Skin
A. Sahib El-Radhi in Paediatric Symptom and Sign Sorter, 2019
Physiological sweating is a vital process for hypothalamic-controlled thermoregulation; there is also emotional sweating regulated by the limbic system. The human body has about 4 million sweat glands; 75% are eccrine. Eccrine sweat glands, found all over the skin surface, cool the body by evaporation of sweat. Apocrine sweat glands become active during puberty and are mainly present in the axillae, anogenital skin and mammary areas and produce viscous fluid to give the body a distinctive odour. Excessive perspiration (hyperhidrosis) is due to overactive sweat glands as a result of dysregulation of the neural sympathetic control of the eccrine sweat glands. It can be generalised or localised to certain parts of the body such as palms, axillae or soles. It can also be primary, usually idiopathic, or secondary caused by an underlying condition (e.g. hyperthyroidism). Excessive sweating is a common problem and can be distressing; leading to embarrassment and avoidance of social contact.
Anatomy and Physiology of the Autonomic Nervous System
Kenneth J. Broadley in Autonomic Pharmacology, 2017
The apocrine glands, in contrast, are larger and distributed mainly around the external genitalia and the axillae (armpits). The apocrine sweat glands become active in adolescence and appear to be involved in sexual function through the release of pheromones in the secretions. These airborne products may stimulate the olfactory senses resulting in release of gonadotrophic hormones, LH (luteinizing hormone) and FSH (follicle-stimulating hormone), from the anterior pituitary gland. These control sexual activity through their release of sex hormones (testosterone and oestradiol) from the gonads. Body odour also arises primarily from the bacterial decomposition of apocrine gland secretions. These glands are not innervated by autonomic nerves but may respond via α-adrenoceptors to circulating catecholamines (adrenaline) released from the adrenal medullae in response to stress.
Botulinum toxins: Pharmacology, immunology, and current developments
Anthony V. Benedetto in Botulinum Toxins in Clinical Aesthetic Practice, 2017
Eccrine sweat glands are widely distributed over the body, with areas around the sweat coil and duct densely vascularized and innervated by sympathetic postganglionic terminals.70 Unlike most sympathetic neurons, those that innervate eccrine sweat glands are cholinergic; they also co-release neuropeptides such as calcitonin gene related peptide (CGRP) and vasoactive intestinal polypeptide (VIP).71 Apocrine sweat glands are distributed only in hairy areas such as axillary, mammary, perineal, and genital regions, where they respond to both epinephrine and norepinephrine, although whether they are activated via sympathetic innervation, circulating levels of these neurotransmitters, or local intradermal release is not yet known. Apocrine sweat glands have also been described in hairy regions where they respond to acetylcholine, norepinephrine, and epinephrine.70
Physiology of sweat gland function: The roles of sweating and sweat composition in human health
Published in Temperature, 2019
Lindsay B. Baker
The apocrine gland is a second type of sweat gland, which was first recognized by Krause in 1844 and later named by Schiefferdecker in 1922 [20,21]. Apocrine sweat glands are located primarily in the axilla, breasts, face, scalp, and the perineum [21,22]. As shown in Figure 1, these glands differ from eccrine glands in that they are larger and open into hair follicles instead of onto the skin surface [12]. In addition, although present from birth, the secretory function of apocrine glands does not begin until puberty [23]. Apocrine glands produce viscous, lipid-rich sweat, which is also comprised of proteins, sugars, and ammonia [21,23]. The function of apocrine glands in many species is generally regarded as scent glands involved in production of pheromones (body odor), although this social/sexual function is rudimentary in humans. Apocrine gland innervation is poorly understood, but isolated sweat glands have been found to respond equally to adrenergic and cholinergic stimuli [23].
Inherent differences in keratinocyte function in hidradenitis suppurativa: Evidence for the role of IL-22 in disease pathogenesis
Published in Immunological Investigations, 2018
Derek Jones, Anirban Banerjee, Peter Z. Berger, Alexandra Gross, Sean McNish, Richard Amdur, Victoria K. Shanmugam
Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory disease of the apocrine sweat glands, characterized by recurrent abscessing inflammation which affects approximately 1–4% of the population (Jemec et al. 1996; Vazquez et al., 2013). There is, currently, no known cure for HS and the pathogenesis is poorly understood. Host innate and adaptive immune responses (Kelly et al., 2014), defective keratinocyte function (Jemec, 2012), and the microbial environment in the hair follicle and apocrine gland (Jahns et al., 2014) have all been postulated to play a role in disease activity. It is known that HS patients develop inflammatory skin lesions with elevated levels of pro-inflammatory cytokines and matrix metalloproteinases (Banerjee et al., 2016; Mozeika et al., 2013). Furthermore, studies investigating cellular and cytokine responses in HS lesional tissue suggest defects in immune responses with increased numbers of infiltrating CD4 + T cells producing IL-17 and IFN-γ, and reduced numbers of IL-22 secreting cells (Hotz et al., 2016). However, there is an unmet need to clarify the role that keratinocytes play in orchestrating the inflammatory responses seen in this disease.
Thermoregulatory effects of guava leaf extract-menthol toner application for post-exercise use
Published in Pharmaceutical Biology, 2021
Titeyut Wongsanao, Wipavadee Leemingsawat, Vipaporn Panapisal, Thanomwong Kritpet
Thermoregulatory and cardiovascular processes, including skin blood flow and sweating, during sustained exercise are significantly associated with increased body heat content due to metabolic heat production (Kenny and McGinn 2017). Sweating mainly reduces core and skin temperature during exercise (Tansey and Johnson 2015); then at the cessation of exercise, sweat production rate decreases rapidly, and the principle route of heat dissipation is likely convection through the skin in the period following exercise (Gerrett et al. 2018). However, sweat alkalinity during excessive perspiration resulting from bicarbonate ions (HCO3-) might alter the skin barrier and cause various skin diseases (Schmid-Wendtner and Korting 2006). Sweating from exercise was reported as the common factor which aggravated the symptoms of atopic dermatitis in school children (12–14 year-olds) (Williams et al. 2004). Moreover, secretion of sweat and leakage into tissues could promote itching for people with atopic dermatitis and aggravate dermatitis (Murota et al. 2018). Additionally, apocrine sweat glands secrete milk-like substances composed of electrolytes, steroids, proteins, vitamins, and lipid compounds, which might be transformed by skin flora bacteria and cause body odour (Fredrich et al. 2013). Therefore, post-exercise hygienic practices should quickly clean sweat stains from the skin, and if there is a way to decrease the remaining post-exercise perspiration, then the occurrence of the aforementioned problems will be prevented. Since the restoration of thermoregulation after exercise turns to be primarily convection through the skin instead, the body is still recovering after a workout.