Transcript Nervous System

Nervous
System
Chapter 20 Section 1
You will learn
 To
describe how the body’s senses
help monitor the environment.
 To explain how the sensory organs
respond to stimuli
 To describe how the nervous system
works with other body systems.
 To infer possible connections
between taste buds and sensitivity
to flavors.
Close Your Eyes
 With
your eyes closed smell the
aroma I put in front of you.
 Keep your eyes closed until I tell you
to open them.
 What
did it smell like?
 How did you know what the smell
was?
Senses connect the human body to
its environment!
 To
maintain
homeostasis your
body constantly
monitors the
environment.
 Your sense organs
(eyes, ears, skin,
tongue, nose) are
responsible for
monitoring: Sight,
smell, touch, hear,
and taste
Senses
Each
sense can detect a
specific type of change in the
environment.
Pain, Pressure, and Temperature
are sensed through what sensory
organ?
A Stimulus
The
sound of the
horn is known as
a:
Stimulus- A
change in your
environment that
you react to, such
as smell, taste,
sound, feeling, or
sight.
Sight
Light
rays enter the eye through the
pupil
They are bent by the cornea (also
protects the eye)
The lens helps focus light.
The pupils change size. Large in dim
light. Smaller in bright light.
Sight
 At
the back of the
eye, the light strikes a
layer called the
retina.
 There
are two types
of cells in the Retina:
 Rods-detects
brightness
 Cones-Sensitive to
color
 These are called
photoreceptors
Hearing
 Your
ears detect sound waves produced by
vibrations
 Sound waves are enter the auditory canal.
The canal ends at the eardrum. The
eardrum vibrates when sound waves hit it.
 These vibration are sent through bones
called the hammer, anvil, and stirrup to the
inner ear.
 Cells in the cochlea detect the vibrations
and send a message to the brain
 RECAP: Auditory Canalear
drumHammerAnvilStirrupCochlea
Hearing
Semi-Circular
Canals: help keep the
body’s balance!
External ear: what you see on the
outside
Auditory nerve: carries sound
vibrations to the brain
Hearing
Touch
You
touch with
tiny receptors in
the skin.
Nerves at the top
of the skin detect
textures.
Nerves deeper in
the skin detect
pressure.
Other receptors
sense hot and
cold.
Smell
 Detects
Chemical Information
 In the back of the nose, there is a patch of
tissue where hairlike fibers covered in mucus,
 Molecules enters your nose, stick to the
mucus, and bind to the receptors in the
hairlike fibers
 The receptors sends an impulse to your brain,
and you perceive the scent.
Taste
Chemical
process
Your tongue is filled with
sensory structures known as
taste buds. They are also
found in the throat and roof
of your mouth.
Taste
 Each
taste bud
contains 100
sensory cells.
 They detect sweet,
sour, bitter, and
salty tastes.
 Taste is also due to
smell.
Central Nervous System
 Consists
of the Brain and Spinal Cord
 Communicates with nervous system
through electrical signals sent through
nerve cells.
 Travel 90 meters per second
 This is like you running the length of an
entire soccer field in a second!
Brain
 Adult:
Contains 100
billion nerve cells
called neurons.
 Controls both
Voluntary and
Involuntary
behavior
 Neurons
communicate
within the brain
Parts of the Brain
 Cerebellum:
controls balance
and coordination
 Cerebrum:
controls
memories,
thoughts, and
sensory organs
 Medulla: controls
involuntary
movement
Medulla
Medulla Oblongata: Part of the
Brain the Controls Anger and
Aggression
http://www.bing.com/videos/search?q=Waterboy+medulla+oblongota+vide
o+clip&view=detail&mid=F1C6648DCA58ACC71079F1C6648DCA58ACC
71079&first=0&FORM=LKVR
Spinal Cord
 Main
pathway for
information from the
brain to other parts
of the body
 Protected by the
vertebral column
 31 pairs of nerves
sends sensory
impulses into the
spinal cord and then
sends them to the
brain.
Peripheral Nerve System
Includes
Sensory and Motor Nerves
Sensory nerves- receive information
from the environment (hot or cold)
and pass information to the Central
Nervous System
Motor Nerves- sends signals from you
brain to your muscles
The Autonomic Nervous System
Controls
the movement of the
heart, the smooth muscles in the
stomach, the intestines, and the
glands. (involuntary)
It
conserves energy
Responds quickly to changes
(Fight or Flight Response)
Voluntary Nervous System
Monitors
movement and
functions that can be
controlled consciously.
Controls the skeletal
system and muscles that
are responsible for
speech and the senses.
Quiz
Explain
the process by which
you hear sound? (Tell me the
Steps)
What happens to the pupil in
dim light?
Quiz
The
top area of skin is responsible
for sensing what?
What
do you have on your
tongue to help you taste?
Quiz
What
two parts are
included in the central
nervous system?
What is the autonomic
nervous system responsible
for?
Nervous System
Peripheral Nervous System
Central Nervous System
Brain
Medulla
Cerebellum
Spinal
Cord
2 types of
responses
2 types
of nerves
Cerebrum
Sensory:
Receives
information
Temp,
Color,
Pressure,
pain, sound
Motor:
Movement
Michael J. Fox
 http://www.anyclip.com/movies/back-to-
the-future/the-flux-capacitor/