Science 2 part 1

Module 9 Life Support Systems (Nervous and Endocrine Systems) What this module is about How did you find the last module? Were you surprised at the immense work of thethree systems? If so, there are more surprises that await you in this module, and moreenjoyable activities, too. Continue studying the modules and see how wonderful the humanmachine is. “Keep in touch” is a line you may have used many times before. This means that youwant to communicate constantly with friends and relatives. Have you ever thought of howyour body communicates with itself or the outside world? There are two main systems that your body uses to stay in touch. These are thenervous system and the endocrine system. This module is composed of three lessons:  Lesson 1 – Nervous system  Lesson 2 – The Sense Organs  Lesson 3 – Endocrine system What you are expected to learn After going through this module, you are expected to: 1. Discuss the functions of the nervous system. 2. Name the three parts that compose the nervous system and discuss their functions. 3. Distinguish between stimulus and response. 4. Identify the organs that assist the nervous system. 5. Describe a neuron. 6. Draw and label the parts of the neuron. 7. Discuss the human sense organs. 8. Identify the sense organs of the human body.

9. Discuss the functions of each sense organ.10. Give the functions of the endocrine system.11. Identify glands and the roles they play in the human body.12. Name and locate the endocrine glands.13. Describe hormones and their actions. How to learn from this module In order to achieve the objectives of this module successfully, you have to rememberthe following: 1. Read and follow instructions carefully. 2. Answer the pre-test before moving on. 3. Take down notes and record points for clarification 4. Take the post test and check your answers with the key at end of the module 5. Remember to get at least 75% level of proficiency in the tests.What to do before (Pretest)A. Match the hormones in Column A with the glands that produce them in Column B. Write only the letters of the correct answer. Column A Column B1. adrenalin a. pituitary2. thyroxine b. thyroid3. melatonin c. parathyroid4. progesterone d. thymus5. testosterone e. ovaries6. parathormone f. testes7. growth hormone g. adrenal8. thymusin h. pancreas9. glucagon i. pineal10. oxytoxin j. hypothalamus -2-

B. Identify the system to which each of the following structures or organs belong.____________1. spinal cord ____________ 6. brain____________2. pituitary ____________ 7. thymus____________3. gonads ____________ 8. nerves____________4. pancreas ____________ 9. sympathetic____________5. adrenal ____________10. Autonomic Key to answers on page 27.Lesson 1. The Nervous System You perform different activities from the time you wake up in the morning to the timeyou sleep at night. Do you know what coordinates all of these actions? This system makesyou feel, know, and do anything. In this lesson, you will study the control system of all yourbody functions – your nervous system. Let’s look at the parts of the human nervous system in more detail. The nervoussystem uses special cells to keep in touch. These cells help the body communicate withother body parts.The Nerve Cell The basic unit of the nervous systemis the nerve cell. Nerve cells are calledNEURONS. Study figure 1 and look at thedifferent parts of the neuron. There arebillions of neurons in the body. Some existalone. Others are joined together to formorgans like the brain and spinal cord. There are billions of neurons in the Figure 1. The Neuronbody. In fact, there are twelve to fourteenbillions of neurons in one part of the brain http//www4.tpgi.com.au/users/amcgann/body/alone. Yet, no two neurons are alike. They nervous.htmlare like snowflakes in that they vary in sizeand shape. But all neurons have a commonstructure. A neuron has a cell bodycontaining the nucleus. Projecting out fromthe cell body are root-like threads. Theseare the DENDRITES and AXON. -3-

Dendrites carry impulses towards the cell body. A cell may have as many as 200dendrites carrying impulses toward the cell body. A single dendrite can be over one meterlong. Look at the parts of the nerve cell below. Figure 2. The Nerve Cell http//www4.tpgi.com.au/users/amcgann/body/nervous.html Axons carry impulses away from the cell body. Axons pass impulses to the dendritesof other neurons.THE PARTS OF THE NERVOUS SYSTEMLevels of Organization ExampleCell NeuronTissue NerveOrgan Brain, Spinal Cord Neurons can be grouped together into bundles called nerves. Thus, nerves aretissues. A nerve is like a telephone cable with smaller wires bound together, as shown infigure 2.Stimulus - (plural: stimuli) is any information received by the nervous system about a condition in the environment. The nervous system also receives information about conditions inside the body. In order to survive, an organism must be able to receive stimuli from inside and outside the body.Response - is a reaction to a condition or stimulus. A stimulus is received by the body and a response is made. To survive, an organism must be able to respond to a stimulus.A Stimulus Causes A Response The nervous system is assisted by five organs - the eyes, ears, nose, tongue, andthe skin. The sense organs are constantly receiving information from the environment andsending messages to the brain. -4-