Histology #1- Tissues

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Histology #1- Tissues
2013-09-21 14:22:18

Flashcards for week 1 of UCVM Histology
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  1. Define histology and cytology
    • histology: microscopic anatomy (microanatomy uses a LM and fine structure uses EM) - so the study of microscopic tissue anatomy
    • cytology: the study of cells  typically from body fluids (smears)
  2. *What are the five cellular characteristics of epithelia?
    • I) the cohesive interaction between cells allowing the formation of continuous cell layers
    • II) the existence of three types of membrane domains: apical, lateral, basal
    • III) the existence of tight junctions between apical and lateral domains
    • IV) the polarized distribution of the different organelles and components of the cytoskeleton
    • V) the quasi-immobility of the group of epithelial cells relative to the local environment
  3. What are the specialized structural/adhesions connecting cells in the epithelium?
    • gap junctions
    • adherens junctions (junction that allows the connection between cells to form lawn)
    • desmosomes
    • tight junctions
  4. What are the Four different types of tissue?
    • 1. Connective tissue: Few cells, lots of extra cellular matrix (ECM)- lots of space! * specialised to bind
    • 2. Nervous tissue: Excitable cells - membrane potential (have ion channels) *specialised to excite/conduct
    • 3. Muscle tissue: contractile cells- intracellular motors (cytoskeleton)-->contains motor proteins in the cell  that contract *specialized to contract
    • 4. Epithelium*: Lawn of cells -intercellular adhesion (tight epithelium barrier, little ECM) *specialized to form lawns
  5. What does Epithelium sit on?
    A basement membrane (which is ECM)
  6. What are the terms used to describe the in and out sides of the epithelium?
    • in = basal (so the attached side where basement membrane is)
    • out = apical (free not attached side)
  7. Is the epithelia avascular?
    YES -but the connective tissue is quite vascularized and inervates the epithelia
  8. What do we mean when we say the epithelia have a high turnover?
    • Lots of cell division
    • and there is a large stem cell population that feeds the turnover
  9. What are the structural features of epithelia?
    • "lawn of cells"
    • has a basement membrane
    • polarity (by apical and basal cell surfaces)
    • avascular (but richly inervated)
    • high turnover
  10. What are the fibrous ropes and tubes and connectors that give the epithelium structural integrity?
    • microfilaments (found in the top villi)
    • microtubules (form cytoskeleton)
    • intermediate filaments ( bind the attachment sites)
  11. What are the functional roles of Epithelia?
    • 1. physical protection
    • 2. control fluid flow -permeability/ capacitance
    • 3. actively moves fluid across surfaces
    • 4. produces specialized secretions (ie the glandular epithelium)
    • 5. provides sensation (neuroepithelia)
  12. What are the different types of epithelia?
    • Simple: squamous, cuboidal, columnar
    • Stratified: squamous, columnar

    • and pseudostratified columnar
    • and transitional
  13. How do glands develop?
    Glands develop as invaginations of epithelium
  14. What are various types of glands defined by?
    architecture: tubular, acinar, tubuloacinar
  15. In the gland what are the duct and the glandular parts roles?
    • Duct- conduit for exocrine glands (so ducts go to surface so secretions can occur)
    • Glandular part- secretory
  16. Do all glands have ducts?
    • NO- ENDOCRINE glands do not have ducts
    • during embryonic development these glands detach from their epithelial origins and have no ducts- their secretions go into the blood stream (ie pituitary)
  17. What are the modes of secretion for exocrine glands?
    • Merocrine gland (is salivary gland) the material is manufactured in the cells and secreted into the duct
    • Apocrine gland (i.e. sweat gland) -part of the cells pinch off and contribute to the secretion
    • Holocrine gland (sebaceous gland)- disintegrating cells and its content dissociate and become the secretion
  18. What is an example of an organ that has both exocrine and endocrine secretions?