Agenda Announcements Do Now, hand back graded work (12) Notes (25) Handout (20) Announcements UNIT TEST next Tuesday!!! Homework packet due Friday Mastery Quiz retakes: today during 5th, 6th in room 401 Stuff to copy: in magenta

Word of the Day!!!! Communication! Our body absolutely HAS to communicate in order for homeostasis to happen!!! What you just saw was how cells communicate!

Receptor molecules let cells communicate In the cell membrane Receive a message from a signal molecule Have a specific shape x Message Message Communication!

What messages have to be transmitted? The Sensory System detects stimuli from the outside environment in 5 ways: VISION 2. HEARING 3. TASTE 4. TOUCH 5. SMELL

What is a stimulus? (plural = stimuli) A stimulus is something that causes (stimulates) a response in your body. Example: Touching a hot stove will make you move your hand away quickly. Pain is a stimulus

What happens to the information from the stimulus? Sensory information (from stimuli) gets communicated by the nervous system The nervous system: 1) tells your body how to respond to that information 2) maintains homeostasis MAIN ORGANS BRAIN, SPINAL CORD, NERVES

Differences? Axon, shape Similarities? Nucleus, membrane How does the nervous system communicate? From the Do Now: A Nerve Cell (Neuron) Nucleus Axon endings Cell Body Axon Axon Axon Dendrites Differences? Axon, shape Similarities? Nucleus, membrane

Nerves COMMUNICATE messages from the sensory system, to the brain, to other parts of your body

Nerves use receptors to COMMUNICATE Nerves send out chemicals, called nuerotransmitters, that fit into receptors in cells x Message Message Communication!

Wrap-Up… Aim: What is the nervous system and how does it use receptors and nerve cells to transmit messages? The nervous system COMMUNICATES! It sends out nuerotransmitters that transmit messages to cells through receptors!

3. The “ouch” signal is communicated by nerve cells (motor neuron) to the muscle. The muscle contracts in response. How do reflexes work? 2.Message is passed along interneurons to the central nervous system (brain and spinal cord) which senses this message as PAIN “OUCH” 1. A nerve cell senses (sensory neuron) the stimulus (the bee sting) and sends an electrical signal to the spinal cord.