14 Cutaneous and Chemical Senses

14 Cutaneous and Chemical Senses - 1 Cutaneous and Chemical...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
11/29/2016 1 Cutaneous and Chemical Senses WEEK 14 Lecture outline Touch Taste (Gustatory sense) Smell (Olfactory sense) Touch Touch Powerful perceptions Sometimes, cannot accurately describe with words Direct, immediate contact with a stimulus Vital for survival Pain, hot, cold, pressure Not proprioception Feeling your current posture and position Not kinesthesis Feeling the movement of your body The Cutaneous System Skin Epidermis Visible part of skin. The “outside.” Dead cells that form hard barrier Dermis Under epidermis Living tissue Has mechanoreceptors Mechanoreceptors Pressure Push/pull Vibration Tearing Mechanoreceptors 1 2 3 4 5 6
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/29/2016 2 Multiple kinds of mechanical sensation Specialized receptors Slowly Adapting receptors (SA) Respond to sustained pressure Merkel disc Ruffini cylinder Rapidly Adapting receptors (RA) A.k.a “Fast - adapting receptors” Respond to a pressure turning ON or OFF Meissner corpuscle Pacinian corpuscle Slow and Fast adaptation Mechanoreceptors Touch pathway Mechanoreceptors fire directly to the spinal cord Yes, these are LONG neurons Afferent neurons/fibers Transmission rate varies Influenced by thickness of myelin sheath Thicker = faster transmission Differences in pain perception Touch pathway To spinal cord Afferent fiber Dorsal root to dorsal horn To thalamus To somatosensory cortex 7 8 9 10 11
Image of page 2
11/29/2016 3 Touch pathway Touch pathway Touch pathway Somatosensory cortex S1: Skin-based sensation S2: Organ-based sensation Somatotopic map Areas of cortex receive signals from specific parts of the body “Homunculus” Touch pathway Somatosensory Homunculus Perceiving touch Perceiving touch High absolute threshold Compared to vision, hearing Requires more energy Different thresholds for different parts of the body High individual differences Resolution Density of mechanoreceptors
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern