Transcript Module 3 Brain`s Building Blocks

Module 3
Brain’s Building Blocks
The Human Brain
 1350 gram > 3 pounds
 1 trillion cells
 2 types of brain cells
 Glial cells (900 billion)
 Neurons (100 billion)
Structure of the Brain
 Genes



Chains of chemicals that
are arranged like rungs
on a twisted ladder
There are about 30,000
genes that contain
chemical instructions that
equal about 300,000
pages of written
instructions
Genes program the
development of individual
parts into a complex
body & brain
Structure of the Brain
 3 functions of glial cells



Provide scaffolding to
guide the growth of
developing neurons and
support mature neurons
Wrap around neurons
and form an insulation to
prevent interference from
other electrical signals
Release chemicals that
influence a neuron’s
growth and function
Structure of the Brain
 Neuron
 Receive and transmit electrical signals at
speeds up to 200 miles per hour
 Information network allows us to:




Receive sensory information
Control muscle movement
Regulate digestion secrete hormones
Engage in complex mental process
 Thinking, imagining, dreaming, remembering
Neuron (structure and function)
Growth of New Neurons
 Humans have a limited capacity to grow new
neurons.

Certain areas can grow new neurons



Frontal cortex (motor movements, cognition)
Temporal cortex (hearing, speaking)
Hippocampus (encoding information)
Neurons vs. Nerves
 Peripheral Nervous
System



Made up of nerves
Located throughout the
body
Except in the brain and
spinal cord
 Nerves


String like bundles of
axons and dendrites
that come from the sinal
cord
Carry information from
the senses, skin,
muscles, and organs to
and from the spinal cord
Central Nervous System
 Made up of neurons
located in the brain and
spinal cord
 Brain/ Spinal Cord
injuries


Fetal neurons
 Pig nuerons
Stem cells
Action Potential
1. Feel a sharp object (Stimuli)
2. Axon membrane: chemical gate
1. Open to allow electrically charged particles to enter or
2.
can close to keep out electrically charged particles
Action Potential
3. Ions: Charged Particles


Electrically charged
chemical particles,
positive and
negative

Like particles
repel

Opposites attract
NA+ attracts
Protein-
Action Potential
4. Resting State:


Charged Battery
 Potential
Sodium Pump- is a
transport process that
picks up any sodium
ions that enter the
chemical gates and
returns them back
outside
Action Potential
5. Action Potential


a tiny electrical current
that is generated when
the positive NA+ ions
rush inside the axon
The increase of NA+
ions inside the axon
causes the axon to
reverse its charge.
The inside becomes
positive and the
outside becomes
negative
Nerve Impulse
 Refers to the series of separate action
potentials that take place segment by
segment as they move down the length of an
axon.
6. Sending Information

like a fuse, burns until it reaches its end.
Transmitters

A chemical messenger
that transmits
information between
nerves and body
organs, such as
muscles and heart.
1.
2.
3.
4.
5.
6.
7.
8.
GABA
Epinephrine
Norepinephrine
Serotonin
Endorphin
Dopamine
Nitric oxide
Acetylcholine
Transmitters
 Excitatory
 Open chemical locks in
the heart and cause it
to beat faster
 Inhibitory
 Block chemical locks in
the heart and cause it
to decrease in rate
 Transmitters
 communicate between
nerves and body
organs (muscles/
heart)
Alzheimer’s Disease
 90% of the time begins after age 65
 10% of the time begins after age 50
 4th leading cause of death among adults
 2000 4 million people (5% of the adults over 65) had
the disease.
 Numbers are expected to rise with increase in life
expectancy
 Causes: genetic, neurological, or environmental
 3 times more likely to get it if 1 parent has it.
 5 times more likely to get it if both parents have it.
 There currently is no cure and it is always fatal.
Alzheimer’s Disease
 Initial Symptoms
 Problems with memory
 Forgetting
 Repeating things
 Getting lost
 Being mildly
confused

Cognitive Deficits
 Problems with
language
 Difficulties
recognizing objects
 Inability to plan or
organize tasks
Alzheimer’s Disease
 Over a period of 5 to 10 years





Profound memory loss
Lack of recognition of friends and family
Deterioration of personality
Emotional outbursts
Fatal
Parkinson’s Disease
 Includes symptoms of:
tremors and shakes in the limbs
 a slowing of voluntary movements
 and feelings of depression.
 As the disease progresses:
 Patients develop a peculiar shuffling walk
 May suddenly freeze in space for minutes or hours at a time.
 Parkinson’s is caused by a destruction of neurons that produce
the neurotransmitter Dopamine
 1.Biochemistry. a catecholamine neurotransmitter in the
central nervous system, retina, and sympathetic ganglia,
acting within the brain to help regulate movement and
emotion: its depletion may cause Parkinson's disease.
 2.Pharmacology. a dopamine preparation used to increase
the force of contraction of the heart in the treatment of shock.
