Control Centre of the Nervous
System- The brain

What are
the
functions of
the
different
parts of the
brain?
Body Systems
Frontal lobe

The frontal lobes are part of the Cerebral Cortex and are
the largest of the brain's structures.

They are the main site of so–called 'higher' Cognitive
functions – involved in attention and thought, voluntary
movement, decision–making, planning, problem–solving,
thinking, voluntary motor control, cognition, intelligence,
attention, language processing and comprehension, and
many others..
Parietal lobe

The parietal cortex plays an important role in integrating
information from different senses to build a coherent
picture of the world. It processes what things are and
where things are. This allows us to coordinate our
movements in response to the objects in our
environment.

The parietal cortex processes attentional awareness of
the environment, is involved in manipulating objects, and
representing numbers.
Occipital lobe

The occipital cortex is the primary visual
area of the brain. It receives projections
from the retina from where different
groups of neurons separately encode
different visual information such as color,
orientation, and motion.
Body Systems
Temporal lobe

The temporal lobes contain a large
number of substructures, whose
functions include perception, face
recognition, object recognition, memory
acquisition, understanding language,
and emotional reactions.
Cerebellum

The cerebellum monitors and regulates motor behavior,
particularly automatic movements.

Associated functions: coordination of voluntary
movement, motor–learning, balance, reflex memory,
posture, timing, sequence learning.
Brain Stem

The brain stem plays an important role in maintaining
homeostasis by controlling functions such as breathing, heart
rate, digestion, perspiration, temperature and blood pressure.

The brain stem can organize motor movements such as reflexes,
it coordinates fine movements of limbs and the face, balance,
alertness and has a sleep function.
Sides of the Brain

The right side is responsible for artistic and musical
ability, intuition and perception. The left takes care of
language, learning mathematics and logical thinking.
Body Systems
Reflex Action

When a receptor is stimulated, it sends a signal to the central nervous
system, where the brain co-ordinates the response.

But sometimes a very quick response is needed, one that does not need the
involvement of the brain.

This is a reflex action.
Reflex Action

Reflex actions are rapid and happen without us thinking.

For example, you would pull your hand away from a hot flame without
thinking about it.

This is what happens:
Reflex Action
receptor detects a stimulus change in the environment
sensory neuron sends signal
to relay neuron
motor neuron sends signal to
effector
effector produces a response
Nervous System Damage

With nerve damage there can be a wide array of
symptoms, depending on the location and type of
nerves that are affected.

Damage can occur to nerves in your brain and
spinal cord.

It can also occur in the peripheral nerves, which
are located throughout the rest of your body.
Nervous System Damage

Autonomic nerve damage may produce the following
symptoms:

Inability to sense chest pain, such as angina or heart attack

Too much sweating or too little sweating

Lightheadedness

Dry eyes and mouth

Constipation

Bladder dysfunction

Sexual dysfunction
Nervous System Damage

Damage to motor nerves may produce the following
symptoms:

Weakness

Muscle atrophy

Twitching

Paralysis
Nervous System Damage

Sensory nerve damage may produce the following symptoms:

Pain

Sensitivity

Numbness

Tingling or prickling

Burning

Problems with positional awareness
The cells of multicellular
organisms cannot survive
independently.
They depend on each other and
work together. Working
together requires
organisation, coordination and
control.
The internal environment in which your cell lives
needs to be kept constant.
Temperature, pH, amounts of micronutrients,
glucose, water and carbon dioxide need to be
within a particular range.
Maintenance of this constant internal
environment is called homeostasis.
Stimulus–response model
For an organism to maintain homeostasis, any
changes or variations in its internal environment
need to be detected.
 changes or variations are called stimuli
 the body utilises receptors to detect changes
within its immediate environment
If a response is needed to any threats this is
communicated to effectors to bring change or
correction so the conditions can be brought back to
normal.
Receptors
- These are special type of cells that help identify
changes inside and outside your body
- These are located in sense organs such as your
eyes, ears, nose, tongue and skin.
Effectors
- These are muscles or glands which receive messages
from the brain to respond to any stimulus.
The response that is effected depends on the
original stimulus.
For example,
- If you feel a fly near your head, the muscles in
your arm may gently move to move it away.
- If your hand touches a very hot surface then
muscles in your arm may respond in a severe
manner to move your hand quickly away from it.
How the ear works
 Stimulus:
sound
 Receptor: mechanoreceptors
The inner ear is made up of two
parts:
 one involved with hearing, the
cochlea and
 the other with balance, the
vestibular system.
How the ear works
 Stimulus:
sound
 Receptor: mechanoreceptors
(cochlea)
The cochlea is a snailshaped chamber filled
with fluid and lined
with sensory receptors
in the form of tiny
hair cells.
How the ear works
 Stimulus:
sound
 Receptor: mechanoreceptors
(cochlea)
 Control
centre:
the brain
The cochlea is attached to the
auditory nerve that lead sound
signals to the brain.
How the ear works
 Stimulus:
sound
 Receptor: mechanoreceptors
(cochlea)
 Control
centre:
 Effector:
the brain
A muscle or gland that is
activated to the stimulus
 Response: we turn our head to the sound
Negative feedback
- occurs when the response is in an opposite
direction to the stimulus.
For example
- If levels of glycose in the blood were too high, then
the response would be to lower the level.
- Likewise, if the level of glucose is too low, then the
response would be to increase this level.
Science Info:
The regulation of glucose levels in your blood involves
negative feedback.
If an increase in blood glucose levels has been detected
by receptors, the pancreas responds by secreting insulin.
This may trigger an increased uptake of glucose by liver
and muscle cells and the conversion of glucose
into glycogen for storage.
This lowers the blood glucose levels.
Positive feedback
Whereas negative feedback involves a response in an
opposite direction to the stimulus, positive feedback
results in the response going in the same direction.
An example of a positive feedback
mechanism is blood clotting.
Once a blood vessel is damaged, platelets
start to cling to the injured site and
release chemicals that attract more
platelets.
The platelets continue to pile up and
release chemicals until a clot is formed.
All under control
To work together effectively, all the
body systems require coordination.
The two systems with this
responsibility are the nervous
system and the endocrine
system.
These systems require
signalling molecules to
communicate messages
throughout the body, but they
operate differenty to each other.
Nervous system
The nervous system is composed of:
 the central nervous system
(brain and spinal cord) and
 the peripheral nervous system
(the nerves that connect the
central nervous system to the
rest of the body).
Nervous system
Messages are taken to the central
nervous system by sensory
neurons and taken away from it
by motor neurons.
The nervous system sends
messages as electrical impulses
along a neuron and then as a
chemical messages
(neurotransmitters) across the
gaps (synapses) between them.
Endocrine system
 The endocrine system is
composed of endocrine glands
that secrete chemical substances
called hormones into the
bloodstream.
These chemical messages are
transported throughout the
circulatory system to specific cells
in which they bring about a
particular response.
Temperature Control
an example
of how the
nervous and
endocrine
systems work
together.
 thermoregulation
Part of your brain called the
hypothalamus contains a region
that acts as your body’s
thermostat. It contains
thermoreceptors that detect the
temperature of blood that flows
through it.
If your body temperature
increases or decreases from within
a particular range, messages from
thermoreceptors in your skin or
hypothalamus trigger your
hypothalamus to send messages to
appropriate effectors.
The effectors
then bring
about a
response that
may either
increase or
decrease body
temperature.