Physiology of skin

Gillespie, J. M. (1983). The Structural Proteins of Hair Isolation, Characterisation and Regulation of Biosynthesis. In Biochemistry and Physiology of Skin, ed. L. A. Goldsmith. Oxford, U.K. Oxford University Press. 

The deeper the peel, the more effective it is, but also the more dangerous. A deep peel, when performed correctly, produces exceptional results in the majority of cases. I have never come across any report of complete facial necrosis after a peel. Fortunately therefore, the problem remains localized. Scarring can be atrophic, hypertrophic or retractile, depending on the depth of the burn and the area treated. To have a better understanding of the risk of post-peel scarring, we must take another look at the physiology of skin healing. 

A primary factor to consider in evaluation is the age of the patient. Changes in the anatomy and physiology of skin and its appendages relate closely to patient age, and for women hormonal status also affects the evaluation. 

Despite the limitations imposed by the physiology of the skin, several marketed controUed release transdermal dmg dehvery systems are available in the United States for example, scopolamine [51-34-3] for the treatment of motion sickness, nitroglycerin [55-63-0] for angina, estradiol [50-28-2] for the rehef of postmenopausal symptoms and osteoporosis, clonidine [4205-90-7] for the treatment of hypertension, fentanyl [437-38-7] as an analgesic, and nicotine [54-11-5] as an aid to smoking cessation. These systems are designed to dehver dmg for periods of one to seven days. 

The veins of skin are organized along the same lines as the arteries in that there are both subpapillary and subdermal plexuses [11]. The main arteriole communication to these is the capillary bed. Copious blood is passed through capillaries when the core body is either feverish or overheated, far more than needed to sustain the life force of the epidermis, and this rich perfusion lends a red coloration to skin. When there is opposite physiological need, the capillary bed is short-circuited as blood is passed directly into the venous drainage by way of the arteriovenous anastomoses. Fair skin noticeably blanches when this occurs. These mechanisms act in part to regulate body temperature and blood pressure. 

From such investigations, the exposure concentration or dose is often unknown and thus, a dose-effect relationship is difficult to evaluate. Therefore, information from clinical and physiological investigations generally has a limited use in the hazard assessment exceptions are identification of skin sensitizers and indications of possible adverse effects to selected organs and tissues depending on the investigations performed. 

Pharmacokinetics Readily absorbed after IM administration. Most absorption occurs within 72 hr remainder within 3-4 wk. Bound to protein to form hemosiderin, ferritin, or transferrin. No physiologic system of elimination. Small amounts lost daily in shedding of skin, hair, and nails and in feces, urine, and perspiration. Half-life 5-20 hr. 

FIGURE 4-2 Physiologic processes that occur after mustard-gas contamination of skin. 

Although the epidermis regenerates readily over an intact or partly intact dermal bed, it is well-known that de novo synthesis of the dermis does not occur spontaneously [65, 66], Likewise, even though the rat sciatic nerve is regenerated spontaneously across a 5-mm gap or occasionally across a 10-mm gap (provided that the cut ends of the nerve are inserted in a saline-filled rubber tube), no such regeneration is spontaneously observed across a 15-mm gap [67,68]. The appropriate use of collagen-GAG matrices leads to synthesis both of skin, complete with dermis and epidermis [79, 80, 84] and of new sciatic nerve [83]. It is this ability to induce de novo synthesis of nearly physiological tissue... 

Yuspa, S.H. (1983). Cutaneous carcinogenesis, natural and experimental page 1115 in Biochemistry and Physiology of the Skin, Goldsmith, L.A., Ed. (Oxford University Press, New Y>rk). 

The principal physiological functions of tins vitamin include growth, production of visual purple, maintenance of skin and epithelial cells, resistance to infection, gluconeogenesis. mucopolysaccharide synthesis, bone development, maintenance of myelin and membranes, maintenance of color and peripheral vision, maintenance of adrenal cortex and steroid hormone synthesis, Specific vitamin A deficiency diseases include xerophthalmia, nyctalopia, hemeralopia, keratomalacia, and hyperkeratosis. 

In order to study the physiologic evolution of the redox properties of skin, cyclic voltammograms are performed with platinum microelectrodes, every 15 min over 7 h. Each measurement was realized with a new microelectrode. For this preclinical study, nine volunteer subjects were involved they remained relaxed in the same room and their diet was checked during the whole experiment. 

Haploinsufficiency of human SPCA1 results in Hailey-Hailey disease (HHD) (Hu et al., 2000 Sudbrak et al., 2000), which highlights the critical role of this housekeeping Ca2+ and Mn2+ pump in cellular ion homeostasis. We will review the properties of this mutated SPCA1 and discuss how SPCA1 contributes to the physiology of the normal skin. 

Among the pathologies associated with RLS, several groups [38, 40] have reported neuropathies and radiculopathies. Evidence of peripheral axonal neuropathy of a mild degree was found in some putative idiopathic RLS patients through electro-physiological (EMG/NCV) and psychophysiological tests, subsequently confirmed by sural nerve biopsy [41], These data have recently been confirmed in 30 % of 22 patients by means of skin biopsy, and related to late onset associated with pain-like symptoms [42],... 

Lansdown, Alan B. G. (1995). Action and Interaction of Metals in the Toxicology and Physiology of the Skin. CRC Critical Reviews in Toxicology 25 397-462. 

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