16.1.1 Interpretation of Signals

Topic 16: Interpretation of Signals
Biology in Focus, HSC Course
Glenda Childrawi, Margaret Robson and Stephanie Hollis
DOT Point(s)
 explain, using specific examples, the importance of correct
interpretation of sensory signals by the brain for the
coordination of animal behaviour
It is very important for correct interpretation of signals by the
brain for the coordination of animal behaviour. Stimuli must be
received and transmitted to the brain or spinal cord before being
interpreted and a response given.
A variety of reasons can cause a ‘short circuit’. Here are a few:
1. Lack of stimulus
2. Trauma
3. Lack of oxygen
4. Legal/illegal drug reaction
5. Disease
6. Pollution
7. Age related damage or deterioration
Multiple Sclerosis
MS is a autoimmune disease
in which there is an
immune attack by the body
on its own myelin protein.
Gradually the myelin
sheaths in the central
nervous system are
destroyed and become hard
substances called scleroses.
Multiple Sclerosis
As the insulating layer becomes non-functional, the impulses are
short circuited and finally conduction of the impulse ceases. Some
common symptoms include: problems controlling muscles
(weakness, clumsiness, urinary incontinence) and visual
disturbances (including blindness).
Alcohol, anaesthetics and sedatives
These can all impair the transmission of messages. They all block
nerve impulses by reducing the plasma membrane’s permeability
to sodium ions. If there is no sodium (Na+) entry, there is no
action potential-no nerve impulse.
Alcohol, anaesthetics and sedatives
Some common symptoms
include: poor coordination of
movements, lack of
concentration, retarded reflexes,
tiredness, blurred vision and
slurred speech.
Cerebral Palsy
Cerebral palsy may be caused by a temporary lack of oxygen to a
baby during a difficult delivery. Cerebral palsy is a neuromuscular
damage, to which the voluntary muscles lack coordination due to
brain cell damage.
Cerebral Palsy
The brain cells are unable to
transmit a message to the
muscles and as a result the
muscles can not be voluntarily
controlled. Some common
symptoms include: impairments
in movement, speech, hearing
and vision.
Rubella is also known as German measles. It is caused by the
rubella virus. The disease causes a fine rash, fever and sometimes,
upper respiratory tract infection. No more trouble than the
common cold.
If however, a woman contracts
rubella in the first three months
of pregnancy, the virus may pass
through the placenta to the
developing baby. Damage to the
brain and spinal cord leads to a
lack of transmission of nerve
signals to various organs. The
baby could then be affected by
rubella congenital syndrome.
Some common symptoms
include: cataracts, congenital
glaucoma and retinopathy of
the eye, loss of hearing,
congenital heart disease, as well
as problems with development
of the brain, spinal cord,
spleen, liver and possibly
Age-related Damage or deterioration
The human brain reaches its maximum size in young adulthood.
From then on the neurones may be damaged and die, contributing
to a gradual loss of weight and volume of the brain. In total, the
change is minimal.
Age-related Damage or deterioration
Some common symptoms include: decline in reaction time and
speed of decision making together with loss of memory.
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