Transcript Neurons and the Brain

The Biological Basis
of Behavior
Chapter 2
Background
1/3 of humanity is dead
2.3 billion have died
Virus is spreading exponentially
No vaccines or cures have been found
Attempts to eradicate have been futile
We are the last hope
Mission Statement
You have been recruited because you are the best and brightest
young minds, work well in groups, and most important of all,
your creativity.
We will be focusing on neuroscience as we have deduced that
the brain plays a very important role in explaining zombie
behavior.
Your goal will be to become a medications development
specialist and create a cure for the zombie plague that is
destroying the world.
Over the course of this unit you must
learn about the following to save our
civilization:
Neurons
Neurotransmission
Neurotransmitters
Neuroanatomy
Medications development
A Neuron is
A specialized cell that receives information and
transmits it to other cells.
Neurons: The Messengers
About 100 billion neurons (nerve cells) in the human
brain
Neurons have many of the same features as other
cells.
Nucleus
Cytoplasm
Cell membrane
What makes neurons unique is their shape and
function.
Neuron under an electron microscope
Structure of Neurons
Dendrites
Carry information to the cell body
from other neurons
Cell Body (Soma)
Contains nucleus
Axon
Carries information to the next
cell
Myelin Sheath
Insulates the axon and speeds up
the neural impulse
Make your own Neuron
Dendrite
Axon
Soma (cell body)
Nucleus
Myelin Sheath
Terminal Buttons
Give your Neuron a name fit for a zombie film
Give it some color, make it spooky
How does it work?
Neurotransmission is a
fancy name for two or
more neurons
communicating with
each other.
The Neural Impulse: resting potential
Neurons stay at rest
with their sodium
ions on the outside of
the cell body (or
soma) and potassium
ions on the inside.
The Neuron isn’t
transmitting information
The Neural Impulse
Neurons are no
longer at rest when
the sodium ions on
the outside of the
cell body rush in and
potassium ions on
the inside rush out.
The Neural Impulse: Action Potential
Sudden, massive
change in charge in the
neuron
Occurs when
depolarization reaches
the threshold of
excitation
Ions flow across cell
membrane
The Neural Impulse
The electrical impulse
races down the axon
The Neural Impulse
All-or-None Law
A neuron either fires or it does not.
When it does fire, it will always produce an
impulse of the same strength.
Intensity of a stimulus is coded by the
frequency of action potentials.
The Neural Impulse
Once the electrical
impulse reaches the
terminal button it triggers
the vesicles (containing
neurotransmitters), to
move toward the bottom
of the terminal button.
The Neural Impulse
Neurotransmitters are
released from
terminal buttons and
cross the tiny space
between it and the
next neuron called the
synaptic gap.
The Synapse (Synaptic space)
Tiny gap between
neurons.
The synapse is
composed of the
terminal button of one
neuron, the synaptic
space, and the dendrites
or cell body of the
receiving neuron
https://www.youtube.com/watch?v=90cj4NX87Yk
https://www.youtube.com/watch?v=-SHBnExxub8
Lets Simulate this process
Neurotransmitters
Neurotransmitters
A neurotransmitter is a
chemical messenger that
carries signals between
neurons as well as other
cells in the body.
These chemicals are
released from the end of
one neuron and cross the
synapse to receptor sites
in the next neuron.
Transmission Between Neurons
Some Well-Known
Neurotransmitters
Acetylcholine (ACH)
It’s the most common neurotransmitter. It is located in
both the central nervous and peripheral nervous
system.
It acts on basic autonomic and muscular functions
Plays an important role in arousal and attention
Loss of ACH producing cells is linked to Alzheimer’s
Dopamine
Affects neurons associated with voluntary
movement and plays a role in learning, memory,
and emotions.
Loss of dopamine-producing cells causes
symptoms of Parkinson's.
Glutamate
Is an excitatory neurotransmitter
Plays a role in learning and memory
Too much can cause seizures
Malfunction of glutamate has also been
associated with Alzheimer's
Epinephrine
Also known as adrenaline
Causes the feeling of being “revved up” or on
edge
Activates a “fight or flight” reaction in the
autonomic nervous system
Serotonin
Attention and other complex cognitive
functions, such as sleep (dreaming), eating,
mood, pain regulation
Neurons which use serotonin are distributed
throughout the brain, stomach and spinal cord
Issues with this leads to Mood disorders like
depression
GABA (gamma-aminobutyric acid)
It’s the most important and common
inhibitory neurotransmitter
Stops the brain from becoming
overexcited
Too much may cause hallucinations
Endorphins
Reduce pain by inhibiting or “turning
down” neurons that transmit pain
information
Our brain evolved over time
1. Lizard Brain - Basic functions
2. Mammalian Brain - More complex
feelings and reactions
3. Human Brain - Logic and reasoning
The Brain Stem or Hindbrain
(The Lizard Brain)
Activity in the brain stem is
important for:
*bodily activities essential
to survival, such as
changes in heartbeat and
breathing
*the focusing of attention
*patterns of arousal (that
is sleeping versus waking)
The Midbrain/ Limbic System
(The Mammalian Brain)
Located in the middle
of the brain
Associated with these
behaviors:
1. Fighting
2. Feeding
3. Fleeing
4. Reproductive behavior
* The part of the brain that regulates emotion
Important parts of the midbrain
The Thalamus
processes and relays
movement and sensory
information.
It is a relay station,
taking in sensory
information and then
passing it on to the
cerebral cortex.
Important parts of the midbrain
The hypothalamus
connects with many
other regions of the
brain and is responsible
for controlling hunger,
thirst, emotions, and
body temperature
regulation.
Important parts of the midbrain
Amygdala
An almond-shaped
structure, involved
in the experience
of negative
emotions like fear.
The Cortex/Cerebrum
(The Human Brain)
The outer layer of the
brain
Responsible for
“executive functioning”
It’s what makes us
human
Thinking
The Frontal Lobe
At the back of the
frontal lobe lies the
Primary motor
cortex. This area
sends messages to
carry out body
movement.
The Parietal Lobe
Within the parietal lobe
is the somatosensory
cortex which registers
sensory information
from the entire body.
The Temporal Lobe
The hippocampus is
located in the
temporal lobe, which
is associated with
memories.
Label the Brain
Go to the class website and
open the document “Label
the Brain Activity”
Page 60 and 61 would be a
good reference for this
activity.