Extra Credit Opportunity(during Spring Break)

Research a Neurological Disorder (up to 25 pts. Possible)

-15 pts. Trifold Display with all Questions & Concepts

-5 pts. Brief Presentation (3-5min) of your disorder

-5 pts. Peer voting of the best display (0-5 pts. poss.)

**If you are planning on presenting you must highlight your name on the sign up list TODAY so I can plan accordingly.

*Presentations will begin this Friday (chosen randomly).

Introduction to the Nervous SystemAlzheimer’s:

-Over 4 million American affected-Ronald Reagan was diagnosed with it-Mental and performance tests are conducted-Plaques become present in the brain

Symptoms include:-memory loss (forgetfulness)-confusion & frustration-depression

Tropicamide-causes pupils to dilate with Down’ Syndrome individuals and people with Alzheimer’s disease

The Nervous System

• Chapter 10

-Structure of a Neuron

-Neuroglial cells

-Classifying Neurons

-Nerve Conduction

-Regeneration

-Synaptic Potentials

-Reflex Arcs

Homework (Mon. 4/16)

• Read Pgs. 356 – 360 in Chapter

• Printout the Study Outline for Chapter 10http://highered.mcgraw-hill.com/sites/0072919329/student_view0/

• Do Pgs. 10-1 & 10-2

Introductory Questions #11) After reading the introduction in chapter 10, name the disorder

that our ex-president Ronald Reagan had. How many American are estimated to have the same disorder? What are some of the symptoms of this disorder? How can this disorder be diagnosed? What drugs are used?

2) Another name for a nerve cell is: . 3) There are TWO types of cells that make up the neural tissue.

Name them4) How do nerve cells transmit information (generally)?5) How do neuroglial cells differ from typical nerve cells?6) What is the name of the small spaces that exist between the

neurons? Can you give an example of a chemical that can be found in this space?

7) How do we classify neurons? What two criteria do we use?8) How many different types of neuroglial cells are there? Name

them.

Characteristics of the Nervous System

• Composed of Blood, connective tissue, and neural tissue

• Two types of nerve cells: Neurons & Neuroglial

• Impulses are sent as electrochemical signals

• Organs include: Brain & Spinal cord (Central NS)

Nerves or neurons (Peripheral NS)

• Three general functions:

-sensory -integration -motor

Three General Function of the Nervous System

A Typical Neuron Cell

Nervous Tissue

Basic Structure of a Typical Neuron

• Cell body- contains the genetic information & organelles• Axon- nerve fiber, conducts impulse away from cell body• Myelin sheath- lipoproteins surrounds the axon• Nodes of Ranvier- gaps in the myelin sheath• Dendrites – nerve fibers that are receptive surfaces• Schwann cells- neuroglial cells compose the sheath• Nissl bodies –membranous sacs (rough ER)• Neurofibrils –proteins that support the tissue

Cross Section of the Axon

Gray vs. White Matter

White matter: Nerve cells that are myelinated-appears white in brain & spinal cord-myelin produced by oligodendrocytes-lack neurolemmal sheaths

Gray Matter: Nerve cells that are unmyelinated-appears gray in the brain & spinal cord-composes most of the CNS tissue

**Note: Myelinated cells more common in the peripheral nervous system produced by schwann cells

Read the Article and answer the following questions:1) What does the book “Driving Mr. Albert” tell about?2) What did Marian C. Diamond discover about Einstein’s

brain?3) What is the traditional thought of what glial cells do?

What is the new view in this article suggesting?4) How are the voltage-sensitive ion channels different in a

glial cell vs. a typical neuron?5) How do glial cells convey messages to other neurons?6) Why are glial cells thought to be able to respond to a

range of chemicals?7) What new laboratory method did scientists devise in order

to determine if glial cells (schwann cells) were sensitive to neuronal signals?

8) How do glial cells and neurons work together? (pg. 57)9) What did Peter Guthrie discover about astrocytes an ATP

in 1999? (pg. 58)

Article QuestionsRead the Article “The Other Half of the Brain” and answer the

following questions:• What does the book “Driving Mr. Albert” tell about?• What did Marian C. Diamond discover about Einstein’s brain?• What is the traditional thought of what glial cells do? What is the

new view in this article suggesting?• How are the voltage-sensitive ion channels different in a glial cell

vs. a typical neuron?• How do glial cells convey messages to other neurons?• Why are glial cells thought to be able to respond to a range of

chemicals?• What new laboratory method did scientists devise in order to

determine if glial cells (schwann cells) were sensitive to neuronal signals?

• How do glial cells and neurons work together? (pg. 57)• What did Peter Guthrie discover about astrocytes an ATP in 1999?

(pg. 58)

Neuroglial cells (glial cells)

• Found in the Central Nervous System• Fill spaces• Provides scaffolding• Guides & stimulates specialization• Produces growth factors• Nourishes other neurons• Removes ions and neurotransmitters that accumulate• Four different Types:Astrocytes Oligodendrocytes Microglial Ependyma

Neuroglial Cells

Classifying Neurons• Size (length)

• Shape: Bipolar, Unipolar, Multipolar

• Function: Sensory, Interneuron, Motor

• Number of Synaptic knobs

Structural Differences of Neurons

• Bipolar neurons: eyes, ears, and nose (sensory)

• Unipolar neurons: (ganglia outside the CNS)

• Multipolar neurons: (brain & spinal cord)

Structural Types of Neurons

Functional Differences in NeuronsSensory neurons

-receptor ends -controls impulses toward the CNS-referred to as afferent neurons

Interneurons -association nerves-multipolar neurons, CNS

Motor neurons-Efferent nerve fibers

-controls impulses away from the CNS -common in glands and muscle tissue

The Four Types of Neuroglial Cells• Astrocytes~ star shaped cells

-found between neurons and blood vessels-provides support & binds structures together-regulated glucose and potassium concentrations-responds to brain injury-nourishes nearby neurons & releases growth factors

• Oligodendrocytes-arranged in rows -forms the myelin sheath around the axons (in CNS)-produces nerve growth factors

• Microglial Cells

-scattered throughout the CNS-provides structural support-Phagocytic (immune protection)

• Ependymal-cuboidal /columnar cells-lines the ventricles (cavities) of the brain-allows free diffusion of CSF (cerebral spinal fluid)

Table-Pg. 366

Neuroglial Cells

Migraine Headaches (pg. 358)

• A response to changes in the diameters of the blood vessels in the brain

• Constriction followed by dilation• Symptoms: pain, vomiting, sensitivity to light• Classical (4-6 hrs) observed in 10-15% sufferes• Common migraines: lasts up to 3 to 4 days• Serotonin levels are abnormal (constrict vessels)-deficiency

• Some think caused by diet: chocolate, wine, nuts, etc.• Beta blockers (imitrex & tricyclic antidepressant)

keep the amount of serotonin available

Nerve Regeneration Pg. 362 • Can occur if the axon is damaged• Will not occur if the cell body is damaged or separated from

the axon• In peripheral nerves

-the proximal ends can regenerate (must be guided)-distal portion will degenerate if damaged -proximal end of injury regenerate with help from the Schwann cells which will proliferate.

• In the CNS regeneration is highly unlikely• Growth rate: 3 to 4 mm per day• Neuromas can develop when the injury gap is more than

3mm.

A Typical Neuron Cell

Cross Section of the Axon

Impulses Conducted through Neurons

Florescent Image of two Neurons

The Axon of a Neuron

An Animated View

• Voltage gated channels & Proteins:

http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html#

**Choose the “sodium-potassium exchange” clip

Introductory Questions #21) How are motor neurons different from sensory neurons? How are

neuroglial cells different from typical nerve cells? Name all four types of neuroglial cells and indicate the one that provides immune protection.

2) What is the name of the small spaces that exist between the neurons? Can you give an example of a chemical that can be found in this space?

3) How does the cell membrane become polarized in a neuron?4) What are the major ions associated with generating a membrane

potential? Which ions are present in large amounts inside and outside the cell? What causes the inside of the cell to be more negative (less positive) compared with the outside? How much of a difference is there?

5) How is the resting potential different from an action potential?6) What does it mean when a membrane is “Depolarized” and

“Repolarized”?

A Look at the Membrane Proteins

Factors that lead to a Resting Potential• A charge difference builds across the membrane

• It becomes Electrically charged (polarized)

• Unequal distribution of ions one each side of the membrane: K+ and Na + (cations)

• Inside is negatively charged vs.the outside which is positively charged

• Involves pores and channels (proteins) that are embedded within the membrane

Factors that Build a Polarized State

• Potassium ion move through the membrane more easily than sodium

• High [Na+] on the outside & low on the inside

• High [K+] on the inside and low on the outside

• Anions are present inside the cell that cannot diffuse through the membrane (impermeable)

(phosphates, sulfates, and proteins)

• Potassium ions can diffuse out faster than sodium ions can diffuse in Animated view:

http://bcs.whfreeman.com/thelifewire/content/chp44/4401s.swf

The Sodium-Potassium Pump: Establishing a Resting Potential

Neural Signaling

Resting Potential & Action Potential

• Resting Potential: – Cell reaches a charge difference of –70mV– More Cations (Na+ & K+) on the outside– More anions inside and very little Na+ & K+ – K+ is diffusing out (high to low)– Na+ can’t diffuse in so remains high outside– Sodium/potassium pump increases this difference

• Action Potential: – A depolarization & repolarization occurs– Speed is one-one millionth of a second

Neural SignalingThreshold potential: Must reachThe action potential involves: Depolarization & Repolarization Voltage-

gated ion channels open & close (Na+& K+)1-Resting state: both channels closed Membrane potential (-70mV)2-Threshold is reached (-50 to -55 mV) caused by a stimulus

- Na+ channels open and sodium rushes in the cell3-Depolarization action potential is generated as Na+ moves in cell -cell

internally becomes more positive: -40mV----20mV---etc***A peak is reached of about +35 mV4-Repolarization- begins once the peak voltage of +35mV is reached

-Na+ channels close-K+ channels open and potassium ions leave the cell -The cell internally becomes negative

5-Undershoot –80mV to –90mV is reached for a brief time -Both gates close-K+ channel is slow to close & resting potential is restored

Introductory Questions #31) After reading Clinical application 10.1 (pg. 358), how does a

migraine headache occur? What can be done to relieve the pain?

2) How does gray matter different from white matter (other than color)?

3) Is it possible for a neuron to regenerate? If so, explain how.4) How does the cell membrane of a neuron become polarized?

What are the major ions associated with with generating a membrane potential?

5) Explain what a threshold potential is and give the voltage value that must be reached by the neuron’s membrane.

6) What happens during the refractory period? 7) What is the peak voltage for the action potential?8) Explain what is happening when “hyperpolarization” occurs.

How is hyperpolarization different from Depolarization?

Key Steps of an Action Potential

An Action Potential

• Voltage gated channels & Proteins:

http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html#

Choose: “Action potential propagation in an unmyelinated axon”

Beginning of an Action Potential

Self-Propagating Signaling• The impulse travels as a “wave of Depolarization”

• The action potential Regenerates itself after refractory period

• Forward direction only

• Action potential speed:

• 1-Axon diameter (larger = faster; 100m/sec)

• 2-Nodes of Ranvier (concentration of ion channels); saltatory conduction; 150m/sec

Homework Fri. 4/20• Do the Practice STAR Test for Biology on my website.

(90 questions)• Continue work on your Study Outline

– Do Pgs. 10-3 & 10-4

Homework Fri. 4/20• Go to my website and do the Practice STAR Test for

Biology. (there are 90 questions)• Write your answers on a separate sheet of paper.• Bring it in on Monday, Receive a stamp, and you will be

able to grade it. • After grading it, then you will able to attempt another 15

Question test and for every THREE questions you get correct you will earn an extra credit point for a total or possible of 5 points.

• Overall you can earn:

5 pts. + 2 pts. + 1 pt. = 8 pts.

(# correct) (stamp) (grading it)

Generating an Action Potential

Neural Signaling• Excitable cells~ cells that can change membrane potentials

(neurons, muscle)• Resting potential~ the unexcited state of excitable cells• Gated ion channels (open/close response to

stimuli)photoreceptors; vibrations in air (sound receptors); chemical (neurotransmitters) & voltage (membrane potential changes)

• Graded Potentials (depend on strength of stimulus):• 1- Hyperpolarization (outflow of K+) increase in

electrical gradient; cell becomes more negative• 2- Depolarization (inflow of Na+) reduction in electrical

gradient; cell becomes less negative

Key Steps of an Action Potential

Depolarized & Repolarized Membrane Activity

Membrane Proteins Role

Synaptic Cleft-Release of Neurotransmitters

Homework (Thurs. 4/19)

• Read Pgs. 356 – 360 in Chapter

• Do more of the Study Outline for Chapter 10http://highered.mcgraw-hill.com/sites/0072919329/student_view0/

• Do Pgs. 10-3 & 10-4

Multiple Synapses: IPSP & EPSP

Neurotransmitters

**There are thirty different types of Neurotranmistters

Acetylcholine (most common) “cholinergic”•skeletal muscle

Biogenic amines (derived from amino acids)•norepinephrine •dopamine •serotonin

Amino acids

•GABA (gamma-aminobutyric acid)Neuropeptides

•endorphins

How Drugs affect Neurotransmitter activity

• Block the binding site for the neurotransmitter• Reduce the effect of the enzyme that breaks down the

neurotransmitter• Enhance the activity of the neurotransmitterDrugs include:

-Nicotine (mimics activity) -Curare (blocks the action acetylcholine)

Inhibitory-Cannabis -Alcohol -Benzodiazepines

Causes Adrenalin release: -Amphetamines -Caffeine -Cocaine

Neurotransmitters affected by a Drug

• Acetylcholine: Curare () & Nicotine ()

• Serotonin: Prozac () & Tryptophan ()

• Norepinephrine: Cocaine & Antidepressants

• GABA: Valium

Read pg. 379-Clinical Application 10.5

What causes people to become addicted to drugs?

Disorders with Neurotransmitters

Look at the tables listed on pg 377 and name the condition and neurotransmitter that causes each condition.

-Excessive sleeping

-Inappropriate emotional responses, hallucinations

-Progressive muscular weakness (also pg. 373)

-Inability to sleep

-Memory loss, depression, and disorientation

-Tremor in the hands, slow movement from rigid muscles

-Uncontrollable movements of facial muscles

Simple Nerve Circuit

• Sensory neuron: convey information to spinal cord• Interneurons: information integration• Motor neurons: convey signals to effector cell (muscle or

gland)• Reflex: simple response; sensory to motor neurons• Ganglion (ganglia): cluster of nerve cell bodies in the PNS• Supporting cells/glia: nonconductiong cell that provides

support, insulation, and protection

Simple Nerve Circuit

Reflex- the Neurons involved

Sensory-Interneuron-Motor Neurons

Assignment Packet

• Study Guide (3 stamps)

• Video notes (2 segments-20 statements)

• Online quiz answers (one quiz only)

• Practice (review) test ----today’s assign.

• IQ’s #1-5

• Notes taken in class

Introductory Questions #4

1) When a nerve cell is depolarizing what is happening in regards to the sodium and potassium protein channels? Is the potential becoming more positive or negative?

2) When an action potential arrives at the synapse, what happens to the neurons permeability enabling the exocytosis of neurotransmitters? Name three types of neurotransmitters. Which is the most common neurotransmitter?

3) From the video, which neurotransmitter was morphine similar to? What happens to a neurotransmitter once it has depolarized the postsynaptic membrane of the next cell?

Introductory Questions #5

1) Name the neurotransmitter that effects sleep. 2) Name three drugs that have an effect on the

norepinephrine neurotransmitter (pg. 373) Name the neurotransmitter that cannot be retaken up and is blocked by Prozac .

3) How is an IPSP different from an EPSP? 4) How is a general visceral efferent nerve fiber

different from an special visceral efferent fiber?5) Name three different reflex behaviors. Name the

five parts of a reflex arc. (See pg. 380, chart 10.7)