This presentation includes structure of apocrine and eccrine glands, their fuctions , mechanism of sweat and applied aspect.

1. APOCRINE AND ECCRINE
GLANDS AND ITS APPLIED
ASPECT

2. TYPES OF SWEAT GLANDS
 3 TYPES :
1. Apocrine
2. Eccrine
3. Apoeccrine

3. Apocrine Glands
 Present in axillae,periumbilical region,perineal and
circumoral areas,prepuce,scrotum,mons pubis,labia
minora.
 Modified apocrine glands are
External Auditory Canals(ceruminous Glands),
Eyelids(Moll’s Glands),
Mammary glands.

4. Development
 Primary epithelial germ layer or hair germs in 4th – 5th
month of IUL
 After 5th month,most regress and persists only in the
sites mentioned
 Small and non-functional until puberty when they
enlarge and start secreting their product

5. FUNCTION
 In humans is not entirely clear
 Continuously secrete very small quantities of an oily
odourless sterile fluid which when modified by
cutaneous bacteria serve as pheromone in animals
 May also play some role in olfactory communication

6. STRUCTURE
Coiled secretory portion
 Lower part of dermis or subcutaneous
tissue
 Lined by columnar or cuboidal cells
depending upon stage of secretion
Ductal portion
 Empties into the infundibulum of
hair follicle slightly above the entrance of
sebaceous duct or directly on surface

7. Apocrine gland
 Lumen lined by a single layer of cuboidal or columnar
cells
 Pale staining cytoplasm
 Round nuclei situated near the base of of the cells
 Apical borders of the cells project into the lumen
 Distal portion of the cells have the appearance of being
“pinched-off” or “decapitated”

8. HPE

9. Secretory cells are surrounded by
 A layer of contractile myoepithelial cells
 A PAS positive basement membrane zone
 Type 3 collagen bundles and elastic fibres of the
periadnexial dermis

10. Apocrine excretory duct
 2 layers of cuboidal cells
 An inner periluminal cuticle
 No outer myoepithelial lining
 Distally the epithelium merges with the epithelium of
a hair follicle
 The intrafollicular portion is straight (spiraled in
eccrine duct)

11. Ultrastuctural features
 Typical of secretory epithelia
 Prominent
rER,GA,ribosomes,mitochondria,lysosomes
 Secretory granules near the lumen
 Reactive histochemically for iron,lipofuscin,neutral
mucopolysaccharides

12. Regulation of secretion
Nervous system
 Sympathetic
 Cholinergic
 Sudomotor transmission
Nerve endings in the close proximity release neurohormonal
transmitters that diffuse into periaadnexial capillary
networks that nourish the secretory coils
Emotional stresses
 Sympathetic discharge causes myoepithelial contraction
and excretion of the secretion

13. APPLIED ASPECT
DISORDERS OF APOCRINE GLANDS
 Bromhidrosis : bacterial decomposition of the secretion on skin surface
modifies it resulting in Rancid body odour(Corynebacterium spp.) and
sweaty odour(Micrococcus spp.)
 Apocrine chromhidrosis – secretion of pigmented(yellow,green,black)
sweat due to Rich lipofuscin content of apocrine sweat or high state of
oxidation, mainly on face and axilla
 ‘Pseudochromhidrosis’ or extrinsic apocrine chromhidrosis – staining
of the sweat by chromogenic bacteria esp. Corynebacterium spp. or
garments
 Apocrine miliria(Fox – Fordyce disease)
 It is chronic,pruritic,papular eruption of the apocrine areas,principally
axilla and pubis. May be due to Occlusion of apocrine ducts by a
keratinous plug induced by functional hormonal changes

14. FOX- FORDYCE DISEASE
APOCRINE CHROMHIDROSIS

15. Hidradenitis Suppurativa
 Syn- Apocrinitis, Acne inversa
 Definition- is a chronic relapsing inflammatory
disease of apocrine gland follicles
 It is follicular occlusion disorder, apocrine glands are
involved secondarily in inflammatory process

17. Eccrine Units
These are true sweat gland in humans
 Present almost everywhere on the human skin except
on the lips,nail beds,clitoris,labia minora and external
auditory canal
 also called as atrichial since they develop from
superficial epidermis and remain independent of the
hair follicle. Eccrine are merocrine and are primarily
involved in thermoregulation.

18. Development
 Embryologically these are specialized downgrowth of
epidermis independent of the folliculo sebaceous unit,
at 4th month of IUL
 Descend to near the junction of dermis and
subcutaneous tissue
 3 million units present at birth , no units formed
thereafter

19.  Eccrine unit can be divided into
1. An irregularly coiled secretory gland(proximally)
2. A dermal duct leading from the gland
3. A spiraled intraepidermal
duct(acrosyringium)

20. Eccrine gland :
SECRETORY PORTION
 2 rows of cells
 A discontinuous outer row of spindle shaped,contractile
myoepithelial cells
 An inner row of pyramid-shaped,secretory epithelial cells
 2 types of cells
 Large glycogen containing pale or clear cells(lumen)
 Smaller mucopolysaccharide containing dark
cells(periphery)

21. HPE

22. Eccrine dermal duct
 Lined by a double layer of
small,darkly
basophillic,cuboidal epithelial
cells
 Each duct enters the
epidermis at the nadir of a rete
ridge and coils and widens as
it spirals upward to open
directly onto the skin surface

23.  Epidermal duct(acrosyringium)
 2 layers of cells lining
 Cuticular cells(lining the lumen)
 Poroid cells(periphery)

24.  Intraepidermal keratinocytesof an eccrine duct are
accomplanied by very few melanocytes but they
contain keratohyaline granulesand are linked to one
another and to neighbouring epidermal keratinocyte
by desmosomes
 Eccrine and apocrine ducts unlike their glands,are
indistinguishable from each other histologically

25. Sweating
 Commences in the pale(clear) cells of the secretory
portion of the eccrine gland
 Energy requirements of sweat secretion are met by the
numerous mitochondria and glycogen particles within
these cells
 Intercellular canaliculi transport the solution secreted
by pale dark cells to the lumen of secretory coil

26.  Secretory and myoepithelial cells of the eccrine gland
are innervated predominantly by the unmyelinated
cholinergic class C nerve fibres(sympathetic nervous
system)
 Maximal rate of eccrine secretion in response to
cholinergic stimulation is 5 times that in response to
adrenergic stimuli

27. Chemical stimuli
 Acetyl choline
 Calcium
 Prostaglandin E1
 Epinephrine
 Norepinephrine
 VIP

28.  These mediators may act on contraluminal plasma membranes
of the pale cells
 Increases their permeability
 Allows sodium,chloride,other electrolytes to diffuse into the
cytoplasm
 An energy requiring Na pump located at the canalicular plasma
membrane of pale cells then may trnsport Na actively into
canaliculi ,folld. By transportation of chloride and water
 A soln of “precursor sweat” is produced that is isotonic to plasma
 Aldosterone acts upon the epithelium that lines eccrine ducts
 Stimulates reabsorption of sodium in partial exchange for
potassium

29. M
Mechanism of sweat formation

30.  The epithelium of excretory ducts is relatively
impermeable to water
 This enables ductal reabsorption of greater amounts
of sodium than of water
 Excretion of a hypotonic solution known as “sweat”
 Myoepithelial cells contract in response to provide
mechanical support the wall of the secretory coil as it
butresses itself against increases in luminal
hydrostatic pressure

31. Eccrine sweat
1. An odorless,colorless,hypotonic solution
2. Specific gravity : 1.005
3. pH : 4.5 – 5.5
4. Sodium- initially low (10-20 mmol) gradually increasing to reach around
100mmol.
5. Potassium- 5-6mmol.
6. Chloride- concentration increases with increase in sweat secretion.
7. pH- 7.2-7.3 and HCo3- 14mmol in primary sweat
8. Lactate- 30-40mmol
9. Solutes :
Na,Cl,K,urea,lactate,HCO3,NH3,Ca,P,lactate,Mg,SO4,Zn,Fe,iodide,amino
acids,proteins,Igs
10. With increased rates of sweating, pH increases, Na and Cl conc
increases,K,lactate and urea conc. decreases

32. Function of eccrine gland
 To produce sweat during periods of stress induced by heat
 Excessive body heat dissipated by evaporation of water
excreted onto the skin surface
 I L of evaporated sweat removes approx. 585 kcal of heat
from the body
 A temperatjure control centre in the preoptic area and
anterior nucleus of the hypothalamus serves as a neutral
thermostat that regulates the temperature of blood with
thermosensory impulses that arise in the skin
 An increases inbody temperature of 0.01 degree C excites
hypothalamic stimulation of eccrine sweating via efferent
pathways of sympathetic nervous system

33.  The 1st response to elevation of temperature is an
increase in the no. of eccrine glands that function
actively
 With increasing thermal stress, an increased amount
of sweat is secreted by each gland
 2 – 3 l of sweat produced per hour by individuals
exposed to high environmental temperature
 During exercise,catecholamines secreted by adrenal
glands help tp mediate the maximisation of sweating
 This is not seen in heat induced sweating

34.  During prolonged stress, for eg. in tropical climates,
eccrine glands become acclamatised , i.e. they acquire
ability to secrete more copious amounts of sweat at a
greater rate in response to relatively smaller elevations
in boby temperature
 At the same time adrenal cortex secretes more
aldosterone which increases the reabsorption of
sodium in swaet duct thereby preventing excessiv e
sodium loss

35.  Eccrine glands of the palms,soles,axillae and forehead
respond predominantly to emotional rather than
thermal stimuli
 Certain heavy metals (eg. Lead, mercury) and some
drugs (eg. Ethanol, griseofulvin)are excreted in sweat

36. Disorders of eccrine glands
Hyperhidrosis
 Causes of generalised hyperhidrosis
 Febrile infective illness-TB, malaria, brucellosis
 Metabolic-DM, Hyperthyroidism, hypoglycaemia,
hyperpituitarism
 Parkinson’s disease
 Menopause
 Internal malignancy and lymphomaNeurological
disorders-Familial dysautonomia,Episodic
hypothermia with hyperhidrosis
 Drugs- fluoxetin

37.  Palmoplantar hyperhidrosis- emotional stimuli
increases sweating of palms and soles.Sweating
may be continuos or phasic.
 Complications include pompholyx, contact
dermatitis, pitted keratolysis

38. Causes of hypohidrosis/ anhidrosis
 Brain lesions- organic lesions, hyperthermia
 Spinal cord and peripheral-
 Organic lesions- syringomyelia, leprosy, DM,
alcoholism, Ross syndrome, anticholinergics and
ganglion blocking drugs
 Sweat gland lesions- aplasia, Congenital ectodermal
dysplasia, Ichthyosis, scleroderma, myelomatosis,
Sjogren’s syndrome, Incontinentia pigmenti

39. SWEAT GLAND LESIONS
 Aplasia
 Hypohidrotic ectodermal dysplasia
 Ichthyosis
 Any cause of atrophy (acro dermatitis chronica atrophicans)
 Scleroderma & sjogren’s syndrome
 Ross’s syndrome
 Consists of wide spread hypohidrosis combined with patchy compensatory
hyperhidrosis together with tonic pupils& loss of deep tendon reflexes. The
changes are due to selective degeneration of sympathetic pathway.
Sweat retention syndromes
 Miliarias
 Tropical anhydrotic asthenia
 Pompholyx

40. Apoeccrine gland
 Present in the axillae of adults
 10 to 45% of all glands in the axilla
 Thought to develop during puberty from eccrine-like
precursors
 Larger than typical apocrine glands
 Ducts open directly onto the surface of the skin via the
epidermis
 Secretory portion is irregularly dilated
 Epithelial lining of the dilated segments of the gland
resembles that of the apocrine gland
 Epithelial lining of the undilated segments resembles that
of the eccrine gland

41.  Apoeccrine glands contribute to axillary sweating in
adults
 Studies have shown that these glands secrete copious
quantities of a serous solution of sweat in response to
cholinergic and adrenergic stimulation