Somatosensation

Question 1

mechanoception

Answer 1

• sensation about pressure

Question 2

intensity

Answer 2

• how quickly neurons fire

Question 3

non-adapting neuron

Answer 3

• equal amount of space between each action potential

- during entire time stimulus is presented, action potentials fire

Question 4

slow-adapting neuron

Answer 4

• APs fire quickly at first, then slow down (space increases between AP)
• slow to adapt to change in stimulus

Question 5

fast- adapting neuron

Answer 5

• APs fire quickly at the start, stop firing in the middle, fire quickly at the end

Question 6

dermatomes

Answer 6

• each part of the body is innervated by a particular nerve that goes up to the brain
• area of skin that is mainly supplied by a single spinal nerve
• each nerve relays sensory information to the brain

Question 7

sensory adaptation

Answer 7

• down regulation of a sensory receptor
• pressure causes AP, but over time, no longer change in pressure, so no more APs
• ex. hand on table- pressure receptors on fingers/palm which send signal to brain, then you don’t feel it anymore–> adaptation
  IF cell is overexcited–> can be harmful to cell, so adaptation is important

Question 8

amplification

Answer 8

• upregulation of some stimulus

- ex. ray of light causes cell to fire, maybe connected to 2 cells that fire again–> on and on= amplified

Question 9

sensory homunculus

Answer 9

• map of body in brain
• information sent through spinal cord to the sensory strip in the brain
• ex. brain tumor- surgeons can use electrode to touch part of cortex and remove parts that are not involved in sensation

Question 10

proprioception

Answer 10

• cognitive awareness of where your body is in space
• sense of position
• includes sense of balance
• sensor = spindle (stretches out w/ muscle contraction)
• when protein is stretched- sends signal to the brain
• can tell how contracted or relaxed muscles are in brain

Question 11

kinesthesia

Answer 11

• different from proprioception
• movement of body in space
• does not include sense of balance
• more behavioral

Question 12

nociception

Answer 12

• ability to sense pain
• TrpV1 receptor = protein
• pain causes conformation change in protein
• ex. when poked by needle- cells break and release molecules that bind to TrpV1–> causes conformational change which sends signal to brain

Question 13

thermoception

Answer 13

• ability to sense temperature
• TrpV1 receptor =protein
• heat causes conformation change in protein
• cells send signal through nerve to brain

Question 14

fibers in nerve that goes to brain (temp)

Answer 14

1. fast- big diameter (lowers resistance) and covered in myelin (greater conductance) –> allows AP signals to travel quickly (Abeta fibers)
2. medium- smaller in diameter, less myelin–> don’t conduct signal as quickly (Adelta fibers)
3. slow- small in diameter and unmyelinated- takes a long time for signal to go to brain (C fibers)
   ex. touch hot stove- hand moves away (Abeta fiber activates), then quick sensation of pain (Adelta fiber sending pain stimulus), then lingering sense of pain (C fibers)

Question 15

capsaicin

Answer 15

• molecule that is in peppers
• when eating- binds to TrpV1 receptors on tongue
• triggers same response at change in temp, so body reacts the same as a change in temp (ex. sweating)