Introduction to nervous system

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Your Nervous System

• Introduction to nervous system

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There are 3 main parts to your Nervous System

• Your Nerves
• Your Brain
• Your Spinal Cord

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Your Nerves

• Your nerves are made of nerve cells that
  transmit messages.
• They carry messages from all parts of your body
  to your spinal cord and brain.
• They carry messages away from your spinal
• cord and brain to all parts of your body.

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• Those nerve cells are called neurons.
• Size-wise, these cells are among the smallest
  cells in your body, but can be the longest cells
  as well. How can this be?
• Cell bodies are small, but axons can be really
  long.

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neuron
Cell Body
Synapse
Axon
Dendrites
Neuron Movie
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Class Activity- Neuron Model

• Here's the most simple model of a neuron I can
  think of...and you don't need any supplies.
• It's your hand! Hold out your arm and spread your
  fingers. Your hand represents the "cell body"
  (also called the "soma") your fingers represent
  "dendrites" bringing information to the cell
  body your arm represents the "axon" taking
  information away from the cell body.

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• The message that is transmitted through neurons
  is called an impulse.
• It enters the neuron through the dendrite and is
  carried away from the cell body through the axon.
• Why are there so many dendrites entering a
  neuron?
• To receive messages from all sides/other neurons

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There are 3 types of neurons
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• An automatic response to a stimulus is known as a
  reflex.
• Most reflexes cannot be controlled consciously
• Why is this a good thing?
• So that you dont have to take time to think
  about it!

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• The path of an impulse when an object moves
  toward your face and you blink in response to the
  stimulusLets say someone throws a ball at you
  and its coming toward your face
• The stimulus is the moving object, which triggers
  a sensory neuron in the eye to send a signal to
  the interneuron in the spinal cord which then
  sends the impulse to the motor neuron which is
  attached to a muscle that makes the eye blink.

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• Neurons dont actually touch each other to
  transmit an impulse. The impulse must move
  across a small space called a synapse in order to
  move from one neuron to another.
• A chemical must be present in this space in order
  for the signal to be transmitted
• The signal will always move in the same
  direction from the dendrite of one neuron to the
  dendrite of the next.

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• There are some diseases in which this signal is
  prevented from moving from one neuron to another.
  
• What might be the symptoms of such a disease?
• Slow reactions to stimulus
• Poor muscle movements or control

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The Reflex
interneuron
Spinal cord
Sensory neuron
Motor neuron
Muscle contracts
Reflex Clip
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Nerves by Brainpop
Nerve Game with Mr. Axon Mr. Dendrite
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The Brain
The Brain by Brainpop
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• Central Nervous System made up of the brain and
  spinal cord
• Peripheral Nervous System made up of all nerves,
  including cranial and spinal nerves

Video Clip
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Your Brain!

• Your brain is made
• up of 3 main parts
• The Cerebrum
• The Cerebellum
• The Brain Stem

Build a Brain worksheet / due 28
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YOUR BRAIN HAS THREE PARTS
The Brain memory
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YOUR BRAIN HAS THREE PARTS
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YOUR BRAIN HAS THREE PARTS
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Brain Clip
CEREBRUM
CEREBELLUM
BRAIN STEM
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SPINAL CORD

• Is an extension of brain stem and is considered
  part of the central nervous system.
• Is made up of bundles of neurons.
• Is about as big around as an adult thumb.
• Is approximately 43 cm in length.
• Contains cerebrospinal fluid. Why?
• To cushion neurons in the spinal cord

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SPINAL CORD

• There are 31 pairs of spinal nerves
• Some are called somatic and control skeletal
  muscles
• Some are called autonomic and control heartbeat,
  breathing, digestion, salivary glands.

Spinal Cord by Brainpop
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Brain Summary

• The Brain

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How good is your short term memory?

• Short Term Memory Test

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Your 5 Senses!

• 1. Sight
• 2. Hearing
• 3. Smell
• 4. Taste
• 5. Touch

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EYES

• You see things because light passes through your
  cornea and is directed on to the retina by the
  lens.

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EYES

• The retina is tissue at the back
• of the eye that is sensitive to
• light
• There are two types of cells found in
• the retina
• 1) CONES--respond to bright light and color.
• 2) RODS--respond to dim light, detect shape
  movement

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EYES

• Light energy stimulates
• impulses in these cells, and
• pass them to the optic
• nerve which carries them to
• the brain.

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EYES

• Your lens in your eye is convex Shape
• What is far-sightedness?
• Eyeball too short/focuses behind retina
• What is near-sightedness?
• Eyeball is too long/focuses in front of the retina

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EYES
SCLERA white part of eye
PUPIL changes size with light
Eyes by Brainpop
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Vision by Brainpop
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Color Deficient
Color Normal
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Lets do a colorblind test!Try to find a circle,
star, and/or square on the Demonstration Card
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• I hope you could see them all because you are
  supposed to see all 3 shapes! Okay now for the
  real test

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Now, can you find circle and triangle in 3
seconds?
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• Colorblind individuals should see the yellow
  square. Color normal individuals should see the
  yellow square and a "faint" brown circle.

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Try and find a circle and/or square in 3 seconds
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• Colorblind individuals should see the yellow
  circle. Color normal individuals should see the
  yellow circle and a "faint" brown square.
• Many people think anyone labeled as "colorblind"
  only sees black and white - like watching a black
  and white movie or television. This is a big
  misconception and not true. It is extremely rare
  to be totally color blind

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The Eye
Human eye and eyesight
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EARS

• Ears have three main sections
• 1) Outer traps sound waves
• 2) Middle eardrum vibrates, moves through bones
  (hammer, anvil, stirrup)
• 3) Inner vibrations cause fluid to vibrate in
  the cochlea and stimulate nerve endings there.

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EARS

• The cochlea is a fluid-filled structure in the
  inner ear that looks like a snail shell.
  Vibrations from sound waves cause the fluid to
  vibrate and stimulate nerve endings there, which
  creates an impulse sent to the brain.

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EARS

• How the nerve endings are stimulated is what kind
  of sound you hear.
• The fluid in the inner ear also controls balance.
• The structures and fluids constantly adjust to
  the position of the head and send impulses to the
  brain to maintain balance.

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EARS
HAMMER, ANVIL, STIRRUP
COCHLEA
OUTER
MIDDLE
INNER
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Your Ears!Brain pop on hearing
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TASTE

• We call the sensory receptors on the tongue
  taste buds.
• You have about 10,000 of them! Some are located
  on the back of the tongue in clumps called
  papillae .

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TASTE
They detect four tastes sweet, sour salty, bitter

BITTER
SALTY/SOUR
SALTY/SOUR
SWEET
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TASTE

• Different parts of the tongue and different taste
  buds respond to different tastes, though some of
  the taste buds can detect more than one or all of
  the tastes.

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TASTE

•   Smell is related to tastein fact if you are
  having trouble smelling, you probably cant taste
  your food.
• Example When you get a stuffy nose food tastes
  bland

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Taste by Brainpop
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SMELL

• Objects give off molecules into the air.
• The nasal passageways are equipped with sensitive
  nerve cells called olfactory cells.
• The cells are kept moist by mucus and stimulated
  by gas molecules that dissolve in the mucus.

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SMELL

• When enough gas molecules
• are present, an impulse is sent
• to the brain
• At the brain, you may
• remember it or create a new
• memoryespecially if it
• stinks!

SMELL by Brainpop
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TOUCH

• Sensory Receptors in
• organs and skin respond
• to touch, pressure,
• pain, and temperature
• and send impulses to
• brain and spinal cord.

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TOUCH
Fingers and Mouths are the most sensitive
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The Endocrine System

• Glands of the endocrine system receive electrical
  messages from the brain and release hormones into
  the blood stream.
• Hormones carry a chemical signal to target
  tissues. These chemical signals may be released
  slowly over long periods of time or may affect a
  tissue immediately and then slowly dissipate.
• Hormones are chemical signals that affect mood,
  growth, blood sugar regulation, tissue function,
  metabolism, digestion, and fight or flight
  response.

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