Histology - Tissue Level Of Organization PDF

THE TISSUE LEVEL OF ORGANIZATION Chapter 4 Unless otherwise noted, the images and text used in this PowerPoint are from: Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., Korol, O., Johnson, J. E., Womble, M., & DeSaix, P. (2022). Chapter 9: Joints. In Anatomy and Physio...

THE TISSUE LEVEL OF ORGANIZATION Chapter 4 Unless otherwise noted, the images and text used in this PowerPoint are from: Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., Korol, O., Johnson, J. E., Womble, M., & DeSaix, P. (2022). Chapter 9: Joints. In Anatomy and Physiology 2e. OpenStax. https://openstax.org/books/anatomy-and-physiology-2e/pages/9-introduction Chapter Objectives: After this chapter, you will be able to: ❑Identify the main tissue types, and discuss their roles in the human body ❑Identify the four types of tissue membranes, and the characteristics of each that make them functional ❑Explain the functions of various epithelial tissues, and how their forms enable their functions ❑Explain the functions of various connective tissues, and how their forms enable their functions ❑Describe the characteristics of muscle tissue, and how these enable function ❑Discuss the characteristics of nervous tissue, and how these enable information processing and control of muscular and glandular activities Types of Tissues SECTION 4.1 Four Types of Tissues Four Types of Tissue: Body ▫ Nervous tissue ▫ Epithelial tissue ▫ Muscle tissue ▫ Connective tissue (Micrographs provided by the Regents of University of Michigan Medical School © 2012) Tissue Membranes Tissue Membranes Connective tissue membranes synovial membranes Epithelial membranes mucous membranes serous membranes cutaneous membrane. Epithelial Tissue SECTION 4.2  Cell Junctions Types of Cell Junctions The three basic types of cell-to-cell junctions are Tight junctions ▫ keep pathogens, toxins out Gap junctions ▫ cell to cell communication Anchoring junctions ▫ Desmosomes ▫ Hemidesmosomes ▫ Adherens resistant to mechanical stress  Epithelial Tissue Characteristics One or more layers of closely adhering cells (very little ECM) Forms a flat sheet with the upper surface exposed to the environment or an internal body cavity – one side of tissue exposed to open free space – Avascular - depends on underlying connective tissue for oxygen (blood supply) Sits on basement membrane – thin layer of collagen and adhesive proteins – anchors epithelium to underlying connective tissue  Epithelial Tissue Two types: – Covering and lining epithelium – Glandular epithelium Functions include: – Protection – Absorption – Filtration – Excretion – Secretion – Sensory reception  Epithelial tissue – Naming Find the apical surface Surface facing the lumen or outside world Find the basal surface Surface facing the basement membrane How many layers 1 layer is simple 2 or more layers of cells is stratified What is shape of cell Is it flat, cube shaped or columnar Epithelial Tissue Goblet Cell Goblet Cell Columnar epithelium cells Pseudostratified columnar cell ▫ The arrows in this micrograph point to the mucous-secreting goblet cells. LM × 1600. (Micrograph provided by the Regents of University of Michigan Medical School © 2012) Epithelial Tissue Simple Squamous Features - Flat, with flattened nucleus 1 layer Function – Diffusion of gases, nutrients, or water Secrete serous fluid Locations Air sacs in lungs Linings of vessels or organs Epithelial Tissue Stratified Squamous Features - Flat, with flattened nucleus many layer Function – Protection from abrasion Locations Skin (keratinized) Esophagus, anus Epithelial Tissue Simple cuboidal Features – 1 layer Cuboid shape, with large nucleus Function – Absorb and secrete Locations Kidney tubules Ducts of glands  Epithelial Tissue Stratified cuboidal Features – 2 layer Cuboid shape, with large nucleus Function – Protection and secretion Locations Mammary glands Sweat glands Salivary glands  Epithelial Tissue Simple Columnar Features - 1 layer Column shape, elongated nucleus Nucleus more evenly distributed Cilia & microvilli, goblet cells Function – Absorb and secrete (mucus & enzymes) Locations Digestive tract (microvilli), lower bronchioles (cilia) fallopian tubes (cilia) and uterus Epithelial Tissue Stratified columnar Features - 3 layer 1 row of Column shape, elongated nucleus 2 layers of cuboid shape Basal layer is cuboid shaped Function – Secret(mucus) & protection Locations Male & female urethra Epithelial Tissue Pseudostratified columnar Features - 1 layer but looks layered Cilia & goblet cells Nucleus are bunched toward the basal surface Function – Secret(mucus) & protection Locations Respiratory passages Epithelial Tissue Transitional Features - Many layers Apical layer is dome shaped Function – Expand and stretch Locations Bladder and ureters Connective Tissue Supports and Protects SECTION 4.3  Connective Tissue characteristics Consists of widely spaced cells separated by fibers and ground substance (ECM) Most abundant and variable tissue type Functions: – connects structures to each other – gives support and protection (physical & immune) – stores energy – movement and transport of materials  Connective Tissue Structural Elements of connective tissue: – Ground Substance – Fibers – Cells Ground substance and Fibers are collectively called the matrix (ECM = extracellular matrix)  Ground Substance of Connective Tissue Gelatinous or rubbery material found in between cells Consists of large molecules – proteoglycans Protein-carbohydrate complexes embedded in plasma membranes create a strong bond to other cells or extracellular matrix – adhesive glycoproteins protein-carbohydrate complexes that bind plasma membrane to collagen or proteoglycans outside the cells Fibers of Connective Tissue Collagen fibers – Made of the protein collagen – tough (stronger than steel fibers of the same diameter!) – resistant to stretch, yet flexible tendons, ligaments and deep layer of the skin (dermis) Reticular fibers – thinner collagen fibers coated with glycoprotein form framework for spleen and lymph nodes  Fibers of Connective Tissue Elastic fibers – thin branching fibers made of elastin – stretch & recoil like a rubber band (elasticity) give skin, lungs and arteries ability to stretch and recoil  Cells of Connective Tissues Blast cells – mitotic cells that secrete ground substance and fibers for the matrix – Fibroblasts produce protein fibers and ground substance – Chondroblasts – product cartilage – Osteoblasts – form bony matrix – Hemocytoblasts – form blood cells Different from other blast cells because they are not located within their own tissue (they are located in bone marrow)  Connective tissue proper: Loose Dense Cartilage: Classes of Hyaline Elastic Connective Fibrocartilage Tissues Bone: Spongy Compact Blood Types of Dense Regular Connective Features Tissue Proper Cells - fibroblast Dense Fibers - collagen Function Increased tensile strength and resist stretching Location Tendons & ligaments  Dense Irregular Types of Connective Features Tissue Proper- Cells - fibroblast Dense Fibers – collagen with small amount of elastic fibers Function Strength but allows for stretching in many directions Location Dermis of skin Walls of organs Connective Tissue Proper - Loose Areolar Connective Tissue Features Cells - Fibroblasts are the most common cell type Fibers – all three loosely spread throughout ECM Functions: – Support – binding tissues together – Holding body fluids (amount of fluid in areolar tissue is = to amount in blood!) – Defend against infections Location Packing material ▫ Surround organs ▫ Dermis of skin  Connective tissue Proper - Loose Reticular tissue Features reticular fibers in loose ground substance Leukocytes - many Function – Framework that provides structure and supports other cells Locations – bone marrow, lymph nodes, and spleen  Connective tissue Proper - Loose Adipose Tissue Features Large, empty-looking cells with thin margins (filled with fat) Nucleus pressed against cell membrane Function Energy storage, insulation, cushioning Location Subcutaneous fat beneath skin and surrounding organs Connective tissue - Cartilage Supportive connective tissue with rubbery matrix Cell - Chondroblasts produce cartilage matrix, once surrounded by cartilage → chondrocytes No blood vessels so diffusion must bring in nutrients and remove wastes – injured cartilage heals slowly Major types of cartilage depend upon fiber types – hyaline, fibrocartilage and elastic cartilage  Cartilage - Hyaline Features Cell – chondrocyte within lacunae Fiber – a few collagen, ECM has a glass-like appearance Function Smooth and flexible allows for smooth movement Location Most abundant Articular surfaces, nose, ribs, trachea  Cartilage - Elastic Features Cell – chondrocyte within lacunae Fiber – a few collagen with more elastic fibers Function Smooth and increased flexibility allowing to retain shape Location Outer ear and epiglottis  Cartilage - Fibrocartilage Features ▫ Cell – chondrocyte within lacunae ▫ Fiber - extensive parallel collagen fibers Function ▫ Resists compression and absorbs shock in some joints Location ▫ Pubic symphysis and intervertebral discs Compact Bone Features Cells – osteocytes in lacunae ECM is filled with a calcium matrix Osteon – functional unit of bone Function Protection to organs and support Location Outer layer of bone Spongy Bone Features Cells – osteocytes in lacunae (hard to see ECM is filled with a calcium matrix Trabeculae – struts that provide structure Function Hematopoiesis ( blood formation) Lighten weight of bone Location Fills heads of long bone Found in flat bones  Fluid CT Blood Features Variety of cells and cell fragments – white blood cells, red blood cells, and platelets – Matrix - plasma Function Many, transport gases, nutrients, protects from pathogens Location Found in heart and blood vessels Muscle Tissue and Motion SECTION 4.4 Muscular Tissue Characteristics Elongated cells that are irritable (respond to stimuli) by contracting (contractile) Function is to exert physical force on other tissues – move bones – push substances through vessels (blood, urine, food etc.) – Pump blood Important source of body heat Three types of muscle – skeletal, cardiac and smooth Skeletal Muscle Features Long, cylindrical, multinucleate, un-branched, voluntary cells with striations Function Movement, facial expression, posture, breathing, speech, swallowing and excretion Locations Skeletal muscles such as in the limbs, biceps brachii Cardiac Muscle Features Short branched, mononucleated cells with striations and intercalated discs Function Pumps blood Locations heart Smooth Muscle Features Short cells; non-striated, mononucleate Involuntary Function Swallowing, GI tract functions, labor contractions, control of airflow, erection of hairs and control of pupil Locations Sheets of muscle in viscera; iris; hair follicles and sphincters Muscle Tissue Muscle Tissue (a) Skeletal muscle cells have prominent striation and nuclei on their periphery. (b) Smooth muscle cells have a single nucleus and no visible striations. (c) Cardiac muscle cells appear striated and have a single nucleus. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012) Nervous Tissue Mediates Perception and Response SECTION 4.5 Nervous Tissue Features Large neurons with long cell processes surrounded by much smaller glial cells lacking dendrites and axons Function Communication and control of bodily functions Locations Found in brain, spinal cord, nerves & ganglia  Nervous Tissue Nervous Tissue Nervous tissue is made up of neurons and neuroglia. The cells of nervous tissue are specialized to transmit and receive impulses. LM × 872. (Micrograph provided by the Regents of University of Michigan Medical School © 2012) Citation Unless otherwise noted, the images and text used in this PowerPoint are from: Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., Korol, O., Johnson, J. E., Womble, M., & DeSaix, P. (2022). Chapter 9: Joints. In Anatomy and Physiology 2e. OpenStax. https://openstax.org/books/anatomy-and-physiology-2e/pages/9-introd uction