1. +

2. HUMAN BRAIN = 1 TO 10 TERABYTES OF INFORMATION STORED
HUMAN BRAIN= 100 BILLION NEURONS
SPINAL CORD = 13.5 MILLION NEURONS
HUMAN BRAIN = 1 TO 10 TERABYTES OF INFORMATION STORED
1 TERABYTE= 1024 GIGABYTES
1 GIGABYTE = 1024 MEGABYTES
SO…….
1 TERABYTE = 1,048,576 MEGABYTES

3. Organization of the
Nervous System and the
Neuron

4. Organization of the Nervous System
The Nervous System “maintains body homeostasis with electrical signals; provides
for sensation, higher mental functioning, and emotional response; and activates muscles and glands.”

5. 3 Overlapping Functions of Nervous System
SENSORY INPUT-
INTEGRATION-
MOTOR INPUT-

7. Works with the Endocrine System to maintain homeostasis.
Nervous System-
Endocrine System-

8. Organization of the nervous system can be
based on:
Structural Classification-
A. CNS-
B. PNS-
2.Functional Classification-
A. Afferent-
B. Efferent-

9. STRUCTURAL CLASSIFICATION

10. FUNCTIONAL CLASSIFICATION

12. Nervous Tissue Nervous tissue is made up of two types of cells-
Supporting and Neurons
Supporting cells of the CNS are called Neuroglia or “nerve glue”.
Neuroglia includes many types of cells that generally support, insulate, and protect neurons.

13. Types of Neuroglial cells-
Astrocytes-
Microglia-
Ependymal cells-
Oligodendrocytes-

15. What about “gliomas”???

16. Supporting Cells of the Peripheral Nervous System
Satellite cells-
Schwann cells-
Myelin

18. And gray matter vs. white matter-
Neurilemma is found covering the
neuronsof the Peripheral Nervous
System and helps regenerate
damaged nerve fibers
Which brings us to bundles of nerve
fibers-
Tracts-
Nerves-
And gray matter vs. white matter-

19. THE NEURON

20. THE NEURON

21. Nerve fibers may be microscopic
May extend 3 to 4 feet
Neurons never touch each other
Axonal terminals release neurotransmitters into the synapse

22. Neurons classified according to structure and function
Functional-
Sensory or Afferent-
Motor or Efferent-
Associative or Interneurons-
2. Structural- based on # of processes extending from cell body

24. Physiology of Neurons Neurons have two major functions Irritability-
2. Conductivity-

25. Irritabililty- the short version
Resting or inactive neuron is polarized
A stimulus excites the neuron to become active and generate an impulse
The stimulus changes the permeability of the neuron’s membrane
Sodium gates open and Na diffuses into the cell
Neuron is now depolarized
Depolarization activates the neuron to transmit an action potential or nerve impulse

26. Depolarization is followed almost immediately by repolarization
Until the neuron repolarizes it cannot conduct
another impulse= absolute refractory period
There also exists a relative refractory period when a stronger than usual stimulus is required

27. The Action Potential

29. GENERATION OF AN ACTION POTENTIAL

30. Alcohol, sedatives, anesthetics-
Cold and continuous pressure-
Warm or remove pressure-

31. Conductivity
No contact between neurons except at electrical synapses (escape reflexes, retina, heart)
Axonal terminals release neurotransmitters which cause depolarization of next neuron
Neurotransmitter is removed from synapse by re-uptake at axonal terminal or enzymatic breakdown

32. YouTube - Neurotransmitter Synapse 3D Animation

33. Peripheral Nervous System
Those nerves found outside the central nervous system
Each nerve is made of bundles of neuron fibers
Neuron fibers are surrounded by a delicate tissue sheath
Groups of fibers are bound by coarser connective tissue wrapping to form bundles called fascicles

34. CRANIAL NERVES
SPINAL NERVES

35. Spinal Nerves

36. DISORDERS AFFECTING NEURONS
POLIOMYELITIS

38. MULTIPLE SCLEROSIS-
BELL’S PALSY-
SHINGLES-

40. And then there’s…
CARPAL TUNNEL SYNDROME-