The Nervous System The nervous system receives information about what is happening both inside and outside your body. It also directs the way in which your body responds to this information. In addition, your nervous system helps maintain homeostasis.
Any change or signal in the environment that can make an organism react is called a stimulus After your nervous analyzes the stimulus, it causes a response. A response is what your body does in reaction to a stimulus.
Maintaining Homeostasis By directing the body to respond appropriately to the information it receives.
The Neuron The cells that carry information through your nervous system are called neurons, or nerve cells. The message that a neuron carries is called a nerve impulse.
On a clean page let’s draw a neuron. Draw and color a lollipop. This is the cell body that contains the nucleus.
Now, give your cell body some “hair.” These extensions are called DENDRITES. The dendrites carry impulses toward the neuron’s cell body. Finally, give your cell body a nucleus.
Your cell body needs a tail! The tail is called the axon. This carries impulses away from the cell body.
The tips of the split tail are the axon tips. These tips actually “connect” to the dendrites of another neuron to allow nerve impulses to travel throughout your body. The space between the axon tip and the dendrites is called the SNAPSE. There is a chemical present that allows the impulse to cross the gap between the two nerves.
Three kinds of Neurons A SENSORY NEURON picks up stimuli from the internal or external environment and converts each stimulus into a nerve impulse. The impulse travels along the sensory neuron until it reaches an INTERNEURON which carries nerve impulses from one neuron to another. Some sensory neurons pass on information to a MOTOR NEURON which sends the information to a muscle or gland, and the muscle or gland reacts in response.
Homework Read pages 626 to 630. Add any additional information to your notes that you feel are necessary. Define key terms page 626 in NB.