ANIMALS HAVE NERVOUS SYSTEMS THAT DETECT EXTERNAL AND INTERNAL

SIGNALS, TRANSMIT AND INTEGRATE INFORMATION, AND PRODUCE RESPONSES

W W W. L E A R N . G E N E T I C S . U T A H . E D U / C O N T E N T / B E G I N / C E L L S /C E L L C O M /

Transmission of information results in changes within and between

biological systems

The neuron is the basic structure of the nervous system that reflects function

A typical neuron has a cell body, axon and dendrites.

Many axons have a myelin sheath that acts as an electrical insulator.

The structure allows for detection, generation, transmission and integration of signal information

Neuron Structure & Function

Schwann cells, which form the myelin sheath, are separated by gaps of unsheathed axon (nods of Ranvier) over which the impulse travels as the signal propagates along the neuron

Action potentials propagate impulses along neurons.

Every cell has a voltage (difference in electrical charge) across its plasma membrane called a membrane potential

The resting potential is the membrane potential of a neuron not sending signals

The Na / K pump maintains concentrations gradients for Na+ and K+

In a resting neuron, the currents of K+ and Na+ are equal and opposite, and the resting potential across the membrane remains steady

Membranes of neurons are polarized by the establishment of electrical potentials across the membranes

Fig. 48-10-5

KeyNa+

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Cytosol

Inactivation loop

Resting state

Sodiumchannel

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Depolarization

Rising phase of the action potential Falling phase of the action potential

5 Undershoot

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Response to Stimulus

Na+ and K+ gated channels sequentially open and cause the membrane to become locally depolarized

Na+/K+ pumps, powered by ATP, work to maintain membrane potential

Fig. 48-15

Voltage-gatedCa2+ channel

Ca2+12

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Synapticcleft

Ligand-gatedion channels

Postsynapticmembrane

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Synaptic vesiclescontainingneurotransmitter

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Transmission of information between neurons occurs across synapses

www.ted.com/talks/sebastian_seung.html

NEUROTRANSMITTERSH TT P: / / Y O U T U. B E / H A N O Q 8 U B S YC

In most animals, transmission across synapses involves

chemical messengers called…

Neurotransmitters

Transmission of information along neurons and synapses results in a response

The response can be stimulatory or inhibitory

The same neurotransmitter can produce different effects in different types of cells

MOUSE PARTYlearn.genetics.utah.edu/content/addiction/drugs/mouse.html

LEARN HOW DRUGS DISRUPT THE SYNAPSE TO MAKE THE USER FEEL

“HIGH”

Vertebrate Brain

Different regions of the brain have different functions

Group Assignment – select a topic, research it, summarize it (in writing with an illustration) and share what you learned with the class. Explain effect of the neurotransmitters -

Acetylcholine, Epinephrine and norepinephrine, Dopamine, Serotonin, and GABA

Identify regions of the brain responsible for vision, hearing, muscle movement, abstract thought, emotion, neuro-hormone production

Identify structures and functions of Forebrain, Midbrain, Hindbrain, and Left & Right cerebral hemispheres

Explain how interaction and coordination between the muscular and nervous systems allow for essential biological activities

Describe how the nervous system detects signals (internal & external), transmits & integrates information and produce responses.

How does the vertebrate brain integrates information to produce a response.