SA Medical - General Medicine And Imaging of Disease

General Organisation; the tactile and Position senses The somatic senses can be divided into three main components Mechanoreceptors  Thermoreceptors Nociception - pain and damage discriminative - precisely localised touch  Crude - poorly localised - proprioception - touch, pressure, vibration and the senses of static body position and movement Exterioceptive sensation  Visceral sensations Detection and Transmission of Tactile Sensation Even though touch, pressure and vibration are often classified as separate and distinct sensations, they are each detected by the same general class of tactile receptors: the Mechanoreceptors Free nerve endings - skin and in the cornea of the eye Meissner's corpuscule -    The   tactile corpuscles of Wagner and Meissner   (Fig. 936)   are oval-shaped bodies.   These tactile corpuscles occur in the papillæ of the corium of the hand and foot, the front of the forearm, the skin of the lips,...

Dizziness refers to an impairment in spatial perception and stability. Dizziness is considered imprecise.Dizziness can be used to mean vertigo, presyncope, disequilibrium, or for a non-specific feeling such as giddiness or foolishness. Vertigo is a specific medical term used to describe the sensation of spinning or having one's surroundings spin about them. Many people find vertigo very disturbing and often report associated nausea and vomiting. It represents about 25% of cases of occurrences of dizziness. Disequilibrium is the sensation of being off balance, and is most often characterized by frequent falls in a specific direction. This condition is not often associated with nausea or vomiting. Presyncope is lightheadedness, muscular weakness and feeling faint as opposed to a syncope, which is actually fainting. Non-specific dizziness is often psychiatric in origin. It is a diagnosis of exclusion and can sometimes be brought about by hyperventilation. A stroke is the...