1. NEED TO SHORTEN 7
49 slides
3 hour & 10 min
The Nervous System

2. I. Overall Functions of the Nervous System
A. Sensory input =
B. Integration =
C. Motor output =

3. II. Organization of the Nervous System A. Structural Classification
1.Central nervous system (CNS) =
a. Parts
b. Function
2. Peripheral nervous system (PNS) =
Ganglia
Nerves:
Functions:

4. B. Functional Classification of the Peripheral N.S.
1. Sensory (afferent):
2. Motor (efferent):

5. III. Nervous Tissue Structure & Function: A. Nervous Tissue Cells
1. Neuroglia (glial): Support cells
a. General functions
Support
Insulate
Protect

6. Nervous Tissue Structure and Function … 2. Neurons
a. Function:
b. Parts–
i) Cell body
Nissl bodies = rough ER
Nucleus
ii) Processes

7. Dendrite
Cell
body
Mitochondrion
Nissl substance
Axon
hillock
Axon
Neurofibrils
Collateral
branch
Nucleus
One
Schwann cell
Node of
Ranvier
Axon
terminal
Schwann cells,
forming the myelin
sheath on axon
(a)
Figure 7.4a

8. Neuron cell body
Dendrite
(b)
Figure 7.4b

9. Nervous Tissue: Neurons …
ii) Processes =
(1) *Dendrites:
(2) *Axons:
Axon Hillock
*Axon Terminal
*Contain Synaptic Vesicles
*Neurotransmitters

10. c. Synaptic cleft = Synapse—gap between adjacent neurons

11. Nervous Tissue: Neurons …
d. Myelin sheath =
Cell that forms
ii) How forms it
iii) Nodes of Ranvier
iv) CNS and PNS
differences

12. Schwann cell
cytoplasm
Schwann cell
plasma membrane
Axon
Schwann cell
nucleus
(a)
(b)
Neurilemma
Myelin
sheath
(c)
Figure 7.5

13. Neurons … B. Terminology
Location cell bodies & Dendrites:
Nuclei =
Ganglia =
Location AXONS
Tracts =
Nerves =

14. Neurons … C. Functional Classification of Neurons
Sensory (afferent) =
Motor (efferent) =
Interneurons (Integration, Association)
Sensory Neurons
a. Function
b. Receptors
i) Free Nerve endings
ii) Touch Receptors

15. Sensory Neurons & Receptors …
iii) Proprioceptors
iv) Others
2. Interneurons (association neurons)
Connect sensory and motor neurons
Location
Function
3. Motor Neurons

16. Central process (axon)
Sensory
neuron
Spinal cord
(central nervous system)
Cell
body
Ganglion
Dendrites
Peripheral
process (axon)
Afferent
transmission
Interneuron
(association
neuron)
Peripheral
nervous system
Receptors
Efferent transmission
Motor neuron
To effectors
(muscles and glands)
Figure 7.6

17. D. Classification of Neurons
1. Multipolar neurons—many extensions from the cell body
All motor and interneurons
2. Unipolar
3. Bipolar
Sensory Neuron shapes

18. IV PHYSIOLOGY: Action Potentials A. Functional Properties of Neurons
1. Irritability
2. Conductivity
B. The Action Potential
The Resting Neuron-- Prior to the Action Potential
Inside Neuron next to membrane:
more positives
More K+ (less K+ outside)
Outside cell membrane:
more negative things
More Na+ (less Na+ inside)

19. + POSITIVE CHARGE + + + _ c. RESULT: Membrane Charges are Polarized
Action Potential …
c. RESULT:
Membrane Charges are Polarized
ii) Two Ion Concentration Gradients
ENERGY
iii) Membrane is impermeable to Na+ and K+ when at rest
+ POSITIVE CHARGE
__ __ __
NEGATIVE CHARGE K+
Na+
Na+
Na+ +
Na+
Na+
Na+ _ K+ K+ K+ K+ K+ K+
Na+

20. Nerve Impulses … _ + 2. Starting the Action Potential a. Stimulus
b. Depolarization = Sodium moves inside neuron
The membrane is now permeable to sodium as sodium channels open along successive regions of the membrane
Sodium (Na+) flows inside the membrane
STIMULUS
Na+
Na+
Na+
Na+
Na+ _
Na+ + K+ K+ K+ K+ K+

21. Potassium ions leave neuron which repolarizes the membrane
Nerve Impulses …
c. Repolarization
Potassium ions leave neuron which repolarizes the membrane
Repolarization involves restoring the inside of the membrane to a negative charge and the outer surface to a positive charge K+ + _
Na+
Na+
Na+ K+ K+ K+ K+ K+
Na+
Na+
Na+

22. d. Redistribution of ions
Impulses …
d. Redistribution of ions
Initial ionic conditions are restored using the sodium-potassium pump.
Three sodium ions are ejected while two potassium ions are returned K+ K+
Na+ K+ K+ K+
Na+
Na+ K+
Na+
Na+
Na+

23. K+
Na+
Na+
Na+
Na+
Na+
Na+ K+ K+ K+ K+ K+
Na+ K+
Na+
Na+
Na+
Na+
Na+ K+
Na+ K+ K+ K+ K+ K+
Na+
Na+ K+
Na+
Na+
Na+
Na+ K+ K+
Na+ K+ K+ K+ K+
Na+
Na+
Na+ K+
Na+
Na+
Na+ K+ K+ K+
Na+ K+ K+ K+

24. Figure 11.12 Propagation of an action potential (AP).
© 2013 Pearson Education, Inc.

25. Nerve Impulses
Impulses travel faster when fibers have a myelin sheath

26. C. Transmission of a Signal at Synapses
1. When action potential reaches the axon terminal, calcium channels open
a. Calcium
diffuses in
Neuron #1
Action
Potential
Arrives at
Axon
Terminal.
Axon terminal
Ca+
Ca+
Ca+
Ca+
Neuron #2
Dendrite

27. Transmission of a Signal at Synapses …
(1) Calcium causes vesicles to move to membrane
Axon terminal
Synaptic
cleft
Vesicles 1
Ca+
Ca+
Dendrite
Ca+
Ca+
Figure 7.10, step 1

28. Ca+ Ca+ Ca+ Vesicle fuses with Axon terminal of plasma Neuron #1
membrane. 2
Axon terminal of
Neuron #1
Ca+
Ca+
Ca+
Synaptic
cleft
Neurotransmitter
molecules
Dendrite or
Neuron #2
Figure 7.10, step 2

29. Ca+ Transmitting neuron Vesicle fuses with plasma membrane.2
Neurotrans-
mitter is
released into
synaptic cleft. 3
Ca+
Synaptic
cleft
Neurotransmitter
molecules
Dendrite
Receiving neuron
Figure 7.10, step 3

30. Transmission of a Signal at Synapses ,,,
(4) Neurotransmitters diffuse across to dendrite of receiving cell
Axon Terminal
Dendrite

31. Ca+ AXON TERMINAL Neurotrans- mitter binds to Receptor . Synaptic5
Neurotrans-
mitter binds
to Receptor .
Ca+
Synaptic
cleft
Receptors
Dendrite
Figure 7.10, step 4

32. (5) … Receptors are proteins that bond with Neurotransmitter
Neuron #1
Receptor
Neuron #2

33. Transmission of a Signal at Synapses …
(6) If enough neurotransmitter is released, the 2nd neuron will send its own Action potential
Neurotransmitter
Ion
Receptor 5
Ion channel opens.

34. (7) Neurotransmitter is removed.
Ion
Figure 7.10, step 6