Preview p 48 1 Take a True False

Preview p. 48 1. Take a True / False Quiz from the front of the room 2. Complete the True / False Quiz (You may write on it and glue in your Notebook)

Neuroscience pp. 52 -65 NB p. 49

Phrenology

Part of the Neuron

Parts of the Neuron

Parts of the Neuron

Parts of the Neuron

Parts of the Neuron

Parts of the Neuron

NEURAL COMMUNICATION

Action Potential • A brief electrical charge that travels down the axon of the neuron. • A neural impulse • Considered an “on” condition of the neuron

Refractory Period • The “recharging phase” when a neuron, after firing, cannot generate another action potential • Once the refractory period is complete the neuron can fire again

Resting Potential • The state of a neuron when it is at rest and capable of generating an action potential • The neuron is set and ready to fire

Neuron firing like a Toilet 1. Like a Neuron, a toilet has an action potential. When you flush, an “impulse” is sent down the sewer pipe

Neuron firing like a Toilet 2. Like a neuron, a toilet has a refractory period. There is a short delay after flushing when the toilet cannot be flushed again because the tank is being refilled

Neuron firing like a Toilet 3. Like a Neuron, a toilet has a resting potential. The toilet is “charged” when there is water in the tank and it is capable of being flushed again 4. Like a Neuron, a toilet operates on the all-or-none principle – it always flushes with the same intensity, no matter how much force you apply to the handle

All-or-None Principle • The principle that if a neuron fires it will always fire at the same intensity • All action potentials are of the same strength. • A neuron does NOT fire at 30%, 45% or 90% but at 100% each time it fires.

COMMUNICATION BETWEEN NEURONS

Synapse • The tiny, fluid filled gap between the axon terminal of one neuron and the dendrite of another neuron • The action potential cannot jump the gap

Neurotransmitters • A chemical messenger that travels across the synapse from one neuron to the next • Can influence whether the second neuron will generate an action potential or not

Neurotransmitters

Excitatory Effect • A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential (impulse) • The second neuron is more likely to fire.

Inhibitory Effect • A neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential (impulse) • The second neuron is less likely to fire.

Class Neuron

NEURAL COMMUNICATION: THE NEURAL CHAIN

Receptor Cells • Specialized cells in the sensory systems of the body that can turn other kinds of energy into action potentials that the nervous system can process • Receptor cells in the eye turn light into a neural impulse the brain understands.

Sensory Neurons • Neurons that carry information to the central nervous system • Connect the sense organs to the brain and spinal cord

Interneurons • Nerve cells in the brain and spinal cord responsible for processing information related to sensory input and motor output

Motor Neurons • Nerves that carry information from the central nervous system • Carries messages from the brain and spinal cord to other parts of your body

A Neural Chain

A Neural Chain

A Neural Chain

A Neural Chain

A Neural Chain

Measuring the Speed of Thought: The Squeeze Chain 1. 2. 3. 4. Receptors in shoulder detect squeeze Sensory nerves carry info to spinal cord Interneurons carry it to the brain Brain says, “Hey, there’s the squeeze! Now what? Oh yea… squeeze next person’s shoulder. ” 5. Motor nerves carry command to squeeze to the right hand 6. Muscles in right hand squeeze

The Squeeze Chain: Shoulders

The Squeeze Chain: Ankles

The Squeeze Chain: Opposite Shoulder Squeeze

THE STRUCTURE OF THE NERVOUS SYSTEM

The Nervous System

Central Nervous System (CNS) • The brain and spinal cord • The brain is the location of most information processing. • The spinal cord is the main pathway to and from the brain.

Peripheral Nervous System (PNS) • The sensory and motor nerves that connect the central nervous system to the rest of the body • Peripheral means “outer region” • The system is subdivided into the somatic and autonomic nervous systems.

Divisions of the Nervous System

Somatic Nervous System • The division of the peripheral nervous system that controls the body’s skeletal muscles • Contains the motor nerves needed for the voluntary muscles

Divisions of the Nervous System

Autonomic Nervous System • The division of the peripheral nervous system that controls the glands and muscles of the internal organs • Monitors the autonomic functions • Controls breathing, blood pressure, and digestive processes • Divided into the sympathetic and parasympathetic nervous systems

Divisions of the Nervous System

Sympathetic Nervous System • The part of the autonomic nervous system that arouses the body to deal with perceived threats • Fight or flight response

Divisions of the Nervous System

Parasympathetic Nervous System • The part of the autonomic nervous system that calms the body • Brings the body back down to a relaxed state

Divisions of the Nervous System

The Sympathetic and Parasympathetic Divisions of the Autonomic Nervous System

Process p. 48 • Does our nervous system’s design – with its synaptic gaps that chemical messenger molecules cross in an imperceptibly brief instant – surprise you? Would you have designed yourself differently?