1. C h a p t e r 12
Neural Tissue
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2. PSR # 6 Ax- [axle] Peri- [all around] Dendr- [tree] Sens- [feeling]
Gangli- [a swelling]
Syn- [together]
-lemm [rind or peel]
Ventr- [belly or stomach]
Mening- [membrane]
Moto- [moving]
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3. Sensory input
Integration
Motor output
Figure 11.1

4. Functions of the Nervous System
Sensory input
Information gathered by sensory receptors about internal and external changes
Integration
Interpretation of sensory input
Motor output
Activation of effector organs (muscles and glands) produces a response

5. An Introduction to the Nervous System
Organs of the Nervous System
Brain and spinal cord
Sensory receptors of sense organs (eyes, ears, nose, etc.)
Nerves connect nervous system with other systems
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6. Divisions of the Nervous System
Central nervous system (CNS)
Brain and spinal cord
Integration and command center
Peripheral nervous system (PNS)
Paired spinal and cranial nerves carry messages to and from the CNS

7. “Fight or Flight” “Rest and Digest”
Central nervous system (CNS)
Peripheral nervous system (PNS)
Brain and spinal cord
Cranial nerves and spinal nerves
Integrative and control centers
Communication lines between the
CNS and the rest of the body
Sensory (afferent) division
Motor (efferent) division
Somatic and visceral sensory
nerve fibers
Motor nerve fibers
Conducts impulses from the CNS
to effectors (muscles and glands)
Conducts impulses from
receptors to the CNS
Somatic sensory
fiber
Somatic nervous
system
Autonomic nervous
system (ANS)
Skin
Somatic motor
(voluntary)
Visceral motor
(involuntary)
Conducts impulses
from the CNS to
skeletal muscles
Conducts impulses
from the CNS to
cardiac muscles,
smooth muscles,
and glands
Visceral sensory fiber
Stomach
Skeletal
muscle
Motor fiber of somatic nervous system
“Fight or Flight”
Sympathetic division
Parasympathetic
division
Mobilizes body
systems during activity
“Rest and Digest”
Conserves energy
Promotes house-
keeping functions
during rest
Sympathetic motor fiber of ANS
Heart
Structure
Function
Sensory (afferent)
division of PNS
Parasympathetic motor fiber of ANS
Bladder
Motor (efferent)
division of PNS
Figure 11.2

9. Peripheral Nervous System (PNS)
Two functional divisions
Sensory (afferent) division (send signals to CNS)
Somatic afferent fibers—convey impulses from skin, skeletal muscles, and joints
Visceral afferent fibers—convey impulses from visceral organs
Motor (efferent) division (send signals from CNS)
Transmits impulses from the CNS to effector organs

10. Motor Division of PNS Somatic (voluntary) nervous system
Conscious control of skeletal muscles

11. Motor Division of PNS Autonomic (involuntary) nervous system (ANS)
Visceral motor nerve fibers
Regulates smooth muscle, cardiac muscle, and glands
Two functional subdivisions
Sympathetic
Parasympathetic

12. Histology of Nervous Tissue
Two principal cell types
Neurons—excitable cells that transmit electrical signals
The basic functional units
Of the Nervous System.

13. Histology of Nervous Tissue
Neuroglia (glial cells)—supporting cells:
Astrocytes (CNS)
Microglia (CNS)
Ependymal cells (CNS)
Oligodendrocytes (CNS)
Satellite cells (PNS)
Schwann cells (PNS)

14. Dissected Human Nerves

15. and conducting region)
Dendrites
(receptive regions)
Cell body
(biosynthetic center
and receptive region)
Nucleolus
Axon
(impulse generating
and conducting region)
Impulse
direction
Nucleus
Node of Ranvier
Nissl bodies
Axon
terminals
(secretory
region)
Axon hillock
Schwann cell
(one inter-
node)
Neurilemma
(b)
Terminal
branches
Figure 11.4b

19. Neurons The Structure of Neurons The multipolar neuron
Common in the CNS:
cell body (soma)
short, branched dendrites
long, single axon

20. Neurons The Structure of Neurons Dendrites Highly branched
Dendritic spines:
many fine processes
receive information from other neurons
80–90% of neuron surface area
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21. Neurons The Structure of Neurons The axon Is long
Carries electrical signal (action potential) to target
Axon structure is critical to function
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

22. Neurons Structures of the Axon Collaterals Branches of a single axon
Telodendria
Fine extensions of distal axon
Synaptic terminals
Tips of telodendria

23. Neurons The Structure of Neurons The synapse Presynaptic cell:
neuron that sends message
Postsynaptic cell:
cell that receives message
The synaptic cleft:
the small gap that separates the presynaptic membrane and the postsynaptic membrane
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24. Neuroglia Neuroglia Half the volume of the nervous system
Many types of neuroglia in CNS and PNS
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

25. Neuroglia Outnumber neurons by about
10 to 1 (the guy on the right had an inordinate amount of them).
6 types of supporting cells
4 are found in the CNS:
Astrocytes
Star-shaped, abundant, and versatile
Guide the migration of developing neurons
Function in nutrient transfer
Repair damaged neural tissue

26. (a) Astrocytes are the most abundant CNS neuroglia.
Capillary
Neuron
Astrocyte
(a) Astrocytes are the most abundant CNS neuroglia.
Figure 11.3a

27. Neuroglia Microglia Ependymal Cells
Specialized immune cells that act as the macrophages of the CNS
Migrate through NS
Clean up cellular debris, waste products, and pathogens
Ependymal Cells
Line central canal of spinal cord and ventricles of brain:
secrete cerebrospinal fluid (CSF)
have cilia or microvilli that circulate CSF

28. (b) Microglial cells are defensive cells in the CNS.
Neuron
Microglial
cell
(b) Microglial cells are defensive cells in the CNS.
Figure 11.3b

29. (c) Ependymal cells line cerebrospinal fluid-filled cavities.
Fluid-filled cavity
Ependymal
cells
Brain or
spinal cord
tissue
(c) Ependymal cells line cerebrospinal fluid-filled cavities.
Figure 11.3c

30. Neuroglia
4. Oligodendrocytes
Produce the myelin sheath which provides the electrical insulation for certain neurons in the CNS
Wrap around axons.

31. Myelin sheath Process of oligodendrocyte Nerve fibers
(d) Oligodendrocytes have processes that form myelin sheaths around CNS nerve fibers.
Figure 11.3d

32. Neuroglia Four Types of Neuroglia in the CNS Oligodendrocytes
Myelination
increases speed of action potentials
myelin insulates myelinated axons
makes nerves appear white
Nodes
nodes (also called nodes of Ranvier)
gaps between the myelinated segments
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33. Neuroglia Four Types of Neuroglia in the CNS Oligodendrocytes
White matter:
regions of CNS with many myelinated nerves
Gray matter:
unmyelinated areas of CNS
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34. Neuroglia 2 types of glia in the PNS Satellite cells (amphicytes)
Surround clusters of neuronal cell bodies in the PNS (ganglia)
Regulate environment around neuron.
Schwann cells (neurilemmocytes)
Form myelin sheaths (neurilemma) around peripheral axons.
Vital to neuronal regeneration

35. (forming myelin sheath)
Satellite
cells
Cell body of neuron
Schwann cells
(forming myelin sheath)
Nerve fiber
(e) Satellite cells and Schwann cells (which form myelin) surround neurons in the PNS.
Figure 11.3e

36. Neuroglia Figure 12–4 An Introduction to Neuroglia.
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37. The Eye Three Layers of the Eye Eyeball Outer fibrous tunic
Middle vascular tunic
Inner neural tunic
Eyeball
Is hollow
Is divided into two cavities:
Large posterior cavity
Smaller anterior cavity
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38. The Eye
Figure 17–4b The Sectional Anatomy of the Eye.

39. The Eye
Figure 17–5 The Pupillary Muscles.

40. The Eye
Figure 17–6b The Optic Disc of the Retina in Diagrammatic Sagittal Section.

41. The Eye
Figure 17–10 Accommodation.

42. Visual Physiology
Figure 17–16 Cone Types and Sensitivity to Color.

43. Photoreceptors: 2 types
Rod cells
More sensitive to light - vision permitted in dim light but only gray and fuzzy
Only black and white and not sharp
Cone cells
High acuity in bright light
Color vision
3 sub-types: blue, red and green light cones
*Know that rods are for B & W and cones are for color

44. Figure 16.7a

45. Visual Physiology
Figure 17–17 A Standard Test for Color Vision.

46. One of the Ishihara charts for color blindness
Commonly X-linked recessive: 8% males and 0.4% females

48. Test for Colorblindness

49. The Eye
Figure 17–7 A Demonstration of the Presence of a Blind Spot.