1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 4 Tissue: The Living Fabric Part A

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Tissues  Tissue is a group of cells similar in structure and function.  The study of tissues is called Histology.  The four types of tissues  Epithelial  Connective  Muscle  Nerve

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Characteristics of the Epithelium: 1.) Cellularity – composed almost entirely of tight packed cells with very little extracellular space. 2.) Special contacts – form continuous sheets held together by tight junctions and desmosomes 3.)Polarity – apical and basal surfaces. 4.) Supported by connective tissue – reticular lamina and basal laminae Underneath the basal surface is a thin sheet of glycoproteins called the basal lamina. This sheet allows the cells to migrate toward a wound and is selectively permeable.

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Characteristics of the Epithelium:  Avascular but innervated – contains no blood vessels but supplied by nerve fibers  Regenerative – rapidly replaces lost cells by cell

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Epithelia  Simple or stratified Figure 4.1a

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Epithelia  Squamous, cuboidal, or columnar Figure 4.1b

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Simple Squamous  Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm  Functions  Diffusion and filtration  Provide a slick, friction-reducing lining in lymphatic and cardiovascular systems  Present in the kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Simple Squamous Figure 4.2a

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Simple Cuboidal  Single layer of cubelike cells with large, spherical central nuclei  Function in secretion and absorption  Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Simple Cuboidal Figure 4.2b  Single layer of cubelike cells with large, spherical central nuclei  Function in secretion and absorption  Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Simple Columnar  Single layer of tall cells with oval nuclei; many contain cilia  Goblet cells are often found in this layer  Function in absorption and secretion  Nonciliated type line digestive tract and gallbladder  Ciliated type line small bronchi, uterine tubes, and some regions of the uterus  Cilia help move substances through internal passageways

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Simple Columnar Figure 4.2c

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Pseudostratified Columnar  Single layer of cells with different heights; some do not reach the free surface  Nuclei are seen at different layers  Function in secretion and propulsion of mucus  Present in the male sperm-carrying ducts (nonciliated) and trachea (ciliated)

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Pseudostratified Columnar Figure 4.2d  Single layer of cells with different heights; some do not reach the free surface  Nuclei are seen at different layers  Function in secretion and propulsion of mucus  Present in the male sperm-carrying ducts (nonciliated) and trachea (ciliated)

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Stratified Squamous  Thick membrane composed of several layers of cells  Function in protection of underlying areas subjected to abrasion  Forms the external part of the skin’s epidermis (keratinized cells), and linings of the esophagus, mouth, and vagina (nonkeratinized cells)

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Stratified Squamous Figure 4.2e  Thick membrane composed of several layers of cells  Function in protection of underlying areas subjected to abrasion  Forms the external part of the skin’s epidermis (keratinized cells), and linings of the esophagus, mouth, and vagina (nonkeratinized cells)

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Stratified Cuboidal and Columnar  Stratified cuboidal  Quite rare in the body  Found in some sweat and mammary glands  Typically two cell layers thick  Stratified columnar  Limited distribution in the body  Found in the pharynx, male urethra, and lining some glandular ducts  Also occurs at transition areas between two other types of epithelia

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Transitional  Several cell layers, basal cells are cuboidal, surface cells are dome shaped  Stretches to permit the distension of the urinary bladder  Lines the urinary bladder, ureters, and part of the urethra

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Transitional Figure 4.2f  Several cell layers, basal cells are cuboidal, surface cells are dome shaped  Stretches to permit the distension of the urinary bladder  Lines the urinary bladder, ureters, and part of the urethra

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epithelia: Glandular  A gland is one or more cells that makes and secretes an aqueous fluid  Classified by:  Site of product release –  endocrine (internally secreting)  Exocrine (externally secreting)  Relative number of cells forming the gland  unicellular  multicellular

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endocrine Glands  Ductless glands that produce hormones.  Release of hormones is via exocytosis  Secretions include amino acids, proteins, glycoproteins, and steroids.  Endocrine glands vary in shape, size and structure.

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Exocrine Glands  More numerous than endocrine glands  Secrete their products onto body surfaces (skin) or into body cavities  Examples include mucous, sweat, oil, and salivary glands

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Unicellular Exocrine Gland  The only important unicellular gland is the goblet cell.  These single celled glands line our digestive, respiratory and intestinal tract.  They sit in between the columnar cells.  They produce mucin which breaks down in water to form mucus.

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Multicellular Exocrine glands  Multicellular exocrine glands are composed of a duct and secretory unit.  Supportive Connective Tissue surrounds the gland and supplies it with blood vessels and nerve fibers.

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Multicellular Exocrine Glands  Classified according to structure:  Simple or compound duct type  Tubular, alvelar or tubuloaveolar

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.3a-d Structural Classification of Multicellular Exocrine Glands

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of Multicellular Exocrine Glands Figure 4.3e-g

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Modes of Secretion  Multicellular glands secrete the chemical in different ways.  Exocytosis: this type of gland is called a merocrine gland.  Rupture: this type of gland has the cells fill with the chemical and then the whole cell ruptures. This type of gland is called holocrine gland.

29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings