NEURONS

Learn about neuron function, parts, and reflexes!

Use the diagram below to answer the questions. 1. Which part of the neuron sends messages away from the cell body? axon cell body dendrite 2. Which part of the neuron receives messages? axon cell body dendrite TYPES OF NEURONS All kinds of different things can happen to your skin, so it has cells to feel them all. Sensory neurons are nerve cells that are found in the body's skin to help it feel pressure, hot, cold, vibration, and pain. They send messages to the brain and spinal cord when they feel something. Sensory neurons do not make decisions about how to handle these sensations. They simply send the message to the brain and spinal cord. The interneurons found in your brain make decisions about how to react. When reacting to pain, the interneurons decide if the body needs to jump, move away, or scream. Once the interneuron decides what needs to be done, a signal is sent back out to the motor neurons. The motor neurons cause your muscles to move in reaction to the message. 3. Which neurons receive messages from your senses and send them to the brain? interneurons sensory neurons motor neurons 4. Which neurons decide how to react to messages? interneurons sensory neurons motor neurons 5. Which neurons send messages to your muscles on how to react to sensations? interneurons sensory neurons motor neurons 6. The gap between neurons is called a _. glial stimulus synapse REFLEXES Have you ever moved quickly from something hot or sharp? Then you've experienced a reflex. A reflex is an involuntary and automatic response to a stimulus. Usually, you can't control reflexes because they occur before you know what has happened. A reflex involves a simple nerve pathway called a reflex arc. Your response is controlled in your spinal cord, not in your brain. For example, as you reach for a slice of pizza, some hot cheese falls on your finger. Sensory neurons in your finger respond to the hot cheese and an impulse is sent to the spinal cord. The impulse passes to an interneuron in the spinal cord that immediately relays the impulse to motor neurons. Motor neurons send the impulse to muscles in your arm. Instantly, without thinking, you pull your arm back in response to the burning food. This is a withdrawal reflex. A reflex allows the body to respond without having to think about what action to take. Reflex responses are controlled in your spinal cord, not it your brain. Your brain acts after the reflex to help you figure out what to do to make the pain stop. 7. Which part of your nervous system controls your reflexes? brain spinal cord peripheral nerves 8. Why are reflexes important? Decide if each description represents a STIMULUS or a RESPONSE. STIMULUS hearing a loud noise seeing a ball thrown towards you smelling something baking in the kitchen feeling a sharp pain in your foot RESPONSE flinching or covering your ears moving your hands to catch a ball stomach growling and mouth salivating jumping away and moving your foot