When the body
exercises, glucose is
used to release
energy. Water and
ions are lost via
sweating-If these
ions aren't replaced,
the body will not
function efficiently
Certain organ systems
are specialised to aid the
exchange of materials.
The villi in the small
intestine provides a large
surface area for
exchange to take place.
They have an extensive
network of blood
capillaries to maximise
absorption of the
products of digestion.
The walls of the
capillaries are very thin,
providing a short
diffusion path
The trachea (windpipe)
has cartilage to prevent
it from collapsing
The bronchus (branch
of trachea)
The Ribs protect the
contents of the thorax
The intercostal muscles
raise and lower the ribs
The Diaphragm divides
the thorax and abdomen
The alveoli is where gas
exchange takes place
The Bronchiole is one of the
many branches of the bronchi
The alveoli in
the lungs are
tiny air sacs
where the
exchange of
oxygen and
carbon dioxide
takes place, this
is maximised by
the millions of
alveoli in each
lung creating a
large surface
area. The great
blood supply.
The walls of the
capillaries
supplying the
blood are very
thin.
Inspiration
Ribcage
moves
outwards
and
upwards
due to
intercostal
muscles
contracting
Diaphragm
becomes
flatter
Increases
the space
in the
thorax,
decreasing
pressure.
Air is
drawn in
Expiration
Ribcage
moves in
and down
as
intercostal
muscles
relax
The
diaphragm
relaxes and
moves
upwards
Decreases
the space
in the
thorax,
increasing
the
pressure
so the air
is forced
out.
LEAVES have the
stomata to allow
carbon dioxide in
and oxygen out (by
diffusion). This
does however lead
to loss of water
vapour in a
process called
transpiration
The size of the plant is
controlled by a pair of guard
cells, these adjust the amount of
water released and CO2 taken in
Transport
Systems in
Plants and
Animals
The upper
chambers
of the heart
are the
atria, the
lower
chambers
are the
ventricles
The blood flowers
into the atria via the
veins, the atria
contracts forcing the
blood out of the
heart. Blood flows
from the heart to the
organs through the
arteries
Arteries have thick walls
containing muscle and
elastic fibres to withstand
blood at high pressure
Veins have thin walls
and have valves to
prevent blood from
flowing backwards
Blood flows through thin walled
blood vessels called capillaries in
organs. Substances pass out of
the blood in these
There area 2
separate circulatory
systems. One
carries blood from
the heart to the
lungs and then
back to the heart.
The other caries
blood from the
heart to all other
organs of the body
Sometimes
arteries
become
narrow and
blood flow
becomes
restricted. A
stent is used
to keep it
open
Blood is composed of
four components,
Plasma (Transports
CO2, Glucose and
waste), Red blood cells
(lots of haemoglobin),
White blood cells
(defence system
against microbes) and
platelets (Help to clot
wounds)
Plants have
2 transport
systems
Xylem tissue
transports water
and mineral ions
from the roots to
the stem and leaves.
The movement is
called transpiration
stream
Phloem tissue
transports
sugars
produced in
the leaves to
the rest of the
plants
Homeostasis
Humans need to
remove waste
products-Two of
these waste
products are CO2
and urea (Left over
from respiration
and produced in
the liver to break
down excess amino
acids.
A dialysis machine is where a person
blood flows between partially permable
membrances. As the blood lfows, it is
seperated from the dialysis fluid by
these partially permeable membranes.
These membranes allow all urea,
excess substances etc to pass from the
blood to the dialysis fluid, restoring
concentrations to normal levels.
Dialysis fluid contains the same
concentration of useful substanced as
blood, ensuring that glucose and
minerals aren't lost through diffusion.
Kidney transplants are an
alternate to dialysis machines
however, antigens may be
produced, rejecting this new
kidney. Donor kidneys with a
tissue type similar to that of
the recipient is useful to stop
rejection. The recipient can
also be treated with drugs
that suppress the immune
response.
Body temperature is controlled by the nervous system.
Monitoring is performed in the brain which has receptors
that are sensistive to the temperature of blood. There are
also temperature receptors in the skin that send impulses
to the thermoregulatory centre.
Humans need to maintain
their temperature at 37
degress (increased by
shivering and narrowing
blood vessels and
decreased by sweating and
widening blood vessels)
Their water content
(gained by drinking, lost
by breathing-excess
water is lost in the urine)
Ion
content
(Gained by
eating and
drinking,
lost by
sweating)
Blood sugar (glucose
is gained by eating
and drinkin and
provides cells with
energy-Glucose is
removed from the
blood and stored as
glycogen)
Urine is produced when blood is filtered
and water and small molecules pass into
the kidney tubules. Sugars in the tubules
are reabsorbed back into the blood,
dissolved ions are reabsorbed and some
water is reabsorbed. Urea, excess ions and
water form urine in the tubule
People that suffer
from kidney failure
are treated by a
kidney dialysis
machine
The blood sugar
concentration is
managed in the
pancrea. THe
pancreas produces
insulin which allows
glucose to move
from the blood into
the clels. Type 1
diabetes is a disease
where the blood
glucose may rise to
a level that the
pancreas does not
produce enough
insulin
Humans and their environment
The earth is suffering from over
population due to developments in
science and medicine, this is causing
a lack of non-renewable materials
such a copper or coal, a higher
production of domestic and
industrial waste meaning more
landfill sites are needed, improper
handling of waste causing an
increase in environmental pollution,
more land is taken up by farms to
grow crops and keep animals, and
cities are expanding which means
there is less land.
Human activities are starting
to pollute water, air and land
Water is being
polluted by toxic
chemicals and sewage.
Air is being polluted by
carbon dioxide, sulfur
dioxide and oxides of
nitrogen-causing acid rain.
Land is being polluted by
toxic chemicals such as
pesticides and herbicides
which may be washed from
the land to the water.
Deforestation is also a growing
problem, it involves large scale
cutting down of trees for timber,
deforestation has increased the
amount of carbon dioxide
released into the atmosphere
due to the burning of wood and
lack of tree respiration, it also
reduces biodiversity and results
in the loss of organisms that
could be of future use.
Along with forests being
destroyed, peat bogs are also
being destroyed. These are
areas of wetland where over
thousands of years, decaying
plants have been formed into
peat, peat is used as a compost
to grow plants. It can also be
burnt as fuel. In many
countries, vast areas of peat
bogs are cleared, drained and
burnt. Destruction of peat bogs
releases large amounts of
carbon dioxide into the
atmosphere, to preserve peat
bogs, the use of peat free
composts is becoming more
important
The greenhouse effect is where
methane and carbon dioxide
"insulates" the earth, stopping
energy from escaping from the
earths surface to space. Without
this, the earth would be frozen
over, however the level of these
gases is rising along with the
temperature of the planet.
Global warming can cause the
following things, climate change, a
rise in sea level, reduced biodiversity,
changes to migration patterns in
birds, changes in the distribution of
species
Biofuels are liquid fuels
made from any living
thing (biomass). They are
normally made by
fermentation of fast
growing crops such as
corn or sugarcane.
Gasohol is a biofuel that
is a mixture of alcohol
(ethanol) and petrol,
used to make cheaper
and cleaner fuel for cars.
There are multiple
reasons for
deforestation: some
land is deforested to
grow crops for which
biofuels can be made.
Some land is
deforested to grow
more food. Some land
is deforested and
turned into cattle
ranches. Some are
deforested for land
and resources.
Biogas is made of
mostly methane, it
can be produced by
anaerobic
fermentation using
a wide range of
organic or waste
material containing
carbohydrates.
Many different organisms are involved in
the digestion of waste material. Waste from
sugar or sewage factories can be used to
provide large amounts of biogas-Biogas
generators can supply the energy needs of
individual families or farms.
Mycoprotein is a meat-free,
high quality protein suitable
for vegetarians. It is produced
by the fungus "fusarium"
which is grown on glucose
syrup in aerobic conditions.
The biomass is then harvested
and purified
Every stage in a food chain loses
energy and is contained in the
biomass of the organisms. Since the
loss of energy and biomass is due to
heat loss, waste and movement, we
can improve the efficiency of food
production by reducing the number
of stages in a chain.
You can input more
energy into an
animal by restricting
the amount of
which it can move,
meaning less energy
is lost
Fish stocks in the ocean are
declining, this is due to
overfishing in order to meet
increasing demands for food.
It is important that we
maintain fish stocks at a level
where breeding can continue,
failure to do this can lead to
certain species disappearing