Name: ____________________________________________
Period: ____
Date: ______________
Chp 9: NERVOUS TISSUE
After identifying the organization of the nervous system into its subdivisions of the CENTRAL NERVOUS
SYSTEM (CNS) and PERIPHERAL NERVOUS SYSTEM (PNS), the histology of the functional neuron cells and
supportive neuroglial is considered. Attention is given to the components of a neuron, and their
structural and functional classification. The physiology of nervous tissue is then discussed. The topic
areas considered are plasma membrane ion channels, membrane potentials, excitability, the All-or-None
Principle, saltatory conduction and speed of nerve impulses. The physiology of impulse conduction
synapses are then considered. Particular attention is given to excitatory and inhibitory transmission,
synaptic integration and alternation of synaptic conduction.
Chp 11: THE AUTONOMIC NERVOUS SYSTEM
Students are introduced to the general functions of the ANS and its comparison to the SNS. The
sympathetic and parasympathetic divisions of the autonomic nervous system are introduced. Attention
is then focused on the structure of the ANS, detailing the components of visceral efferent pathways. The
components discussed are preganglionic neurons, autonomic ganglia, and postganglionic neurons. The
functional aspects of the autonomic nervous system are then discussed by considering
neurotransmitters and numerous ANS activities.
Chp 12: SENSATIONS
This chapter offers a general introduction to the location of sensory apparati and the way in which
stimuli are detected. Somatic cutaneous sensations such as tactile and discriminative touch, pressure,
pain, and temperature are considered. The special senses of smell, taste, vision, and hearing are then
introduced with a discussion of the physiological features.
OBJECTIVES
Nervous Tissue
1. Describe the organization of the nervous system.
2. Compare the structure and functions of neuroglia and neurons.
3. Describe how a nerve impulse is generated and conducted.
Autonomic Nervous System
1. Outline the main structural and functional differences between the somatic and autonomic
nervous systems.
2. Identify the structural features of the autonomic nervous system.
3. Discuss the functions of the sympathetic and parasympathetic divisions of the autonomic
nervous system.
Sensations
1. Define a sensation and describe the conditions necessary for a sensation to occur.
2. List and describe the somatic sensations.
3. Define proprioception and describe the structure of proprioceptive receptors.
4. Describe the receptors for olfaction and the olfactory pathway to the brain.
5. Describe the receptors for gustation and the gustatory pathway to the brain.
6. Describe the receptors for vision and the visual pathways to the brain.
7. Describe the mechanism involved in vision.
8. Describe the receptors for hearing and equilibrium, and their pathways to the brain.
ASSIGNMENTS
1. Read Chapter 9; pages 229-245.
2. Read Chapter 11; pages 277-288.
3. Read Chapter 12; pages 289-319.
4. Complete this packet as you read and listen to classroom lectures or discussions; answer all
Checkpoint Questions and Critical Thinking Applications when directed to do so.
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Chapter 9: Nervous Tissue
I. OVERVIEW OF THE NERVOUS SYSTEM
OBJ: Describe the organization of the nervous system.
Explain the three basic functions of the nervous system.
A. Organization of the Nervous System
1. Two main subsystems of the nervous system:
a. ___________________________________________: consists of the brain and spinal
cord
i. Brain contains ~ ______________________ neurons
ii. Spinal cord contains ~ _______________________ neurons and is encircled by
bones of vertebral column.
iii. Function: ____________________________________________________________
____________________________________________________________________
____________________________________________________________________
b. ___________________________________________: includes all nervous tissue outside
the CNS.
i. Components of PNS:
(1) ___________________; bundle of hundreds to thousands of axons plus
associated connective tissue and blood vessels lying outside the brain and spinal
cord.
Cranial nerves I-XII emerge from base of the brain.
Spinal nerves emerge from spinal cord.
(2) ___________________; are small masses of nervous tissue, consisting mostly of
neuron cell bodies and are located outside the brain and spinal cord; closely
associated with ________________ and _____________ nerves.
(3) Enteric plexuses:
Found: _______________________________________________
Function: _____________________________________________
(4) Sensory receptors:
Found: _______________________________________________
Function: _____________________________________________
Recall:
CNS - brain and spinal cord; integrates and correlates many different kinds of incoming sensory
information; source of thoughts, emotions, and memories.
PNS – cranial nerves and their branches, spinal nerves and their branches, ganglia, and sensory
receptors; functions divided into subdivisions….
SUBDIVISIONS OF PNS:
1. Somatic nervous system (SNS)
a. ______________________________: convey information from somatic receptors in head,
body wall, and limbs, and from receptors for special senses of vision, hearing, taste, and
smell to CNS
b. __________________________: conduct impulses from CNS to _____________muscles
only; can be consciously controlled, voluntary actions
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2. Autonomic nervous system (ANS)
a. _____________________________: convey information from autonomic sensory
receptors, located in visceral organs (stomach, lungs) to CNS
b. __________________________: conduct nerve impulses from CNS to ____________,
________________ muscles and glands; cannot be consciously controlled, involuntary
actions
c. Two divisions of ANS are: ____________________ and __________________________;
these divisions usually perform opposite functions
i. “Fight-or-flight” responses  ____________________________
ii. “Rest-and-digest” activities  ____________________________
3. Enteric nervous system (ENS)
a. Known as ___________________________________; operation is involuntary
b. Neurons found in and extend through ________________________________________
c. _____________________________: monitor chemical changes within the GI tract and
the stretching of its walls
d. _________________________: govern ___________________ of GI tract smooth
muscle, _____________________ of GI tract organs, and activity of GI tract endocrine
cells.
Get a copy of checkpoint questions 1-3 and the applicable
critical thinking application, complete them and hand them in…
B. Functions of the Nervous System
1. Sensory functions
a. ______________________________ detect stimuli inside and outside the body.
b. Types of neurons that carry out sensory functions:
i. __________________________________________________
Carry sensory information to brain and spinal cord.
2. Integrative functions
a. Do what?
________________________________________________________________________
________________________________________________________________________
b. Types of neurons that carry out integrative functions:
________________________________________________________________________
________________________________________________________________________
3. Motor functions
a. Do what?
________________________________________________________________________
b. Types of neurons that carry out motor functions:
________________________________________________________________________
________________________________________________________________________
II. HISTOLOGY OF NERVOUS TISSUE
OBJ: Contrast the histological characteristics and the functions of neurons and neuroglia.
Distinguish between gray matter and white matter.
What two types of cells make up nervous tissue? _________________________________________
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Neurons provide for what:
__________________________________________________________________________________
__________________________________________________________________________________
What do neuroglia do?
__________________________________________________________________________________
A. Neurons
Consists of three parts:
(1) ____________________
Contains: ____________________________________________________________________
What is synthesized here? ______________________________________________________
Processes or extensions:
(2) ____________________(“little trees”)
How many? __________________________
Combined with cell body what is their function? ____________________________________
Shape: _____________________________________________________________________
(3) ____________________
Function: ___________________________________________________________________
___________________________________________________________________
Shape: _____________________________________________________________________
What is an axon hillock? _______________________________________________________
What are axon collaterals? _____________________________________________________
What are axon terminals? ______________________________________________________
What is a synapse? __________________________________________________________________
What are synaptic end bulbs? _________________________________________________________
What are synaptic vesicles? ___________________________________________________________
What are neurotransmitters? _________________________________________________________
1. Classification of Neurons
STRUCTURAL CLASSIFICATION
 ______________________________: have several dendrites and one axon; most in
brain and spinal cord
 ______________________________: have one main dendrite and one axon; retina
of the eye, inner ear, olfactory area of brain
 ______________________________: dendrites and one axon fused together
forming a continuous process that emerges from cell body; begin in embryo as
bipolar neurons; most function as sensory receptors for touch, pressure, pain, or
thermal stimuli. Cell bodies of most of this type located in ganglia of spinal and
cranial nerves.
FUNCTIONAL CLASSIFICATION
 ______________________________: once sensory receptor activated, these form
an action potential in their axon that is conveyed into the CNS through spinal and
cranial nerves
contain sensory receptors at their distal ends or are located just after sensory
receptors that are separate cells; most unipolar in structure
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 ______________________________: convey action potential away from CNS to
effectors (muscles and glands) in PNS through cranial and spinal nerves
Most are multipolar in structure
 ______________________________: integrate incoming sensory information from
sensory neurons and then elicit a motor response by activating appropriate motor
neurons
Located within CNS between sensory and motor neurons; most multipolar in
structure
B. Neuroglia
Describe neuroglia: ______________________________________________________________
______________________________________________________________
Functions: _____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
What are gliomas? _________________________________________________________________
C. Myelination
A myelin sheath, many-layered covering composed of lipids and protein, surround the axons of
most of our neurons.
Two Functions:
(1) ________________________________________________________
(2) ________________________________________________________
What name is given to the gaps in myelin sheath? ____________________________________
Define myelinated: _____________________________________________________________
Define unmyelinated: ___________________________________________________________
The amount of myelin increases from ___________________ to ____________________
Its presence increase what? ________________________________________________
What two diseases are known to destroy myelin sheaths? ______________________________
D. Collections of Nervous Tissue
1. Clusters of Neuronal Cell Bodies
 __________________________: cluster of neuronal cell bodies located in PNS
 __________________________: cluster of neuronal cell bodies in CNS
2. Bundles of Axons
 ____________________: bundle of axons located in PNS; cranial nerves connect
brain to periphery and spinal nerves connect spinal cord to periphery
 ____________________: bundle of axons located in CNS; tracts interconnect
neurons in spinal cord and brain
3. Gray and White Matter
 What is white matter?
____________________________________________________________________
____________________________________________________________________
 What is gray matter?
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
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obtain and complete the worksheet ‘the anatomy of the neuron’
Quiz on nervous system basics on: __________________________________
Know the components of the CNS and PNS
Know what the ANS, ENS, and SNS controls (Figure 9.1, page 254 may help)
Know the anatomy of a neuron
III. ACTION POTENTIALS
OBJ: Describe how a nerve impulse is generated and conducted.
What is another name for action potentials? ___________________________
What two features of plasma membrane do action potentials in muscle fibers and in neurons
depend on?
(1) ___________________________________________________________
(2) ___________________________________________________________
_________________________________, difference in the amount of electrical charge inside and
outside a plasma membrane. A membrane that has potential is said to be ____________________.
When muscle fibers and neurons are ‘at rest’, the voltage across the plasma membrane is termed
the __________________________________________.
In living tissues, the flow of ions constitutes electrical currents.
A. Ion Channels
Let specific ions move from areas of high concentration to areas of low concentration, or from
positively charged areas to negatively charged areas or visa versa to equalize differences in
charges or concentration.
1. Two types of ion channels:
Leakage channels___________________________________________________________________________
___________________________________________________________________________
Gated channels:
___________________________________________________________________________
___________________________________________________________________________
2. What are voltage-gated channels used for?
___________________________________________________________________________
B. Resting Membrane Potential
1. What kind of charge does the resting neuron have on the outside surface of the plasma
membrane? _____________________________ on the inside? _______________________
2. Potential energy in cells is measured in ____________.
3. What is the resting membrane potential in neurons? _________mV
4. Why is it a negative value? _____________________________________________________
5. Interstitial fluid is rich in __________ ions and _____________ ions.
6. Cytosol is rich in ____________ ions.
7. What offsets the small inward leak of Na+ and outward leak of K+?
____________________________________
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8. The diagram below will help you to understand how resting membrane potential arises from
the unequal distributions of various ions in cytosol and interstitial fluid. You should read
over this material carefully on page 260 of your textbook.
C. Generation of Action Potentials
what happens during an action potential (AP) or impulse?
______________________________________________________________________________
______________________________________________________________________________
Ability of muscle fibers and neurons to convert stimuli into action potential is called
_______________________________.
What causes an action potential to arise?
______________________________________________________________________________
1. Two main phases:
Depolarizing phase___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Repolarizing phase___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
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2. Explain the process of action potential from threshold state to depolarization to afterhyperpolarization phase.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
3. What is the all-or none principle?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
4. What type of stimuli elicit an action potential? _____________________________________
5. What is a refractory period?
___________________________________________________________________________
6. Label 1-7 on the diagram below:
2.
3.
4.
5.
7.
1.
6.
D. Conduction of Nerve Impulses
What is propagation or conduction?
______________________________________________________________________________
What is continuous conduction? What type of axons does it occur in?
______________________________________________________________________________
What is saltatory conduction? What type of axons does it occur in?
______________________________________________________________________________
What type of axons have the largest diameter? ________________________________
What type of axons have the smallest diameter? _______________________________
What type of factors influence the speed of nerve impulse conduction?
______________________________________________________________________________
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IV. SYNAPTIC TRANSMISSION
OBJ: Explain the events of synaptic transmission and the type of neurotransmitters used.
What is synaptic transmission?
__________________________________________________________________________________
__________________________________________________________________________________
What is the neuron sending the signal called? _________________________________________
What is the neuron receiving the signal called? ________________________________________
A. Events at a Chemical Synapse
What separates the presynaptic and postsynaptic neurons? ____________________________
B. Neurotransmitters
Different neurotransmitters are found in synaptic vesicles. These different neurotransmitters
have different effects.
Obtain and complete the synaptic events worksheet…
When done with this packet you will receive packet for chapters
11 & 12…
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