OHHS AP Biology Chapter 50 (Class Presentation)


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OHHS AP Biology Chapter 50 (Class Presentation)

  1. 1. Sensory and Motor Mechanisms<br />Chapter 50<br />
  2. 2. Complex sensory systems that facilitate survival.<br />
  3. 3. Bats use sonar to detect prey.<br />
  4. 4. Moths can detect the bat’s sonar.<br />
  5. 5. Include diverse mechanisms that sense stimuli and generate appropriate movement.<br />
  6. 6. All stimuli represent forms of energy.<br />Sensation involves converting energy into a change in the membrane potential of sensory receptors.<br />
  7. 7. All stimuli represent forms of energy.<br />Function of sensory pathways: sensory reception, transduction, transmission, an integration.<br />
  8. 8. Sensation and perceptions begin with sensory reception.<br />Detection of stimuli by receptors – both inside and outside of the body.<br />
  9. 9. Sensory transduction: conversion of stimulus energy into change of membrane potential.<br />Change is called receptor potential – many are very sensitive.<br />
  10. 10. Transmission: sensory cell facilitate the movement of action potentials.<br />Larger receptor potential = more rapid action potentials.<br />
  11. 11. Integration: receptor potentials integrated through summation.<br />
  12. 12. Perception: the brain’s construction of stimuli<br />Brain distinguishes stimuli from different receptors by the area where the action potentials arrive.<br />
  13. 13. Type of Sensory Receptors<br />
  14. 14. Mechanoreceptors: sense physical deformation.<br />TOUCH!<br />
  15. 15. Chemoreceptors: information about the total solute concentration of a solution.<br />Respond to individual kinds of molecules.<br />
  16. 16. Electromagnetic receptors: detect electromagnetic energy such as light, electricity and magnetism.<br />
  17. 17. Thermoreceptors: respond to heat or cold.<br />Regulate body temp. by signaling both surface and core temp.<br />
  18. 18. Nociceptors: naked dendrites in the epidermis.<br />Pain receptors.<br />
  19. 19. Hearing and perception of body equilibrium are related in most animals.<br />Mechanoreceptors<br />
  20. 20. Most invertebrates maintain equilibrium using statocysts.<br />Detect movement of granules called statoliths.<br />
  21. 21. Many arthropods sense sounds with body hairs that vibrate.<br />“Ears” consisting of tympanic membrane and receptor cells.<br />
  22. 22.
  23. 23. Vibrations create percussion waves that vibrate tympanic membrane.<br />Bones of the middle ear transmit the vibrations.<br />
  24. 24. Vibrations create waves of fluid that move through vestibular canal.<br />Waves cause the basilar membrane to vibrate, bending hair cells.<br />
  25. 25. Bending of hair cells depolarizes the membranes.<br />Sends action potential to the brain via the auditory nerve.<br />
  26. 26. Ear conveys information about volume and pitch.<br />
  27. 27. Fishes have only a pair of inner ears near the brain.<br />Also have lateral line system that detect and respond to water movement.<br />
  28. 28. Taste and smell rely on similar set of sensory receptors.<br />Terrestrial animals:<br />Gustation: Taste, detection of chemicals called tastants.<br />Olfaction: Smell, detection of odorant molecules.<br />
  29. 29. Taste and smell rely on similar set of sensory receptors.<br />Taste buds detect five taste perceptions: sweet, sour, salty, butter, and umami – different regions of the tongue.<br />
  30. 30. Olfactory receptors are neurons that line the upper portion of the nasal cavity.<br />
  31. 31. Muscle Function<br />
  32. 32. Muscle activity is a response to input from the nervous system.<br />The action of a muscle is always to contract.<br />
  33. 33. Skeletal muscle characterized by a hierarchy of smaller and smaller units.<br />Consists of a bundle of long fibers – each a single cell – running the length of the muscle.<br />Each muscle fiber is a bundle of smaller myofibrils.<br />
  34. 34. Two kinds of myofilaments.<br />Thin: two strands of actin, one strand of regulatory protein.<br />Thick: staggered arrays of myosin molecules.<br />
  35. 35. Skeletal muscle also called striated muscle – arrangement of myofilaments create light and dark bands.<br />Functional unit of a muscle is called a sarcomere – bordered by Z lines.<br />
  36. 36. Sliding-filament model: filaments slide past each other, producing overlap.<br />Based on interaction between actin of thin filaments and myosin of the thick filaments.<br />
  37. 37. Fig. 50-27-1<br />Thick filament<br />Thinfilaments<br />Thin filament<br />Myosin head (low-energy configuration<br />ATP <br />Thickfilament<br />
  38. 38. Fig. 50-27-2<br />Thick filament<br />Thinfilaments<br />Thin filament<br />Myosin head (low-energy configuration<br />ATP <br />Thickfilament<br />Myosin binding sites<br />Actin<br />ADP<br />Myosin head (high-energy configuration<br />P i<br />
  39. 39. Fig. 50-27-3<br />Thick filament<br />Thinfilaments<br />Thin filament<br />Myosin head (low-energy configuration<br />ATP <br />Thickfilament<br />Myosin binding sites<br />Actin<br />ADP<br />Myosin head (high-energy configuration<br />P i<br />ADP<br />Cross-bridge<br />P i<br />
  40. 40. Fig. 50-27-4<br />Thick filament<br />Thinfilaments<br />Thin filament<br />Myosin head (low-energy configuration<br />ATP <br />ATP <br />Thickfilament<br />Myosin binding sites<br />Thin filament movestoward center of sarcomere.<br />Actin<br />ADP<br />Myosin head (low-energy configuration<br />Myosin head (high-energy configuration<br />P i<br />ADP<br />ADP<br />+<br />P i<br />Cross-bridge<br />P i<br />
  41. 41. Skeletal muscle fiber contract only when stimulated by a motor neuron.<br />Muscle at rest, myosin-binding sites on thin filament blocked by protein tropomyosin.<br />
  42. 42. For a muscle fiber to contract, myosin-binding sites must be uncovered<br />This occurs when calcium ions (Ca2+) bind to a set of regulatory proteins, the troponin complex<br />Muscle fiber contracts when the concentration of Ca2+ is high; muscle fiber contraction stops when the concentration of Ca2+ is low<br />
  43. 43. The synaptic terminal of the motor neuron releases the neurotransmitter acetylcholine<br />Acetylcholine depolarizes the muscle, causing it to produce an action potential<br />
  44. 44. Action potentials travel to the interior of the muscle fiber along transverse (T) tubules<br />
  45. 45. The action potential along T tubules causes the sarcoplasmic reticulum (SR) to release Ca2+<br />
  46. 46. The Ca2+ binds to the troponin complex on the thin filaments<br />
  47. 47. This binding exposes myosin-binding sites and allows the cross-bridge cycle to proceed<br />
  48. 48. Types of Skeletal Muscle Fibers<br />Skeletal muscle fibers can be classified<br />As oxidative or glycolytic fibers, by the source of ATP<br />As fast-twitch or slow-twitch fibers, by the speed of muscle contraction<br />
  49. 49. Oxidative and Glycolytic Fibers<br />Oxidative fibers rely on aerobic respiration to generate ATP<br />These fibers have many mitochondria, a rich blood supply, and much myoglobin<br />Myoglobin is a protein that binds oxygen more tightly than hemoglobin does<br />
  50. 50. Glycolytic fibers use glycolysis as their primary source of ATP<br />Glycolytic fibers have less myoglobin than oxidative fibers, and tire more easily<br />In poultry and fish, light meat is composed of glycolytic fibers, while dark meat is composed of oxidative fibers<br />
  51. 51. Fast-Twitch and Slow-Twitch Fibers<br />Slow-twitch fibers contract more slowly, but sustain longer contractions<br />All slow twitch fibers are oxidative<br />Fast-twitch fibers contract more rapidly, but sustain shorter contractions<br />Fast-twitch fibers can be either glycolytic or oxidative<br />
  52. 52. Most skeletal muscles contain both slow-twitch and fast-twitch muscles in varying ratios<br />