Physiology CH 10 lecture notes


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Physiology CH 10 lecture notes

  2. 2. Receptors and Sensations 5 Types of Receptors a) chemoreceptors b) pain receptors c) thermoreceptors d) mechanoreceptors e) photoreceptors
  3. 3. Sensation - a feeling that occurs when impulses are interpreted by the brain Projection - the brain causes these feelings to seem to come from the area being stimulated Sensory adaptation - impulses fail to send signal due to continuous stimulation
  4. 4. Somatic Senses  senses that are associated with the skin, muscles, joints, and organs 1. Touch and Pressure Senses a) sensory nerve fibers A b) Meissner’s Corpuscles - sensitive to the motion of objects that barely contact the skin B C
  5. 5. c) Pacininan Corpulscles - stimulated by heavy pressure and deep pressure 2. Temperature Senses - are 2 types of free nerve endings - heat receptors - cold receptors
  6. 6. 3. Sense of Pain - are free nerve endings that are widely distributed throughout the skin and internal organs Visceral Pain - widespread pain from the internal organs - can cause referred pain - pain feels like it is coming from other part of the body
  7. 7. Sense of Taste - occurs on the taste buds on the tongue taste buds - taste bud made up of: - taste cells - taste pores - taste hairs taste cell taste hair taste pore
  8. 8. Sense of Smell  olfactory sense olfactory bulb olfactory receptor cells - chemical must enter the nose as a gas and be partially dissolved in fluid to smell - chemicals detected by the olfactory receptor cells , sent to the olfactory bulb , and then sent to the brain via the olfactory tract - each olfactory receptor cell can detect a different type of smell
  9. 9. - chemicals must be dissolved in a watery fluid for the taste cells to detect stimuli - the sense of smell also helps us taste our food 5 Taste Sensations a) sweet b) sour c) salty d) bitter e) umami
  10. 10. Sense of Hearing 1. External Ear pinna external auditory meatus - functions to collect sound waves
  11. 11. 2. Middle Ear tympanic membrane malleus incus stapes auditory tube
  12. 12. 3 smallest bones in the body
  13. 13. 3. Inner Ear Inner ear
  14. 14. semicircular canals cochlea
  15. 15. - semicircular canals - involved with equilibrium - cochlea - interprets sound waves Organs of Corti - sound vibrations move hairs  stimulates nerves  sends to brain Sense of hearing 3. Inner Ear
  16. 16. Sense of Equilibrium Static Equilibrium - help maintain stability
  17. 17. Dynamic Equilibrium - detects motion of the head - helps maintain balance while moving
  18. 18. Sense of Sight Visual Accessory Organs 1. eyelids 2. conjuctiva - membrane that lines inner surface of eyelids 3. extrinsic muscles - 6 muscles that moves the eyeball
  19. 19. eyelid conjuctiva muscle muscle
  20. 20. 4. lacrimal gland - secretes tears to moisten and lubricate eye - decreases chance of eye infection
  21. 22. Structure of the Eye 3 Layers 1. Outer Tunic a) cornea - transparent covering over the eye b) scelera - white part of the eye c) optic nerve
  22. 23. 2. Middle Tunic a) choroid coat - contains blood vessels - contains melanocytes to absorb excess light b) ciliary body - moves the lens so it can focus c) lens - very flexible so it can focus on objects - accomodation - the adjustment of the lens
  23. 24. d) iris - colored part of the eye - allows a certain amount of light into the eye e) pupil - opening into the eye
  24. 25. 3. Inner Tunic a) retina - contains photoreceptors - fovea centralis - point on retina where the light rays focus - produces the sharpest vision - optic disk - place where nerve fibers leave retinal and become optic nerve - causes the blind spot b) vitreous humor - fluid inside the eyeball
  25. 26. Visual Receptors 2 Types a) rods - 100X more sensitive than cones - allow us to see in dim light b) cones - allows us to see in color - gives sharper vision
  26. 27. Visual Pigments Rhodopsin - color vision seems to be related to the presence of 3 sets of cones containing different light-sensitive pigments a) red b) blue c) green