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. 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 4 th leading cause of death among adults 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.