Biology 220 Anatomy Physiology I Unit II TISSUES

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

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

Epithelial Tissues http: //www. usc. edu/hsc/dental/ghisto/epi/c_28. html Features: • Closely packed cells with little extracellular matrix Single (simple) or multi-layered (stratified) Associated with underlying connective tissue http: //www. usc. edu/hsc/d ental/ghisto/epi/d_9. html • 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

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

Cell Junctions Tight junctions • tight seals between cells prevent movement of substances between cells • • Desmosomes aka. anchoring junctions loose connections help maintain integrity of epithelial tissue allow materials to pass 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

Classification of Epithelial Tissues Based on: *number of layers Fig. 4. 1, p. 116 *shape of cells

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

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

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) Simple columnar epithelium • secretion (e. g. , enzymes of GI tract) • absorption (e. g. , nutrients from GI tract) http: //www. usc. edu/hsc/dental/ ghisto/epi/d_14. html http: //www. usc. edu/hsc/d ental/ghisto/epi/d_9. html Modifications: • Cilia (movement of materials; e. g. , uterine tubes) • Microvilli (increase surface area for absorption; small intestine) • Goblet cells (secrete mucous; lubrication)

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)

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/de ntal/ghisto/epi/d_29. html

Stratified Epithelial Tissues Stratified columnar epithelium (ducts of male reproductive system, interlobular ducts of liver; functions: protection and secretion) http: //medic. med. uth. tmc. edu/edprog/histolog/liv er-gb/hist-10 b. htm http: //medicine. creighton. edu/medschool/Video. Atlas/epithel ial%20 tissue%20 source/web%20 stuff/Stratified%20 Column ar%20 Ep%201. html Stratified cuboidal epithelium (ducts of sweat glands, salivary glands, mammary glands; function: protection) http: //education. vetmed. vt. edu/Curricu lum/VM 8054/Labs/Lab 4/Examples/Exs trcub. htm

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

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

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

Connective Tissues: 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

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

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 http: //www. lima. ohiostate. edu/biology/images/anat omy/Areolar%20400 X. jpg

Connective Tissue Proper A. Loose CTs (con’t) 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 Proper B. Dense CTs Provide strength and elasticity Dense Regular (fibrous) CT • collagen fibers roughly parallel • resists tension primarily in one direction • poorly vascularized • forms tendons (muscle-bone); ligaments http: //www. usc. edu/hsc/dental/ ghisto/ct/c_36. html (bone-bone), aponeuroses (wide tendons) 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 Proper B. 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] http: //www. pathguy. com/histo/052. htm

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

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 http: //www. usc. edu/hsc/dental/ghisto/cart/c_7. html

Cartilage: B. Elastic Cartilage and C. Fibrocartilage 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/Video. Atlas/Cart. %20%26%20 Bone%20 Tissue%20 source/webstuff/Fibrocart ilage%202. html

Cartilage Comparison • Two types of cartilage are seen here – what are they? http: //medicine. creighton. edu/medschool/Video. Atlas/Cart. %20%26%20 Bone%2 0 Tissue%20 source/webstuff/Fibrocartiage%203. 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) http: //www. usc. edu/hsc/dental/ghisto/bld/c_8. html

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)

Compact Bone Osteocyte in lacuna Lamellae - layers of matrix Perforating canal Canaliculi allows cells to communicate and pass nutrients/ wastes Central (Haversian) Canal (passageway for blood vessels and nerves) Osteon http: //medicine. creighto n. edu/medschool/Video Atlas/Cart. %20%26%2 0 Bone%20 Tissue%20 so urce/webstuff/Dense%2 0 Bone%20 Hav%20 Sys %203. html

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

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) Transverse (cross) Section Longitudinal Section http: //www. usc. edu/hs c/dental/ghisto/musc/c _15. html

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

Muscle Tissue: B. 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: C. Smooth Muscle • no visible striations, involuntary, uninucleate • walls of hollow organs, including blood vessels http: //www. usc. edu/hsc/dental /ghisto/musc/c _3. html http: //www. usc. edu/hsc/dental/g histo/musc/c_1. html http: //www. usc. edu/hsc/den tal/ghisto/musc/c_9. html

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

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

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

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

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)

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])

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)