1. Neural Tissue
The nervous system includes all the neural tissue in the body.

2. Structure of the nervous system

3. The Nervous System
Central Nervous System
Peripheral Nervous System
Afferent
Efferent
Brain
Spinal Cord
Central Nervous System - brain, spinal cord, blood vessels, connective tissue
PNS- delivers sensory information to the CNS
Somatic
Autonomic
Sympathetic
Parasympathetic

4. Peripheral Nervous System
Afferent - bring sensory
Efferent - carry commands

5. Efferent Division
Somatic - skeletal muscle contractions (voluntary) & involuntary reflexes
Autonomic (visceral motor system) -Involuntary (smooth muscles, cardiac muscle
& glandular secretions)

6. Autonomic Nervous System
Parasympathetic - nonstressful
rest & digest
Sympathetic –
stressful
fight or flight
Antagonistic effects

7. Functional & Structural unit of the nervous system
Neuron
Functional & Structural unit of the nervous system

8. Multipolar Neuron Nissl bodies - Rough ER & free ribosomes
dendrites
perikaryon
dendritic spines
dendrites
nucleus
axon
telodendria
Nissl bodies
mitochondria
axon hillock
Initial segment
of axon
telodendria
axon
Nissl bodies - Rough ER & free ribosomes
perikaryon - cytoplasm
Golgi apparatus
synaptic
terminals
neurofilaments
nucleolus
nucleus
Multipolar Neuron

9. Vocabulary dendrites - typically highly branched, carry messages
axon - propagates an electrical impulse away from the cell body
initial segment - base of an axon

10. Vocabulary cont. axon hillock - thickened region
soma - cell body, houses organelles but lack centioles
telodendria - fine extensions off the axon
synaptic terminal - ends of the telodendria

11. Structural Classification of Neurons
axonic - small, located in brain & special sense organs
Bipolar - rare, special sense organs (sight, smell, hearing)
Unipolar - most sensory neurons in PNS - longest is tip of toes to spinal cord
multipolar - most common in CNS, all motor neurons, longest to muscles of toe
anaxonic neuron
bipolar neuron
unipolar neuron
multipolar neuron

12. Functional Classification of Neurons
Sensory neurons (afferent) - from sensory receptors
to CNS
somatic sensory neurons - monitor the outside
world & our position in it
visceral sensory neurons - monitor internal
conditions & the status of the organs

13. Sensory receptors proprioceptors interoceptors exteroceptors
proprioceptors - monitor the position & movement of skeletal muscles & joints
interoceptors - digestive, respiratory, cardiovascular, urinary, reproductive systems & taste, pain
exteroceptors - touch, temp, pressure sensations, sight, smell and hearing
proprioceptors
interoceptors
exteroceptors

14. Functional Classification
of Neurons
Motor Neurons (efferent) -
carry instructions
from
the CNS to peripheral effectors

15. Functional Classification of Neurons
Interneurons (association) -
outnumber all other types
mostly in brain & spinal cord
situated between sensory & motor
neurons

16. Cerebral Spinal Fluid (CSF) and the brain & spinal cord
Ependymal Cells
line the central canal & ventricles which house the brain & spinal cord, creates a barrier between the
Cerebral Spinal Fluid (CSF) and the brain & spinal cord

17. Astrocytes Maintain the blood-brain barrier
Create a 3-D framework for the CNS
Repair damaged nerve tissue
Guide neuron development
Control the interstitial environment
Maintain - isolates CNS from general circulation to keep out hormones & other chemical, form blankets around capillaries, Repair - structural repair to stabilize the tissue & prevent further damage, Guide - direct growth & interconnection in the embryonic brain, Control - regulate concentration of sodium ions & potassium ions & CO2, provide rapid transport of nutrients, ion & dissolved gases, controls the volume of blood flow, absorbs & recycles neurotransmitters, releases chemical that enhance or suppress communication across synaptic terminals

18. Form the myelin sheath along the length
Oligodendrocytes
Form the myelin sheath along the length
of the axon
myelin - increases the speed of the
action potential along the axon
myelin sheath - membrane wrapping
around the axon
internodes - area of the axon wrapped
myelin (1 - 2 mm in length)
nodes - small gaps (few micrometers)
between internodes with no myelin
white matter - CNS, areas with
myelinated axons, high lipid content
gray matter - areas containing neuron
cell bodies, dendrites & unmyelinated axons

19. The Myelinated Axon

20. Microglia least numerous
cleanup by engulfing cellular debris, waste products & pathogens