Unit II TISSUES

1. Biology 220 Anatomy & Physiology I Unit IITISSUES Chapter 4 pp. 114-143 http://www.usc.edu/hsc/dental/ghisto/index.html http://medicine.creighton.edu/medschool/VideoAtlas/Cart.%20%26%20Bone%20Tissue%20source/webstuff/Fibrocartiage%203.html E. Gorski/ E. Lathrop-Davis/S. Kabrhel

2. Definitions and Types • Group of cells with similar origin and function • 4 types • Epithelial tissues: cover surfaces, line cavities, form secretory parts of glands • Connective tissues: connect other tissues; support, protect; transport (blood); insulate (fat) • Muscle tissues: movement • Nervous tissue: coordinates activities by recognizing and responding to stimuli (changes in environment); transfer information

3. http://www.usc.edu/hsc/dental/ghisto/epi/c_28.html Single (simple) or multi-layered (stratified) Associated with underlying connective tissue http://www.usc.edu/hsc/dental/ghisto/epi/d_9.html Epithelial Tissues • Features: • Closely packed cells with little extracellular matrix • Not innervated (receptors found in connective tissue underlying them) • Highly able to regenerate (mitotic cell division) • Avascular (no blood vessels; blood supplied by underlying connective tissue) • Polarized • Cells joined by cell junctions

4. Apical surface (free edge) Basal surface • Basement Membrane (filtration and repair) • Basal lamina - associated with epithelium • Reticular lamina - associated with underlying connective tissue Epithelial Tissues: Polarity Lumen http://www.usc.edu/hsc/dental/ghisto/epi/c_24.html

5. Cell Junctions • Desmosomes • aka. anchoring junctions • loose connections • help maintain integrity of epithelial tissue • allow materials to pass between cells • Tight junctions • tight seals between cells prevent movement of substances between cells Fig. 3.4, p. 71 Gap Junctions - allow transfer of chemicals including ions from one cell to another adjacent cell; important to communications between some neurons

6. Classification of Epithelial Tissues Based on: *number of layers *shape of cells Fig. 4.1, p. 116

7. Types of Epithelial Tissues • Simple Tissues • Simple Squamous* • Simple Cuboidal* • Simple Columnar* • Pseudostratified Columnar* • Stratified Tissues • Stratified Squamous* • Stratified Columnar • Stratified Cuboidal • Transitional*

8. Simple Epithelial Tissues Simple squamous epithelium • Filtration, exchange of materials, secretion • Locations: • kidneys (glomerulus; filtration of solutes from blood) • lungs (alveoli; exchange of gases between blood and air) • endothelium (lining of blood and lymphatic vessels, heart) • mesothelium (serous membranes of ventral body cavity) http://www.usc.edu/hsc/dental/ghisto/epi/c_3.html

9. Simple columnar epithelium • secretion (e.g., enzymes of GI tract) • absorption (e.g., nutrients from GI tract) Simple Epithelial Tissues • Simple cuboidal epithelium • Secretion and absorption • kidneys (controllable change of materials between blood and urine) • glands (secrete chemicals into ducts or blood) http://www.usc.edu/hsc/dental/ghisto/epi/d_9.html • Modifications: • Cilia (movement of materials; e.g., uterine tubes) • Microvilli (increase surface area for absorption; small intestine) • Gobletcells (secrete mucous; lubrication) http://www.usc.edu/hsc/dental/ghisto/epi/d_14.html

10. Simple Epithelial Tissues Pseudostratified columnar epithelium • secretion • all cells rest on basement membrane, but nuclei at different levels give the appearance of being multilayered • cilia (respiratory system -- moves mucus upward) • goblet cells (respiratory system -- secrete mucus that traps airborne particles)

11. Stratified Epithelial Tissues Defined by the shape of the outer cells Stratified squamous epithelium • protection against abrasion • Keratinized (epidermis of skin) • contains keratin (water-proof protein) that protects against water loss • Non-keratinized (mouth, esophagus, vagina, anus) • lacks keratin; water may be lost across these surfaces http://www.usc.edu/hsc/dental/ghisto/epi/d_29.html

12. Stratified columnar epithelium (ducts of male reproductive system, interlobular ducts of liver; functions: protection and secretion) http://medic.med.uth.tmc.edu/edprog/histolog/liver-gb/hist-10b.htm Stratified cuboidal epithelium (ducts of sweat glands, salivary glands, mammary glands; function: protection) http://medicine.creighton.edu/medschool/VideoAtlas/epithelial%20tissue%20source/web%20stuff/Stratified%20Columnar%20Ep%201.html http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab4/Examples/Exstrcub.htm Stratified Epithelial Tissues

13. Distended, the uppermost cells are stretched into a squamous shape Relaxed, the outermost cells become bulbous Transitional Epithelium http://neuromedia.neurobio.ucla.edu/campbell/epithelium/wp_frame.htm

14. Connective Tissues (CT) Features: • generally, well-innervated and highly vascular (except cartilage) • consist of relatively few cells embedded in large amount of extracellular (outside the cell) matrix • each type of CT has its own associated cell type(s) and matrix

15. Connective Tissues (CT) Classification • is based on structure (type of matrix [ground substance, type and amount of fibers] and cells) and function • cells: each CT group has its own associated cell type(s) • “-blast” = mitotically active (produce new cells; e.g., fibroblasts, osteoblasts) • “-cyte” = mature cell (e.g., adipocytes, osteocytes) • all connective tissues arise from an embryonic form called mesenchyme

16. Connective Tissues: Matrix Matrix consists of ground substance and fibers: • Ground substance = thick (generally), amorphous (undefined structure), non-staining interstitial “fluid” (generally); consistency varies from rock-hard (bone) to watery fluid (plasma) • Fibers -- proteins of differing structure (and function) • collagenous -- most abundant; strong; resists pulling tension; composed of thick strands of collagen • reticular -- fine strands of collagen forming continuous network around blood vessels, soft organs, basement membrane • elastic -- consists of elastin; stretch and recoil without breakage; found in skin, lungs, blood vessels

17. Connective Tissues Types of connective tissues: • Connective tissue proper A. Loose connective tissue -areolar, adipose, reticular B. Dense connective tissue - dense regular, dense irregular • Cartilage A. Hyaline cartilage B. Elastic cartilage C. Fibrocartilage • Bone • Blood

18. http://www.lima.ohio-state.edu/biology/images/anatomy/Areolar%20400X.jpghttp://www.lima.ohio-state.edu/biology/images/anatomy/Areolar%20400X.jpg Connective Tissue Proper • Two subclasses :A. Loose connective tissues • B. Dense connective tissues • Defined by: • fiber content varies with type of tissue • ground substance = hyaluronic acid (hyaluronidase - enzyme) • classification depends on type, amount, orientation of fibers • A. Loose CTs • Areolar CT • all three types of fibers • fibroblasts, macrophages, mast cells • water and solute reservoir • associated with most epithelial membranes • forms lamina propria of mucous membranes • forms papillary layer of dermis

19. Adipose • specialized for fat storage • cells = adipocytes • insulates, absorbs shock, stores energy • liposuction http://www.usc.edu/hsc/dental/ghisto/ct/c_45.html • Reticular CT • lots of reticular fibers • forms delicate, supporting networks (stroma) of some organs (e.g., spleen, liver, lymphatic tissue) http://www.usc.edu/hsc/dental/ghisto/ct/c_42.html Connective Tissue ProperA. Loose CTs (con’t)

20. Dense Regular (fibrous) CT • collagen fibers roughly parallel • resists tension primarily in one direction • poorly vascularized • forms tendons (muscle-bone); ligaments (bone-bone), aponeuroses (wide tendons) http://www.usc.edu/hsc/dental/ghisto/ct/c_36.html • Elastic CT • form of dense regular CT with lots of elastic fibers • recoils after stretching • around large arteries and large lymphatic vessels http://www.usc.edu/hsc/dental/ghisto/ct/c_40.html Connective Tissue ProperB. Dense CTs Provide strength and elasticity

21. http://www.pathguy.com/histo/052.htm Connective Tissue ProperB. Dense CTs (con’t) • Dense Irregular CT • fibers irregularly arranged • resists tension in many directions • lower dermis, perichondrium, periosteum, and fibrous capsules around some organs (kidneys, testes, heart [fibrous pericardium]

22. Cartilage • Features: • avascular • perichondrium = dense irregular CT surrounding cartilage; supplies blood (brings nutrients/oxygen, removes wastes) • lack innervation • cells = chondroblasts (during cartilage formation) and chondrocytes (mature) found in openings called lacunae (lacuna) • Types • A. Hyaline Cartilage • B. Elastic Cartilage • C. Fibrocartilage

23. http://www.usc.edu/hsc/dental/ghisto/cart/c_7.html Cartilage: A. Hyaline • most abundant • collagen fibers make it strong, yet pliable (fibers not visible) • tip of nose, trachea, epiphyseal plate (growing bone), much of the fetal skeleton, articular cartilage

24. B. Elastic cartilage • elastic fibers allow recoil after bending • pinna (external ear), epiglottis http://www.usc.edu/hsc/dental/ghisto/cart/c_13.html • C. Fibrocartilage • compressible without permanent change • intervertebral disks, menisci (knee), symphysis pubis http://medicine.creighton.edu/medschool/VideoAtlas/Cart.%20%26%20Bone%20Tissue%20source/webstuff/Fibrocartilage%202.html Cartilage: B. Elastic Cartilage and C. Fibrocartilage

25. Cartilage Comparison • Two types of cartilage are seen here – what are they? http://medicine.creighton.edu/medschool/VideoAtlas/Cart.%20%26%20Bone%20Tissue%20source/webstuff/Fibrocartiage%203.html

26. http://www.usc.edu/hsc/dental/ghisto/bld/c_8.html Blood • Features: • cells & cell fragments (suspended in liquid matrix = plasma) • leukocytes = white blood cells [WBCs] • erythrocytes = red blood cells [RBCs] and • platelets (cell fragments) • contains solutes (ions, nutrients, wastes) and suspended substances (e.g., large proteins) • fights disease (WBCs) • transports substances (e.g., nutrients, wastes, hormones, respiratory gasses)

27. Bone • forms the skeletal system (along with cartilage); • Functions: • provides support, • leverage for movement (muscle attachment), • protection, • hemopoiesis ( hematopoiesis) = blood cell formation • Features: • cells in hard matrix (calcium and magnesium carbonate and phosphate salts); collagen fibers and other proteins • Types: • spongy bone (plates of bone called trabeculae) • compact bone • based on osteon (formerly Haversian system)

28. Osteocyte in lacuna Lamellae - layers of matrix Perforating canal Canaliculi allows cells to communicate and pass nutrients/ wastes Osteon Central (Haversian) Canal (passageway for blood vessels and nerves) Compact Bone http://medicine.creighton.edu/medschool/VideoAtlas/Cart.%20%26%20Bone%20Tissue%20source/webstuff/Dense%20Bone%20Hav%20Sys%203.html

29. Muscle Tissue Features: • high rate of metabolic activity when active • highly vascular (needs good supply of oxygen and nutrients when active) • structure specialized for contraction to produce movement of body parts (including movement of materials through tubes) • cells = muscle fibers Types: A. Skeletal B. Cardiac C. Smooth

30. Longitudinal Section http://www.usc.edu/hsc/dental/ghisto/musc/c_15.html Transverse (cross) Section Muscle Tissue: A. Skeletal Muscle • attached to bones • movement of skeleton; voluntary control of sphincters • striated (banding pattern), voluntary, multinucleate (develops from union of cells)

31. Skeletal Muscle/Tendon Comparison • Compare the skeletal muscle (m) with the tendon (t) – tendon is composed of dense regular CT http://www.usc.edu/hsc/dental/ghisto/musc/c_15.html

32. Cardiac Muscle • striated, involuntary, uninucleate, branching • intercalated disks allow rapid spread of impulses from one fiber to another • myocardium (muscular wall of heart) http://www.usc.edu/hsc/dental/ghisto/musc/c_22.html Muscle Tissue: B. CardiacMuscle

33. http://www.usc.edu/hsc/dental/ghisto/musc/c_3.html http://www.usc.edu/hsc/dental/ghisto/musc/c_1.html http://www.usc.edu/hsc/dental/ghisto/musc/c_9.html Muscle Tissue: C. SmoothMuscle • no visible striations, involuntary, uninucleate • walls of hollow organs, including blood vessels

34. Nervous Tissue Features: • specialized for recognizing environmental changes (stimuli; receptors; sensory function) • integrates sensory inputs and motor outputs • controls motor outputs (muscle contraction, glandular secretion

35. Neurons • conduct information (sensation, motor impulses) • Neuroglia • protect, insulate, support neurons http://www.usc.edu/hsc/dental/ghisto/nerv/c_4.html Nervous Tissue

36. Epithelial Membranes Features: • Consist of epithelial tissue and CT Three types: A. Serous Membranes B. Cutaneous Membrane C. Mucous Membranes

37. Epithelial Membranes:A.Serous Membranes • Consist of simple squamous epithelium (mesothelium) & areolar CT • Secrete serous fluid (lubricates to prevent friction and allow freer movement) • Line ventral body cavity (except pelvic cavity) • parietal layer - lines wall of cavity • visceral layer - overlies organs

38. A. Serous Membranes (con’t) Three ventral body cavities with a serosa • pericardium surrounds and covers heart • pleura overlies lungs and line thoracic cavity • peritoneum lines abdominal cavity and covers organs Inflammation of serosa due to irritation and/or disease • in pleural cavity (pleurisy) • in abdominal cavity (peritonitis) • in pericardium (pericarditis)

39. Epithelial Membranes: B.Cutaneous Membrane • forms skin • consists of: • keratinized stratified squamous epithelium (epidermis) • connective tissue (dermis) • areolar CT [papillary layer], and • dense irregular CT [reticular layer])

40. Epithelial Membranes: C.Mucous Membranes • line body cavities open to the outside (digestive tract, respiratory tract, reproductive tract, urinary tract) • mostly non-keratinized stratified squamous epithelium (or stratified columnar) or simple columnar (absorptive areas of gut) • “wet” membranes (bathed in secretions-mucus, urine)