Más contenido relacionado



  1. Animal Tissues By Fayez A. Elmabhouh Department of Biology
  2. Introduction  Histology = study of tissues  Tissue = group of cells with similar structure and function  They are classified according to the shape of the cell, size, intracellular matrix.  Four types of human tissues:  Epithelial tissue  Connective tissue  Muscular tissue  Nervous tissue The organ can may consists of one (heart) or combination of these tissues (stomach, skeleton, skin)
  3. Four Tissue Types: 1 2 3 4
  4. Epithelial Tissues Characterized by:  Their closely connected cells.  Having very little intracellular substance.  Resting on a basement membrane.  Arise from the three germ layers.  No blood vessels enter between its cell but nerves do  Covers body surfaces and forms glands.
  5. Basement membrane
  6. Embryonic Tissues – all adult tissues are derived from one of three embryonic tissues gut Ectoderm = “outside skin” Endoderm = “inside skin” Mesoderm = “middle skin” Cross section through embryo Animal embryo
  7. Classification of Epithelium 1. Covering epithelia. 2. Glandular epithelia.
  8. Covering epithelia  The primary function of this type of epithelia is protection.  Covering epithelia classified according to the arrangement of the cell into simple epithelia and stratified epithelia.
  9. Simple epithelia  These tissues divided into four types according to the shape of cell and location of nucleus.  Consists of a single layer of cells that are in contact with the basement membrane.
  10. 1. Simple Squamous Epithelium:  The cells are flat with smooth edges.  They appear spindle- shaped in cross section  Each cell containing a nucleus in the widest area.  Found in the lining blood vessels, covering serosa
  11. Blood vessel
  12. Serosa
  13. Simple Squamous Epithelium Simple Squamous Epithelium Bowman’s capsule
  14. 2. Simple Cuboidal Epithelium  The cells in this epithelium are square-shaped in cross section.  Have central and round nucleus.  Lining the kidney tubules and Follicles of thyroid gland
  15. Follicles of thyroid gland
  16. Simple Cuboidal Epithelium cells single layer of cube shaped cells; large nuclei
  17. 3. Simple Columnar Epithelium  Built of long pillar- shaped cells.  Containing an oval nucleus. a. Ciliated: Bronchioles b. Non Ciliated: lining the ileum
  18. 4. Pseudo-stratified Epithelium  Single layer of cells which rest on a basement membrane but do not all reach to the free surface of the epithelium.  Their nuclei found at different levels giving the a false stratified appearance.  Cells that reach the surface carry cilia at their free ends.  Lining the trachea.
  19.  Keratinized: the epithelium is covered with keratin layer which is formed by the dead squamous cells (horny layer) Skin.  Non- keratinized: esophagus
  20. Non- keratinized
  21. Keratinized: Skin 1. Epidermis (Stratified Squamous Epithelium) 2. Dermis
  22. Transitional- stratified  Found in the urinary tract (urinary bladder)  Rest on a non clear and non wavy basement membrane.  Its superficial cells are cuboidal in shape, and may contain 2 nuclei.  The basal cell layer is formed of high cuboidal cell.  The intermediate layer are polyhydral cells.  Empty  Full, the cell change into to squamous cell
  23. Glandular Epithelium  The cells are specialized in secretion and thus form glands.  Formed from collections of Epithelial cell  Glands with ducts are termed exocrine  Glands without ducts are termed endocrine
  24. Exocrine Glands 1. Unicellular: formed of single cell present in the respiratory tract and intestinal tract
  25. Multicellular gland  Made of many cells and each consist of a secretary portion and duct.  They are either tubular, alveolar in form and may be simple or compound.
  26. Simple tubular glands  In the digestive glands, stomach, Large intestine
  27. Simple alveolar gland  Form of a flask with a round secretary portion and a narrow tubular duct.  Mucous and sebaceous gland skin
  28. Compound tubular glands
  29. Compound alveolar gland  Parotid gland