ECCRINE GLANDS

OVERVIEW

• Major Sweat Glands

• Primates

• ‘Atrichial’

• Temp Regulation • Grip• Minor Excretory

ETYMOLOGY

Merocrine (Gk: Meros – Part + Krinien – Separate)

Sudoriferous (Lat: Sudare – Sweat Fer – to carry / bear)

Eccrine (Gk : Ekkrinien – to secrete)

Exocrine Glands

DENSITY / DISTRIBUTION

• Generalized distt INCL Glans / Prepuce EXCL Vermillion Border

Lip Nail Bed Clitoris / Labia Minora Ext Aud Canal

02 – 04 Million Glands / BSA30 – 40 mcg Indl Weight (Cum – 100 g)Males > Females > Pre-pubertal Distt

DISTRIBUTION (Glands/cm2)

• Volar 600 – 700

• Forehead 181

• Forearm 108

• Back 64

EMBRYOLOGY

• Epidermal downgrowths in Fetal Life (Ectodermal Origin)

• 03 Months – Palms / Soles• 05 Months – Other Areas• 08 Months - Adult Morphology

No Post-natal development

DEVELOPMENT

STRUCTURE

• SIMPLE COILED TUBULAR Glands

• Spiral Intraepidermal duct (ACROSYRINGIUM)• Straight Intradermal duct UPPER DERMIS• Coiled Terminal Portion (ACINUS / FUNDUS)

2/3rd SECRETORY1/3rd DUCTAL

SECRETORY COIL

• 02-05 mm Uncoiled Length ; 60-80 microns Dia

Large CLEAR CELLS (CC) Secretory / Pyramidal / Rest on ME

Lipofuschin Autofluoroscent Granules Aqueous Substance + Glycogen

House Na+ - PUMP for Active Ion Tpt

SECRETORY COIL• Small DARK Cells (DC)

Mucoid / Cuboidal / Rest on CCPAS – positive GlycoproteinsSialomucin secretion

• Myo-Epithelial Cells (ME)Spindle / Rest on BM / Support CCMyofilaments / Mechanical Support

? Propel Sweat to the surfaceNon-Secretory

COLLAGEN-RICH HYALINE BASEMENT MEMBRANE

ULTRASTRUCTURE OF SECRETORY COIL

INTRADERMAL SWEAT DUCT

• LUMINAL Cells – Inner / Small / Cuboidal / Basophilic

• DUCTAL Cells – Outer (Basal) / Na – K –

ATPase Activity ? Ductal Reabsorption of Sweat

Tonofilament – rich Pseudo-Cuticle Rigidity

ACROSYRINGIUM

• Intraepidermal Ductal System• Rete Ridge Corneal Surface• Single layer of Inner Luminal Cells• 02-03 Layers of Outer Basal Cells

Cells contain Desmosomes, few Melanocytes and undergo Kertainization

Final Propulsion of Formed Sweat to Surface via Pore

FUNCTIONS• SWEATING

Heat Stress – Evaporative Heat Loss (1 L 585 kCal)

Emotional Stimuli Gustatory Stimuli

• MOISTURIZING

For Improved Grip

• EXCRETION Minor / Adjunct Organ

except Certain Drugs

MAINTAIN ELECTROLYTE-BALANCE

ANTI-MICROBIAL PEPTIDES (DERMICIDIN - ‘Sweat Antibiotic’)

CONTROL OF ECCRINE SWEATING

03 PHYSIOLOGICAL STIMULI

THERMOREGULATORY (Hypothalamus)

EMOTIONAL (?Frontal)

GUSTATORY (Medulla)

THERMOREGULATORY MECHANISM

INNERVATION OF ECCRINE GLANDS

• Via Efferent Sudomotor Pathway through Postganglionic non-myelinated C fibres to Eccrine Glands

• SKIN SUPPLY UPPER LIMB T2 – T8TRUNK T4 – T12

LOWER LIMB L2 – L4

• Sympathetic nerve supply - MUSCARINIC & CHOLINERGIC R

• Alpha / Beta Adrenergic Receptors

SUDOMOTOR PATHWAY

THERMOREGULATION

• HEAT LOSS - radiation, convection, conduction and evaporation

• Thermal Sweating keeps Body Temperature constant

• High environmental Temp Evaporational Heat Loss provides maximum regulation

THERMOREGULATION

FACTORS :

LOCAL SKIN TEMP10 deg C Rise 3X Local

Sweating

CORE TEMPSimilar Rise 9X Local Skin

Temp

SWEATING

• CLEAR ODOURLESS ECCRINE SECRETION PERSPIRATION

• Comprises WATER + electrolytes

• SWEAT RATE No of Active Sweat Glands per area X Rate of

Sweating / Gland (Max 02-20 micro L / gland)

• 10 L SWEAT / DAY in Acclimatized indl

CONTENTS

• pH : 4.3 – 4.7• WATER • Inorganic ions – sodium, chloride, potassium • Lactate / Urea (Moisturizers)• Glucose +/-• Ammonia and amino acids• Proteins including proteases

MECHANISM OF SWEAT PRODUCTION

• 02 STEPS :

(1) SECRETORY COIL ‘ULTRAFILTRATE’ISOTONIC FLUID i/r/o Ach

(2) DUCTAL SYSTEM REABSORBS NaCl HYPOTONIC SURFACE SWEAT

• ACh stimulates EG by inc intracellular Ca2+

• Opens K+ Cl- Channels in CC Loss of K+ Cl- H20

• Eccrine Gland Shrinkage

• Na K ATPase Pump Activated to facilitate Intracellular entry of Na+ K+ Cl-

• Isotonic NaCl in Lumen of Coiled Tubule

DUCTAL REABSORPTION

• Na+ Re-Entry via Na+ Channels and Transport across BDC by Na+ K+ ATPase Pump

• SWEAT ACIDIFICATION by Carbonic Anhydrase

OTHER FACTORS AFFECTING SWEATING

• Environmental conditions(Ambient Temp / Air Velocity

• Clothing (Insulation and Moisture Permeability)

• Degree of Acclimatization

• Physical activity level

• Emotional stress

EXCRETORY FUNCTION

• MINOR ROUTE for Water / Electrolytes / Metabolic Wastes

• ACTIVE EXCRETION of DRUGS : – Griseofulvin / Ketoconazole / ?Fluconazole– Ciprofloxacin / Sulpha Drugs – Phenobarbitol / Other AEDs– ?? Chemotherapeutic Agents / DMARDs ??

ECCRINE GLAND DISORDERS

THANK YOU