1. Tissues: Living Communities Chapter 4

2. Introduction Cells of similar type and function cluster together to form ________________. Cells in our bodies are differentiated and have lost the ability to exist as an isolated entity on their own. Cells exist in cooperative communities in multi-cellular organisms

4. Classification of Tissues Epithelial tissue Covers and lines Connective tissue Provides support Muscle tissue Enables movement Nervous tissue Controls work

6. Classification continued Most organs contain all 4 tissue types. The study of microscopic structures of tissues and organs is called ___________________ or microscopic anatomy. What is gross anatomy?

7. Epithelial Tissue Composed of sheets of cells that cover and line other types of tissue. Have an exposed surface that affords access to the surrounding environment or to the inner openings of chambers and ducts. Acts as interface layer that separates and defines the beginning and ending of different types of tissues.

8. Six Epithelial Tissue Functions _________________________________

9. Characteristics of Epithelia Can be composed of single layer or multiple layers depending on location. Epithelial cells share the following characteristics: 1. Polar - Each epithelial cell has an apical surface and a basal surface _________________faces the lumen or body cavity __________________faces the underlying connective tissue 2. Lateral surfaces are connected to neighboring cells by _______________________________ 3. Epithelial cells are ____________________- they have no blood supply 4. Most epithelial cells are __________________- they DO have nerve supply

10. Epithelial Tissue: Cellular Attachments Between the cell membranes of adjacent cells are channels that carry nutrients to the cells and waste away Junctional Complexes – specialized attachments between epithelial cells 3 major types: ______________________ Welded plaque Tough, resist tension and stretching (like Velcro) Found in: Skin, heart, uterus ______________________ Cytoplasm continuous Exchange ions, nutrients – quickly transmit signals through connexons Found in: Cardiac, smooth muscles _______________________ Nothing can penetrate Prevent leakage Found in: Bladder, GI tract

12. Epithelial Cells: Basement Membrane Also called basal lamina - foundation of epithelial cells Meshwork of fibers that cements epithelial cell to underlying connective tissue (CT) Varies in thickness Helps prevent cell from being torn off by intraluminal pressures Acts as a partial barrier between epithelial cell and underlying CT – substances have to travel through basement membrane to get in and out of epithelial cells.

14. Surface Specializations Surfaces vary depending on location in body and function May be smooth or contain _______________-fingerlike projections If the cell contains microvilli, it is said to have a _____________________. Brush border helps to increase surface area, which aids in absorption. (can add up to 20 times of surface area). Hair-like projections, _________________- function to move substances past the cell surface Skin cells may have ______________- protective, waterproof substance

17. Classifications of Epithelia Characterized by 3 characteristics 1. Number of layers of cells Single layer is called ________________ Found in protected parts of body because provide minimal protection to underlying structures More than one layer is called ____________. Thicker and stronger and are on parts of body that are subjected to mechanical or chemical stress. 2. Shape of cells Based on shape that is on exposed or on the luminal surface ____________ 3. Presence of surface specializations Keratin, cilia

19. Simple Squamous Epithelium Single layer of squamous shaped cells Found lining surfaces involved in the passage of either gas or liquid Examples:_______________________________ Mesothelium – includes lining of chest _____________, lining of the abdomen ____________________, and lining of the heart _______________ Endothelium – includes lining of blood vessels

20. SIMPLE SQUAMOUS

21. Simple Cuboidal Epithelium Single layer of cube-shaped cells Round, dark-staining nuclei aligned in a single row Occurs in areas of the body where secretion and absorption take place Examples:__________________________________________________ ____________________________

22. SIMPLE CUBOIDAL

24. Simple Columnar Epithelium Single layer of columnar shaped cells Nuclei aligned in a row at the base of the cell near the basement membrane Found in: __________________________________________________ _____________________________ _________________- apical surface is blanketed by dense microvilli that maximize absorption by increasing surface contact with nutrient-filled lumen. Another type of cell may be found between absorptive cells. __________________- manufacture and store mucus for lubrication

25. SIMPLE COLUMNAR

27. Stratified Squamous Epithelium Multiple layers of squamous shaped cells Occur in areas of the body subject to mechanical and chemical stresses Examples: __________________________________ __________________________ Continually being worn away or sheared off Replaced by cells from a deeper layer

28. STRATIFIED SQUAMOUS

30. Stratified Cuboidal Epithelium Multiple layers (usually two) of cuboidal cells Found primarily along large excretory ducts Examples:_____________ _____________________ _____________________ _________

31. STRATIFIED CUBOIDAL

32. Stratified Columnar Epithelium Found only in select parts of the respiratory, digestive, reproductive systems and along some excretory ducts Rare Function in secretion and protection

33. STRATIFIED COLUMNAR

34. Pseudostratified Columnar Epithelium “False” stratified – truly one layer of cells Cell nuclei are found at different levels across the length of the tissue Some cells do not reach luminal surface but all attach to basement membrane. Usually ciliated Found in: ________________________________________________________ ____________

35. PSEUDOSTRATIFIED COLUMNAR

37. Transitional Epithelium Multiple layers of cells with varying shapes basal layer of _______________or _____________ cells superficial layer of ______________ or ___________________cells Ability to stretch - found in areas where changes in volume occur Examples: ________________________________________________ ___________________________ As epithelia stretches, layers often thin depending on how much volume is present

38. TRANSITIONAL EPITHELIUM

40. Glandular Epithelia _________________- a cell or group of cells that have ability to manufacture and discharge a secretion. _________________- specialized protein molecules that are produced in the Rough ER, packaged by the golgi and discharged from the cell. Glands can be organized by factors: Endocrine vs. Exocrine Presence or absence of ducts Unicellular vs. Multicellular Number of cells that compose them Simple vs. compound Shape of secreting ducts Tubular, acinar, tubuloacinar Complexity of the structure Mucoid or serous Type of secretion made Merocrine, apocrine, or holocrine Manner in which secretions are stored and discharged

41. Endocrine Glands No ducts Blood stream delivers secretions to entire body Secretion is usually a hormone Regulate body functions (growth, maturity, sex cycle) Part of Endocrine System

42. ENDOCRINE GLANDS

43. Exocrine Glands Contain ducts (except for Goblet cells) Have local effect Examples:___________________________ ___________________________________ _______________________

44. GOBLET CELL

45. ENDOCRINE vs. EXOCRINE GLANDS

46. Unicellular Exocrine Gland: Goblet Cell Ductless Opens into GI, respiratory tracts, conjunctiva Composed of modified columnar epithelial cell Secretes ______________: mixed with water → mucus

47. Multicellular Exocrine Glands Contains: 1) ________________ usually surrounded by connective tissue rich in blood vessels and nerve fibers 2) ________________ May be surrounded by myoepithelial cells that assist with the discharge of secretions into the glandular duct

48. Classification of Multicellular Exocrine Glands: Shape Based on shape and number of tubes

49. Classification of Exocrine Glands: Manner of secretion _____________________ glands package their secretions and release them via exocytosis as they are manufactured Majority of glands (ex: pancreas, sweat, salivary ) ______________________ glands store their secretions and then release the top part (apex) of the cell into the duct system (ex: mammary, some sweat) _____________________ glands store their secretions and then release the entire contents of the cell (ex: sebaceous )

54. Classification of Exocrine Glands:Type of Secretions Produced Type of secretion produced ________________________ Watery Contain a high concentration of enzymes Pancreatic secretion _____________________ Thick, viscous Mucus membranes (GI, resp) Composed of glycoproteins Mixed exocrine glands contain both mucous and serous components

55. Connective Tissue Represents most abundant tissue by weight. Some systems are almost exclusively composed of connective tissue Skeletal, integumentary Appearance varies. Form and function may be different. Reserve for energy Protection Provides framework for structural support Is vascularized. Level of vascularity varies among connective tissue type.

56. Connective Tissue Components All connective tissue is composed of distinct components 1. __________________________ Collagenous Reticular Elastic 2. _____________________________ 3. _____________________________ Cells that stay in the tissues-____________ Fibroblasts Adipocytes (fat cells) Reticular cells Cells that are able to migrate in and out of tissues- _____________________________ Mast cells Leukocytes (white blood cells) Macrophages (fixed and wandering)

57. Connective Tissue Components

58. Connective Tissue Components: Ground Substance An homogenous material that ranges from liquid to gel to solid. Composed of glycoproteins called __________________________ (GAGs) Is a medium through which cells exchange nutrients and waste with the bloodstream. Acts as shock absorbing cushion and helps to protect underlying delicate cells. Serves as obstacle for invading microorganisms.