2.2.a How does communication happen within the body?
Electrical Signals Nervous System
Chemical Signals Endocrine System
The nervous system is made up of neurons. Neurons communicate just like people do, but they send messages using action potentials (electricity passing through their axons). Each neuron picks up signals at its dendrites, passes the signals down the axon, into the axon terminals, and into the synapses. The synapse then drops neurotransmitter into the synaptic cleft between the first neuron’s synapse and the next neuron’s dendrites. That signals neuron #2 to pass the message on.
2.2.b What is the basic structure and function of a neuron?
Sends electrical signals through body
Dendrites (“trees”)—pick up signal
Axon—carry signal long distances (up to 3 ft)
Myelin Sheath—insulates axon
Nodes (“knots”) of Ranvier—allow nutrients in, waste out
Axon Terminals (“ends”) —branch to meet other neurons Synapses—place one neuron connects to next
Synaptic Cleft—joint between neurons
Neurotransmitters (“to carry across a nerve”) — chemicals that allow neurons to communicate with each other
2.2.c How do the different types of neurons work together to send and receive signals?
Pick up signals through senses
(sight, smell, touch, etc)
Connect sensory neurons to motor neurons Receive signals from CNS, causing movement
Send info from PNS to CNS
Found in CNS
In PNS, receive info from CNS
2.2.d How are electrical impulses created in the human body?
Na+/K+ pump keeps outside of membrane + and inside – by pumping positive ions out of the membrane, priming the membrane to carry charges
During an action potential, there’s a sudden reversal of charge, carrying a message down the axis
How do neurons convey information using both electrical and chemical signals?