The Human Body
A body system is a collection of parts able to
work together to serve a common purpose –
growth, reproduction and survival.
Each part of a system depends on the other
parts to perform tasks that can’t be achieved
by single parts acting alone.
Each individual system works in conjunction
with other systems to improve our chances of
survival by maintaining a stable internal body
environment. This stable environment is known
as homeostasis. http://www.sciencelearn.org.nz/Science-Stories/Our-Senses/Body-systems
• Your body uses the glucose from the food you
digest as a source of energy.
• Glucose reacts with oxygen to produce energy
– this process is called respiration.
Glucose + Oxygen Carbon Dioxide + Water + Energy
The dissolved food and oxygen required for
respiration are carried around the body by the
• When you inhale your body is taking in the
oxygen required for respiration.
• When you exhale your body is removing the
waste product of respiration – carbon dioxide.
• Left side of the heart pumps oxygen rich
blood to the body.
• Oxygen poor blood travels from the body to the
rights side of the heart.
• The right side pumps the oxygen poor blood to
• Oxygen rich blood returns to the left side of the
• Called double circulation because during a single
circuit of the body blood passes through the
• Saliva is an enzyme.
• Enzymes speed up reactions.
• Different enzymes
– Carbohydrases digest carbohydrate
– Proteases digest protein
– Lipases digest fats (lipids)
• Mouth – teeth, tongue and saliva
• Swallow – food moves to the pharynx (back of
• The epiglottis covers the trachea (to the lungs)
• Food travels to stomach – containing hydrochloric
acid (mucus protects stomach lining)
• Large molecules are digested
to produce small soluble
molecules that can be
absorbed by the blood.
• Particles travel from the stomach to the small
• Gastric juices are very acidic – mucus and bile
stop the acid from damaging the lining of the
• Bile is produced in the liver.
• The liver, gall bladder, pancreas and small
intestine are all important for fat digestion.
• The small intestine is where to absorption of
useful molecules occurs.
• The molecule pass across the lining of the
small intestine and enter the blood stream.
• The food that enters the
large intestine (colon) is
waste material and
• The blood reabsorbs the
• The waste material
passes to the rectum.
• From here the faeces
passes out through the
• The human body is made up of trillions of
• Cells of the nervous system, called nerve cells
or neurons, are specialised to carry
"messages" through an electrochemical
process. The human brain has approximately
100 billion neurons.
• Neurons have specialised projections called
dendrites and axons. Dendrites bring
information to the cell body and axons take
information away from the cell body.
• Information from one neuron flows to another
neuron across a synapse.
• Communication of information between
neurons is accomplished by the movement of
chemicals across a small gap called the
• Chemicals, called neurotransmitters, are
produced at the end of a neuron’s axon. They
carry the impulse across the
synapse to the next neuron.
Peripheral Nervous System
From Spinal cord to the rest of your body.
• Sensory Neurons - Relay messages from
receptor to the brain or spinal cord.
• Motor Neurons - Relay messages from the
brain or spinal cord to muscles and organs.
• Interneuron - Connects the various neurons
within the brain and spinal cord.
• The kidney plays a central
role in homeostasis,
forming and excreting
urine while regulating
water and salt
concentration in the
• It maintains the precise
balance between waste
disposal and an animal's
needs for water and salt.
Ammonia, the nitrogenous
waste product from protein
metabolism in cells, is highly
toxic and needs to be
removed as quickly as
possible or converted to a
less harmful form.
Aquatic animals, fish and invertebrates mostly
excrete ammonia. Ammonia is toxic, but can be
released continuously (out of respiratory
structures such as gills) and directly into the
On land, however, animals need to conserve
water. By converting ammonia into less toxic
forms, they can hold it for longer in the body
and excrete it periodically.
Internal structure of the kidney
• Mammals have two kidneys.
• Each kidney is made up of about one million
small filtering units called nephrons. It is in
these structures that urine is produced.
The formation of urine - the kidneys
continuously process an enormous volume of
blood to form a small volume of urine. There are
three processes in the formation of urine:
filtration, reabsorption and secretion.
• Coordinates the body's organs so they are
• This system is based on the production of
hormones – chemical messengers.
• Hormones are produced by
glands that are located in
different parts of the body.
• Hormones are responsible for coordinating
long-term processes such as growth and
• Diabetes results from blood sugar levels being
• Blood sugar is regulated by the hormone
insulin that is produced in the pancreas.