1. THE
NERVOUS
SYSTEM

2. Why Do Animals Need a Nervous System?
Because the world is always coming at you!

3. Many animals have nervous tissue, but mammals have the most organized and efficient nervous system.

4. Nervous System Central nervous system Peripheral nervous system
cerebrum
cerebellum
spinal cord
cervical
nerves
thoracic
lumbar
femoral
nerve
sciatic
tibial
Central nervous system
brain & spinal chord
Peripheral nervous system
nerves from senses
nerves to muscles

5. Nerve Cells Neuron building blocks of the nervous system
sends signals so your body can respond to the environment

7. Labeling A Nerve Cell 1. Cell Body 2. Nucleus 3. Dendrites
9. Terminal branch
4. Axon
7. Node of Ranvier
5. Schwann cell nucleus
6. Schwann cell
10. Synaptic knobs
8. Myelin Sheath .

9. Fun Facts about Nerve Cells
Most specialized cell in animals
Longest cell
blue whale neuron
10-30 meters
giraffe axon
5 meters
human neuron
1-2 meters
Nervous system allows for 1 millisecond response time

10. Myelin Coating Axon coated with insulation made of myelin cells
controls speed of signal
signal hops from node to node
myelin coating
Multiple Sclerosis
immune system (T cells) attacks myelin coating
loss of signal

11. Each axon may have synapses with up to 1000 other neurons
Junction between nerve cells
Can be electrical or chemical
Each axon may have synapses with up to 1000 other neurons

12. Synapse A chemical synapse involves release of a neurotransmitter.
Neurotransmitters are removed from a synapse by enzymes, or they are reabsorbed from the pre-synaptic neuron.
This is where drugs effect the system.

13. Reflexes
Now that we know about neurons…how do they work in the system as a whole?
They work by reflexes, or automatic response

14. Sensory Neuron - RECEPTORS
Sensory Neuron - neurons activated by sensory input (vision, touch, hearing, etc.), which send external stimuli to the central nervous system 
A receptor is a structure which receives something

15. Interneuron A neuron that forms a connection between other neurons.
These neurons receive signals in the brain and spinal cord.

16. Motor Neuron - EFFECTORS
Neurons that receive signals from the brain to perform motor functions.
Movement
Twitch
Run/Walk/Etc
The effectors are the organs which respond to the signals

17. Video sensory neuron (from senses) interneuron (brain & spinal cord)
motor neuron
(to muscle)
Video

18. Simplest Nerve Circuit
Reflex, or automatic response
rapid response
automated
signal only goes to spinal cord
no higher level processing
advantage
essential actions
don’t need to think or make decisions about
blinking
balance
pupil dilation
startle

19. Testing Your Reflexes - Video

20. Nerve Potential
Nerve cells use IONS to function.

21. Nerve Potential
Membrane Potential – difference in electrical charge (caused by ions) across cell membrane.
How many ions on each side?
Action Potential – causes a nerve impulse – uses ions
Resting Potential – membrane potential of a neuron at rest, neuron not working – but can when needed (all or none response).

23. HUMAN
BRAIN

24. Human Brain

25. People in “vegetative” states only use their primitive brain.
The “lower brain”
medulla oblongata
pons
cerebellum
Functions
basic body functions
breathing, heart, digestion, swallowing, vomiting
homeostasis
coordination of movement
People in “vegetative” states only use their primitive brain.

26. Higher Brain Cerebrum 2 hemispheres left = right side of body
right = left side of body
The right side of your brain perceives and controls the left side of your body
Left side of brain perceives and controls right side of your body

27. Higher Brain Corpus callosum connection between 2 hemispheres
These two sides work together. It’s difficult to use only one side of the brain. For example: Have your right hand tap your head while your left hand rubs your stomach
Corpus callosum
connection between 2 hemispheres
When your corpus callosum is severed, you can use each half of the brain independently

28. Division of Brain Function
Left hemisphere
“logic side”
language, math, logic operations, vision & hearing details
fine motor control
Right hemisphere
“creative side”
pattern recognition, spatial relationships, non-verbal ideas, emotions, multi-tasking

30. Activity – Left or Right Test
Clockwise = Right Dominant
Counter-Clockwise = Left Dominant
Lets take a Paper Test to see if this is TRUE…

31. Cerebrum Specialization
55555 Test
Cerebrum Specialization
Regions specialized for different functions
Lobes
frontal
speech, control of emotions
temporal
smell, hearing
occipital
vision
parietal
speech, taste reading
frontal
parietal
occipital
temporal

32. Memory Loss and Amnesia is due to Limbic System Damage
Controls basic emotions (fear, anger), involved in emotional bonding, establishes emotional memory
Memory Loss and Amnesia is due to Limbic System Damage

33. Attention Video Speaking of Memory….
Do you really pay attention? How much stuff do you miss when you think you’re observing carefully…
Attention Video

34. The Ear
Your ears convert sound waves into electrical signals that are interpreted by your brain
The cochlea is the auditory portion of the inner ear. It is shaped like a snail shell.
Bones of the ear:
Anvil
Hammer
Stirrup

35. The Eye
Eyes enable us to see in color and to distinguish fine details and movement.
The retina is the lining on back inner surface of the eye – consists of photoreceptors.
The optic nerve exits the back of the eye and connects in the brain to the thalamus. It contains many neurons that process visual information.
Rods - respond to dim light and black and white shading.
Cones- respond to bright light and enables the sight of the colors.

36. The Eye
Lens
Cornea
Iris
Pupil

38. The Tongue

39. Optical Illusions