2 - Other Senses

Question 1

Smell

Answer 1

• chemoreceptors in nose in BACK of nasal cavity
• volatile/aerosolized compounds / noxious chemicals bind to olfactory chemoreceptors/nerves in olfactory epithelium in upper nasal cavity
• many kinds of chemoreceptors

-signal to HIPPOCAMPUS, not thalamus!

• signal to olfactory bulb in back of midbrain, which projects via olfactory tract into limbic system/hippocampus (memory; hence we get memories when we smell things)
• olfactory bulb does sensory processing
• Smell- interpersonal signals- pheromones- animal social/foraging/sexual behavior —perfume
• Expt- men sweaty T-shirts- women like smell of their s/o’s shirt, esp when they’re ovulating
• The way you smell signals something about immune system- slightly/optimally different from yours- diversity in offspring immunity (pheromone theory of attraction)

Question 2

Taste

Answer 2

Flavor: Salt, Sweet, Sour, Bitter, Umami/savory- meat/Glutamate

Flavor is a combo of smell and taste
smell is stronger than taste

-response to taste is hardwired genetically (Baby eating lemon = ew)

• taste chemoreceptors respond to dissolved molecules in saliva
• receptors = taste buds, in papillae (bumps on tongue)
• all taste buds for all tastes spread throughout tongue
• no location of receptors / map corresponding to location of smell/taste
• you have taste receptors in palate and back of mouth so you can still taste w/o your tongue (but most on tongue)
• info to thalamus then higher-order brain regions

Question 3

Touch = Somatosensation

Answer 3

Touch = somatosensation

4 modalities / things we can sense in terms of touch:

• Pressure
• Vibration
• Pain - nociceptors
• Temperature - thermoreceptors

Pressure and vibration:

• Pacinian corpuscles: deep pressure / vibrations
• Meissner - light touch
• Merkle discs - deep pressure & texture
• Ruffinian endings - stretch
• Free nerve endings = pain and temp
• To thalamus, then parietal lobe’s somatosensory cortex
• gate theory of pain

Question 4

Touch perception: 2 point threshold

Answer 4

Two-point threshold - how far apart 2 stimuli have to be in order to determine there are 2 stimuli and not just one

• smallest 2-pt threshold: TONGUE - 1.1 mm difference, then fingertips/hands, then face
• largest: back/shoulders- takes 3-8 cm

Question 5

Physiological Zero

Answer 5

Temp of outside env that feels neutral
anything warmer feels hot, anything cooler feels cold

Pools:)

Skin normally 90 degrees (86-97)
-can change w/ adaptation, up or down

Question 6

Gate theory of pain

Answer 6

• When pain signal down spinal column, spinal column only lets so much signal through
• pain sensation nociceptor to spinal column at a small nerve fiber
• Other sensations: larger nerve fibers in spinal cord
• When you get enough sensation from large nerve fibers in spinal cord, it shuts the gate of smaller nerve fibers = experience lesser pain
• rub affected area / confuse nerve cells b/c nerve fibers larger than pain ones so shut down pain sensation, feel touch instread
• kids- bump head, kiss forehead- same thing

Question 7

Kinesthetic sense = proprioception

Answer 7

-where’s your body at
-receptors at muscles and joints
-nerve cells signal your brain where your limbs are
(vestibular in ear = head)
=you can tell where your limbs are even if you close your eyes

Deafferentiated limbs doesn’t disrupt kinesthetic sense but makes it not want to be moved
-sleep on arm wrong - hard to move arm = arm is heavy

-hand-eye coordination, balance, mobility

Question 8

SEE YOUR NOTES FROM MAMM PHYS

Answer 8

plz :)