1. Nervous Tissue
Ch 11

2. Organization of the Nervous System

3. Anatomical Divisions of the Nervous System
Enteric Nervous System
gut
Central Nervous System (CNS)
brain
spinal cord
Peripheral Nervous System (PNS)
cranial nerves (12 pr)
spinal nerves (31 pr)

4. CNS
PNS

5. Enteric Nervous System
Myenteric plexus
Submucosal plexus

6. Function of the Nervous System
sensory input
motor input
sensory receptor
effector
Function of the Nervous System
integration

7. Neuroglia of CNS Astrocytes Ependymal Cells
Regulate extracellular brain fluid composition
Promote tight junctions to form blood-brain barrier
Ependymal Cells
Line brain ventricles and spinal cord central canal
Help form choroid plexuses that secrete CSF

8. Neuroglia of CNS Microglia Oligodendrocytes Specialized macrophages
Form myelin sheaths if surround axon

9. Neuroglia of PNS Schwann cells Satellite cells
Wrap around portion of only one axon to form myelin sheath
Satellite cells
Surround neuron cell bodies in ganglia, provide support and nutrients

10. Typical Neuron
Dendrites convey incoming messages to the cell body

11. Myelin Sheath Speed: small, unmyelinated fibers = 0.5 - 2.0 m/sec
large, myelinated fibers = up to 120 m/sec

12. Myelin Sheath

13. Types of Neurons bipolar unipolar multipolar eye, ear, & olfactory
Dorsal root
ganglion cells
multipolar
most abundant type
in CNS

14. Neuron Interaction & Integration
Interaction Between Neurons

15. Resting Potential of an Axon
Negative charge (-70 mV)
Na+ more concentrated in the ECF
K+ more concentrated in the ICF

16. Resting Potential of an Axon

17. Depolarization of the Axon Membrane

18. Action Potential

19. Propagation of an Action Potential

20. Propagation of an Action Potential

21. Propagation of an Action Potential

22. Refractory Period

23. Saltatory Conduction

24. Synapses Ca2+ Presynaptic neuron Postsynaptic membrane
Synaptic vesicles containing neurotransmitters

25. EPSP & IPSP

26. Synapses

27. Neurotransmitters Acetylcholine- slows heart rate; PNS
Glutamate- most prevalent neurotransmitter in the brain
Aspartate- in CNS
GABA- inhibitory neurotransmitter
Glycine- inhibitory neurotransmitter
Norepinephrine- awakening from deep sleep
Epinephrine- increase heart rate
Dopamine- movement of skeletal muscles
Seratonin- sensory perception, temp regulation, mood, sleep
Nitric oxide- may play a role in memory and learning
Enkephalin- inhibit pain impulses by suppressing release of substance P
Substance P- enhances perception of pain
tyrosine

28. Neurotransmitters

29. Types of Circuits in Neuronal Pools

30. Neuronal Circuits Converging circuit same source
Pacinian corpuscles- pressure
different sources
control of respiration
Diverging Circuit
permits broad distribution
of a specific input types
A.  amplification
B.  divergence into multiple tracts

31. Neuronal Circuits Parallel after-charge circuit
several neurons process same information at one time
each chain has a different number of synapses, but eventually they all reconverge on a single output
output neuron may go on firing for some time after input has ceased
important in withdrawal reflexes
longer-lasting output from small period of pain 

32. Neuronal Circuits Reverberating Circuit
axons extend back toward the sources of an impulse and further stimulate the presynaptic neuron
helps maintain consciousness, muscular coordination, normal breathing, short term memory... 

33. Neuron to Neuron Transmission
synapses
Afferent (sensory)
Integration center
Interaction Between Neurons
Efferent (motor)

34. Disorders of the Nervous System
Multiple Sclerosis
Autoimmune disease
Destruction of myelin sheath
Scar tissue may form
Interaction Between Neurons

35. Disorders of the Nervous System
Epilepsy
Rapid synchronous firing of neurons
Seizure
Treatments:
Drugs
Implants
Brain surgery
Interaction Between Neurons

36. INQUIRY What voltage is the threshold potential?
Describe depolarization, repolarization and hyperpolarization.
Which ion causes the neurotransmitters to be released across the synapse?
Name 2 instances that you can stimulate a neuron to depolarize.
What disease is characterized by myelin sheath degeneration?
Can all parts of the CNS regenerate if damaged?