Nervous System

1. Nervous System Chapter 20 Section 1

2. You will learn • To describe how the body’s senses help monitor the environment. • To explain how the sensory organs respond to stimuli • To describe how the nervous system works with other body systems. • To infer possible connections between taste buds and sensitivity to flavors.

3. Close Your Eyes • With your eyes closed smell the aroma I put in front of you. • Keep your eyes closed until I tell you to open them. • What did it smell like? • How did you know what the smell was?

4. Senses connect the human body to its environment! • To maintain homeostasis your body constantly monitors the environment. • Your sense organs (eyes, ears, skin, tongue, nose) are responsible for monitoring: Sight, smell, touch, hear, and taste

5. Senses • Each sense can detect a specific type of change in the environment. • Pain, Pressure, and Temperature are sensed through what sensory organ?

6. A Stimulus • The sound of the horn is known as a: Stimulus- A change in your environment that you react to, such as smell, taste, sound, feeling, or sight.

7. Sight • Light rays enter the eye through the pupil • They are bent by the cornea(also protects the eye) • The lens helps focus light. • The pupils change size. Large in dim light. Smaller in bright light.

8. Sight • At the back of the eye, the light strikes a layer called the retina. • There are two types of cells in the Retina: • Rods-detects brightness • Cones-Sensitive to color • These are called photoreceptors

11. Hearing • Your ears detect sound waves produced by vibrations • Sound waves are enter the auditory canal. The canal ends at the eardrum. The eardrum vibrates when sound waves hit it. • These vibration are sent through bones called the hammer, anvil, and stirrup to the inner ear. • Cells in the cochlea detect the vibrations and send a message to the brain • RECAP: Auditory CanaleardrumHammerAnvilStirrupCochlea

12. Hearing • Semi-Circular Canals: help keep the body’s balance! • External ear: what you see on the outside • Auditory nerve: carries sound vibrations to the brain

13. Hearing

14. Touch • You touch with tiny receptors in the skin. • Nerves at the top of the skin detect textures. • Nerves deeper in the skin detect pressure. • Other receptors sense hot and cold.

15. Smell • Detects Chemical Information • In the back of the nose, there is a patch of tissue where hairlike fibers covered in mucus, • Molecules enters your nose, stick to the mucus, and bind to the receptors in the hairlike fibers • The receptors sends an impulse to your brain, and you perceive the scent.

16. Taste • Chemical process • Your tongue is filled with sensory structures known as taste buds. They are also found in the throat and roof of your mouth.

17. Taste • Each taste bud contains 100 sensory cells. • They detect sweet, sour, bitter, and salty tastes. • Taste is also due to smell.

18. Central Nervous System • Consists of the Brain and Spinal Cord • Communicates with nervous system through electrical signals sent through nerve cells. • Travel 90 meters per second • This is like you running the length of an entire soccer field in a second!

19. Brain • Adult: Contains 100 billion nerve cells called neurons. • Controls both Voluntary and Involuntary behavior • Neurons communicate within the brain

20. Parts of the Brain • Cerebellum: controls balance and coordination • Cerebrum: controls memories, thoughts, and sensory organs • Medulla: controls involuntary movement Medulla

21. Medulla Oblongata: Part of the Brain the Controls Anger and Aggression http://www.bing.com/videos/search?q=Waterboy+medulla+oblongota+video+clip&view=detail&mid=F1C6648DCA58ACC71079F1C6648DCA58ACC71079&first=0&FORM=LKVR

22. Spinal Cord • Main pathway for information from the brain to other parts of the body • Protected by the vertebral column • 31 pairs of nerves sends sensory impulses into the spinal cord and then sends them to the brain.

23. Peripheral Nerve System • Includes Sensory and Motor Nerves • Sensory nerves- receive information from the environment (hot or cold) and pass information to the Central Nervous System • Motor Nerves- sends signals from you brain to your muscles

24. The Autonomic Nervous System • Controls the movement of the heart, the smooth muscles in the stomach, the intestines, and the glands. (involuntary) • It conserves energy • Responds quickly to changes (Fight or Flight Response)

25. Voluntary Nervous System • Monitors movement and functions that can be controlled consciously. • Controls the skeletal system and muscles that are responsible for speech and the senses.

26. Quiz • Explain the process by which you hear sound? (Tell me the Steps) • What happens to the pupil in dim light?

27. Quiz • The top area of skin is responsible for sensing what? • What do you have on your tongue to help you taste?

28. Quiz • What two parts are included in the central nervous system? • What is the autonomic nervous system responsible for?

29. Nervous System Peripheral Nervous System Central Nervous System 2 types of responses 2 types of nerves Spinal Cord Brain Voluntary Medulla Involuntary Cerebrum Sensory: Receives information Temp, Color, Pressure, pain, sound Cerebellum Motor: Movement

30. Michael J. Fox • http://www.anyclip.com/movies/back-to-the-future/the-flux-capacitor/