Introduction to the BRAIN

(And neurons)

On the paper around the room, write what you know about the Brain, the Nervous System, a Neuron, and/or the Endocrine System.◦ Everyone must write SOMETHING.

Brain Brain Dump

Thumbs up for TRUE

Thumbs down for FALSE

Preassessment

Plasticity refers to the brain tissues ability to take on new roles when a part of the brain has been damaged.

1.

TRUE

If Sammy (age 55) damages the same part of the brain as a Jenny (age 12), Sammy’s brain is more likely to recover faster and take on more roles then Jenny’s brain

2.

FALSE

The human brain produces its own natural opiates that elevate mood and ease pain.

3.

TRUE

We ordinarily use only 10% percent of our brain.

4.

FALSE

Some people can write but are unable to read.

5.

TRUE

Removal of an entire brain hemisphere would necessarily result in a person’s death.

6.

FALSE

When looking at human brains, researchers cannot tell the difference between people from different racial backgrounds. (European, American, Asian, African, etc.)

7.

TRUE

The central nervous system is a major division of the nervous system and consists of the brain and the spinal cord.

8.

TRUE

The pituitary gland is an endocrine gland which secretes hormones that do not affect anything but the sex glands

9.

FALSE

The fight or flight response refers to physiological changes such as increased heart rate, accelerated breathing, dry mouth, and perspiration that occur in response to perceived threats or danger.

10.

TRUE

The parasympathetic nervous system is a branch of the autonomic nervous system that produces rapid physical arousal in response to perceived emergencies or threats.

11.

FALSE

The all or none principle states that a neural message either fires or it doesn’t.

12.

TRUE

If you hook an EEG to a blob of jell-o, you will get EEG wave pattern that is almost identical to a human

13.

TRUE

When looking at human brains, researches cannot tell the difference between a male and female brain.

14.

FALSE

Electrically stimulating a cat’s brain at a certain point can cause the animal to cower in terror in the presence of a small mouse.

15.

TRUE

We are going to start small and go big

Neurons: The Building Blocks

of the Nervous System

A small thing in the nervous system that communicates.

Kind of like a cell phone, or maybe even us.

A neuron RECIEVES information, and then GIVES information to the next neuron.

What IS a Neuron?

The concept of a neuron is simple: It receives information, carries information, and sends information

However, there are fancy words scientists use to label each part of the neuron.

This is what a neuron looks like

Here’s a different angle.

Information comes to a neuron through the DENDRITES

They’re branchy fibers that receive information

Let’s start with the beginning…

There they are.

LIFE GIVING FORCE! It’s the reason the neuron is alive Information does not pass through the soma, but without it, the neuron would die. Oh no!

Soma (Cell Body)

Filled with the juice of life.

Axons carry the message!It’s the long, skinny part.

Axon

See?

Fatty substance insulating the axon

SPEEDS UP the communication

FAST FAST FAST

Myelin Sheath

SENDS the information away to the new neuron

Contains neurotransmitters

Axon Terminal

We can become a neuron.

STAND UP!

On a sheet of paper (I will give you) DRAW AND LABEL a neuron. ◦Under each part of the neuron, write its function.

◦Number each part of the neuron to explain the where the impulse goes (for instance, Dendrites are number 1)

◦MAKE IT PRETTY. USE COLORS!

Draw and Label

Neural Communication:

The Neural Impulse

Electrical stimulation!◦A neural impulse.An electrical current travels down the axon.

How do neurons communicate?

Action potentials are created by changing CHARGES inside and outside the neuron

Ions: Some + and some are – Polarization: there is a difference between charges inside and outside the neuron◦Outside is POSITIVE; inside is NEGATIVE

Action Potential

There is excess Sodium outside the neuron There is excess Potassium inside the neuronThey want to be equal (CHEMISTRY)

Thus, when a neuron is stimulated by another neuron- depolarization occurs.

Action Potential

When depolarization occurs, there is EXCITATION because there is a + charge inside the neuron, giving the neuron the stimulus it needs to begin the action potential.

Depolarization

Demonstration!!

6 people

I will guide you through it once, and then the class will have to guide you through again.

Depolarization

A neuron either fires, or it doesn’t- there is no half firing.

There is a base amount of excitation that the neuron needs, and if it gets that, it will ALWAYS fire.

Each time it fires, it fires with the same intensity.

If the base number is 30, it will fire the same at 30 , 31, and 500. If it is 29, it will not fire.

All-or-None Law

After an action potential, there is a certain amount of time that the neuron is unable to fire again. (It needs to recharge!)

Once the refractory period is complete, it can recharge again.

Refractory Period

The state of a neuron when it is at rest and capable of generating an action potential

The neuron is set and ready to fire, but does not. It is RESTING.

Resting Potential

Can anyone think of any other examples that relate to the all-or-nothing?

Set up dominoes in groups and complete the sheet.

DOMINOES!!!!!

Axon Terminals- Terminal Buttons

Synapse- point of communication between two neurons

Synaptic gap: Neurons do not touch each other, so there is a TINY fluid filled space separating them

Communication between Neurons

Neurons communicate through neurotransmitters.

They are natural chemicals your brain produces that can affect your mood.

When they are overproduced or under produced, they are involved in many psychological disorders.

Neurotransmitters

Enables muscle action, REM sleep, and memory

Undersupply, as ACh-producing neurons deteriorate, marks Alzheimer’s disease

Acetylcholine (ACh)

Reward and Motivation, Motor Control over Voluntary Movements

Excessive dopamine receptor activity is linked to schizophrenia; a lack of dopamine produces the tremors and lack of mobility of Parkinson’s disease

Dopamine

Affects mood, hunger, sleep, and arousal

Undersupply is linked to depression; Prozac and other anti-depressants raise serotonin levels

Serotonin

Helps to control alertness and arousal

Undersupply can depress mood

Norepinephrine

Muscular movement; inhibition of brain activity

Undersupply linked to seizures, tremors, and insomnia

Anxiety disorders

GABA

Involved in memory

Oversupply can over stimulate the brain, producing migraines or seizures

Glutamate

Natural opiates that are released in response to pain and vigorous exercise

Endorphins

Adrenaline Burst of Energy (small amounts in brain)

Epinephrine