Unit IIIA Outline

I. Neural Communication

Information systems of humans very similar

Ease of study (squid, sea slugs, primates)

Cars are different, but have similar parts

Engines, Accelerators, Steering Wheels, Brakes

A. Neurons

Three “types”

Sensory Neurons-Sensory receptors to the brain and spinal cord

Motor Neurons-Brain and spinal cord out to muscles and glands

Interneurons-Neurons in the brain and spinal cord that act between sensory input and motor output

Information traveling at phenomenal speeds

Anywhere from 2 to 200 Mph

Measured in milliseconds (thousandths of seconds)

Firing of a neuron

Action Potential-A neural impulse

Ions-Positively and negatively charged

Resting Potential-Positive outside/negative inside

Selective permeability

Firing of a neuron

Depolarization

Refractory period

Excitatory (accelerator) vs Inhibitory (brake)

Threshold

All or none response (like a gun)

B. How Neurons Communicate

Synapse-The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Synaptic gap or cleft

Neurotransmitters-Chemicals that travel across the synaptic gap and bind to receptor sites

Reuptake-Waste not, want not.  Reabsorption of neurotransmitters by the sending neuron

C. How Neurotransmitters Influence Us

i. How Drugs and Other Chemicals Alter Neurotransmission

Agonists vs Antagonists

Agonists mimic the effects of neurotransmitters

Antagonists block a neurotransmitters functioning

II. The Nervous System

A. The Peripheral Nervous System

Made up of the Somatic and Autonomic systems

Somatic-AKA-Skeletal Nervous System

Voluntary movement

Autonomic-AKA-”Automatic” Nervous System

Involuntary movement

Divided into the Sympathetic and Parasympathetic Nervous Systems

B. The Central Nervous System

40 billion neurons in the brain

Each connected to 10,000 other neurons

Grain of sand contains 100,000 neurons and 1,000,000,000 synapses

Reflexes (knee jerk)

III. The Endocrine System

“Snail Mail”

Endocrine messages outlast neural messages

Upset feeling linger

Adrenal glands on top of kidneys