The Eight Senses: Touch, Pain, Balance and Kinesthesis

 

 

Types

Physical stimulus

Equipment

Sub-Structures

Roles of the Brain

Theories

Touch Cutaneous receptors for stimuli:

pressure, vibration, heat, cold, etc.

Hair follicle ending (in the skin): for hair displacement

Ruffini endings (under epidermis): for pressure

 

Krause corpuscle (lips, tongue, genitals): for pressure

 

Pacinian corpuscle (deep skin layers): for vibration (150-300 Hz)

 

Meissner corpuscle (deep hairless skin layers): for vibration (20-40 Hz)

 

Merkel discs (hairless skin top layer): for pressure

 

Thermoreceptors (under epidermis): for temperature (30-43o)

 

Cold receptors (under epidermis): for temperature (20-35 o)

Receptors -> action potential -> afferent nerve tracts -> spinal column -> thalamus -> parietal lobes (cerebral cortex) Primary somatosensory cortex, motor cortex:

frontal lobe (elaboration of thought, mastication, motor elaboration, swallowing, tongue);

occipital lobe (bilateral vision, contralateral vision), cerebellum;

parietal lobe (sensory elaboration, salivation);

temporal lobe (perceptual judgment, visual and auditory recollection, hearing);

motor (arm, leg, hand, lips, articulation);

sensory (arm, leg, hand, lips, tongue, mouth);

The sensory homunculus

Phantom limb phenomenon:

the brain has specific space for the limb, stimulation in neighboring areas

-> cause physical sensation

Pain Nociception:

an unpleasant response caused by tissue damage and emotional responses as warning messages to avoid self-injury

Nociceptor: free nerve endings for sending pain messages (action potentials -> afferent nerve tracts -> spinal cord)   Pain + touch messages  -> primary somatosensory cortex Gate control theory:

pain messages have to get through a neuronal gateway -> proceed/block

Substance P: elevate pain signals Pain -> brain -> emotional response (with memory in the limbic system) -> avoid future stimuli
Endorphins: decrease substance P’s effects Hypnosis, placebo effect -> pain relief
Balance Vestibular sense:

head position, head/body moving speed

Semicircular canals: in different directions, with fluid, hair cells   Posture, movements, self-protection Motion sickness:

conflicts of information between the balance system (e.g., no motion) and the visual system (e.g., motion)

Otolith organs: otoliths (calcium carbonate particles) -> hair cells -> cranial nerve 8 -> the brain
Kinesthesis Limb and joint motions, weights;

procedural memory

Proprioceptors/mechanoreceptors:

Muscle spindle in skeletal muscles for muscle stretching;

Golgi tendon organs for tension in tendons;

Joint receptors around joints for joint motions

  Muscle, tendons, joint information -> brain regions  

 

Leave a Reply

Copyright © 2006-2017 PharmTao.com. All Rights Reserved.

Disclaimer: By using this site, the readers agree that the content on our web pages is for information purpose only. The information provided on our web pages is not intended for diagnosis, or to treat, cure or prevent any diseases, conditions or symptoms, or to endorse any products. Personal directions and the use of health products should be provided by qualified health professionals.

Mind-Body, Personalized, and Systems Medicine