Nervous System and drug addiction

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Slide 1

Today’s Lesson Nervous System and Drug Addiction

Slide 2

Overview of Lesson

Nervous system

Synapses and neurohormones

Drug addiction

Slide 3

Neuron

Based on: Raven et al., Biology, McGraw-Hill

Slide 4

Sensory neurons - carry impulses to the

interneurons of the brain

Interneurons of the brain - interpret impulses

Motor neurons - carry impulses to the muscles

Types of Neurons

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

Slide 5

Nerve Impulse

Stimulation of neuron, opens channels so

that sodium (Na+) goes in, depolarizing the

membrane

The adjacent section of membrane allows

Na+ to go in, depolarizing it

This wave of depolarization continues at a

rapid rate down the neuron, resulting in a

nerve impulse traveling to the brain in

milliseconds

Slide 6

Neuron at Rest: Polarized Membrane

Outside of neuron is positively charged due to positive sodium ions

Inside of neuron is negatively charged due to negative ions

+ + + + + + + + +

- - - - - - - - - - -

Inside of Neuron

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+ + + + + + + +

- - - - - - - - - -

+ + + + + + + +

- - - - - - - - - -

+ + + + +

- - - - - -

0 0 0 0

Neuron

Neuron

Neuron

Polarized membrane of resting neuron

Sodium (Na) moves inside to depolarize

Nerve impulse is wave of depolarization moving down neuron

Nerve

impulse

Nerve Impulse

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Depolarization and Repolarization

Based on: Starr, C., Biology: Concepts and Connections, Brooks/Cole

Slide 9

Operates when neuron is at rest or

not transmitting nerve impulse

Pump is a membrane protein

The protein actively transports Na out

of the axon to re-establish polarity of

membrane

Sodium Pump

Slide 10

Overview of Lesson

Nervous system

Synapses and neurohormones

Drug addiction

Slide 11

There are gaps or junctions between neurons called synapses