MCB 32 Lecture 12

Neuron Travel

Both touch and Pain/temperature go to the opposite side of the (S1) from the side experienced. Touch crosses over in the medulla and Pain/temperature crosses over in the spinal cord

If the second order pain neurons on the right side of the medulla were damaged (i.e. the second neuron in the pathway), which side of the body would lose some pain sensation?

Left Side

4 general steps in a sensory system

Reception of stimulus, sensory transduction, send to CNS, sensory coding (quality of stimulus),

Sensory Trasnduction

The energy from the stimulus is transformed into an electrical response in a process known as ______

Based on the body map in the somatosensory cortex, which of the following areas of the body is most sensitive to touch sensation?

Thumb

Proprioceptors

are located in skeletal muscles, tendons and joints and send information about the bodys position to the brain.

Primary somatosensory cortex (S1)

located in the parietal lobe. For touch sensation First synapse is in the medulla, second neuron crosses over to the other side of the body and goes to thalamus and then to the _______

Which somatosensory receptors send information about skeletal muscles to the brain?

proprioceptors

Mechanoreceptors

sense light touch pressure vibration and stretch. They have ion channels that are mechanically gated and open when the membrane is deformed

Nociceptors

sense painful stimuli that can damage body. Extreme temperatures, pressures or chemicals released by damaged tissue

Thermoreceptors

sense temperature. They have ion channels called TRP that are temperature sensitive.

Somatosensory System

senses body sensations such as touch, temperature, pain and body position.

When heat opens TRP channels, we call this process:

sensory transduction