Specific Sensory Systems – General Senses

Question 1

What is Somatic Sensation?

Answer 1

• to and from Skin, skeletal muscle, bones, joints, tendons
• Initiated by somatic receptors
  (mechano/thermo/chemoreceptors)
• Distinct receptors for sensations of heat, cold, touch, pressure, limb position/movement, pain and itch

Question 2

What do Touch and Pressure Sensors provide information about?
Where are they most commonly found

4

Answer 2

• Stimulation of mechanoreceptors within the skin
• Touch sensations provide information about shape or texture
• Pressure sensations provide information about the degree and frequency of mechanical distortion
• There are millions of mechanoreceptors within the body, with the greatest diversity found in the skin

Question 3

What are Touch and Pressure Sensors Examples?

4

Answer 3

Question 4

What is Proprioception?

Answer 4

• Receptors that provide information about our body’s position in space

Question 5

Proprioception

What are Golgi tendon organs (mechanoreceptors)?

Answer 5

Located in tendons of skeletal muscles  activated by deformation of the tendon, which occurs during muscle stretch and during muscle contractions

Question 6

Proprioception

What are Muscle spindle stretch receptors
(mechanoreceptors)?

Answer 6

Located in skeletal muscle  activated by muscle stretch and monitor the rate of change in muscle length

Question 7

What are Temperature (thermoreceptors)?

Answer 7

• Small diameter afferent neurons with little or no myelination
• Originate in tissues as free neuron endings (they lack capsular endings common in tactile receptors)
• Some neurons have proteins that also respond to painful stimuli (important for perception of extreme temperatures)

Question 8

What are Transient Receptor Potential (TRP) Proteins?

Answer 8

• Temperature-sensing ion channels
• Different isoforms have gates that open to different temperature ranges
• When activated, depolarizing effects caused by influx of Ca2+ and Na+

Question 9

What is Capsaicin?

Answer 9

• Some TRP proteins can be opened by chemical ligands
• Capsaicin (found in chili peppers) and ethanol are perceived as being hot when ingested

Question 10

What are Pain (nociceptors)?

Answer 10

Stimuli that cause or could potentially cause tissue damage (excessive stretch, temperature etc.)

• Small diameter afferent neurons with little or no myelination that originate in tissues as free neuron endings
• Respond to chemicals, many of which are released from damaged cells or the immune cells responding to the area damage -> H+ (acid), histamine, cytokines, prostaglandins etc

Question 11

What is Referred Pain?

Answer 11

• Pain sensations experienced at a site other than the injured/diseased tissue
• Occurs because visceral and somatic afferents converge on the same neurons in the spinal cord and the location of receptor activation is “referred” to the somatic source

Question 12

How is Referred Pain involved in Heart Attacks?

Answer 12

Pain in the upper back, chest, shoulders arms and jaw are common during a heart attack

Question 13

What is the The Endogenous-Opioid System?

Answer 13

1. Interneurons release endogenous opiate neurotransmitters
2. Opiate receptors on the presynaptic cell inhibit NT release
3. Opiate receptors on postsynaptic cell inhibit ascending neurons
4. Morphine inhibits pain in a similar manner

Question 14

photos

Answer 14

frequency of auditory potential