Epithelium 2: Glands Flashcards
What are the types of glands?
Exocrine glands
Endocrine glands
Mixed glands
What are exocrine glands?
Pass secretions through a duct system onto an epithelial body surface
Secretions are normally enzymes
What are endocrine glands?
Pass secretion directly into blood or lymph (internal secretion)
Secretions are normally hormones
What are mixed glands?
Have both exocrine and endocrine components
How can exocrine glands be classified?
Based on shape of secretory unit & branching pattern of duct
Based on mechanism of release of their product
Based on the nature of their secretion
How can glands be classified according to number of cells?
Unicellular glands: Single secretory cells, e.g. goblet cells
Muticellular glands: Group of epithelial cells which discharge secretion directly or through duct systems, e.g. parotid glands
How can glands be classified according to the structure of the duct?
Simple
Compound
Characteristics of simple glands
Unbranched excretory ducts
Contain a single secretory unit
Types of simple glands
Characteristics of compound glands
Excretory duct is branched
Bulky and contain many individual secretory units
Types of compound glands
Examples of complex glands
What are the classifications of glands according to their mode of secretion?
Holocrine
Apocrine
Merocrine
Characteristics of holocrine glands
Whole cell dies and the discharges go together with cellular contents
E.g. sebaceous and tarsal gland cells
Characteristics of apocrine glands
Small portion of cell body lost during secretion
E.g. mammary glands
Characteristics of merocrine glands
Only cell products are discharged
E.g. Sweat and salivary glands
How can glands be classified according to the nature of their secretions?
Serous glands
Mucous glands
Seromucous glands
Describe the secretions of serous glands
Thin
Watery
Rich in enzymes
Protein in nature
Describe the cellular characteristics of serous glands
Stain darkly with H/E
Nuclei are rounded and placed near the center to the basal side
Pyramidal in shape
Small cell
Describe the secretions of mucous glands
Contains mucopolysaccharides which collects in the apical part of cell
Describe the cellular characteristics of mucous glands
Stain very lightly with H/E stain & therefore gives empty look
The nucleus is basally placed & flattened
Cells are short, columnar and pyramidal in shape
Describe the structure of mixed glands
Contain both serous & mucous secretory units
Describe the cellular characteristics of mixed glands
Serous cells form crescentic caps on mucous acini called serous demilunes
