Module 3Brain’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 or2. 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 Potential5. 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. GABA2. Epinephrine3. Norepinephrine4. Serotonin5. Endorphin6. Dopamine7. Nitric oxide8. 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.