Stimulus Response Lab

1. Stimulus Response Lab

2. Research… • Each student should pick from the following list of disorders to research & answer the questions on the worksheet. Be prepared to share with the class. • Bells Palsy • Cerebral Palsy • Multiple Sclerosis • Parkinson’s Disease • Huntington’s Disease • Tay-Sach’s • Amyotrophic lateral sclerosis (Lou Gherig’s Disease) • Epilepsy • Meningitis • Alzheimer’s Disease • Muscular Distrophy • Any other nervous disorder you may find on the internet!

3. Do Now • Take out your research on your disease/disorder. • Explain your disorder to a partner. • Each partner is going to share what they learned from each other!

4. The Nervous System Chapter 9

5. Objectives • To identify the basic structure of a neuron. • To explain the main components of the nervous system. • To compare and contrast the central nervous system and the peripheral nervous system. • To differentiate between the somatic and autonomic nervous systems.

6. Nervous System • Think back to when we talked about nervous tissue. What is it’s function? How does it go about doing this? • General Functions: • Sensory (detect change) • Integrative (make sense of it) • Motor (cause a response)

7. Structure of a Neuron • Neuron= Nerve Cell • Reacts to physical/chemical changes in surroundings • Transmit information through nerve impulses to other neurons and other cells.

8. Structure of a Neuron

9. CNS vs. PNS • CNS (Central Nervous System): • Brain • Spinal Cord • PNS (Peripheral Nervous System): • Cranial nerves • Spinal Nerves

10. PNS • Contains a sensory division and a motor division. • Sensory Division: • Contains sensory receptors that convert info into a nerve impulse and transmit it back to the CNS to make sense of it. • Monitors environmental changes such as light and sound • Detects changes in homeostasis ( ex: temperature, oxygen level)

11. Motor Division • Utilize peripheral neurons to carry impulses from the CNS to an effector which will cause a response • Ex: muscle contraction, gland secretion, etc.

12. Motor Division • Somatic Nervous System: • Controls skeletal muscle and voluntary movement. • Autonomic Nervous System: • Controls effectors that are involuntary • Ex: heart, smooth muscle, certain glands

13. Lets put that all together…

14. Do Now • What are the 2 divisions of the nervous system? • Name as many parts of a neuron that you can remember. • What are the 3 main functions of the nervous system?

15. Objectives • To identify and explain the 3 different structures of neurons. • To compare and contrast sensory, motor, and interneurons and explain a general pathway. • To determine the functions of the 5 types of neuroglia.

16. Lets Review… • General Neuron structure and action potential

17. Types of Neurons Multipolar: • Many processes stemming from cell body. • *most neurons in brain and spinal cord are multipolar

18. Types of Neurons Bipolar: • Only two processes (one at each end. • *found in eyes, nose, ears..

19. Types of Neurons Unipolar: • One single process extending from cell body. • one side of axon is the peripheral process associated with body part, other side is the central process that enters brain or spinal cord. • Cell bodies create a tissue mass called ganglia.

20. Types of Neurons

21. Neuron Classification • Sensory Neurons (afferent): • Carry impulses from PNS to CNS • Contain “receptor ends” at the tips of dendrites • Changes outside the body stimulate receptor ends triggering an impulse • *Most are unipolar

22. Neuron Classification • Interneurons (association): • Completely in brain or spinal cord. • Link neurons together. • *multipolar

23. Neuron Classification • Motor Neurons (efferent): • carry impulses out of brain or spinal cord to the effector and stimulate response.

24. General Pathway

25. Neuroglial Cells *More numerous than neurons, support neurons in different ways. • Microglial Cells: • Phagocytize bacterial cells and cellular debris • Oligodendrocytes: • Provide insulating layers of myelin • Astrocytes: • Provide structural support • join parts (ex: neuroncapillary) • help regulate concentrations of nutrients and ions • Form scar tissue in the CNS • Ependymal Cells: • Forms membrane that covers specialized brain parts and forms inner linings within the brain and spinal canal • Schwann cells: • Forms myelin sheath around axons.

26. Myelin • A lipid that sometimes coats axons • White matter = myelinated axons in CNS • Gray matter = cell bodies & unmyelinated axons in CNS • Produced by some neuroglial cells • Insulates neurons & increases efficiency of nerve impulses

27. Neuroglial Cells • Oligodendron, astrocytes, and microglial cells

28. Neuroglial Cells

30. Do Now • Which sub-division of the PNS is responsible for your heart beating? • What is the difference between afferent and efferent neurons? • What part of the neuron carries messages to the CNS? • Where are bipolar neurons commonly found?

31. Objectives • To explain how a nerve impulse occurs. • To determine what types of stimuli elicit an action potential. • To explain different things that inhibit an action potential. • To understand components of a neuron that contribute to impulse velocity.

32. Cell Membrane Potential • The membrane is electrically charged, “polarized” due to Na+ and K+ ions • Greater concentration of sodium ions outside and potassium ions inside. • Potassium ions pass through more easily • Active transport (sodium/potassium pump) maintains balance • This is essential in the propagation of a nerve impulse.

33. Resting Potential • When a nerve cell membrane is undisturbed, the membrane remains polarized staying more negative on the inside and positive on the outside.

34. Threshold Potential • If the nerve cell detects a change in light/temp/pressure it effects the resting potential and the membrane begins depolarizing. • Sodium channels open and + ions flow in, making the inside less negative. • Change in potential is proportional to the intensity of the stimulation. • Stimulation + more stimulation before initial stimulation subsides is called summation. • Once the threshold is reached, an action potential occurs.

35. Action Potential

36. Impulse Conduction • Unmyelinated nerve = impulse conducted over the entire surface. • Myelin insulates and prevents ion flow, would prevent conduction if it were continuous and didn’t have the nodes of ranvier. • Myelinated nerve= impulse jumps from node to node and creates a saltatory response and is much faster than unmyelinated.

38. All-or-None • Nerve impulses create an “all or none response”. Once the stimulus reaches threshold, it generates an action potential.

40. Action Potential Animation • http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter8/animation__action_potential_propagation_in_an_unmyelinated_axon__quiz_2_.html

41. PhysioEx Lab • “Neurophysiology of Nerve Impulses” • Complete the physioEx lab. Answer the questions. You DON’T have to print the graphs. • Complete the “review sheet” when you are done with your lab. • You will have a LAB QUIZ next lab day on this material. (Next Wednesday)

42. Do Now • How is an impulse generated? • What are some ways to generate an impulse? • List the different inhibitors that can prevent an action potential and how?

43. Objectives • Identify the different components of a reflex arc. • Explain different autonomic reflexes found throughout the body.

44. Article • Read the article about impulses and answer the questions!

45. Responses • How would you explain how your body responds to a stimulus? (use what you know about neurons)

46. Reflexes • Ordinarily, a receptor sends a signal to the brain where the brain coordinates a response. • What happens when you touch something hot?

47. Reflex Arc • A reflex is a rapid action that happens without thought and does not involve the brain. • Lets take a look… • http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/thenervoussystemrev3.shtml

48. Reflex Arc • Receptor- sense organ in skin, muscle, or other organ • Sensory Neuron- carries impulse towards CNS from receptor • Interneuron- carries impulse within CNS • Motor Neuron- carries impulse away from CNS to effector • Effector- structure by which animal responds (muscle, gland, etc).

49. Reflex Arc

50. Types of Reflexes