Chapter 10 physiology exam 3

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  1. Sensory Organs (Receptors)
    • Monitor the internal and external environment (Heat, Cold, Pain, Pressure, Light, Sound...)
    • Transmit signals from periphery to CNS for processing
    • Critical for homeostasis
  2. Nociceptors
    • PAIN
    • respond to tissue damage
  3. Photoreseptors
    respond to light
  4. Mechanoreceptors
    Respond to mechanical energy

    (touch, pressure, vibration)
  5. Thermoreceptors
    respond to temperature changes
  6. Chemoreceptors
    respond to changes in chemical concentration
  7. Nociceptors
    • pain receptors that depolarize when tissues are damaged
    • stimuli can include heat, cold, pressure or chemicals
  8. Sensory Adaptation
    response of sensors to constant stimulation
  9. Sensory Adaptation

    Tonic Receptors
    • Exhibit little adaptation
    • Maintain constant firing rate as long as stimulus is applied
  10. Sensory Adaptation

    Phasic Receptors
    Exhibit sensory adaptation

    Firing rate of receptor (#of action potentials) decreases with constant stimulus
  11. what are the 4 steps to Sensation
    • Stimulation
    • Transduction
    • Conduction
    • Perception
  12. Perception
    Step 4 of the four steps to Sensation
    • Awareness of environmental change by CNS
    • Evaluation of nature and magnitude of stimulus
  13. Conduction
     Step 3  in the 4 steps to sensation
    Relay information through a sensory pathway to the specific CNS region
  14. Stimulation

    Step 1 of the 4 Steps to Sensation
    • Application of stimulus
    • (if the stimulus isn't strong enuff the nerve will not fire)
    • once the nerve starts firing the stronger the stimulus the more rapid the firing
    • The receptor is turning that stimulus into an AP that's called transduction
  15. Transduction

    Step 2 of the 4 Steps to Sensation
    Turns the stimulus into a nerve impulse
  16. Somatesthetic Senses
    • senses located over wide areas of the body
    • information usually conducted to the spinal cord first (then possibly the brain)

    example: tactile
  17. Special Sneses
    • changes detected only by specialized sense organs in the head
    • Information conducted directly to the brain
    • relay info through cranial nerves

    vision, hearing, smell...
  18. Proprioceptors
    • sensory receptors in muscles, tendons and joints
    • Detect stretch in  the muscles, limb movements, position of body parts

    Ex: spindle fibers, Golgi tendon organs
  19. Cutaneous receptors
    sensory receptors present in the skin

    • touch and pressure
    • heat and cold
    • pain
  20. the two point touch threshold test
    • the minimum distance at which 2 points of touch can be perceived as separate
    • measure the distance between receptive fields
    • Some parts of the body have a higher number of receptors
  21. pain receptors
    may be myelinated or unmyelinated

    • Sudden, sharp pain is transmitted by myelinated neurons
    • Dull, persistent pain is transmitted by unmyelinated neurons

    Nociceptors may be activated by chemical released by damaged tissues
  22. Taste (Gustation)
    • Detection of chemical concentrations in the oral cavity
    • taste cells  depolarize when stimulated and release neurotransmitter to associated sensory neurons
    • Information is relayed by cranial nerves VII facial and IX glossopharyngeal to the postcentral gyrus for perception
  23. Proprioception
    • sensors that help maintain body position and limb position
    • which helps with balance, muscle memory coordination

    allows you to feel your way around a pitch black room
  24. what causes the 5 different taste sensations
    • salty: high sodium
    • Sour: high hydrogen, acidic
    • Sweet: various organic molecules
    • Bitter: toxins, quinine Alkaline
    • Umami: glutamate, amino acid
  25. different tastes are derived from activation of different signaling pathways with in the cells
    • saltines and sour: depolarization of taste cell driven by direct flow of Na+ or H+ into the cell through ion channels
    • Sweetness, bitterness and Umami: Binding of molecules to receptor proteins activates 2nd messenger pathways leading to depolarization
  26. Smell
    • the odorants bind to receptor proteins on the cilia
    • AP travel to olfactory bulb
  27. inner ear
    houses structures for senses of equilibrium and hearing
  28. Hearing
    sound waves are turned into vibrations and then the vibrations are turned into AP

    outer ear funnels and collects sound waves into the ear canal waves strike the tympanic membrane.
  29. Bony Labyrinth
    • made up of 2 distinct regions
    • Cochlea anterior - Hearing
    • Vestibular Appratus, posterior - equlibrium
  30. Nystagmus and Vertigo
    • when a person's body is spinning, eye movements are toward the opposite direction of the spin to maintain a fixationpoint
    • when the body comes to a stop, the cupula is bent by fluid inertia and eye movements are still affected
    • The jerky eye movement produced is called Nystagmus
    • Nystagmus can cause loss of equilibrium called vertigo
  31. vestibular apparatus
    • fluid filled compartments in the inner ear
    • Semi-circular canals distinguish the rotation of the head
    • Otolith Organs distinguish the linear movement of head and orientation relative to gravity
    • Sensory relay through VIII vestibulcochlear to the cerebellum and medulla oblongata
  32. Otolith Organs

    linear movements of head and orientation relative to gravity
  33. Semi circular canal
    inner ear
    distinguishes the rotation of the head
  34. what is the cranial nerve for equilibrium and where does nerve take info
    • VIII vestibulocochlear
    • to the cerebellum and medulla oblongata
  35. hair cells used in equilibrium

    bending stereocilia alters membrane potential

    • bending towards the Kinocilium opens the ion channels, depolarizing the membrane
    • Bending away from the kinocilium closes the ion channels, hyperpolarizing membranes
  36. conduction deafness
    sound waves are not conducted from the outer ear to the inner ear

    • may be de to wax, damage to the eardrum
    • impairs hearing of all sound frequencies
    • can be helped with hearing aids
  37. Sensorineural / Perceptive deafness
    nerve impulses are not conducted from the cochlea to the auditory cortex

    • may be due to damaged hair cells from loud noises
    • may only impair hearing to particular sound frequencies
    • may be helped by cochlear implants
  38. cornea
    • transparent, lets light pass into the eye
    • fixed convex lens (bends light inward)
  39. Iris
    thin ring of pigmented muscle in front of lens
  40. Pupil
    • opening at center of the iris
    • muscles alter pupil size, thus the amount of light passing into the eye

    • Dilation opens the pupil to let in more light (Sympathetic)
    • Constriction closes pupil in bright light (Parasympathetic)
  41. Accommodation
    • changing lens shape to focus light from objects at different distances on the retina
    • Achieved by contracting ciliary body to different degrees
  42. refractive disorders
    • Nearsightedness, distant object brought into focus in front of the retina
    • eyeball is too long
    • Abnormally high convexedness to cornea or lens
    • Corrected with Concave Lenses
  43. Hyperopia
    • farsightedness
    • close object brought into focus behind the retina
    • Shortened eyeball
    • corrected with convex lens
  44. Astigmatism
    • oblong shape to cornea or lens (not perfectly symmetrical curve)
    • Different parts refract light to different degrees

    Corrected with uneven lens that compensates for asymmetry
  45. Fovea Centralis
    point where light from the center of the visual field is focused

    High density of cone cells
  46. Optic disc
    Where optic nerve joins the eye


  47. rods

    more numerous than cones

    • cannot distinguish different colors
    • many rods converge onto single ganglion cells

    • HIGHLY SENSITIVE TO LIGHT (low light levels detected)
    • LOW VISUAL ACUITY (image not as sharp)
  48. Photoreceptors

    • Found mainly in Fovea Centralis
    • Can distinguish among colors
    • few cones cells converge on single ganglion cell

    • LOW LIGHT SENSITIVITY (need more light to see with cones)
    • HIGH ACUITY (image is sharper)
  49. Rhodopsin
    rod cell photopigment
  50. consists of retinal and opsin
    Retinal undergoes a photochemical change when struck by light
  51. Cone Cell Photpigment
    • Each one has 1 or 3 different opsins
    • responds to different wavelengths of light
    • Blue (S), Green (M), Red(L)
    • enable color discrimination
Card Set:
Chapter 10 physiology exam 3
2014-04-08 05:21:08
physiology exam
Physiology Exam 3
chapter 10
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