Transcript The Nervous System

The Nervous
System
JORDIE SMELLS LIKE FEET IN THE
SUMMER ON A HOT DAY BECAUSE
HE LIKES TO EAT “HOTDOGS” ALL
THE TIME.
Organization of the body
 The levels of organizations in a
multicellular organism goes as follows:
 Cells, tissues, organs and organ
systems.
 There are 11 organ systems that help
maintain homeostasis.
Homeostasis
 It means to keep things in balance.
 Homeostasis keeps internal conditions
relatively constant despite change to
external environments.
Feedback Inhibition
 The process in which the stimulus
produces a response that opposes the
original stimulus.
 Systems controlled by feedback inhibition
are generally fully automated and very
stable.
 Ex: Like a thermostat.
The Actual Nervous
System
 The nervous system controls and
coordinates function throughout the body
and responds to internal and external
stimuli.
 The messages carried by the nervous
system are electrical signals called
impulses.
 These cells are called neurons. 
CONTINUED
 The largest part of a typical neuron is the cell
body, it contains the nucleus and much of the
cytoplasm.
 The dendrites which are attached to the cell
body, carry impulses from the environment or
other neurons to the cell body.
 It is then carried away from the cell body
through a long fiber called the AXON. 
CONTINUED AGAIN
 The axon is surrounded by the myelin
sheath.
 The myelin sheath basically increases
the speed at which a impulse can travel.
The Synapse
 The synapse is the location at which a
neuron can transfer an impulse to
another cell.
 NEUROTRANSMITTERS are chemicals
used by a neuron to transmit an impulse
across a synapse to another cell. 
Central Nervous System
 It relays messages, processes information &
analyzes information.
 It consists of the brain and spinal cord. 
 Cerebrospinal fluid bathes the brain and spinal
cord and acts as a shock absorber to protect
the central nervous system!
 It allows for exchange of nutrients and waste
products between blood and nervous tissue. 
The Brain
 Pinky and the Brain are awesome. 
 The cerebrum is the largest part of the
brain, its responsible for intelligence,
learning, and judgment.
Still part of the Brain
 The cerebellum is the second largest part
of the brain.
 It coordinates and balances the actions
of the muscles so the body can move
efficiently.
More Brain Parts
 The Brain Stem connects the brain and
spinal cord.
 It regulates the flow of information
between the brain and the rest of your
body.
 Blood pressure, heart rate, breathing &
swallowing are controlled by the BRAIN
STEM! 
The other part of the
central nervous system
 The spinal cord is the main
communication link between the brain
and the rest of the body.
 A reflex is a quick automatic response to
a stimulus such as SNEEZING and
BLINKING. 
 I know you all blink.
The Peripheral Nervous
System
 It is divided up into the sensory division
and motor division.
 Sensory division takes care of the
senses, such as smell, seeing, hearing,
feeling and taste.
 Motor division takes care of movements,
such as thrusting and walking.
The Somatic and
Autonomic System
 The somatic system
is anything you have
conscious control
over.
 Such as, moving you
finger around, and
wiggling your tongue
unbelievably fast.
 The autonomic
system is anything
you DON’T have
conscious control
over.
 Such as breathing
heavily and blinking.
The Eye
 It sees stuff.
 Light enters the eye through the cornea,
the cornea helps focus the light which
then passes through the chamber filled
with fluid called the aqueous humor.
 At the back of this chamber is the iris, the
color part of the eye with an opening
called the pupil.
More Eye Stuff
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There are two types of photo receptors.
Rods.
Cones.
Rods are extremely sensitive to light but
they do not distinguish different colors.
 Cones are less sensitive then rods but
they do respond to light of different colors
producing color vision.
Drugs
 Stimulates increase heart rate, blood
pressure, in addition stimulates increase
the release of neurotransmitters at some
synapse in the brain.
 Depressants slow down heart rate,
breathing rate, lower blood pressure,
relax muscles and relieve tension.
More Drugs
 COCAINE causes sudden release in the
brain of neurotransmitters called
dopamine.
 Opiates mimic natural chemicals in the
brain known as endorphins, which
normally help to overcome sensations of
pain.
THE END
By: Sassie and Sierra and then
Jordie.