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Nervous System Chapter 20 Section 1
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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.
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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?
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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
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Senses Each sense can detect a specific type of change in the environment. Pain, Pressure, and Temperature are sensed through what sensory organ?
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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.
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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.
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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
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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 ear drum Hammer Anvil Stirrup Cochlea
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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
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Hearing
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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.
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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.
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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.
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Taste Each taste bud contains 100 sensory cells. They detect sweet, sour, bitter, and salty tastes. Taste is also due to smell.
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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!
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Brain Adult: Contains 100 billion nerve cells called neurons. Controls both Voluntary and Involuntary behavior Neurons communicate within the brain
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Parts of the Brain Cerebellum: controls balance and coordination Cerebrum: controls memories, thoughts, and sensory organs Medulla: controls involuntary movement Medulla
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Medulla Oblongata: Part of the Brain the Controls Anger and Aggression http://www.bing.com/videos/search?q=Waterboy+medulla+oblongota+vide o+clip&view=detail&mid=F1C6648DCA58ACC71079F1C6648DCA58ACC 71079&first=0&FORM=LKVR
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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.
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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
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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)
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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.
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Quiz Explain the process by which you hear sound? (Tell me the Steps) What happens to the pupil in dim light?
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Quiz The top area of skin is responsible for sensing what? What do you have on your tongue to help you taste?
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Quiz What two parts are included in the central nervous system? What is the autonomic nervous system responsible for?
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Medulla Cerebrum Cerebellum Involuntary Sensory: Receives information Temp, Color, Pressure, pain, sound Motor: Movement Nervous System Central Nervous System Peripheral Nervous System Brain Spinal Cord 2 types of nerves 2 types of responses Voluntary
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Michael J. Fox http://www.anyclip.com/movies/back-to- the-future/the-flux-capacitor/ http://www.anyclip.com/movies/back-to- the-future/the-flux-capacitor/
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