Cutaneous Glands

Cutaneous Glands

1. Exocrine glands

   • Release secretion to the skin surface via ducts
   • As these glands are formed by the cells of the stratum basale, they push into the deeper skin regions and ultimately reside almost entirely in the dermis
   • Sebaceous (Oil) Glands
     • Found all over the skin except on the palms of the hands and the soles of the feet
     • Their ducts usually empty into a hair follicle but some open directly onto the skin surface
     • Product of the sebaceous gland: Sebum
       • Mixture of oily substances and fragmented cells
       • Lubricant that keeps the skin soft and moist and prevents the hair from becoming brittle
       • Contains chemicals that kill bacteria, so it is important in preventing the bacteria present on the skin surface from invading the deeper skin regions
     • Become very active when male sex hormones are produced in increased amounts in both sexes during adolescence
       • The skin tends to become oilier during this period of life
   • Sweat Glands
     • Also called the sudoriferous glands are widely distributed in the skin
     • Eccrine glands
       • Far more numerous and are found all over the body
       • They produce sweat
         • Clear secretion that is primarly wastes and some salts (sodium chloride)
         • Vitamin C
         • Traces of metabolic wastes
           • Ammonia
           • Urea
           • Uric Acid
           • Latic Acid
             • Chemical that accumulates during vigorous muscle activity
         • Is acidic (pH from 4 to 6)
           • A characteristic that inhibits the growth of certain bacteria, which are always present on the skin surface
         • Reaches the skin surface via a duct that opens externally as pores
       • Body's heat regulating equipment
         • Have nerve-endings that cause them to secrete sweat when the body temperature is high
           • When sweat evaporates from the skin surface, it carries large amounts of body heat with it
             • On a hot day it is possible to lose up to 7 liters of body water
         • If internal body temperature changes by a few degrees, life-threatening changes occur in the body.
     • Apocrine Glands
       • Largely confined to the axillary (armpits) and genital areas of the body
       • Usually larger than the eccrine glands and their ducts empty into hair follicles
       • Their secretion contains fatty acids and proteins as well as substances present in eccrine glands
         • May have milky or yellowish color
         • The secretion is odorless but when the bacteria that live on the skin uses its proteins and fats as a source of nutrients for their growth, it takes on a musky and unpleasant odor
       • Begin to function during puberty under the influence of androgens (male sex hormones)
       • Although their secretion is produced almost continuously, they pay a minimal role in thermoregulation
         • Their function is not known yet, but they are activated by nerve fibers during pain and stress and sexual foreplay