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Introductory activity

Introductory activity. Optical illusions: http://www.planetperplex.com/en/color_illusions.html How do these work?. Ch. 36: The NERVOUS system. The Neuron A. The nerve cell: The basic unit of structure of the nervous system. The Neuron. Parts of a Neuron (Draw and Label)

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Introductory activity

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  1. Introductory activity Optical illusions: http://www.planetperplex.com/en/color_illusions.html How do these work?

  2. Ch. 36: The NERVOUS system • The Neuron • A. The nerve cell: The basic unit of structure of the nervous system

  3. The Neuron • Parts of a Neuron (Draw and Label) • 1) Dendrites – the branchlike extensions that RECEIVE impulses and carry them TO the cell body. • 2) Cell Body- transmits impulses to axon. (and does normal “cell stuff”) • 3) Axon – Carries impulses away from cell body and towards other neurons, muscles, or glands.

  4. Parts to the Neuron Animation http://itc.gsw.edu/faculty/gfisk/anim/neuronparts.swf

  5. Myelin sheath • On some neurons, the myelin sheath covers the axon and the impulse moves quicker.

  6. How do neurons work? • They transmit an electrochemical impulse down the axon. • How? • Depolarization of the neuron/ Action potential • charge flips from negative to positive • travels down the axon http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html Action potential practice and animation: http://outreach.mcb.harvard.edu/animations/actionpotential.swf (see intro, summary of action potential, zoom out) http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html# C:\Documents and Settings\BBAUGHMAN\Desktop\Desktop\animations from bio powerpoints\Chapter 36 BDOL IC

  7. Synapse – the gap between end of an axon and the next neuron. • Neurotransmitters are sent across the gap. • Neurotransmitters are chemicals that keep the message going to the next cell. • Eventually, Enzymes break down neurotransmitters in synapse • C:\Documents and Settings\BBaughman.CORONADOUSD\Desktop\bio powerpoints\Chapter 36 BDOL IC Cool animation: http://www.hhmi.org/biointeractive/molecular-mechanism-synaptic-function

  8. II. 3 Types of Neurons • Sensory—carry impulses to the spinal cord and brain • Interneurons—process impulses and are found only in the spinal cord and brain • Motor—carry response impulses away from brain and spinal cord to muscles and glands. Why is this awesome? Check out Brain Power OR Sensation: Pushing the limits C:\Documents and Settings\BBAUGHMAN\Desktop\Cool Videos

  9. Exit Questions • Draw and label a neuron. Clearly explain the functions of each part. (8 POINTS) • Explain how a neuron sends an impulse to allow for communication between cells. (2 POINTS) • Explain how a synapse works and why synapses are important. (3 POINTS) • Describe the three types of neurons and their functions, giving an example for how each one is used. (6 POINTS)

  10. Reflexes • The reflex arc • Message relayed to spinal cord. • Action occurs automatically (without thinking) • Think: What types of neurons are involved? What does each do?

  11. IV. There are two divisions of the nervous system: • Central Nervous System (CNS) • Peripheral Nervous system (PNS)

  12. CNS = brain and spinal cord Parts of brain • cerebrum—controls intelligence, muscle movements , etc. • cerebellum—at back of brain, controls balance, coordination. • brain stem-3 parts • medulla oblongata—involuntary activities (breathing, heart rate) • pons –acts as a pathway • midbrain—acts as a pathway Brain man: http://www.cbsnews.com/stories/2007/01/26/60minutes/main2401846.shtml How memory works: http://www.pbs.org/wgbh/nova/body/how-memory-works.html

  13. Face Blindness (60 Minutes clip) • http://www.cbsnews.com/news/face-blindness-when-everyone-is-a-stranger-20-03-2012/

  14. V. Peripheral Nervous system (PNS) • All other nerves besides CNS • Divided into 2 systems: • somatic nervous system • controls voluntary actions • Autonomic nervous system • Controls Involuntary responses. • Autonomic nervous system divided into two: • sympathetic -controls body in times of stress • parasympathetic—controls when body is relaxed.

  15. Activity • Write out one situation where you would use each of the following divisions of the nervous system and explain how it is used. • CNS • PNS • Somatic • Autonomic • Sympathetic • Parasympathetic

  16. End of necessary stuff

  17. IV. Central Nervous System (CNS)= brain and spinal cord • Parts of brain • cerebrum—controls conscious activities, intelligence, memory, language, skeletal muscle movements, and senses. • Divided into two hemispheres • Cerebral cortex= outer surface (folded and grooved to increase surface area) involved in complex thought etc. • cerebellum—at back of brain, controls balance, coordination. • brain stem • medulla oblongata—involuntary activities (breathing, heart rate) • pons – connects various parts of brain with each other • midbrain-- connects various parts of brain with each other http://60minutes.yahoo.com/segment/44/brain_man http://www.disenchanted.com/dis/lookup.html?node=1852

  18. V. Peripheral Nervous system (PNS) • Carries impulses between body and CNS • Divided into • somatic nervous system • controls voluntary actions and reflexes (reflexes don’t go to brain). • Autonomic nervous system (carries impulses from CNS to internal organs) Involuntary responses. Autonomic nervous system divided into: • sympathetic nervous system—controls many internal functions during times of stress • parasympathetic—controls when body at rest, relaxed.

  19. 36.2 The Senses • I. Chemical senses (smell/taste) • A. Smell • 1. chemicals stimulate hair-like nerve endings in upper part of nose--> olfactory nerve--> brain (interprets) http://health.howstuffworks.com/adam-200014.htm • B. Taste • 1. chemicals dissolved in saliva contact taste buds (sensory receptors on tongue)--> brain and interpreted • 2. Bitter= back, sweet/salty= tip, sour=sides http://health.howstuffworks.com/adam-200015.htm

  20. II. Sensing light • A. Cornea • B. Iris • C. pupil • D. lens • E. retina • F. Rods • G. Cones • H. macula and fovea • I. Optic nerve • J. See diagram on p.985 on depth perception etc. • C:\Documents and Settings\BBaughman.CORONADOUSD\Desktop\bio powerpoints\Chapter 36 BDOL IC • http://health.howstuffworks.com/adam-200013.htm • Eye games and tricks • http://www.planetperplex.com/en/color_illusions.htmlhttp://faculty.washington.edu/chudler/chvision.html

  21. III. Sensing Mechanical stimulation (hearing, touch, balance) • A. Hearing • 1. vibrations of air= sound waves • 2. these enter outer ear and travel down ear canal where they strike the tympanic membrane (eardrum) • 3. eardrum vibrates and causes three bones in middle ear, the malleus, incus and stapes to vibrate. • 4. causes fluid in cochlea to move like waves and stimulate hair cells lining the walls of the cochlea. • 5. This causes the hairs to bend producing nerve impulses that travel down auditory nerve to brain where it’s interpreted • C:\Documents and Settings\BBaughman.CORONADOUSD\Desktop\bio powerpoints\Chapter 36 BDOL IC

  22. B. Touch • 1. Receptors in skin respond to changes in temperature, pressure and pain. • 2. Different types of receptors are more concentrated in different areas of body. • a. light pressure= fingertips, eyelids, lips, tongue, palms etc. • b. heavier pressure= joints, muscle, certain organs • c. pain receptors • d. heat receptors—deep in dermis • e. cold receptors—closer to surface of skin • http://health.howstuffworks.com/adam-200009.htm

  23. C. Balance • 1. semicircular canals in inner ear filled with fluid and lined with hair cells • 2. movement of fluid causes hair cells to bend and produce impulses that are interpreted by brain.

  24. Some Alternate Slides…

  25. http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html#http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html# • III. How Neurons Work • At rest • Neuron is polarized (more positive outside the membrane and more negative inside) Why? • Sodium potassium pump pumps 3 positive sodium ions (Na­­+) out and 2 potassium ions (K­+) in every time it pumps. (see diagram) • Negatively charged proteins and organic phosphates in interior of neuron make it negative.

  26. Transmitting an impulse (can only occur if the threshold level is reached) • Gated sodium channels open. (What will sodium do?...) • Sodium rushes into cell causing the inside to become suddenly more positive than outside (called depolarization = a flip in charge) • This depolarization moves down the axon and is called an action potential. Action potential practice and animation: http://outreach.mcb.harvard.edu/animations/actionpotential.swf • http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html# • C:\Documents and Settings\BBaughman.CORONADOUSD\Desktop\bio powerpoints\Chapter 36 BDOL IC

  27. Myelin sheath/Schwann cells • The myelin sheath (a fatty coating around the axon) causes the impulse to move more quickly down the axon by causing the impulse to jump from gap to gap.

  28. Repolarization: Getting back to rest! • After depolarization, the neuron needs to return to normal (rest) • How? • Potassium channels open • Potassium rushes out. • This makes the inside of the neuron more negative (back to normal) • The Sodium potassium pump continues to keep the neuron polarized.

  29. Synapse = gap between end of axon and next cell. • When impulse reaches end of axon, calcium channels open • Calcium enters and causes neurotransmitter vesicles to fuse with axon terminal membrane • Neurotransmitter chemicals are released into synapse by exocytosis. • Neurotransmitters travel to receptors on dendrite and stimulate it to pass on an impulse • Eventually, Enzymes break down neurotransmitters in synapse (why?) • C:\Documents and Settings\BBaughman.CORONADOUSD\Desktop\bio powerpoints\Chapter 36 BDOL IC Cool animation: http://www.hhmi.org/biointeractive/media/molecular_mech-lg.mov

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