Neural and Hormonal SystemsWill Explain Why We FEEL……

Pain

Strong

Sick

Nervous

It all Starts with the Neuron

Neuron Structure

Neurons do NOT touch each other- the space in between is call the synapse.

How a Neuron FiresIt is an electrochemical

process•Electrical inside the neuron•Chemical outside the

neuron (in the synapse in the form of a neurotransmitter).

•The firing is call Action Potential.

The All-or None Response•The idea that

either the neuron fires or it does not- no part way firing.

•Like a gun

Steps of Action Potential• Dendrites receive neurotransmitters from

another neuron across the synapse.• Reached its threshold- then fires based on the

all-or-none response.• Opens up a portal in axon, and lets in positive

ions (Sodium) which mix with negative ions (Potassium) that is already inside the axon (thus Neurons at rest have a slightly negative charge).

• The mixing of + and – ions causes an electrical charge that opens up the next portal (letting in more K) while closing the original portal.

• Process continues down axon to the axon terminal.

• Terminal buttons turns electrical charge into chemical (neurotransmitter) and shoots message to next neuron across the synapse.

Action Potential

Excitatory Effect

• A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential or “fire”

.

Inhibitory Effect

• A neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential or “fire”

A Neural Chain

A Neural Chain

A Neural Chain

A Neural Chain

Neurotransmitters•Chemical messengers

released by terminal buttons through the synapse.

•We should know at least 4 types and what they do.

Acetylcholine•Its function is motor

movement and maybe memory.

Too much and you will….

Not enough and you will….

Lack of ACH has been linked to Alzheimer’s disease.

Dopamine•Its function is motor

movement and alertness.Lack of dopamine is associated with Parkinson’s disease.Overabundance is associated with schizophrenia.

Serotonin•Function deals with mood

control.

Lack of serotonin has been linked to depression.

Endorphins•Function deals with pain

control.

We become addicted to endorphin causing feelings.

Agonists and Antagonists

Types of NeuronsSensory NeuronsMotor NeuronsInterneurons

SAME!

Sensory Neurons(Afferent Neurons)

•Take information from the senses to the brain.

Interneurons•Take messages

from Sensory Neurons to other parts of the brain or to Motor Neurons.

Motor Neurons(Efferent Neurons)

•Take information from brain to the rest of the body.

SAME•S•A•M•E

Divisions of the Nervous System

Sympathetic Nervous SystemFlight or Fight Response

A Simple Reflex

The Endocrine SystemA system of glands that secrete hormones.Similar to nervous system, except hormones work a lot slower than neurotransmitters.

Neurotransmitters

Hormones

The Major Endocrine Glands