2. HISTOLOGY عملي حيوان Zoology 106

3. Biological tissue is a group of cells that perform a similar function.cells Cells-->tissues-->organ-->system-->individual The study of tissues is known as histology,histology Orin connection with disease, histopathologyhistopathology

4. What are Tissues? The word tissue is derived from a Latin word meaning to "weave." Cells that make up tissues are sometimes "woven" together with extracellular fibers. Or part of an organism consisting of an aggregate of cells having a similar structure and function. Likewise, a tissue can sometimes be held together by a sticky substance that coats its cells. The fundamental types of tissues in animals are epithelial, nerve, connective, muscle, and vascular tissues.tissuesanimals epithelialnerveconnectivemusclevascular

5. 1. Epithelial Tissue The covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances.coveringinternalexternalsurfaces bodyliningvesselssmall cavitiescellssmallamountssubstances Function: -helps to protect organisms from microorganisms, -injury, and fluid loss. - Lining of mouth and nose, internal surface of GIT, -respiratory system, genitalia and urinary system.

6. - - characterized by bonding of each cells together - -has thin layer that supports cells called basement membrane (on which epithelium can grow and regenerate after injuries). -name is derived from the number of cells and shape of cells Epithelium is classified according to number of cells: 1.Simple- composed of single layer of cell (found where absorption and filtration occur). 2. Stratified- composed of two or more layers of cells 3. Pseudostratified Epithelium is classified according to shape of cells 1. Columnar 2. Cuboidal 3. Squamous

8. Simple Columnar Epithelium

9. Stratified squamous epithelium

10. Stratified columnar epithelium

11. 2. CONNECTIVE TISSUES -to support, anchor and connect various parts of the body Connective tissue proper 1.Adipose - adipocytes that store fat (little matrix) – around eyes and kidneys 2. Areolar (loose) – fibroblasts and a matrix of tissue fluid, collagen, and elastin fibers –

12. The fibres of areolar connective tissue are arranged in no particular pattern but run in all directions and form a loose network in the intercellular material. Collagen (collagenous) fibres are predominant. They usually appear as broad pink bands. Some elastic fibres, which appear as thin, dark fibres are also present.

13. Microscopic view of areolar connective tissue.

14. Loose or areolar connective tissue Name the arrows

15. Schematic representation of the adipose connective tissue. Quiz Draw the ACT

16. Enlarged microscopic view of adipose connective tissue.

17. microscopic image adipose tissue

18. 3. Muscle Tissue Function: Specialized for contraction Specific terms for muscle tissue: 1. muscle cells – fibres 2. cytoplasm - sarcoplasm; 3. cell membrane- sarcolemma.

19. Three types of muscle tissue according to its structure, function and location: a. Skeletal or striated b. Smooth c. Cardiac SSC

20. a. SKELETAL (STRIATED) MUSCLE CELLS Characteritics of skeletal muscle cell 1. Highly modified 2. Giant 3. Have lots of cells (fiber) 4. Each fiber is cylindrical in shape 5. Nucleus is located at the edge of the cell inside the sarcolemma. 6. Cross- striped (or striated) appearance of light and dark banding 7. Voluntary (contraction under conscious nervous control)

21. Schematic Representation of Skeletal Muscle Tissue

22. Microscopic view of skeletal muscle tissue (tongue)

23. Label the skeletal muscle fiber (section of a tongue)

24. Microscopic view of skeletal muscle tissue

25. 3. CARDIAC MUSCLE TISSUE - Cardiac muscle is a highly specialized tissue restricted to the wall of the heart. - It is also an involuntary type of muscle, as its contraction is not consciously controlled. - Intercalated discs- junction of one cell with one another

26. Schematic representation of cardiac muscle tissue

27. Heart muscle showing branching fibers