Transcript Ch 11 Fundamentals of the Nervous System

Read pgs 347 – 356, 367 – 368, 374 - 375
Ch 11 Fundamentals
of the Nervous
System
1.
2.
3.
4.
5.
6.
7.
8.
Chapter Learning Objectives
List the basic functions of the nervous system.
Explain the structural and functional divisions of the nervous system.
Describe neuroglia and cite their function(s).
Define a neuron including its characteristic anatomy and functions.
Discuss ganglia; also myelin sheaths.
Classify neurons structurally and functionally.
Explain how nerve impulses travel (use the terms synapse and
neurotransmitters).
Identify common neurotransmitters and what they do.
Got nerve cells? There are more nerve cells in the human brain than
there are stars in the Milky Way. (BTW, the human brain has about
100,000,000,000 (100 billion) neurons).
11 Interesting Facts About Einstein's Brain
After Death
Dr. Ellen Weber September 29, 2006
Did you know these facts about the life of Einstein’s brain after his death?
1. On April 18, 1955 at Princeton Hospital in Trenton, New Jersey , the amazing life of Einstein’s brain ended.
2. His body arrived at the cremation oven incomplete the day he died… it was lacking a brain.
3. In a jar of formaldehyde in Dr. Thomas Harvey, the pathologist who performed Einstein's autopsy, stored the
brain for his own study.
4. Some say that Einstein offered his brain for research, but the executor of his estate said that Einstein's son
Hans made the decision to keep it.
5. When the press soon learned that Einstein's brain had been set aside for study, Dr. Harvey became very
protective of the brain… and the attention infuriated the genius’ family.
6. Harvey divided the brain into 240 sections, kept in jars at his home.
7. In spite of studying the organ for many years, he published no findings, saying that there was nothing unusual
about it.
8. Over time… Harvey offered parts of the brain to researchers, such as Dr. Marian Diamond from UC Berkeley,
who reported its interesting features.
9. Dr. Diamond reported the percentage of glial cells … which nourish neurons … in Einstein's brain … contained
about 73% more than the average male brain. There had been a greater metabolic need … his brain cells needed
and used more energy.
10. In 1996 Dr. Harvey surrendered the remaining pieces of Einstein's brain to Dr. Elliot Krauss, at Princeton
Hospital , who donated it to McMaster University where it was described as remarkable.
11. Researchers measured a 15% wider than average brain, with the inferior parietal regions on both hemispheres
… much more developed than most.
Do you think the journey of one genius' brain after death ... can teach the rest of us anything new about
intelligence in life...?
If We Lined Up All the Neurons (Nerve Cells) in
Our Body, How Long Would That Line Stretch?
Assume that one neuron is about 10 microns long (this is
just an example, because neurons come in all different
sizes). So, if we line up 100 billion neurons which are 10
microns long . . . (can you do the math?) Try it!
This may help with the math (or not):
1000 microns= 1milimeter (mm)
10 mm= 1centimeter (cm)
100 cm= 1 meter (m)
1000 m= 1 kilometer (km)
Functions of the Nervous System, pg 347
Instructions: Quickly find and write down the 3 functions of the nervous
system. Time: 1 minute
1.
2.
3.
Discussion
• Can anyone name the two main
categories that the nervous system is split
into for study purposes?
One Highly Integrated Nervous System
Divided into two principal parts for study
purposes:
• Central nervous system (CNS)
*we will cover it more in Ch 12
– ________ and ______________
– Integration and command center
• Peripheral nervous system (PNS)
*more in depth in Ch 13
– Paired _______ and _______ nerves
– Carries messages __________ the spinal
cord and brain
PNS: Two Divisions
1. __________ (or afferent) division
a) Sensory afferent fibers – carry impulses from
skin, skeletal muscles, and joints to the brain
b) Visceral afferent fibers – transmit impulses
from visceral organs to the brain
2. _______ (or efferent) division
– Transmits impulses from the CNS to certain
target organs called effector organs
Motor Division Further Divides Into
• ________nervous system which is voluntary
– ____________ control of skeletal muscles
• ________ nervous system (ANS)
– Regulates _____ muscle, _______ muscle, and
________ and is involuntary.
– Divisions:
a) ____________ – mobilizes body systems during
activity *more in Ch 14
b) _______________ – conserves energy; promotes
housekeeping functions during rest * more in Ch 14
Self-Practice & Reinforcement
Instructions: In order to help yourself better understand the way the nervous
system is divided, take time to complete the following graphic organizer in your
notes:
Nervous System
Divided into two what two principal parts?
EXAMPLE
I. CNS or
________________
II. ________________
This one is further divided into:
1) Sensory
2) ____________
This one is further divided into:
a.
b.
(or voluntary)
(or involuntary)
i.
ii
Two Main Cell Types of the
Nervous System
1. _________ – excitable cells that transmit
electrical signals
2. ______________ – cells that surround
and wrap neurons
Supporting Cells continued
• The supporting cells are collectively known
as _______ or ___________. They:
– Provide a supportive scaffolding for neurons
– Segregate and insulate neurons
– Guide young neurons to the proper
connections
– Promote health and growth
6 Types of Neuroglia
Instructions: See practice handout & study guide
Astrocytes
• Most ________, versatile, and highly ____
glial cells
• They cling to neurons and their synaptic
endings, and cover capillaries
• Functionally, they:
– Support and brace neurons
– Anchor neurons to their nutrient supplies
– Guide migration of young neurons
– Control the chemical environment
Microglia and
Ependymal Cells
Microglia – small, ovoid cells
with spiny processes
- Phagocytes that monitor the
health of _________
Ependymal cells – range in
shape from squamous to
columnar
- They line the central cavities
of the __________________
Oligodendrocytes,
Schwann Cells, and
Satellite Cells
Oligodendrocytes – branched cells that wrap
CNS ____________
Schwann cells (neurolemmocytes) – surround
fibers of the PNS
Satellite cells surround neuron cell bodies with
ganglia
Neurons
• ______________ of the nervous system
– Composed of a body, axon, and dendrites
– Long-lived, amitotic, and have a high
metabolic rate
• Their plasma membrane functions in:
– Electrical signaling
– Cell-to-cell signaling during development
Basic Neuron Structure
Label your practice diagram.
Disorder: Multiple Sclerosis
In multiple sclerosis (MS), the ______________
are gradually destroyed and causes shortcircuiting and eventually impulse conduction
ceases. This autoimmune disease affects mostly
young adults.
Symptoms: visual disturbances, problems
controlling muscles, clumsiness, speech
disturbances, urinary incontinence, and
ultimately paralysis
Structure Meets Function, pgs 350 - 353
INSTRUCTIONS: What do these structures do? Match the structure with its
function. Write the letter of the answer only next to this slide. Estimated Time: 5-6
minutes
a. neurofibril nodes or gaps in the myelin
1. axon
sheath that occur along a myelinated axon
2. dendrites
b. rough endoplasmic reticulum
3. Nissl bodies
c. short, branching structures responsible
4. Schwann cell
primarily for reception or input
5. Node of Ranier
d. single structure on each neuron also
6. Myelin sheath
known as a nerve fiber; generates and
7. neurilemma
transmits nerve impulses
e. neurolemmocytes that surround and
form myelin sheaths around the larger
nerve fibers in the PNS
f. a portion of a Schwann cell
g. whitish-fatty protein material that
protects and insulates fibers and increases
the speed of nerve transmission
How Do Neurons Work?
• Neurons talk to one another with
___________ and __________ signals
• Neurons do not touch one another (there
is a gap or __________) between them
• Chemicals called ______________ help
conduction of nerve impulses.
Check it out:
http://video.google.com/videoplay?docid=7134684121021483823&q=neuron+imp
ulse&total=22&start=0&num=10&so=0&type=search&plindex=0
Neurotransmitters, pg 374 - 375
Neurotransmitters are essential to the nervous system and brain chemistry.
There are more than 50 identified neurotransmitters. We’re going to focus on
4 key ones.
Acetylcholine - triggers
muscle contraction and
stimulates the excretion of
certain hormones. In the
CNS, it is involved in
wakefulness, attentiveness,
anger, aggression, sexuality,
and thirst, among other
things.
Dopamine is an inhibitory
neurotransmitter involved in
controlling movement and
posture. It also modulates
mood and plays a central
role in positive reinforcement
and dependency.
Alzheimer’s disease is
associated with a lack of
acetylcholine in certain
regions of the brain.
The loss of dopamine in
certain parts of the brain
causes the muscle rigidity
typical of Parkinson’s
disease.
Neurotransmitters continued
Norepinephrine is a
neurotransmitter that is
important for attentiveness,
emotions, sleeping,
dreaming, and learning. It is
also released as a hormone
into the blood, where it
causes blood vessels to
contract and heart rate to
increase.
Serotonin contributes to
various functions, such as
regulating body
temperature, sleep, mood,
appetite, and pain.
Norepinephrine plays a role
in mood disorders such as
manic depression.
Depression, suicide,
impulsive behavior, and
aggressiveness all appear
to involve certain
imbalances in serotonin.
Neurotransmitter Review Questions
1. If a patient is known to have Alzheimer's,
what neurotransmitter is lacking?
2. If a patient has manic depression, what
neurotransmitter is not properly
balanced?
3. How about a patient displaying suicidal
behavior, aggression, and clinical
depression?
4. Parkinson’s with muscle rigidity?