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Histology_glands.pptx
The document provides a detailed overview of glands, including their definitions, types (exocrine and endocrine), classifications based on duct shape, secretion modes, and nature of secretion. It discusses major and minor salivary glands, their functions, and structural differences between serous and mucous acini. References and multiple-choice questions related to the content are also included.
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Histology_glands.pptx
- 1. Dr Mathew JosephMBBS, MD(AIIMS), BCC(Palliative Medicine) Assistant Professor Department of Anatomy Amala Institute of Medical Sciences Thrissur
- 2. Glands A glandis an organ that consists of specialized secretory cells. Secreted material is usually a liquid. Epithelial in origin. Present in singly or in groups. Unicellular or Multicellular 2 types: Exocrine Endocrine
- 3. Unicellular Glands Singlecell distributed among non-secretory cells.
- 4. Multicellular Glands Formedby invagination of epithelial layer in deeper tissue to form a diverticulum: Proximal part forms duct. Distal part forms secretory element.
- 5. Exocrine: pour their secretionsonto an epithelial surface, directly or through ducts. Endocrine (ductless): pour their secretions directly into the blood.
- 6. Classification of Exocrineglands Based on shape & branching pattern of duct Based on mode of release of their product Based on the nature of their secretion
- 7. Classification based onshape & branching pattern of duct Based on shape of secretory units (tubular or alveolar) & branching pattern of ducts. 2 types: Simple Compound
- 8. Classification based onshape & branching pattern of duct Simple glands • Simple tubular • Simple coiled tubular • Simple branched tubular • Simple branched alveolar Compound glands Compound tubular Compound alveolar Compound tubulo- alveolar
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- 11. Crypt of LieberkuhnSweat glands Fundic glands of stomach Meibomian glands Brunner glands Submandibular gland Mammary gland
- 12. Classification based onmode of secretion • Merocrine: secretion is released by exocytosis of secretory granules (pancreas, parotid gland, protein component of milk from mammary gland). • Apocrine: apical portion of cell along with secretory product is pinched off (lipid component of milk from the mammary gland). • Holocrine: entire cell is shed along with secretory product (sebaceous glands).
- 13. Modes of secretion Merocrine:secretion by exocytosis
- 14. Modes of secretion •Merocrine: secretion by exocytosis • Apocrine: secretion by loss of cytoplasm • Holocrine: secretion through loss of entire cell
- 15. Classification based onthe nature of secretion • Serous glands • Mucous glands • Mixed glands
- 16. Serous Glands Secretion:Thin, watery, rich in enzymes, protein in nature. Cytoplasm: granular (stain darkly from pink to dark purple with H/E stain) & rich in RER. Nuclei: rounded & basally placed.
- 17. Mucous glands Secretion:contains mucopolysaccharides which collects in the apical part of cell. Cytoplasm: stain very lightly with H/E stain & therefore gives empty look. Nuclei: basally placed & flattened (mucoid pushes the nuclei).
- 18. Mixed glands Containboth serous & mucous secretory units. Sometimes serous cells form crescentic caps on mucous acini called as serous demilunes.
- 21. Major glands Liecompletely outside the alimentary tract & connected to it by an excretory duct. Compound alveolar or tubuloalveolar in type. Parotid, submandibular, sublingual.
- 22. Minor glands Smallsalivary glands situated in the mucous membrane of: Lip (labial) Cheeks (buccal) Soft palate (palatine) Tongue (lingual)
- 23. Functions of Salivaryglands Secrete saliva composed of water, mucus, proteins, salts, salivary amylase (ptyalin), immunoglobulins (IgA) & lactoperoxidase. Serves to moisten food. Lubricates & moistens oral mucosa and lip. Initiates the digestion of carbohydrates.
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- 25. Different types ofacini Mucous Serous Mixed
- 26. Features of serous& mucous cells EM LM Serous cell Mucous cell
- 27. Differences between serous& mucous acini
- 28. Differences between serous& mucous cells
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- 34. References 1. diFiore’s Atlasof Histology with functional Correlations, 12th Edition. 2. Textbook of Human Histology. Inderbir Singh, 1st Edition. 3. Textbook of Histology. GP Pal, 3rd Edition.
- 35. MCQ 1. All aremajor salivary glands except: a) Palatine b) Parotid c) Submandibular d) Sublingual
- 36. MCQ 2. Holocrine typeof secretion is a feature of: a) Mammary gland b) Parotid gland c) Sebaceous gland d) Pancreas
- 37. MCQ 3. Sweat glandis an example of: a) Simple tubular gland b) Simple coiled tubular gland c) Simple branched tubular gland d) Simple alveolar gland
- 38. MCQ 4. All aretrue about serous acini except: a) Smaller in size b) Stain dark c) May present as demilune d) Wide lumen
- 39. MCQ 5. Expelling ofsecretion through contraction is a feature of: a) Serous cell b) Mucous cell c) Serous demilune d) Myoepithelial cell
- 40. Body Cavities &Membranes
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