Body senses

• Balance, body pos, touch, skin temp, pain

Vestibular System

• Inner ear
• Pos and movmement in head, mantain balance
• if mid ear is inflamed or convesion, connected to throight, pressure on inner ear can cause dissiness
• Two parts:
  • Semicircular canals
    • Stims hair cells inside (like cochlea)
  • Otolith Organs
    • Sacual
      • Calcilum carbinate stones, otoliths, in gelatinous layer
      • AS head moves, weight of stone opulls layer along and its silia are also pulled from once side to other,
      • give us pefceptions like accelerating
    • Ultricle

Touch

• Free nerve endings and encaspulated strucutres
• sense preasure, vibration, stretch and texture
• provide feedback about pos of joints
• Mechanoreceptors
  • ROugh estimates of each type of receptor to touch experience.
  • 
• Some hae large receptive fields, others have small. Small have detailed localization

Two-point discrimination test

• See how close together our two points can be before we can only sense one thing
• varies across body
• insensitive on back, half of leg, compared to fingers and lips

Somatosensory fiber types

Alpha-alpha, feedback from muscle fibers
Ab - Skin, merkels disc, pacinina corpuscles
ruffimis endings
Ad- pain and temp, free nerve endings, mylinated and fast
C FIbers - unmilenated (same as Ad)

Dermatomes - areas of skin served my dorsal root, used ot make map

• Inflamed by itchy area served by single dorsal root in shinkles

Touch pathways

• turf in thalamus, then goes to parietal lobe
• 
• Sensory Homunculus
  • more brain is resrved for lips and hands
  • whiskeyrs in cats
  • size of body parts correlates with brain space each gets, but is not positively correlated

Phantom Limb

• Brain capable of reorginizing after losing body part, but takes time
• phantom - doesnt exist but percieve its still there
• House Md. mirror trick works

Neglect Syndrome

• Loses half of world, eat half of dinner, draw half of dinner, cant see half of side
• parietal stroke
• neglects half of shit

Pain

• Pain has reason
• Ashlyn blocker cant feel pain
  • must be watched carefully since they can injur themselves seirously wihtout known
  • parents, great parents, didnt know she had broken ankle
• Nociceptors
  • usually free nerve endings, respond to variety of singles indicating tissue damage
  • chronic pain is pain lasting longer than 3 months, doesnt respond well to medications that affect these receptors

Pathways

• two potential targets
• Antieror cingulet cortex
  • emotional responses
• Somatosensory cortex
  • other
• Gate Theory of Pain
  • Event goes to gate in the spinal cord which is how pain is epxerience,
  • Gate can be closed by rubbing elbow, high levels of arounsal, etc
  • Factors that open gate, chronic stress
• Decending Control of Pain
  • dependence on mindset
  • Establishing a sense of control aids in relief of pain
  • paitents who can control own morphine use less morphoine
  • athletes dont describe normal pain as pain bc of experiencing changing mindset.