The respiratory system supply’s the cell by breathing in air
throw the nose and mouth, down the pharynx, it continues down the larynx to the
trachea. The airway divides in two tubes called bronchi which lead to the lungs,
these divide into smaller tubes called bronchioles which end in alveoli.
The alveoli filled with air go through a process called
diffusion which passes the oxygen from the air into the blood stream through
capillaries. Once in the blood stream the oxygen is picked up by haemoglobin in
the red blood cells, it is pumped through the arteries to tissues throughout
Oxygen is released from the haemoglobin and moves into the
cells. CO2 is produced as the oxygen is diffused and converted into plasma of
The CO2 is passed into the blood stream and past out of the
body in a reverse cycle.
b) the cardiovascular system pumps nutrients and oxygen to
all cells within the body. There are two circulatory systems in the body and
are both connected;
1) the systemic circulation provides the organs, tissues and
cells with oxygenated blood and other substances throughout the body and
deoxygenated blood is pumped back to the heart.
2)pulmonary circulation is the deoxygenated blood that has
come from the systematic circulation being pumped to the lung to be
re-oxygenated and pushed back to the heart to start the cycle over.
The way the nutrients and oxygen get into the organs,
tissues and cells is through the capillary’s, the exchange of substances
includes water, oxygen and glucose into the cells. Leaving the cells are water,
carbon dioxide, uric acid, lactic acid, urea and creatinine.
c) the gastrointestinal system receives nutrients by
breaking down complex substances into simple molecules. The carbohydrates get
broken down into sugars and glucose and passed into the blood stream, used or
stored as energy in the liver as fat or glycogen these can be converted back
into energy when required. Glycerol is used for energy and converts fatty acids
into fat that can be stored.
Fatty acids are used to drive the release of energy.
Proteins are broken down into amino acids.
Catabolism breakdown complex substances into simple ones
which release energy. This breakdown of substances can be used in the cells
through cellular respiration and produce ATP, which is a high-energy molecule.
Anabolism creates proteins from simple molecules, the process requires energy
The body thermoregulation is done by the hypothalamus. Any
changes in the body temperature internal or external will trigger a response to
try and reset the body’s temperature back to normal. The hypothalamus regulates
temperature by adjusting the endocrine (hormonal) system and nervous system. It
does this by receiving information about the body’s temperature from areas of
the skin and other regions of the body. The hypothalamus will stimulate the
thyroid gland to release thyroxine witch increases metabolism. All this creates
an important thermogenic response throughout the body and if the body was too
warm it would decrease metabolism keeping the body in homeostasis.
The body’s homeostasis temperature is important because enzymes
in the body break down nutrients, these work at optimum temperature which is 37
degrees in humans, if the temperature increases it denatures enzymes as they
are proteins and become soluble at higher temperatures, whereas lower
temperatures start to deactivate enzymes altogether shutting down the body’s
ability to process nutrients.
When the body’s temperature changes, the central nervous
system sends out messages to the hypothalamus. This triggers signals to various
organs and systems in the body. When it gets too hot, the body realises sweat
through sweat glands on the skin, which cools the skin as it evaporates of the
body. This intern lowers the body temperature. If the body’s temperature rises
due to physical activity but the environment is cool, it could lead to the
enzymes shutting down and hypothermia setting in.
Vasodilation is another way the body reduces temperature.
The blood vessels widen, this increases blood flow to the extremities and to
the skin, releasing heat through heat radiation.
If the body’s cold and needs to warm up, the body uses
vasoconstriction, the blood vessels constrict and narrow, decreasing blood flow
to the body’s extremities and further from the skin, keeping the heat from
Thermogenesis is the body’s organs, muscles, and brain
producing heat. One of the ways this is achieved is through shivering. This
produces heat by converting chemical energy ATP, into kinetic energy causing
energy to show up as heat.
Homeostasis keeps the body’s environment in-balance and
perfect conditions for cells to live and function. Enzymes speed up chemical reactions
that a cell depends on to stay alive and carry out its job. This work best at particular
temperatures, so homeostasis is vital to cells as it maintains a constant body temperature.