Systems Physiology and Anatomy PDF

Systems Physiology and Anatomy Secretory Dr Pip Garner [email protected] Learning Outcomes 1. Know what a gland is 2. Know what can be secreted from glands 3. Know the differences between the different gland classifications, and examples of each 4. Show understanding of the s...

Systems Physiology and Anatomy Secretory Dr Pip Garner [email protected] Learning Outcomes 1. Know what a gland is 2. Know what can be secreted from glands 3. Know the differences between the different gland classifications, and examples of each 4. Show understanding of the secretory mechanisms, and examples 5. To know the different morphological classifications, and be able to identify them 6. To know the structure of a mammary gland and some of the control mechanisms What Is a Gland? An organised collection of secretory epithelial cells. Most glands are formed during development by proliferation of epithelial cells Project into the underlying connective tissue. Some glands retain their continuity with the surface via a duct and are known as EXOCRINE GLANDS. Other glands lose this direct continuity with the surface when their ducts degenerate during development. These glands are known as ENDOCRINE glands. Glandular epithelium Secrete wide range of products: Hormones Enzymes Milk Sweat Mucous Oil Glands - classification Exocrine Pour products into ducts that open into lumen of organ or onto the skin Glands - classification Endocrine Have no duct system – ductless glands – secrete into empty tissues spaces – eventually enter blood stream Secretory mechanisms Merocrine e.g. salivary gland – secretion passes from cells without damage to plasma membrane – exocytosis Most glands secrete this way Secretory mechanisms Holocrine e.g. sebaceous gland – cellular debris part of secretion (sebum) Involves death of the cell Secretory mechanisms Apocrine e.g. mammary gland Apical end pinched off Morphological classification Simple – single tube Compound – branched duct system Branches Tubular Acinar/alveolar (grape like) Simple tubular glands in the colon Mammary Gland Each breast = 15-25 secretory lobes Modified sweat gland Secretes mammalian milk Lobe = compound tubular acrinar gland Control Hormonally (prolactin and oxytocin) Mechanical (suckling, milk removal) Mechanical stimulation Tongue movement video Mechanical Stimulation Mammary Gland Lactation and Milk production Lactation and Milk production Video Summary Glands are a collection of secretory epithelial cells Wide range of products Different classifications Different Mechanisms Range of morphological classifications Mammary gland – modified sweat gland Controlled by hormones and mechanical stimuli Recommended reading Guyton and Hall textbook of Medical Physiology. Physiology (Linda Costanzo).