Sensory Receptors And Signal Transduction Flashcards
What are the five types of receptors?
- Mechanoreceptors
- Their More captors
- Nociceptors
- Electromagnetic receptors
- Chemoreceptors
What is transduction?
Converesion of one form of energy to another
What is receptor adaptation?
Characteristic of all sensory receptors where they change due to constant stimulus
What is characteristic of Tonic Adapting receptors?
- Slow adapting
- Signal intensity of prolonged stimulus
- Continue to transmit impulses as long as stimulus is present
- Muscle spindles, Pressure receptors, slow pain
What is characteristic of Phasic receptors?
- Rapidly adapting
- Decrease AP frequency over time from constant stimulus
- Olfactory receptors, Pacinian corpuscles
What are the common locations of referred pain and affected organs?
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
What are the visceral receptors?
Chemoreceptors
Baroreceptors
Mechanoreceptors
Compare Visceral and somatic pain
Somatic: Initially sharp, later burning or throbbing
Visceral: Poorly localized, dull, aching, nauseating with pronounced autonomic activation.
What is the effect of lesions of the primary somatosensory cortex?
- Afects quality of pain sensations
- Ability to localize exact spot
What are the types of sensory fibers and their functions?
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
What are the nerve fiber numbers? Type?
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
Compare fiber type diameter, conduction, and location.
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
What is nystagmus?
Rapid back/forth movements of the eye.
What is dysarthria?
Difficulty producing coherent speech
What is dysdidochokinesia?
Inability to coordinate rapidly alternating movements such as pronation/supination of wrist
What is dysmetria?
Inability to judge distance
What are common sensory problems associated with thalamic ischemia?
Thalamic syndrome - hypersensitivity to stimuli
Thalamic corticol stroke - Sensory deficits on contralateral side
Compare anterior and posterior hypothalamus and regulation of temperature.
Posterior hypothalamus - Heat producing reflexes
Anterior hypothalamus - Core body temperature and deep tissue temperature; Heat reducing reflex (sweating/vasodilation)
Where ate 1st, 2nd, 3rd, and 4th order neurons located?
1st: Receptor —> Spinal cord
2nd: Spinal cord—> Thalamus
3rd: Thalamus -> Cerebral cortex
4th: Cortex -> Other part of cortex
What are the two somatosensory pathways? Where do they deccusate?
DCS-MEdial leminiscal: Fine touch, pressure, proprioception
Decussate in brainstem
Anterolateral system (Spinothalamic): Pain, temperature, crude touch
Decussate in spine
Which side is sensation loss for lesions Below/Above medulla of the DCML system?
Below - Ipsilateral
Above - Contralateral
Which side is sensation loss for lesions Below/Above medulla of the ALS system?
Contralateral side of body below point of lesion
What is Tabes Dorsalis?
- Late-stage manifestation of Syphilis where dorsal root neuron ganglia are destroyed; degeneration of myelinated afferent fibers in dorsal columns
What are the effects of cobalamin?
- Vitamin B12 deficiency
- Often secondary to Pernicious anemia
- Demyelination and atonal degeneration Of DCS leadings to numbness, parasthesias, weakness, and ataxia
