module 3 brain’s building blocks. the human brain 1350 gram > 3 pounds 1 trillion cells 2 types...
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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
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 gate1. 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. GABA
2. Epinephrine
3. Norepinephrine
4. Serotonin
5. Endorphin
6. Dopamine
7. Nitric oxide
8. 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.