Download AP2B NervSys Ch 12a-OpenS-2016

Chapter 12 Outline
12.1 Basic Structure and Functions of the Nervous System
A. Overall Function of the N.S. & Basic Processes Used
B. Classification of the Nervous System
12.2 Histology of Nervous System
A. Neuroglia Cells
B. Neurons
C. Types of Neurons
12.4 The Action Potential
A. Electrically Active Cell Membranes
B. Membrane Potentials That Act As Signals
C. Graded Potentials (See Text section 12.5)
D. Action Potentials
12.5 Communication Between Neurons
A. Basic Concepts and Terms
B. Synapses
C. Neurotransmitter Systems
12.3 The Functions of the Nervous System– How the Parts All
Work Together
12.1 Basic Structure and Functions of the
Nervous System
A. Overall Function of
the Nervous System &
Basic Processes Used
• Afferent =
• INTEGRATION
• Efferent =
Figure 7.1
B. Classification of the Nervous System
1. CNS =
 Parts
 Functions:
2. PNS =
 Parts
 Functions
2. Functional Subdivisions of the Peripheral N.S.
a. Sensory
(Afferent)
b. Motor
(Efferent)
Figure 7.2
2. Peripheral Nervous System …
a. Afferent (Somatic)
Division
Components
•
•
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2. Peripheral Nervous System …
b. Motor division
Functional Subdivisiions
i) Somatic nervous system
= ____________
ii) Autonomic nervous
system = ___________
 Parasympathetic =
Peace
 Sympathetic =
Stress
12.2 Nervous Tissue—Histology
A. Neuroglia (Glial) Cells– 6 types
1. in CNS
1. Astrocytes –
2. Microglial
II-A
3. Ependymal –
4. Oligodendrocyte –
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Neuroglia …
PNS
5. Satellite cells--
6. Schwann cells--
Nuerons
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B. Neurons = _______________________
 1. Neuron anatomy
a. Cell body
 Function
 Nissl Body
 Nuclei & Ganglion
b. Neuron Processes:
i) Dendrites:
ii) Axons:
 Functon
 Axolemma
 Axon Hillock
Nissl Body
B-ii
 Axon Collaterals =
 Terminal Branches
(telodendria): _____________
 Axon terminals:
 Synaptic Vessicles
 Nuerotranmitters
 Synapse & Synaptic Cleft
Terminal
Branch
II-B
c. Myelin sheath:





Which Axons
Function:
Process:
Neurilemma:
Nodes of Ranvier:
Schwann Cells
Nerve fiber myelination by Schwann cells in PNS.
Myelin
sheath
Schwann
cell
cytoplasm
Axon
Neurilemma
(b) Cross-sectional view of a myelinated axon
(electron micrograph 24,000X)
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Copyright © 2009 Pearson
Education,©Inc.,
publishing
as Benjamin
Cummings
Copyright
2010
Pearson
Education,
Inc.
Copyright © 2009 Pearson
Education,©Inc.,
publishing
as Benjamin
Cummings
Copyright
2010
Pearson
Education,
Inc.
Neurons …
C. Types of Neurons
1. Functional Classification
a. Motor
b. Sensory
c. Association (Interneuron)
Neurons …
C. Types of Neurons …
2. Structural Classification of Neurons
a. Multipolar neurons:
 Abundance
 Functional Types:
Figure 7.8a
Structural Classification of Neurons …
b. Bipolar neurons: ______________
b. Abundance:
c. Functional Types:
Figure 7.8b
Structural Classification of Neurons …
c. Unipolar neurons:
• Functional Types:
Figure 7.8c
2. Functional Types of neurons
Motor
Sensory
Association, Interneurons
GP
12.4 The Action Potential
AP
GP
AP
A. Nerve Impulse Components:
KEY
1) Graded Potential
2) Action Potential
1) Neurotransmitter at Synapse
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GP
12.4 The Action Potential …
B. Electrically Active Cell Membranes
1. Electricity across Membranes
a. Opposite charges
b. Separated charges
c. Voltage (V) =
d. Flow of charge
2. Role of IONS
3. Role of Transmembrane
Proteins-REVIEW
a. Carrier Proteins
b. Channels
c. Pumps
Role of Transmembrane Proteins-REVIEW …
b. CHANNELS:

Allow:
Two main types:
1. Leakage (ungated) channels:
2. Gated channels (3 types):
 Chemically gated (ligand-gated):

Voltage-gated:

Mechanically gated:
c. Pumps
1. Characteristics
2. Example: Na+/K+ Pump
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3. Resting Membrane Potential (RMP)
a. Differences in Ionic Composition
• Occurs at membrane surface
• Chemical Gradient
i. INSIDE:
 K+ most
 Negative Proteins
& Amino Acids
Dendrites
Axon
ii. OUTSIDE:
 Na+
b. Electrical
Gradient
• Membrane Potential = _______
c. Membrane is polarized
A- K+
Na+
Na+
Cell
Body
3. Resting Membrane Potential …
 d. Maintenance of RMP
 Differences in Plasma Membrane Permeability:
• Impermeable to negative proteins
• Leakage of Na+ and K+
 Na+/K+ ATPase PUMP
Outside cell
K+
(5 mM )
K+
(140 mM )
Inside cell
Na+
(140 mM )
Na+
(15 mM )
Resting Membrane Potential (Vr)
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C. Membrane Potentials That Act as Signals
1. Signal = Changes in membrane potential due to
a. Movement of ions through
b. Gated channels
2. Two types of signals
• Graded potentials
• Action potentials (APs)
GP
GP GP
AP
GP
GP
GP
GP
Nerve Impulses– involve movement within
and between neurons
AP
GP
AP
GP
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3. Terms for Graded and Action Potentials
• Depolarization =
• Repolarization =
• Hyperpolarization =
• Presynaptic Neuron & Postsynaptic Neuron
Synapse
D. Graded Potentials (Local currents) Text page 500
1. Mechanism
a. Voltage Moves in one direction:
b. Part of Neuron involved:
c. Where:
d. Initiated by Chemicals = Neurotransmitters  ions
move:
e. Local Current generated– ions that enter or leave will
then:
D. Graded Potentials (Local currents) …
1. Mechanism …
f. Membrane not myelinated so:
g. Distance traveled:
• Depends on Strength of Stimulus
GP
GP GP
AP
GP
GP
GP
2. Characteristics
a. Channels involved:
b. Ions Involved determine:
c. Result:
d. Naming
i) Generator Potentials:
ii) Post Synaptic Potentials (PSP)
• Excitatory-- EPSP
• Inhibitory– IPSP
Stimulus
Plasma
membrane
* REVIEW OF MECHANISM & CHARACTERISTICS
 Neurotransmitter  Chemical Gated Channel
  Ions move across membrane
  ions move along membrane
  reach Axon Hillock
Neurotransmitters
Synapse
Graded Potentials …
3. Affect of PSP on generation of AP
a. EPSP  Depolarization
• Threshold:
• Chance of AP:
• Ion of Channel:
Depolarizing stimulus
Graded Potentials …
b. IPSP  Hyperpolarization =
• Inside axon becomes:
• chance of AP
• Ion of Gated Channel
•
•
Hyper-polarization
Graded Potentials …
c. number of graded potentials per neuron
Different
Neurotransmitters
Synapse
Synapse
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4. Summation of graded potentials at a neuron:
a. Spatial summation =
E1
E1
b. Temporal =
c. Inhibitory and Excitatory
together
1
E1 + E2
E. The Action Potentials (AP) *** NEXT PPT
GP
AP
END
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Review Questions
sensory (or afferent)
The PNS is further divided into _________
nerves and motor (or ________)
efferent nerves. The
myelin sheath surrounds the _______
axons of some
________
oligodendrocytes in the
neurons and is formed by _________________
CNS.
Review Questions
Depolarization diminishes the magnitude of the
_______________
membrane potential and increases the chance of
an AP while ______________
hyperpolarization does the opposite.
What 2 types of leakage channels are always open
in a neuron’s membrane?
Na+ and K+
Which one above is leakier and is most responsible
for resting potential?
K+