Glandular Tissue And Secretion Flashcards
Define exocrine gland
With duct
Define gland
An epithelial cell specialised for secretion
Define endocrine gland
Ductless, secrete directly into blood
Define merocrine secretion
By exocytosis
1) membrane bound compartment migrates to surface
2) fuses with membrane
3) contents released into extra cellular space
Define apocrine secretion
Non,embrace bound e.g. Lipid approaches surface
Makes contact and pushes up apical membrane
Thin layer of apical cytoplasm drapes around droplet
Membrane surrounding droplet pinches off from cell
Plasma membrane transiently smaller
Describe holocrine secretion
Disintegration of the cell
Release contents
Discharge of whole cell
Describe the mechanism of endocytosis
1) engulf material from outside cell
2) pinch off part of membrane to form a vesicle
3) membrane bound within the cell
How to endo and expcytosis allow trans epithelial transport?
Material endocytosed at one surface
Transport vesicles shuttles across cytoplasm via microtubules
Material exocytosed st opposite surface
Describe the structure of the golgi
Stack of disc shaped cisternae
One end of discs flattened, the other concave
Discs have swellings at edges
Describe function of the golgi
Transport tbrough sequential golgi cisternae
Packaging kf sorted contents through condensation
Glycosolation of proteins and lipids
Where is the destination of products from the golgi?
In secretory vesicles some retained in cell for jse e.g. Lysosome others enter plasma membrane (glycolyx)
Why is the golgi important?
Branching sugars offer complex shapes for specefic interactions
Destruction of this layer bu enzymes alters many specificity based properties of cells e.g. Adhesion, mobility, communication
Describe role of secretion in cell functions
?
Describe nervous control of secretion
Sympathetic nervous stimulation of adrenal medullary cells leads to release of adrenaline
Describe endocrine control of secretion
Adrenocorticotrophic hormone stimulates coretex of adrenal gland to release cortisol