Transcript The Nervous system

The Nervous
system
By Amber Henry and Sarah-Jade
Mckillop.
The
Nervous
system
The Eye
How does it work??
Light enters the eye through the cornea, in dim light,
•
the pupil expands to allow more light in and in bright
light,. the pupil contracts to allow less light in to the eye.
The light then passes through the lens, causing it to
converge and cross. The lens can change shape
depending on the distance of the object from the eye.
When the light reaches the retina, the rods and cones
convert the image into an electrical signal, The brain
analyses the information and interprets the signals as
light. The brain then reverses the image and, if
necessary, fills in the blind spot, leaving the image of
what we see through our eyes in our brain.
The Brain…
How it works??
• It is a network that controls and coordinates all the
activities by transmitting messages or signals from the
brain to the different regions of the body and vice versa.
It works with the help of nerves or neurons, which
conduct the signals or impulses between the two
components of the nervous system
The brain in turn processes these stimuli and sends them
back to the other parts of the body telling them to react to
a particular type of stimulus. The motor neurons are
responsible for receiving signals from the brain and
spinal cord and transmitting them to the other organs of
the body.
•
•
•
The human brain can be divided into three parts,
forebrain, midbrain and hindbrain,.
The forebrain consists of the cerebrum, which is the
largest part of the brain and is the center of
intelligence, memory, emotion, personality, speech and
the ability to feel.
The inner part consists of the thalamus, hypothalamus
and pituitary gland. The thalamus transmits the
messages from the sensory organ to the cerebrum.
while the hypothalamus is responsible for regulating
pulse, appetite and automatic processes
• The midbrain is located underneath the middle
of the forebrain and sends messages or
impulses coming to and from the brain. On the
other hand, the hindbrain, which is located
below the back end of the cerebrum, consists of
the cerebellum, pons and medulla. The
cerebellum controls movement and balance,
while the pons and the medulla coordinate
messages and automatic functions like
breathing, heart rate, digestion and blood
pressure
Neurons.
Nervous system
• The nervous system is a network of cells
called neurons which transmit information
in the form of electrical signals. Your brain
has about 100 billion neurons, and each
communicates with thousands of others –
as many connections as in the internet,
the biggest connection on the planet.
Neurons communicate with each other by
chemicals moving across the gap between
them.
Neurons-transmit info to the brain
Depression
• depression of the central nervous system that
can result in decreased rate of breathing,
decreased heart rate, and loss of consciousness
possibly leading to coma or death.
means slowing down of the nervous system. Nervous
system depression causes things like slowed heartbeat,
dulled mental ability, and slow reflexes. Some drugs and
medical conditions can cause this. Sedatives are one
medication that causes depression of the nervous
system.
Pain killers
• When part of your body is injured, special
nerve endings send pain messages back
to your brain. Painkilling drugs interfere
with these messages, either at the site of
the injury, in the spinal cord or in the brain
itself. Many painkillers are based on
aspirin and opiates.
Thank You!!!
http://www.sciencemuseum.org.uk/WhoAmI/FindOutMore/Yourbrain/Howd
odrugsaffectyourbrain/Howdopainkillerswork.aspx.
http://kidshealth.org/parent/general/body_basics/brain_nervous_system.ht
ml
http://en.wikipedia.org/wiki/Nervous_system