1. Biology 211 Anatomy & Physiology I Histology The study of tissues

2. Recall: SYSTEMS are composed of one or more organs, all serving a common function ORGANS are composed of one or more types of tissues, all serving a common function TISSUES are composed of one or more types of cells and their products, all serving a common function The study of structure at the level of tissues is called histology.

3. All tissues: - -

5. With only a few, rare exceptions, all organs of the human body are composed of four types of tissue: lines internal and external surfaces, including hollow organs. Also forms glands. provides support and fills spaces produces movement carries and integrates electrical information Each of these can have one or more subtypes

6. Epithelium - Covers body surfaces (e.g. skin, cornea) - Lines body cavities (e.g. peritoneal cavity, pericardial cavity - Lines insides of hollow organs (e.g. stomach, heart, lung. aorta, oviduct) - Forms glands (e.g. sweat glands, pancreas, salivary glands)

7. Characteristics of Epithelium - Highly cellular, with very little extracellular matrix - Cells form close contacts with each other - Avascular - High capacity for regeneration Functional characteristics of epithelia depend on the cells, rather than the extracellular matrix which is unspecialized

8. Epithelium always supported by connective tissue and separated from it by a basement membrane. Depends on connective tissue for vessels, nerves, etc. Epithelium Basement membrane Connective tissue Mucous Membrane or Serous Membrane

9. Epithelium Different types for different functions. Classified according to: a) Number of layers of cells b) Shape of cells in the top layer Single layer = Two or more layers = Actually one layer but looks like more = Flat = Cube-shaped = Taller than wide = Change shape from squamous to cuboidal =

11. Epithelium Number of layers Shape of surface cells Squamous Simple Cuboidal Stratified Columnar Pseudostratified Transitional

12. Simple Squamous Epithelium

13. Simple Cuboidal Epithelium

14. Simple Columnar Epithelium

15. Pseudostratified Columnar Epithelium

16. Stratified Squamous Epithelium

17. Stratified Cuboidal Epithelium

18. (Stratified) Transitional Epithelium

19. Epithelium No good examples of stratified columnar epithelium. Found only in parts of the male reproductive system

20. Epithelium also forms all glands in the body Glands classified by a) Whether or not they have ducts b) Their method of secretion Yes = Duct carries product to surface No = Product secreted into surrounding extracellular matrix, picked up by blood vessels Product released from undamaged cells Top part of cell lost during secretion Entire cell lost during secretion

21. Exocrine glands also classified by c) Shape, and whether or not either the duct and/or the secretory part branches

22. Characteristics of Connective Tissue - Lots of extracellular matrix; Relatively few cells - Cells usually do not communicate with each other - Highly vascular - Different types of CT all arise from embryonic mesenchyme Functional characteristics of connective tissues depend primarily on the extracellular matrix, which is often highly specialized, and not on the cells.

23. Connective Tissues Common cells Fibers

24. Connective Tissues Ordinary connective tissues Specialized connective tissues

25. Loose Areolar Connective Tissues

26. Adipose Connective Tissues

27. Dense Regular Connective Tissues

28. Dense Irregular Connective Tissues

29. Specialized Connective Tissues: Hyaline Cartilage

30. Specialized Connective Tissues: Elastic Cartilage

31. Specialized Connective Tissues: Fibrous Cartilage

32. Specialized Connective Tissues: Bone

33. Muscle Tissue: Skeletal Muscle Cardiac Muscle Smooth Muscle

34. Very long Unbranched Shorter Branched Short Unbranched Spindle-shaped Hundreds per cell Peripheral One or two per cell Central One per cell Central Yes No Skeletal Cardiac Smooth Muscle Muscle Muscle Myocytes Nuclei Striations

35. Skeletal Cardiac Smooth More detail on muscle tissues and their cells when we discuss the muscular system

36. Nervous Tissue: (no subtypes) 1) Neurons (Excitable cells) Carry electrical signals from one place to another 2) Supporting Cells Nonexcitable Support & nourish neurons Glia in CNS Satellite cells Schwann cells More detail on nervous tissue and its cells when we discuss the nervous system