B4 - organising animals and plants Flashcards
what are the components of blood
plasma
red blood cells
white blood cells
platelets
what does blood plasma carry around the body (apart from blood cells)
waste carbon dioxide
urea formed in the liver
small soluble products of digestion
what are the adaptations of the red blood cells
bioncave discs - increased SA:V ratio for diffusion
packed with haemoglobin - binds to oxygen
no nucleus - more space for haemoglobin
what does each type of white blood cells do
lymphocytes - form antibodies against microorganisms
form antitoxins against posions made by microorgansism
phagocytes - engulf and digest incading bacteria and viruses
what is the role of platelets
clot the blood at the site of a wound
what is blood clotting
a series of enzyme controlled reactions resulting in coverting fibrinogen into fibrin
produces network of protein fibres that collect RBC and platelets
forms a jelly like clot
what do the arteries do
carry oxygenated blood away from your heart to the organs of your body
describe the structure of arteries
thick walls containing muscle and elastic fibres
small lumen
what do veins do
carry deoxygenated blood from the organs to the heart
describe the structure of veins
thinner walls than arteries
have valves to prevent backflow of blood
large lumen
what do capillaries do
form a network of tiny vessels linking the arteries and the veins
diffuse oxygen and glucose easily out of blood into cells
describe the structure of capillaries
narrow
very thin walls
what is a double circulatory system
one transport system carries blood from the heart to the lungs and back again, allows oxygen and carbon dioxide to be exchanged with the air in the lungs
other transport system carries blood from heart to other organs of your body and back again
why is a double circulatory system important in animals
makes system very efficient
how is oxygen supplied to the muscles of your heart
coronary arteries
describe the passage of blood through the heart
blood enters the top chambers of your heart (artria)
blood coming into right atrium from vena cava is deoxygenated blood
blood coming into left atruym in pulmonary artery is oxygenated blood
atria contract together and force blood down into ventricles
what is a common cause of coronary heart disease
buildup of fatty material on the lining of the vessels
causes narrow coronary arteries
what are the effects of coronary heart disease
supply of oxygen to heart muscle is reduced
causes pain, heart attacks, death
what is a stent
a metal mesh that is placed in the artery to open up the blood vessel
what are the benefits of stents
can be put in place without general anaesthetic
can open a blocked artery almost anywhere
can release drugs to prevent blood clotting
what is bypass surgery
when the narrow or blocked coronary artery is replaced with bits of veins from other parts of the body
what are the benefits and disadvantages of bypass surgery
BENEFITS - works for badly blocked arteries (where stents cannot help)
DISADVANTAGES - expensive,
risk associated with general anaesthetic
what are statins
drugs that reduce blood cholesterol levels
slows down rate at which fatty material is deposited into coronary arteries
how can you help leaky valves
replace with mechanical valves (made of titanium and polymers)
replace with biological valves (taken from animals such as pig, cattle, or human donors)
benefits and disadvantages of mechanical heart valves
BENEFITS - last a long time
DISADVANTAGES - need to take medicine for the rest of your life
benefits and disadvantages of biological valves
BENEFITS - work extremely well, the patient needs no medication
DISADVANTAGES - only last around 12-15 years
what does a pace maker do
correct irregularities in the heart rate
benefits and disadvantages of an artificial pacemaker
BENEFITS - increase in quality and length of life
DISADVANTAGES - regular medical check ups needed
advantages of an artificial heart
gives people a chance to live a normal life whilst they wait for a donor
give diseased hearts a rest to recover
disadvantages of an artificial heart
need lots of machinery
most patients have to stay in hospital until transplant
risk or blood clotting
how do the lungs ventilate
by the contraction and relaxation of intercostal muscles between ribs and diaphragm
what happens when your breathe in (the physical process, not involving gases)
ribs move up and out, diaphragm flattens, volume of chest increases
increased volume means lower pressure in chest
atmospheric air at higher pressure than chest, air is drawn into lungs
what happens when you breathe out (physical process not involving gases)
ribs fall, diaphragm moves up, volume of chest gets smaller
decreased volume means increased pressure in chest
pressure in chest higher than outside, air is forced into lungs
what happens when you breathe in (in terms of gases)
oxygen rich air moves into lungs
maintains steep concentration gradient with blood
oxygen diffuses into bloodstream
what happens when you breathe out (in terms of gases)
removes carbon dioxide rich air from lungs
maintains concentration gradient
carbon dioxide diffuses out of bloodstream into air in lungs
adaptations of the alveoli
rich supply of blood capillaries (maintains concentration gradient)
later of cells between air in lungs and blood in capillaries is only one cell wide (allows diffusion to easily take place)
large surface area
what do epidermal tissues do
cover the surface of plants and protects them
secrete waxy substance that waterproof surface of leaf
what does the palisade mesophyll tissue do
contain lots of chloroplasts (carry out photosynthesis)
what does the spongy mesophyll tissue do
contains some chloroplast
big air spaces
large surface area to make diffusion of gases easier
what does the xylem do
carry water and dissolved mineral ions from roots up to leaves
what does the phloem do
carry dissolved food from the leaves around the plant
what’s the role of the stem in plants
support leaves and flowers
what’s the role of the roots in plants
take up water and minerals from soil
what’s the role of the leaf in plants
carry out photosynthesis
what is translocation
the movement of dissolved sugars from the leaves to the rest of the plant
how do aphids and greenfly kill plants
they push shard mouthparts into the phloem and feed on the sugary fluid
because the plant is not getting its food it dies
why are young trees vulnerable to animals
their xylem lies in a ring just underneath the bark
if a complete ring of bark is eaten transport in the xylem stops
the tree cannot get water which means it cannot perform photosynthesis
it dies
why is transport of sugars important
all the cells need sugars for respiration and to provide materials for growth
why does a plant need water
photosynthesis
hold itself upright
what do guard cells do
control the size of the stomata and their opening and closing
what is transpiration
the loss of water vapour through the leaves
what is the transpiration stream
the constant movement of water molecules through the xylem from the roots to the leaves
describe the transpiration stream
water moves into roots from soil by osmosis (replaced water constantly moving up stem)
water moves up from roots into stem
water moves through stem into leaves to replace water lost by evaporation
water is lost from leaves by evaporation through stomata
what are the factors that affect transpiration
temperature
humidity
amount of air movement
light intensity
how does light intensity affect transpiration
higher light intensity = more photosynthesis
more photosynthesis = stomata opening up to let in CO2
when stomata are open, rate at which water is lost by evaporation and diffusion increases
increase in light intensity=increase in rate of transpiration
how does humidity affect transpiration
hot windy conditions means more water evaporates from cells and diffusion happens quicker
water vapour diffuses quicker into dry air due to concentration gradient
windy conditions keeps concentration gradient high by moving water vapour
how does temperature affect transpiration
molecules move quicker when temperature increases so diffusion happens quicker
rate of photosynthesis increased as temperature increases (more stomata open for gas exchange to take place)
how does the cuticle prevent water loss
waxy and waterproof or thick and shiny
what will a plant do if it loses water too fast
plant may wilt - reduces surface area available for water loss
stomata close - stops photosynthesis risks overheating BUT prevents most water loss
what does a potometer do
show how uptake of water by plant changes in different conditions
