Transcript Neurons and Neurotransmitters

Chapter 2 pt. 1: Biology, Neurons,
and Brain Imagery
Warm Up - Reading Quiz

Study until the bell. You will have 7 minutes for the
reading quiz.
The Neuron

The basic building block of the nervous system is
called the neuron or a nerve cell.
Parts of the Neuron
1.
Dendrites: branching extensions that
receive incoming messages and pass messages
toward the cell body. (Dendron = “tree” in Greek)
2.
Soma: is the
cell body - contains
the nucleus. (Soma
= “body” in Greek)
Parts of A Neuron

3. Axon: extension of a
neuron which sends
messages from the soma to
other neuron. Longest part of
the neuron. (Think “axis” … a
long line.)

4. Terminal Buttons:
located on end of the axon.
Release neurotransmitters to
communicate with other
neurons. (“Terminal” just
means “end”)
Parts of A Neuron
5.
Myelin Sheath: a layer of fatty cells encasing
the fibers of many axons which allows faster
transmission speeds in neurons.
How Does A Neuron Communicate?

Action Potential: neural impulse or brief electrical
charge that travels down an axon at speeds as fast as
200 mph. It happens when you feel something. “ALL
OR NOTHING” response (like a gun firing).

Resting Potential: refers to the neuron when it is not
active. Is negatively charged.

Threshold: refers to the minimal level of stimulation
required for a neural impulse to fire.
Neuron Communication With Other
Neurons

For two neurons to
communicate, the
impulse (the message)
from one must jump over
a gap called the
synapse to the other
one.

Synapse: space
between the axon which
is sending the signal and
the dendrite which is
receiving the signal.
Neuron Communication
At
the end of the
axon, the terminal
buttons release
neurotransmitters.

Neurotransmitters
are chemicals that
carry messages across
the synapse. They
influence whether
another neural impulse
will take place.
(Epilepsy video)
Answer these in your notes:
1) What is epilepsy?
2) How do electrical messages cross the
space between nerve endings?
3) What are the two types of
neurotransmitters? (Describe what the
each do – the video didn’t say their
names).
Types of Neurotransmitters
GABA: helps relax
and calm down the
body.
– Shortage may
cause Anxiety
or Epilepsy.
Types of Neurotransmitters

1. A-ce-tyl-cho-line
– Important in learning and
memory.
– Best known for allowing muscle
contraction.

Shortage may lead to
Alzheimer’s disease or
muscular disorders.
Types of Neurotransmitters

2. Serotonin: mood,
hunger, and arousal.
– Shortage may lead to
depression

3. Dopamine: movement,
attention, and emotion.
– Excess may lead to
schizophrenia and
Parkinson’s disease.
Types of Neurotransmitters

4. Norepinephrine: helps control
alertness and arousal when you are
scared or excited.

5. Endorphins: “The morphine
within.” Linked to pain control and
pleasure. (Runner’s high)
Agonists vs. Antagonists

Agonists are chemicals that mimic the effects of a
neurotransmitter.

Antagonists are chemicals that block the transmission
of a neurotransmitter.