?
to transfer oxygen to the blood and to remove waste carbon dioxide from it.
How does the lungs do its job?
Contain millions of little air sacs called alveoli where gas exchange takes place.
What happens with blood arriving at the alveoli?
Just returned to the lungs from the rest of the body, so it contains a lot of CO2 and not much O2. Maximises the concentration gradient for diffusion in both gases.
What does concentration gradient mean?
Difference in concentration.
Substances diffuse faster if…
Theres a big difference in concentration between the area they are diffusing from and the area they are diffusing to.
Where does O2 diffuse out of and into?
Out of the air, in the alveoli and into the blood.
Where does CO2 diffuse?
In the opposite direction to O2 to be breathed out.
How are the Alveoli adapted for efficient gas exchange?
Moist lining - for dissolving gases.
A good blood supply - to maintain the concentration gradients of O2 and CO2.
Very thin walls - minimising the distance that gases have to move.
An enormous surface area.
What is the job of red blood cells?
To carry oxygen from the lungs to all the cells in the body.
Why do red blood cells have bio concave disc shape?
To give a large surface area for absorbing oxygen.
Why do red blood cells not have a nucleus?
To allow more space for more oxygen to be carried.
What is haemoglobin?
A red pigment, which contains iron. In the lungs haemoglobin binds with oxygen to become oxyhaemoglobin. In body tissues the opposite happens.
What are Phagocytes?
White blood cells that can change shape to engulf unwelcome microorganisms.
What are Lymphocytes?
White blood cells that produce antibodies against microorganisms. Some also produce antitoxins.
When you have an infection…
your white blood cells multiply to fight it off.
What are Platelets?
Small fragments of cells, which have no nucleus. Help the blood to clot at a wound to stop blood pouring out and to stop microorganisms getting in.
What is Plasma?
Pale straw-coloured liquid, makes the blood watery so it can flow. Carries everything in the blood.
What do Arteries do?
A type of blood vessel which carry blood away from the heart.
What do Capillaries do?
A type of blood vessel which are involved in the exchange of materials at the tissues.
What do Veins do?
A type of blood vessel which carry blood to the heart.
Why do arteries have a thick wall?
To withstand the blood which the heart pumps out at high pressure.
Why do arteries have a thick muscle layer?
To allow them to change their size and direct blood flow.
Why do arteries have a thick elastic layer?
To allow the artery to stretch and recoil, so that blood pressure doesn’t change too much.
What do arteries branch into?
Capillaries.
Why are capillaries one cell thick?
Short distance for diffusion into and out of the capillaries.
Why do capillaries have permeable walls?
To allow substances to easily move in and out of the capillaries.
Why do capillaries have a narrow lumen?
Slows down the blood, allowing more time for diffusion.
What do capillaries supply?
Food and oxygen, and take away waste like CO2.
What do capillaries eventually join up to form?
Veins.
Why don’t the walls in veins need to be as thick as the walls in artery walls?
The blood is at lower pressure in the veins.
Why do veins have a wide lumen?
To allow more blood to flow through them at low pressure.
Why do veins have valves?
To keep the blood flowing in the right direction.
What is the role of the circulatory system?
To transport substances around the body via the blood.
What do is it mean by a double circulatory system?
Our circulatory system has two circuits, one that passes through the lungs and another that passes around the body.
What is the advantage of having a double circulatory system?
The blood loses a lot of pressure as it passes through the lungs, so by returning to the heart, the pressure can be increased again before it passes around the body. This allows blood to move around the body more quickly.
What is the role of the heart?
To pump blood to the lungs and body.
What are the 4 chambers in the heart?
Right atrium, Right ventricle, Left atrium Left Ventricle.
Which artery carries deoxygenated blood from the right atrium of the heart, to the lungs?
Pulmonary artery.
What vein carries oxygenated blood away from the lungs to the left atrium of the heart?
Pulmonary vein.
What does the aorta do?
Carry oxygenated blood from the left ventricle to the body.
Why do ventricles have thicker muscular walls than the atriums?
They have to pump the blood around the lungs or body, whereas the atria only have to pump blood into the ventricles.
Why does the left ventricle have a thicker wall than the right ventricle?
It has to pump blood around the entire body, whereas the right ventricle only has to pump blood around the lungs.
What do valves prevent?
The black flow of blood in the heart.
What is Cardiac output?
The total volume of blood pumped by a ventricle every minute.
What is the equation used to calculate Cardiac output?
Heart rate X Stroke volume.
What is the heart rate?
The number of beats per minutes.
What is the stroke volume?
The volume of blood pumped by one ventricle each time it contracts.
What is Respiration?
A chemical process that releases energy from the breakdown of organic compounds. (usually glucose).
Is Respiration an exothermic or endothermic reaction?
Exothermic because it involves the release of energy.
What can the energy then be used for?
(Respiration)
Metabolic processes, contracting muscles, maintaining temperature.
What is metabolism?
The process by which your body converts food and drink into energy.
What is the word equation for Aerobic respiration?
Glucose + Oxygen -> Carbon Dioxide + Water.
What is Aerobic respiration?
Chemical process in which oxygen is used to produce energy from food.
What is the word equation for Anaerobic respiration in animals?
Glucose -> Lactic acid.
What is the word equation for Anaerobic respiration in plants and fungi?
Glucose -> Ethanol + Carbon dioxide.
What is anaerobic respiration?
Metabolic process that breaks down food without oxygen to produce energy.
What type of respiration is the more efficient way to transfer energy?
Aerobic respiration releases the most energy.
Anaerobic respiration doesn’t break down the glucose molecule completely, so doesn’t release as much energy.
Why don’t animals always carry out aerobic respiration?
It requires oxygen, and during intense exercise there may not be enough oxygen.
