Introduction To Glands Flashcards
What is a gland?
An epithelial cell or an aggregate of epithelial cells that are specialised for the secretion of a substance.
What are the two types of gland and how do they differ?
Endocrine and exocrine glands. Endocrine glands are ductless, they secrete (hormones) directly into blood flowing through them. Where as exocrine glands secrete into a location or region of the body through a duct
How does branching occur?
Immature fibroblast release FGF10 and epithelial cells move towards the signal. This then causes tubule elongation and tubule branching.
What are the types of epithelial cell in exocrine glands?
Cells lining the ducts and cells that make secretory products.
What are the three types of secretion?
Merocrine, apocrine and holocrine
How do merocrine cells glands secrete?
Fusion of vesicles with apical membrane e.g. acinar and endocrine glands of the pancreas.
How do apocrine glands secrete?
Partial loss of cytoplasm, e.g. lactating mammary gland, sweat glands in the axilla and external genitalia.
How do holocrine glands secrete?
Complete loss of cytoplasm (or cell) e.g. sebaceous gland in skin and tarsal glands in eyelid
How do cytocrine glands secrete?
Cells are released as a secretion, e.g. sperm in the seminiferous tubule (testis)
What is glycosylation?
The covalent attachment of sugars by enzymes to proteins and lipids to form glycoproteins and glycolipids.
Roles of glycosylation.
To aid protein folding, prevents protein digestion by intracellular proteases, prevents lipid digestion by intracellular lipids, cell recognition.
Exocytosis vs endocytosis.
Exo: secretion of molecules outside the cell via a vesicles fusing to a membrane. Endo: engulfing of molecules inside the cell via a vesicles formation.
Phagocytosis vs pinocytosis.
Phagocytosis is the process where cells engulf other cells or particles, whereas pinocytosis is the process where liquid droplets are ingested by cells.
