Vestibular Apparatus: From 1 Different Sources
those parts of the inner ear involved with balance. They comprise the *semicircular canals, *saccule and *utricle. See ear; vestibular system.
an apparatus for treating haemorrhoids in which a tight elastic band is applied across their base to cause ischaemic necrosis leading to sloughing off within a few days.... barron’s banding apparatus
a collection of vesicles and folded membranes in a cell, usually connected to the *endoplasmic reticulum. It stores and later transports the proteins manufactured in the endoplasmic reticulum. The Golgi apparatus is well developed in cells that produce secretions, e.g. pancreatic cells producing digestive enzymes. [C. Golgi (1844–1926), Italian histologist]... golgi apparatus
(JGA) a microscopic structure within the kidney that is important in regulating blood pressure, body fluid, and electrolytes. It is situated in each nephron, between the afferent arteriole of the glomerulus and the returning distal convoluted tubule of the same nephron. The JGA consists of specialized cells within the distal tubule (the macula densa), which detect the amount of sodium chloride passing through the tubule and can secrete locally acting vasoconstrictor substances that act on the associated afferent arteriole to induce a reduction in filtration pressure (tubuloglomerular feedback). Modified cells within the afferent arterioles secrete *renin in response to a fall in perfusion pressure or feedback from the macula densa and form a central role in the renin-*angiotensin-aldosterone axis. Mesangial cells support and connect the macula densa and the specialized cells in the afferent arteriole and have sympathetic innervation, facilitating the renin response to sympathetic nervous stimulation.... juxtaglomerular apparatus
(VEMP) a test used to measure the response of the *saccule. It is used in the diagnosis of *superior canal dehiscence syndrome, *Ménière’s disease, and other disorders of the inner ear.... vestibular evoked myogenic potential test
the two pairs of glands that open at the junction of the vagina and vulva. The more posterior of the two are the greater vestibular glands (Bartholin’s glands); the other pair are the lesser vestibular glands. Their function is to lubricate the entrance to the vagina during coitus.... vestibular glands
the division of the *vestibulocochlear nerve that carries impulses from the semicircular canals, utricle, and saccule of the inner ear to the brain, conveying information about the body’s posture and movements in space and allowing coordination and balance.... vestibular nerve
(vestibular neuritis) a condition characterized by the sudden onset of vertigo without hearing loss or other auditory symptoms (compare labyrinthitis). It generally lasts days to weeks and the cause is unknown.... vestibular neuronitis
a slow-growing benign tumour arising on one of the *vestibular nerves. It is also known as an acoustic neuroma, but this is a misnomer as the tumour arises from *Schwann cells rather than nerve cells and on a vestibular nerve rather than the cochlear (acoustic) nerve. Symptoms include hearing loss, tinnitus, and imbalance and there is an increased prevalence of the tumour in patients who have *neurofibromatosis type II. Diagnosis is by MRI scan and treatment is not always required. In those cases where treatment is necessary, this may be by surgery, radiotherapy, or *gamma knife.... vestibular schwannoma
those parts of the body involved in balance. The peripheral vestibular system, or *vestibular apparatus, is in the inner ear. The central vestibular system comprises those parts of the brain that are involved in balance. The central vestibular system receives other inputs as well as from the ear, in particular inputs from the eyes and proprioceptors.... vestibular system
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