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A hair follicle consists of : The papilla is a large structure at the base of the hair follicle. [4] The papilla is made up mainly of connective tissue and a capillary loop. Cell division in the papilla is either rare or non-existent. [contradictory] Around the papilla is the hair matrix. A root sheath composed of an external and internal root ...
Another common type of trichome is the scale or peltate hair, that has a plate or shield-shaped cluster of cells attached directly to the surface or borne on a stalk of some kind. Common examples are the leaf scales of bromeliads such as the pineapple , Rhododendron and sea buckthorn ( Hippophae rhamnoides ).
The dermis is composed of three major types of cells: [3] fibroblasts, macrophages, and mast cells.. Apart from these cells, the dermis is also composed of matrix components such as collagen (which provides strength), elastin (which provides elasticity), and extrafibrillar matrix, an extracellular gel-like substance primarily composed of glycosaminoglycans (most notably hyaluronan ...
Papilla (worms), small bumps on the surface of certain worms; Basilar papilla, a sensory organ of lizards, amphibians and fish; Dental papilla, in a developing tooth; Dermal papillae, part of the skin structure; Major duodenal papilla, in the duodenum; Minor duodenal papilla, in the duodenum; Genital papilla, a feature of the external genitalia ...
The integumentary system includes skin, hair, scales, feathers, hooves, claws, and nails. It has a variety of additional functions: it may serve to maintain water balance, protect the deeper tissues, excrete wastes, and regulate body temperature , and is the attachment site for sensory receptors which detect pain, sensation, pressure, and ...
Fatty fish are also protein-rich and contain selenium, and vitamins B and D. Selenium, a trace mineral, helps regulate thyroid hormone levels and plays a role in limiting oxidative stress on the ...
The structure, consisting of hair, hair follicles, arrector pili muscles, and sebaceous glands, is an epidermal invagination known as a pilosebaceous unit. [ 4 ] Sebaceous glands are also found in hairless areas ( glabrous skin ) of the eyelids , nose , penis , labia minora , the inner mucosal membrane of the cheek , and nipples . [ 4 ]
The molecular biology of hair cells has seen considerable progress in recent years, with the identification of the motor protein that underlies somatic electromotility in the outer hair cells. Prestin's function has been shown to be dependent on chloride channel signaling and that it is compromised by the common marine pesticide tributyltin .