Communication

Comparison of the nervous and endocrine systems

How does a Nerve Impulse work?

SENSATIONStimuli are received

by receptorsINTEGRATION

Interpretation of the stimulus to choose an appropriate response

REACTIONUsually activation of a

muscle or gland

How does the message travel in the nervous system?

dendrite

syna

pse

Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called the synapse, between two neurons.

Neurotransmitters

Synapse (gap)

The message is transferred when RECEPTORS receive neurotransmitters.

(pinkspheres)

Response to an external stimulus

Response to an internal stimulus

Draw a flow diagram to illustrate this feedback loop

How does the endocrine system work?

ENDOCRINE GLANDProduces hormone

HORMONEA chemical messenger

that is secreted into the bloodstream

TARGET CELLSCells that have

receptors for the hormone

How does the message travel in the endocrine system?

Draw a flow diagram to illustrate this feeback loop

Comparison of endocrine and nervous systemsFeature Endocrine system Nervous system

Type of signal

Name of chemical messenger

Method of delivery

Speed of message

Length of action

How much messenger is needed

Target cells

Hormone Neurotransmitter

Slow Fast

Action lasts a long time

Action lasts a short time

Through the blood Along the nerves

Lots because it is diluted as it travels through the body

A little because it is delivered directly to the place it is needed

Chemical only Chemical & electrical

Any cell with the receptor Nerves, muscles, glands