1 / 19

Histology : It is the science which deals with the microstructures of tissues and organs.

Explore the microstructures of tissues and organs in the human body, including the four basic tissue types and their functions. Learn about epithelial tissue characteristics, functions, and classifications. Understand glandular epithelium and muscular tissues.

paulgrubbs
Download Presentation

Histology : It is the science which deals with the microstructures of tissues and organs.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Histology: It is the science which deals with the microstructures of tissues and organs. • The tissues • A basic tissue type is a group of similar cell and able to perform a common function. • Our body is composed of only four basic tissue types:

  2. In most animals, combinations of various tissues make up functional units called organs, and groups of organs that work together form systems. • For example, the human digestive (system )consists of a stomach (organ) small intestine, large intestine, and several other organs, each a composite of different tissues (epithelium- connective-muscles-nervous) .

  3. 1-Epithelial Tissue • means covering body surface and lining body cavity. General characters of epithelial tissues : • The cells are closely aggregated with very little intercellular substance (matrix) of acid mucopolysaccharides . • The cells are regular in shape .They are held tightly together byjunctional complex • Epithelial cells are firmly bound to the underlying CT by a thin membrane called basement membrane. • Blood vessels do not penetrate the epithelium (avascular). • Epithelium can be derived from all three embryonic germ layer : ectoderm ------------- epidermis of the skin endoderm-------------epithelium of alimentary canal mesoderm-------------kidney • Epithelium is in a continuous process of degeneration and regeneration. It has a high mitotic activity .It has a high renewal rate.

  4. General Functions of epithelium

  5. Classification of the epithelia Classification of epithelia according to A-number of layers B-Shape of cells 1-Simple epithelium (one layer) 1-Squamous(flat) 2-Cuboidal (Height = width) 2-Stratified epithelium ((more than one layer 3-Columnar (Hight is 2-5 greater than width)

  6. Based on the last two criteria we classify the epithelium:

  7. II-glandular epithelium Glands can be classified according to:

  8. 1-number of cells • a-unicellular glands consists of one cell (goblet cell of small intestine) • b-multicellular glands composed of cluster of cells

  9. 2-The presence or absence of a duct system : • a- Exocrine(in which secretion is released through ducts (salivary glands) • b-Endocrine glands (secretion released directly to the blood) thyroid glands. • c- Mixed glands (endocine and exocrine)----pancrease

  10. 3-According to the mode of secretion (mechanism) • a-Merocrineglands (no loss of its cellular material) pancreas (exocytosis) • b-Holocrineglands (complete destruction of the cell)---sebaceous gland • c- Apocrine glands ( secretory product is discharged with apical parts of the cytoplasm) ----mammary glands

  11. II-glandular epithelium Glands can be classified according to:

  12. 2-Muscular tissue ( skeletal, smooth, cardiac muscles) - Muscular tissue is composed of long cells called muscle fibers that are capable of contracting when stimulated by nerve impulses. -It has large numbers of myofibrils made of the contractile proteins actin and myosin. -The sliding filament is accepted as the mechanism that accounts for muscular contraction.

  13. There are three types of muscle tissue in the vertebrate body: 1- Skeletal muscles connected to the skeleton and is concerned with body movements. 2- Cardiac muscles forms the contractile portion of the heart . 3-Smooth muscles does not exhibit striations. It is found as part of the walls of the viscera.

More Related