Intro Epithelium and Glands 8_12.pdf Flashcards
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Intro Epithelium and Glands 8_12.pdf Flashcards
Intro Epithelium and Glands 8_12.pdf Flashcards
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What is histology?
Histology is the scientific study of the body's structures microscopically.
What are histology courses based on?
Histology courses are based on the appearance of tissues under light microscopy.
What is the role of Oral Maxillofacial Pathologists?
One of Oral Maxillofacial Pathologists' primary roles is looking at biopsy specimens from the head and neck under a microscope.
What is the first step in the biopsy procedure?
The surgical biopsy procedure is performed and the tissue is placed IMMEDIATELY in formalin.
What is formalin?
Formalin is a chemical fixative that prevents autolysis (self-disintegration or rupture) and helps sustain the integrity of the tissue so that the cell structure is visible to the pathologist.
What happens to the specimen after being placed in formalin?
The specimen is then dehydrated in alcohol and embedded into paraffin wax, preserving the tissue for making slides.
What is the most commonly used staining method in histology?
The most commonly used staining method and the gold standard for diagnosis is hematoxylin and eosin stain.
What colors do hematoxylin and eosin stains produce?
Hematoxylin produces a purplish-blue color, while eosin produces a red color.
What cellular structures are stained by hematoxylin and eosin?
Nuclei stain with hematoxylin, while the extracellular matrix and cytoplasm stain with eosin.
What is the significance of eosinophilic vs basophilic staining?
A significant part of histopathologic diagnosis is based on how eosinophilic or basophilic a cell or cellular components appear.
What are the two types of electron microscopy?
The two types of electron microscopy are transmission electron microscopy (TEM) and scanning electron microscopy (SEM).
What is the difference between light and electron microscopy in terms of dimensions?
Light microscopy shows cells in 2D, while electron microscopy shows cells in 3D.
What is immunohistochemical staining?
Immunohistochemical (IHC) staining is a laboratory technique that uses antibodies to check for certain antibodies or markers in a sample of tissue.
What types of tissues are mammalian organs divided into?
Mammalian organs are divided into four basic tissue types: Epithelial, Connective, Muscle, and Nervous.
What are the characteristics of epithelial tissue?
Epithelial tissues are composed of closely aggregated polyhedral cells that adhere strongly to one another and to the extracellular matrix, forming cellular sheets that line organs and cover body surfaces.
What are the two main groups of epithelia?
Epithelia can be divided into two main groups: Covering (lining) and Secretory (glandular).
How can epithelial layers be classified based on cell layers?
Epithelial layers can be classified as simple (one cell layer) or stratified (multiple cell layers).
What are the classifications of epithelial cells based on shape?
Epithelial cells can be classified as squamous (thin, flat cells), cuboidal (cell width and thickness roughly similar), or columnar (cells taller than they are wide).
What is keratinization in stratified squamous epithelium?
Stratified squamous epithelium can be subclassified into keratinized (packed with keratin filaments) or non-keratinized (sparse content of keratin filaments).
What is a key feature of transitional epithelium?
Transitional epithelium has a superficial layer of large dome-like cells, often referred to as umbrella cells, which protect tissues from the cytotoxic effects of urine.
What are the functions of secretory epithelial cells?
Secretory epithelial cells function mainly to produce and secrete various macromolecules and compromise specialized organs called glands.
What types of gland secretion mechanisms are there?
There are three basic mechanisms for releasing secretory products: Merocrine secretion, Apocrine secretion, and Holocrine secretion.
What is the process involved in merocrine secretion?
Merocrine secretion involves exocytosis from membrane-bound vesicles or secretory granules, causing no damage to the cells.
What occurs during apocrine secretion?
In apocrine secretion, the product accumulates at the cell's apical end, and portions are pinched off to release the product surrounded by a small amount of cytoplasm and cell membrane.
What is holocrine secretion?
Holocrine secretion is a process where cells accumulate product continuously and, as they enlarge, they undergo differentiation culminating in complete cell disruption that releases the product into the glandular lumen.
What happens to the cell during holocrine secretion?
Holocrine secretion destroys the cell.
In which glands is holocrine secretion best seen?
Holocrine secretion is best seen in sebaceous glands producing lipid rich material in the skin.
How are exocrine glands classified structurally?
Exocrine glands are classified into simple and compound based on branching.
What characterizes simple exocrine glands?
Simple exocrine glands do not branch.
What characterizes compound exocrine glands?
Compound exocrine glands have ducts from several secretory units that converge into a larger duct.