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.
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
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