Presentation is loading. Please wait.

Presentation is loading. Please wait.

Nervous System The excitable highway.

Similar presentations

Presentation on theme: "Nervous System The excitable highway."— Presentation transcript:

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

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

Download ppt "Nervous System The excitable highway."

Similar presentations

Ads by Google