Sensory Receptors And Signal Transduction

Question 1

What are the five types of receptors?

Answer 1

1. Mechanoreceptors
2. Their More captors
3. Nociceptors
4. Electromagnetic receptors
5. Chemoreceptors

Question 2

What is transduction?

Answer 2

Converesion of one form of energy to another

Question 3

What is receptor adaptation?

Answer 3

Characteristic of all sensory receptors where they change due to constant stimulus

Question 4

What is characteristic of Tonic Adapting receptors?

Answer 4

• Slow adapting
• Signal intensity of prolonged stimulus
• Continue to transmit impulses as long as stimulus is present
• Muscle spindles, Pressure receptors, slow pain

Question 5

What is characteristic of Phasic receptors?

Answer 5

• Rapidly adapting
• Decrease AP frequency over time from constant stimulus
• Olfactory receptors, Pacinian corpuscles

Question 6

What are the common locations of referred pain and affected organs?

Answer 6

Lower Abdomen —> Large Bowel/Bladder

Umbilicus —> Small bowel/Pancreas

Upper abdomen —> Stomach/duodenum

Behind sternum —> Esophagus/trachea

Tip of shoulder —> Diaphragm

Chest, left arm, neck, abdomen —> Heart

Back of head/neck —> Meninges

Question 7

What are the visceral receptors?

Answer 7

Chemoreceptors
Baroreceptors
Mechanoreceptors

Question 8

Compare Visceral and somatic pain

Answer 8

Somatic: Initially sharp, later burning or throbbing

Visceral: Poorly localized, dull, aching, nauseating with pronounced autonomic activation.

Question 9

What is the effect of lesions of the primary somatosensory cortex?

Answer 9

• Afects quality of pain sensations

- Ability to localize exact spot

Question 10

What are the types of sensory fibers and their functions?

Answer 10

Aa - Proprioception;somatic motor

Ab - Touch,pressure

Ay - Motor to spindle

As - Pain, temperature

B - Preganglionic autonomic

C, DR - Pain, Temperature

C, SymNS - Postganglionic sympathetic

Question 11

What are the nerve fiber numbers? Type?

Answer 11

1a - Muscle spindle, annuli-spiral ending (Aa)

1b - Golgi tendon orgain (Aa)

II - Muscle spindle; pressure (Ab)

III - Pain and cold receptors; some touchreceptors (As)

IV - Pain, temperature, and other - C

Question 12

Compare fiber type diameter, conduction, and location.

Answer 12

Aa: Large, Fast, extrafusal

Ay: Medium. Medium speed, Intrafusal

B: small; medium; preganglionic autonomic controls cardiac and smooth muscle, glands

C: Smallest, slowest: Postganglionic autonomic control cardiac/smooth muscle and glands

Question 13

What is nystagmus?

Answer 13

Rapid back/forth movements of the eye.

Question 14

What is dysarthria?

Answer 14

Difficulty producing coherent speech

Question 15

What is dysdidochokinesia?

Answer 15

Inability to coordinate rapidly alternating movements such as pronation/supination of wrist

Question 16

What is dysmetria?

Answer 16

Inability to judge distance

Question 17

What are common sensory problems associated with thalamic ischemia?

Answer 17

Thalamic syndrome - hypersensitivity to stimuli

Thalamic corticol stroke - Sensory deficits on contralateral side

Question 18

Compare anterior and posterior hypothalamus and regulation of temperature.

Answer 18

Posterior hypothalamus - Heat producing reflexes

Anterior hypothalamus - Core body temperature and deep tissue temperature; Heat reducing reflex (sweating/vasodilation)

Question 19

Where ate 1st, 2nd, 3rd, and 4th order neurons located?

Answer 19

1st: Receptor —> Spinal cord
2nd: Spinal cord—> Thalamus
3rd: Thalamus -> Cerebral cortex
4th: Cortex -> Other part of cortex

Question 20

What are the two somatosensory pathways? Where do they deccusate?

Answer 20

DCS-MEdial leminiscal: Fine touch, pressure, proprioception

Decussate in brainstem

Anterolateral system (Spinothalamic): Pain, temperature, crude touch

Decussate in spine

Question 21

Which side is sensation loss for lesions Below/Above medulla of the DCML system?

Answer 21

Below - Ipsilateral

Above - Contralateral

Question 22

Which side is sensation loss for lesions Below/Above medulla of the ALS system?

Answer 22

Contralateral side of body below point of lesion

Question 23

What is Tabes Dorsalis?

Answer 23

• Late-stage manifestation of Syphilis where dorsal root neuron ganglia are destroyed; degeneration of myelinated afferent fibers in dorsal columns

Question 24

What are the effects of cobalamin?

Answer 24

• Vitamin B12 deficiency
• Often secondary to Pernicious anemia
• Demyelination and atonal degeneration Of DCS leadings to numbness, parasthesias, weakness, and ataxia

Question 25

What is the pathophysiology of shingles?

Answer 25

• Chicken pox virus lies dormant inside dorsal root ganglion neurons
• Virus damages and leaves sensory nerve terminals damaging the dermatome

Question 26

What symptom is common for individuals with Herpes Zoster?

Answer 26

Thoracic rash affecting two adjacent dermatomes

Question 27

What is the primary purpose of Merkel’s disks?

Answer 27

Detect light touch and superficial pressure

Question 28

What is the primary purpose of Meisner corpuscles?

Answer 28

Two point discrimination

Question 29

What is the primary purpose of ruffinis end organs?

Answer 29

Detects continuous touch and pressure

Question 30

What is the primary purpose of pacinian corpuscle?

Answer 30

Deep pressure, vibration, and proprioception

Question 31

What is sciatica, and what is the common cause?

Answer 31

• Backpain which radiates down leg

- Spinal disk herniation which impinges upon spinal nerve affecting a dermatome

Question 32

Describe Brown-Square syndrome

Answer 32

• Loss of pain and temp on one side of body and proprioception, vibration, and touch on the Contralateral side.
• Lesion which involve half of spinal cord

Question 33

Which side do somatosensory cortex lesions affect?

Answer 33

Contralateral

Question 34

What are the homonculus?

Answer 34

Maps of different parts of the brain connected to different parts of the body

Motor - Maps which parts of motor cortex control certain body parts

Sensory - Map sensory locations in somatosensory cortex

Question 35

How do opioid receptors function?

Answer 35

Inhibitory metabotropic receptors which decrease cAMP concentrations

Question 36

What are the different types of opioid receptors?

Answer 36

Mu1 - Spinal And Supraspinatus analgesia

Mu2 - Respiratory depression, euphoria, dec gut mobility

Delta - Spinal analgesia

Kappa - Spinal analgesia, supra-spinal analgesia