Exchange and Transport Flashcards
volume and surface area relationship
the larger the organism is, the smaller it’s surface area is compared to its volume
Why can substances directly diffuse across a membrane?
because they have a large surface area compared to their volume
why is it good to have a large surface area compared to volume?
it means enough substances can be exchanged across the membrane to supply the volume of the cell
what is the lungs job?
to transfer oxygen to the blood and remove waste carbon dioxide
how do substances diffuse faster?
if there is a bigger difference in concentration
what does the blood arriving at the alveoli contain?
lots of CO2 and not much O2
why does it not have a lot of O2?
because it has just returned to the lungs from the rest of the body
how is the alveoli adapted?
moist lining to dissolve gases
good blood supply to maintain concentration gradient
very thin walls to minimise distance gases have to move
enormous surface area
what is the other name for red blood cells?
erythrocytes
what is the job of red blood cells?
carry oxygen from the lungs to all the cells in the body
what shape are red blood cells?
biconcave disc
what is good about a biconcave disc shape?
gives a large surface area to absorb oxygen
why don’t red blood cells have a nucleus?
allows more room to carry oxygen
what is haemoglobin?
red pigments in red blood cells which contain iron
how does oxyhaemoglobin get made?
when haemoglobin binds with oxygen
what is phagocytosis?
when white blood cells change shape to engulf unwelcome micro organism
what is another name for a white blood cell?
phagocytes
do white blood cells have a nucleus?
yes
what do platelets do?
help blood clot at a wound to stop blood pouring out and stop micro organisms getting in
what are platelets?
small fragments of cells with no nucleus
what is plasma?
liquid that carries everything in blood
what do arteries do?
carry blood away from the heart
what do capillaries do?
exchange materials at tissues
what do veins do?
carry blood to the heart
why do arteries have strong walls?
because they carry high pressure blood
features of an artery
thick lumen
thick layers of muscle
elastic fibres to allow them to stretch and spring back
why are capillaries narrow?
so they can squeeze between gaps and get really close to cells to exchange substances
why do capillaries have permeable walls?
so substances can diffuse in and out
why are capillaries walls one cell thick?
it increases the rate of diffusion by decreasing the distance which it occurs
why do veins have thin walls?
because they carry low pressure blood
why do veins have bigger lumen?
to help the blood flow despite it being low pressure
why do veins have valves?
to stop backflow of blood
what kind of circulatory system does animals have?
double
what type of blood do veins carry?
de oxygenated blood
how does the circulatory system work?
- the heart pumps deoxygenated blood to the lungs
- oxygenated blood returns to heart
- oxygenated blood goes to other organs
- deoxygenated blood returns to heart
Right Atrium
receives deoxygenated blood from body
right ventricle
pumps deoxygenated blood to the lungs
left atrium
receives oxygenated blood from lungs
left ventricle
pumps oxygenated blood sound the whole body
why does the left ventricle have a thicker wall than the right?
because it needs more muscle to pump high pressure blood around the whole body
how to calculate how much blood is pumped around the whole body?
heart rate * stroke volume
what is respiration?
the process of transferring energy from the breakdown of organic compounds
what type of reaction is respiration and why?
exothermic because energy is transferred to the environment
aerobic respiration equation
glucose + oxygen = carbon dioxide + water
what happens in anaerobic respiration?
glucose is only partially broken down and lactic acid is produced
equation for anaerobic respiration in animals
glucose = lactic acid
equation for anaerobic respiration in plants
glucose = ethanol + carbon dioxide
what is the energy used for in respiration?
metabolic processes
contracting muscles
maintaining steady body temp
