The system that produces and drains tears. The lacrimal apparatus of the eye includes the main and accessory lacrimal glands and the nasolacrimal drainage duct. The main gland lies just within the upper and outer
margin of the eye orbit and drains on to the conjunctiva. It secretes tears during crying and when the eye is irritated. The accessory gland lies within the conjunctiva, and maintains the normal tear film, secreting it directly onto the conjunctiva. Tears drain through the lacrimal puncta, tiny openings towards the inner ends of the upper and lower eyelids. The puncta are connected by narrow tubes to the lacrimal sac, which lies within the lacrimal bone on the side of the nose. Leading from the sac is the nasolacrimal duct, which opens inside the nose.
the structures that produce and drain away fluid from the eye (see illustration). The lacrimal gland secretes *tears, which drain away through small openings (puncta) at the inner corner of the eye into two lacrimal canaliculi. From there the tears pass into the nasal cavity via the lacrimal sac and the *nasolacrimal duct.
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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