B8 - exchange and transport Flashcards
why do substances need to be exchanged in animals
to take in substances that are needed from the environment and get rid of waste products
what substances need to be exchanged in animals and why?
oxygen and carbon dioxide - aerobic respiration
water, food - energy and to stay healthy
urea - diffuses from cells to blood and then removed by kidneys
what is diffusion
movement of particals going along a concentration gradient
what is osmosis
movement of water across a partially permeable membrane going along a concentration gradient
what is active transport
movement of particals across a membrane against a concentration gradient, using energy
what is a concentration gradient
going along a concentration gradient = from area of high to low concentration
what is the function of co2 in the body
balances gas levels in blood, also is a waste product of aerobic respiration
what is the function of water in body
regulates body temperature and transports substances
what is the function of food in body
provides nutrients for a healthy balanced diet
what is urea
waste product that comes out in urine removed from the body by kidneys
what substances are taken in by the body
oxygen, water and food molecules
what substances are excreated from the body?
carbon dioxide, urea, water and food molecules
what is surface area
measure of exposed area an object has
measured in (x^2)
what is volume
amount of ‘3D’ space a substance occupies
measured in (x^3)
what is surface area to volume ratio
the proportion of surface area of a substance compared to its volume
how to calculate SA:V ratio
calculate SA and V then write in the form ‘SA:V’ (in its simplest form)
how is a large SA:V ratio more effective
The higher the surface area to volume ratio cells have, the more effective the diffusion of materials in and out of the cell can be as there is more exposed edges
what is the job of the lungs?
to transfer o2 to the blood and remove waste co2 from it
where does gas exchange in the lungs happen?
millions of little air sacs - alveoli
how are alveoli adapted for efficient gas exchange?
- moist lining, for dissolving gases
- constant supply of blood to maintain the o2 and co2 concentration gradients
- walls that are 1 cell thick for a short diffusion pathway
- large surface area to process large amounts of gases that are breathed in
what are the 4 components of blood
red blood cells
white blood cells
platelets
plasma
what is the scientific term for red blood cells?
erythrocytes
what is the function of red blood cells?
carry oxygen from the lungs to all the cells in the body
how are red blood cells adapted to their function?
biconcave disc shape- large SA for o2 absorbtion
no nucleus - more room for o2
contain haemoglobin - binds to o2
what are the scientific names for white blood cells
phagocytes and lymphocytes
what do phagocytes do?
change shape to engulf unwelcome microorganisms
what do lymphocytes do?
produce antibodies against microorganisms
what are platelets?
small fragments of cells without a nucleus that help the blood clot at a wound and stop microorganisms entering the body
what is plasma?
pale liquid that carries everything in the blood
what does plasma carry?
rbc, wbc, platelets, nutrients (glucose and amino acids), CO2, urea, proteins, hormones
name the types of blood vessel
arteries, veins and capillaries
what do arteries do?
carry oxygenated blood (pulmonary artery is the only exeption) away from the heart to all the bodies tissues
what do veins do?
carry deoxygenated blood (pulmonary vein is the only exeption) back to the heart when used by body tissues
what do capillaries do?
small, thin blood vessels that connect the arteries and the veins. involved in the exchange of materials at tissues.
how are arteries adapted to their function?
- strong elastic walls to withstand blood that is pumped at high pressures
- thick walls and narrow lumen to maintain hig presures
- thick layer of muscle and elastic fibres to allow strech and spring
how are veins adapted to their function?
- thinner walls as blood travels at low pressure
- big lumen to maintain blood flow despite low pressure
- valves to prevent backflow
how are capillaries adapted to their function?
- narrow to get in gaps between cells so blood can get to all the cells in the body
- permable walls, substances can diffuse in and out
- one cell thick walls short diffusion pathway to maximise diffusion.
what is a double circulatory system?
the heart pumps blood around in 2 circuits
1st circuit- heart pumps deoxygenate blood to lungs for O2
2nd circuit- oxygenated blood to rest of body to deliver O2
deoxygenated blood returns back to heart
what animals have a single circulatory system?
fish
describe the flow of blood through the heart
deoxygenated:
vena cava, right atrium, right ventrical, pulmonary artery, lungs (and gets oxygenated)
oxygenated:
pulmonary vein, left atrium, left ventricle, aorta, body (and becomes deoxygenated)
what is the divide between the left and right side of the heart called?
the septum
what type of blood does each side of the heart carry?
right - deoxygenated
left - oxygenated
what is the heart made of?
muscle tissue
how does blood leave the ventricles?
the tissue in the walls contract
why does the heart contain valves?
to maintain the direction of blood flow and prevent back flow (blood traveling in the wrong direction)
why does the left ventricle of the heart more muscular than the right?
has to pump blood a further distance (around the whole body) at high pressure
where does each side of the heart pump blood?
right - lungs
left - body
what is heart rate?
the number of time the heart beats per minute (bpm)
what is stroke volume?
volume of blood pumped form left ventricle to aorta per beat (cm3)
what is cardiac output?
total volume of blood pumped from a ventricle per minute (cm3/min)
how to calculate cardiac output?
cardiac output = heart rate x stroke volume
what must be remembered when looking at a heart diagram?
it is inverted, left is the right side and right is the left side of the heart
what is respiration?
the process of releasing energy from the breakdown of organic compounds (glucose) - happens in every cell in the body continuously
what is energy used for?
movement
thermoregulation
chemical reactions (making and breaking down substances, muscle contractions)
is respiration exothermic or endothermic?
exothermic as transfers energy is into the surroundings.
what are the two types of respiration?
aerobic and anaerobic respiration
what is aerobic respiration?
with oxygen, happens when O2 supply is plentiful and it is the most efficient way of transfering energy from glucose. happens all the time in plants and animals
what is the equation for aerobic respiration?
glucose + oxygen ——> carbon dioxide + water (+energy)
where in the cell does aerobic respiration take place?
mitocondria - very efficient as they have a high SA due to inner folds
what is anaerobic respiration?
without oxygen, happend when O2 supply is limited and is only 5% as efficient as aerobic respiration
what is the equation for anaerobic respiration?
glucose ——> lactic acid (+energy)
where in the cell does anaerobic respiration take place?
cytoplasm
why is lactic acid produced during anaerobic respiration?
glucose is only partially broken down so lactic acid is also produced - this builds up in the muscles and can be painful and lead to cramps
why does the body sometimes need to respire anaerobically?
during (and after) vigorous exercise, body cant supply enough O2 to muscles for aerobic respiration - even though HR and breathing rate increase, muscles have to respire anaerobically aswell.
what is oxygen debt?
build up of lactic acid = not enough O2
it is the amount of oxygen required to remove the lactic acid, and replace the body’s reserves of oxygen
what is an independant variable?
variable you change
what is dependant variable?
variable you measure
what is control variable?
variable you kee the same for a fair test
what does rate of respiration practical show?
as temperature increases, rate of respiration increases as enzymes work faster in high temps
