1. Nervous System
The excitable highway

2. Brainstorm
Groups of 3-4
On Chart Paper, make a mind map of what you know of the nervous system
Thoughts, ideas, knowledge

3. Gallery Walk
Take about 3-4 Minutes to look around at other groups Mind Maps
Bring your group’s marker to add any thoughts or ideas
What do these mind maps look like?

4. Learning Goals Learn the components of a neuron
Differentiate amongst the three different types of neurons

5. Nerve Cell (Neuron) Dendrite: Receivers
Cell Body: Houses the nucleus and the majority of the organelles of the cell
Nucleus: Brain of the cell
Nodes of Ranvier

6. Nerve Cell (Neuron) Axon: Conducts the nerve impulse along the cell
Myelin Sheath: Some neurons are covered in a fatty myelin sheath
Axon Terminals: relay messages to other neurons
Nodes of Ranvier: Gaps where there is no myelin covering

7. Nerve Highway Neurons are the primary component of the nervous system
Nervous system includes the brain, spinal cord and peripheral ganglia
Neurons can be divided into different specialized neurons: Sensory, Motor and Interneurons

8. Different types of Neurons
Split into 3 different groups
Using Chart Paper, describe your group’s designated neuron
Designate a few members to present findings to the class

9. Sensory Neuron Convert external stimulus into an internal stimulus
Stimulated by sensory input (touch, sound, smell, temperature) and send information to the brain
Unlike neurons from the central nervous system, which are activated by other neurons, sensory neurons are activated by a physical sensory input

10. Motor Neuron
Composed of neurons within the CNS, and extend axons out of the CNS, to control muscular contractions
Somatic Motor Neurons: Control skeletal muscular contractions
Visceral Motor Neurons: Innervate cardiac and smooth muscle

11. Interneurons All neurons within the CNS are composed of interneurons
Local connections within specific neurons
Form chain networks and “highways”

12. Recap Neuron/Nerve Cell Structure Sensory Neuron Motor Neuron
Interneuron

13. Learning Goals Understand the concept of an Action Potential
Look at the importance of the Sodium-Potassium Pump

14. How do Neurons transmit a nerve impulse
Nerve Impulse: a message that is sent or convey information along a neuron
Measured using oscilloscope (voltage expressed in millivolts mV – measure of the electrical potential difference between two points)

15. Resting Potential
Voltmeter is attached along the axon of a neuron, we can monitor the difference in voltage
-65 mV
Write on board – Resting Potential -65 Millivolts, higher concentration of K+ inside, higher concentration of NA+ outside, maintained actively by membrane pumps

16. Threshold
Sodium pumps begin to open, changing the flux in gradient

17. Action Potential - Depolarization
Rapid change in polarity across the membrane
All or none principle
Sodium Gates Open
+ 40 mV
All or none - mousetrap
A stronger impulse will trigger the axon potential to occur more often
Sodium flows down concentration gradient

18. Action Potential – Repolarization
Potassium gates open and potassium flows down the concentration gradient
-70mV

19. Refractory Period
After the depolarization period, the axon undergoes a “limbo” period, where the Sodium gates cannot open
This ensures the AP can only move towards the axon terminal
-65 mV

20. DEMO
PHET Neuron

21. Speed of Transmission
In Myelinated axons, gated Sodium-Potassium pumps are concentrated at the Nodes of Ranvier
The action potential skips from node to node, creating a faster action potential
Therefore AP’s travel faster on myelinated axons that non-myelinated axons

22. Recap Nerve Impulse Resting Period Action Potential Refractory Period
Depolarization
Repolarization
Refractory Period
Speed of Transmission

23. Draw an Action Potential Graph
Graph out a Nerve Impulse
Include, stages of an action potential charges, extra/intracellular sodium and potassium levels, Na, K gates,

24. Recap

25. How do Neurons transmit messages
Recall that axons end in branched axon terminals.
Axon terminals are within close proximity to dendrites of other neurons
No physical contact, separated by a gap called the synaptic cleft (synapse)

26. Learning Goals How do neurons send messages amongst each other
Learn a few of the primary neurotransmitters

27. Synapse – Relayed Message
Occurs when an AP reaches the axon terminal
Triggers the influx of Sodium to the terminal
Stimulates vesicles filled with Neurotransmitter to fuse with the synaptic membrane to release the neurotransmitter
Neurotransmitter cross the synaptic cleft and bind to receptors proteins on the post synaptic membrane to trigger Sodium gates to open, causing an action potential to begin

28. Reuptake
Neurotransmitter is either reabsorbed by the presynaptic neuron OR
Broken down by specific enzymes
Acetylcholine > acetylcholinerase

29. Neurotransmitter
Chemicals that transmit signals from a neuron to a target cell across the synapse
Depending on the neurotransmitter, can cause a excitatory or inhibitory response
Acetylcholine (ACh) – responsible for muscular contractions at the neuromuscular junction
GABA – primary inhibitory transmitter in the brain
GABA- amino butyric acid

30. Neurotransmitter Project
STSE – Society, Technology, Science, Environment
Form groups of 2 people
Sign up for a topic on things that may effect neurotransmitters or disorders of the brain
Create a 5-7 minute presentation on your specific topic – Can be a powerpoint, skit, demo, etc…
Include a 1 page (double spaced) write up of your findings – APA format referencing
Presentations on Monday!

31. Example
GOOGLE “MOUSE PARTY” – interactive demo

32. iPad work Period
Use iPad’s to work on project!

33. Learning Goals
Learn the components of the Central Nervous System (CNS)
Understand the functions of the CNS

34. Central Nervous System
Composed of the brain and spinal cord
Sensory information is received, motor initiation begins
Protected by bone – skull and vertebrae
Also cushioned by Cerebrospinal fluid
Lumbar tap – checks cerebrospinal fluid for blood – if a cerebral aneurysm has occurred
Usually CSF drains into cardiovascular system – can get blocked and caused problems – puts pressure on the brain

35. Central Nervous System
Brain contains interconnecting cavities called ventricles, which connect to the central canal of the spinal cord.

36. Spinal Cord Spinal cord is protected by individual vertebrae
Vertebrae are separated by intervertebral discs
If the intervertebral discs are ruptured or moved due to heavy lifting or injury, spinal cord may get injured - hernia

37. Spinal Cord
Grey matter contains sensory neurons, motor neurons and interneurons. Dorsal Root of the spinal nerve contains sensory fibers entering grey matter
Ventral Root contains motor fibers exiting the grey matter
Join before leaving the vertebral column
Ventral and dorsal root join before leaving the vetrebral canal – spinal nerves are part of the PNS

38. Spinal Cord
White matter contains tracts of neurons taking information to or from the brain
Dorsally: Ascending tract to the brain
Ventrally: Descending tract away from the brain
Dorsally: towards the back
Ventral: front of the body

39. The Brain
The brain is composed of: cerebrum, diencephalon, cerebellum, brain stem
Divided into 2 hemispheres
Each hemisphere is composed of the frontal lobe, parietal lobe, occipital lobe, and temporal lobe

40. The lobes
Frontal Lobe: Higher order processes, executive functions and movement
Parietal Lobe: integrating sensory information
Occipital Lobe: Visual processing centers
Temporal Lobe: Auditory perception
Parietal: sensing, tasting

41. The Brain
Gallery Activity -
Cerebrum
Cerebellum
Medulla Oblongata