Name:
THE NERVOUS SYSTEM: NEURONS
Cell bodies of interneurons found in the human brain. You are born with approximately
twice as many neurons as you have now. The die-off of neurons occurs early in
life, and with more room, the remaining neurons make many connections with other
existing neurons. The degree of interconnectedness apparently determines our
intelligence and memory. It is estimated that the human brain contains
100 billion (1011) interneurons averaging 1000 synapses on each; that is, some
1014 connections. If you had 1014 pennies, how much money would you have?
SVHS ADVANCED BIOLOGY
ANATOMY AND PHYSIOLOGY
UNIT #7
SPRING SEMESTER 2013
SVHS ADVANCED BIOLOGY
2012-2013
UNIT #7: NERVOUS SYSTEM - NEURONS
OUTCOMES:
A)
B)
C)
D)
E)
F)
G)
H)
Be able to explain how the body has two systems of communication; a fast nervous
system and a slow endocrine system. (Page 225)
Be able to describe how an impulse is created and why it moves along an axon or dendrite.
(Pages 230-234)
Be able to explain how the nervous system is composed of two types of cells; neurons and
neuroglial cells. Explain the different types of neuroglial cells and their functions.
(Pages 228-231)
Be able to describe the structure of a typical neuron. (Pages 228-230)
Be able to explain what saltatory conduction is and the role of the myelin sheath.
(Pages 233)
Be able to contrast an action potential and resting potential in terms of charges on the
membranes and the ion concentrations. (Pages 230-234)
Be able to explain how an impulse bridges the gap between two neurons. (Pages 235-237)
Explain what factors determine if neurons can regenerate. (Page 230)
Tuesday 1/8
Discussion:
Lab: packet
Homework:
Introduction to Nervous System
Activity A, begin Activity B
Complete D.R. #9.1
Wednesday 1/9
Discussion:
Lab: packet
Homework:
Structure of neurons.
Complete Activity A and B
Complete D.R. #9.2
Friday 1/11
Discussion:
Lab: packet
Homework:
Conduction of nerve impulses.
Activity C: Reaction time lab. (No caffeine)
Complete D.R. #9.3
Tuesday 1/15
Discussion:
Lab: packet
Homework:
Conduction of nerve impulses. (Cont.)
Activity C: Reaction time lab (with caffeine).
Study guide, work on data analysis
Wednesday 1/16
Discussion:
Conduction across a synapse & regeneration of nerve tissue
Friday 1/18
Lab:
Homework:
Reaction Time Lab (with caffeine)
Prepare lab write up, work on study guide, complete packet
Monday 1/21
Martin Luther King Holiday
Wednesday 1/23
Unit #7 Test: Nervous System: Neurons
SVHS ADVANCED BIOLOGY
UNIT #7: CENTRAL NERVOUS SYSTEM LAB ACTIVITIES
PART “A”: Neuron Types.
Label each type of neuron shown below. See notes regarding types of
neurons. Describe where each type might be found. Explain how each
type differs in structure.
Neuron Type:
Neuron Type:
Neuron Type:
Found:
Found:
Found:
Differences:
Differences:
Differences:
Explain what this picture might be showing. Label
structures using arrows.
Using page 229 of Tortora, label the structures
of the neuron shown below. (Use each of the
names listed in the table on the next page.)
Identify the structures being pointed to in the
diagram of the axon cross section. Below, briefly
describe the role played by that structure.
#1:
#2:
#3:
#4:
PART "B":
OBSERVATION OF NEURONS FOUND IN THE SPINAL CORD.
Using the sample of cow spinal cord diagram 3 neurons and their associated structures. Also
diagram the neuroglial cells found in the sample. Label all structures observed.
In the space below name and describe the role of the
different types of neuroglial cells. Refer to page 208 of
Tortora.
Spinal Cord Neurons (400X)
Structure of Neuron
Cell Body
Dendrite
Axon
Axon Collateral
Axon Terminals
Synaptic end bulbs
Myelin Sheath
Node of Ranvier
Schwann Cell
Function
REACTION TIME EXPERIMENT.
PART “C”:
In this lab you will use a “reaction time ruler” to measure your lab partner’s reaction time. After a
predetermined number of practice runs an average of ten trials will determine the reaction time. We will
then compare a “caffeine” reaction time with a “non-caffeine” reaction time. Only willing participants who
regularly use caffeine will be involved in the comparison portion of the lab.
The procedure described below must be followed exactly as stated in order to get reliable results.
TEST PROCEDURE:
1) The subject to be tested must sit in a chair.
2) The releaser stands facing the subject and holds the release end of the ruler at his/her eye level.
3) The subject positions the thumb and first finger over the “thumb line”. The distance between the
thumb and the first finger should be 1inch.
4) when ready the subject tells the releaser to “start”.
5) Once told to start, the releaser must release the ruler within a 10 sec time frame. The releaser must
not look at the subject until after the subject has caught the ruler.
6) The subject must catch the ruler as quickly as possible after the release.
7) The line under the middle of the subjects thumb is used to determine the reaction time.
8) After 10 practice trials the actual 10 test trials are performed.
9) Record each test result.
Trial
1
2
3
4
5
6
7
8
9
10
Average
Practice
Test w/o
caffeine
Test with
caffeine
Unit #7: NERVOUS SYSTEM SELF STUDY GUIDE
1) From pages 225-230, be able to:
A)
B)
C)
D)
E)
Name the system that responds quickly and the system that responds slowly to the body’s needs.
Name the three basic functions of the nervous system.
Name the two types of cells found in the nervous system.
Contrast neurons and neuroglial cells as to size, numbers, and types.
Identify and give a function for the following structures of a neuron; cell body, axon, dendrite, axon
collaterals, axon terminals, synaptic end bulbs, synaptic vesicles.
F) Describe the structure and role of the myelin sheath.
G) Contrast white and gray matter as to myelin sheath.
2) From pages 230-234, be able to:
A) List two striking characteristics of neurons.
B) Characterize a nerve impulse.
C) Explain how ions play a role in creating an impulse.
D) Explain how ion channels play a role in nerve impulses.
E) Characterize a neuron that is resting regarding charges, ion concentrations.
F) Explain the role of the sodium – potassium pump in a neuron.
G) Explain what a resting potential means in terms of a neurons membrane.
H) Explain when a neuron’s membrane said to be “polarized”.
I) Explain what is meant by the term “excitability”.
J) Explain what is meant by “depolarization” and “repolarization”.
K) Explain the term “threshold” regarding a stimulus to a neuron’s membrane.
L) Explain what happens when the “threshold’ is reached.
M) Define “action potential”.
N) Explain how the “refactory period” impacts the neuron.
3) From page 232-234, be able to;
A)
B)
C)
D)
E)
F)
G)
Define threshold stimulus.
Explain the “all-or-none” principle.
Explain how a sub-threshold stimulus is different compared to a threshold stimulus.
Explain what is meant by the term “summation”.
Define and contrast continuous and saltatory conduction.
Describe three factors that determine the speed of the impulse along a neuron.
Explain how size of the nerve fiber determines speed and which size is myelinated and which is not.
4) From pages 233-236 titled “Conduction Across a Synapse”, be able to;
A)
B)
C)
D)
E)
F)
G)
Explain what a synapse is and where it would be found.
Contrast pre-synaptic and post-synaptic neurons.
Explain the role of a neural transmitter.
Describe the structure and role of synaptic vesicles.
Explain how an impulse bridges a synapse.
Explain why impulses can only travel in one direction.
Explain the three possible results of a postsynaptic neuron receiving an impulse.
5) From page 230, be able to;
A) Explain what types of neurons can regenerate themselves after injury.
B) Explain what factors determine if a neuron will regenerate.