| What are secretory cells? | Any cells thatexport out of their cytoplasm molecules they synthesized. |
| What are glandular cells? | epithelial cells specialized in secretion; products are stored in secretory vesicles and are released on demand. |
| Talk about the histogenesis of glandular cells | they result from the differentaition of some covering epithelia that bud to form a cellular mass. that enters an underlying mesechyme they are either
exocrine glands, maintain contact with covering epithelium and lumen of an organ through a duct
endocrine glands; detach from covering epithelium, isolating in vascularized mesenchymal tissue. |
| How are glands classified? | exocrine-endocrine-amphicrine |
| What are exocrine glands? | glands that discharge their secretory products in the external enivroment or in a natural cavity towards the outside. |
| Why do we call the exocrine glandular cells polarized? | since they show a morpho-functional polarization by having an
apical pole which is bordering the lumen, poor in cell organelles and elaborated products are stored in it until secretion.
Basal pole, rests on basement membrane that separates epi from CT |
| What is the contractile myoepithelial cells? | cells located between glands and basal lamina help in secretion via contaction. |
| How do we classify exocrine glands by number of cells? | uni cellular (goblet cells in intestine digestive and respiratory system producing mucus to protect them
multicellular (secretory part and excretory part envelped by CT) |
| How do we classify exocrine glands by excretory canal (duct) | simple (having a unique excretory duct associated either with one or more secretory portions
compound having branched excretory duct and branched secretory portions. |
| How do we classify exocrine glands based on secretory portions? | Acinous glands: acinus is a spherical or viral like structure, the wall is made of glandular cells in the form of a pyramide; the lumen of the secretory protion and the execretory duct are reduced (simple or compound)
Tubular glands: elongated tube appearance with a wall made of cuboidal or columnar cells (striaght simple tubular, branched coiled compound...)
Alveolar glands: in the form of a bag with a wide lumen relative to the acinous lumen of secretory portion are greater in size than acinous. |
| can all kinds of secretory portions be avialabe at a specific gland? | yes (submaxillary glands) |
| How can we classify exocrine glands according to their nature of secretory products? | Serous/Mucousal/ Sero-Mucosal (Submaxillary)/neither (sweat/sebous/salivary) |
| What are serous glands? | Their secretory products are fluid consistency (acinar cells of pancreas, stomach..) |
| Describe serous cells? | Rounded nuclues localized at junctions of middle and lower third of the cell, apical pole has granulation, limits barely the visibility of its lumen, basal pole rich in RAR and mitochondrion, golgi apparatues developed, secretory apparatues occupy the top of the cell, densely, containing active or inactive enzymes (zymogen) merging with apical pole plasma membrane before going out |
| What are musous glands? | secretory products are viscous liquids rich in GAG. |
| Describe mucous cells? | cytoplasm filled with mucigenic grains, flattened nucleus pushed to the lower part of the cell, wide lumen visiblilty |
| How do we classify exocrine glands according to the mode of secretion? | Merocrine : most common, cells produce and eject secretions by exocytosis cell integrity is respected (parotids)
Apocrine: Secretory products are gradually accumelated at the apical pole detaching a small part of the cell in the form of a large vacuole ,released respecting integrity of cell membrane (mammary glands)
Holocrine: secretory product completely fills cell cyroplasm for the cell undergoes degenration which then ruptures and releases its accumelated secretory substances (sebacceous glands) |
| What are endocrine glands? | cells capable of synthesizing storing and secreting into internal medium, via the bloodstream without a duct. |
| What are hormones? | any substance that are secreted via blood and will act on the receptors of target cells. |
| How can we classify endocrine glands according to their hormone type? | Steroid secreting: (androgens, estrogen) abundant with SER and mitochondria and lipid vacuoles. their lipid type makes them diffuse freely through plasma membrane without exocytosis.
THYROID: synthesize thyroglobulins liposoluble hormones (T3 and T4) diffuse freely through plasma membrane
Peptides : water soluble hormones (insulin) are released via exocytosis characterized by abundant RER
Amino acid derivatives: (serotonin, melatonin) water soluble hormones rejected by exocytosis |
| How are endocrine glands classified according to mode of action of receptors? | steroid and thyroid act on an intracytoplasmic or even intranuclear receptors, while peptides and aa bind to membrane receptors that will act on metabolism via a second messenger. |
