Lecture 23 - Somatic sensation

Question 1

Detected by receptors in skin, muscle and joints

Answer 1

Somatic senses

Question 2

Detected by receptors in internal organs

Answer 2

Visceral senses

Question 2

To convert or change from one form to another

Answer 2

Transduction

Question 3

The conversion of a sensory stimulus into an action potential

Answer 3

Sensory transduction

Question 4

Briefly explain the concept of touch-action potential

Answer 4

1 Touch something with your finger
2 Mechanoreceptor in fingertip/skin gets squished
3 Deforms membrane opening mechanically gated Na+ channels
4 Allows Na+ to enter and depolarise membrane
5 Sends action potentials to brain to make you aware of the touch

Question 5

List the 4 major types of info that are coded when touch is converted to action potential

Answer 5

Modality
Duration
Intensity
Location

Question 6

Nerve endings with temperature gated ion channels

Answer 6

Thermoreceptors

Question 7

What happens to the cell when sodium is let into it?

Answer 7

It becomes more positive

Question 8

Briefly explain the concept of transduction of temperature stimuli

Answer 8

Temperature stimuli open temperature gated Na+ channels and let sodium inside the cell, making the cell more positive and if the threshold in the thermoreceptor is reached and action potential will fire and propogate to the brain

Question 9

Briefly explain the concept of transduction of chemical stimuli

Answer 9

Chemical stimuli bind and open chemically gated Na+ channels
Allowing Na+ to enter and depolarise the membrane
If the threshold is reached in chemoreceptor, an action potential will fire and propogate to the brain

Question 10

Briefly explain the concept of transduction of mechanical stimuli

Answer 10

When muscle stretches it causes mechanically gated ion channels to open and let sodium into the cell and depolarises the membrane. If threshold is reached in mechanoreceptor an action potential will fire and propogate to the brain

Question 11

Type of mechanoreceptor that responds to light touch, pressure, and/or skin stretch

Answer 11

Tactile receptor

Question 12

Tonic

Answer 12

Slow adapting

Question 13

Phasic

Answer 13

Fast adapting

Question 14

Example of tactile receptor - deep in skin, detecting stretch and constantly sending info

Answer 14

Bulbous corpuscles

Question 15

Example of tactile receptor - closer to edge of skin, detecting vibration and detect initial vibration then stop firing after a while

Answer 15

Lamellar courpuscles

Question 16

Awareness of where your limbs are in relation to your torso

Answer 16

Proprioception