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Tissues

Tissues . Function and Location For Epithelial, Connective, Muscular and Nervous. Nervous tissue: Internal communication • Brain, spinal cord, and nerves. Muscle tissue: Contracts to cause movement • Muscles attached to bones (skeletal) • Muscles of heart (cardiac)

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Tissues

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  1. Tissues Function and Location For Epithelial, Connective, Muscular and Nervous

  2. Nervous tissue: Internal communication • Brain, spinal cord, and nerves Muscle tissue: Contracts to cause movement • Muscles attached to bones (skeletal) • Muscles of heart (cardiac) • Muscles of walls of hollow organs (smooth) Epithelial tissue:Forms boundaries, protects, secretes, absorbs, filters • Skin surface (epidermis) • Lining of GI tract organs and other hollow organs Connective tissue: Supports, protects, binds • Bones • Tendons • Fat and other soft padding tissue

  3. Characteristics of All Epithelial • Composed mainly of cells bound closely together • A free surface exposed to the environment, passageway or internal chamber • Basement membrane • Avascular • Regeneration • May have villi, microvilli or cilia

  4. Functions of Epithelial Tissue • Physical Protection • Intercellular connections/gap junctions and tight junctions • Control Permeability • Provide Sensation • Produce specialized secretions • Exocrine – secretions are discharged unto the surface or through duct • i.e. sweat, milk • Endocrine – secretions are released into blood stream • i.e. hormones

  5. Classifying Epithelial • Classified by number of cell layers • Simple – one cell layer • Stratified – more than one layer of cells • And Cell shape • Squamous – cells are thin and flat, • Cuboidal – small boxes, appear square, nucleus lies near center of cell • Columnar – column like cells with oval nuclei. • (Shape of nucleus is similar to shape of cell.)

  6. Simple Squamous C: flattened cells; fried egg appearance F: thin, permeable, used for filtration/absorption by diffusion FUNCTIONS: Reduces friction; controls vessel permeability; performs absorption and secretion LOCATIONS: lines heart and blood vessels, Covers organs, portions of kidney tubules; cornea; alveoil of lungs Cytoplasm Nucleus Connective tissue Lining of peritoneal cavity

  7. Simple Cuboidal C: one layer of cube-like cells w/ large spherical central nuclei F: secretion and absorption L: glands, ducts, portions of kidney tubules LOCATIONS: Glands; ducts; portions of kidney tubules; thyroid gland Connective tissue FUNCTIONS: Limited protection, secretion, absorption Nucleus Cuboidal cells Kidney tubule Basement membrane

  8. Simple Columnar (c) Simple columnar epithelium C: single layer of tall closely packed cells; oval nucleus; may cilia and goblet cells. Goblet cells secrete mucus. F: absorption and secretion; some can hold and secrete mucus, enzymes L: digestive tract, uterine tubes, c. ducts of kidneys Microvilli LOCATIONS: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys Cytoplasm Nucleus Intestinal lining Basement membrane Loose connective tissue FUNCTIONS: Protection, secretion, absorption

  9. Overview of Simple Columnar (c) Simple columnar epithelium Description: Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus- secreting unicellular glands (goblet cells). Simple columnar epithelial cell Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action. Location: Nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus. Basement membrane Photomicrograph: Simple columnar epithelium of the stomach mucosa (860X).

  10. Simple Columnar in the Digestive Tract • Goblet Cells • Cilia

  11. Pseudostratified Columnar C: One layer of cells with varying heights; nuclei seen at different levels; may have goblet cells (secrete) and have cilia F: secrete mucus primarily L: lining of nasal cavity, bronchi and trachea

  12. Pseudostratified from trachea LOCATIONS: Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract Cilia Cytoplasm Nuclei FUNCTIONS: Protection, secretion Basal lamina Loose connective tissue Trachea

  13. Stratified Squamous Epithelium C: free surface cells are squamous; deeper layers are cuboidal F: protection against abrasion, pathogens,chemical attack L: surface of skin, extends into every opening FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina Squamous superficial cells Stem cells Basal lamina Connective tissue Surface of tongue

  14. Generally 2 layers of cube-like cellsFunction: ProtectionLocation: sweat glands and other large glands Stratified Cuboidal Lumen of duct LOCATIONS: Lining of some ducts (rare) Stratified cuboidal cells FUNCTIONS: Protection, secretion, absorption Basal lamina Sweat gland duct Nuclei Connective tissue

  15. Transitional Epithelium C: resembles both stratified cuboidal and stratified squamous; basal cells resemble columnar or cuboidal; surface cells similar to squamous F: stretch and recoil Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch. Transitional epithelium Function: Stretches readily and permits distension of urinary organ by contained urine. Basement membrane Location: Lines the ureters, urinary bladder, and part of the urethra. Connective tissue Photomicrograph: Transitional epithelium lining the urinary bladder, relaxed state (360X); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine.

  16. LOCATIONS: Glands; ducts; portions of kidney tubules; thyroid gland Connective tissue FUNCTIONS: Limited protection, secretion, absorption Nucleus Cuboidal cells Basal lamina Kidney tubule LOCATIONS: Lining of some ducts (rare) Lumen of duct FUNCTIONS: Protection, secretion, absorption Stratified cuboidal cells Basal lamina Nuclei Connective tissue Sweat gland duct LOCATIONS: Urinary bladder; renal pelvis; ureters FUNCTIONS: Permits expansion and recoil after stretching Epithelium (relaxed) Basal lamina Connective tissue and smooth muscle layers EMPTY BLADDER Epithelium (stretched) Basal lamina Connective tissue and smooth muscle layers FULL BLADDER Urinary bladder

  17. Glandular Epithelium Two types: Endocrine – ductless; secrete hormones into extracellular space; eventually enters blood stream. Exocrine – more numerous; secrete products using ducts i.e sweat, oil, mucus, enzymes Classified by structure, mode and type of secretion.

  18. Unicellular Exocrine glands • Ductless • Goblet cells secrete mucus directly into organ; mucus never makes it to bloodstream

  19. Merocrine Glands Secrete products by exocytosis Cells aren’t changed after secretion i.e pancreas, sweat glands, salivary glands

  20. Apocrine Glands Accumulate products underneath cell surface; eventually cell pinches off Cell repairs itself; repeats process I.e. mammary glands, sweat glands under arm pits

  21. Holocrine Glands Oil gland Accumulate product until they rupture “die for cause” Secretions include product plus cell debris i.e. sebaceous (oil) glands

  22. Secretory vesicle Golgi apparatus Nucleus Salivary gland Merocrine Breaks down Mammary gland Golgi apparatus Secretion Regrowth Apocrine Cells burst, releasing cytoplasmic contents Hair Cells produce secretion, increasing in size Sebaceous gland Hair follicle Cell division replaces lost cells Stem cell Holocrine

  23. Functions of Connective Tissue • Binding, support and protection • Insulation/Storing Energy • Defending the body • Transportation of substances

  24. Characteristics of Connective Tissue • Common origin – all arise from same embryonic tissue: Mesenchyme (next slide) • Degree of vascularity • Many Specialized cells • Composed mainly of extracellular material; not cells • Matrix- includes fibers and ground substance • Ground substance – fluid of tissue

  25. Blast: immature cell Cyte: mature cell Clast: cell that breaks down others. I.e. osteoclasts break down bone

  26. Matrix • Amorphous; has no distinct shape or form • Ground substance – material that fills space between cells; fluid of tissue • 3 Types of fibers • Collagen – long, straight, thick white fiber; strong but flexible unbranched fiber • Elastin – branched and wavy fiber that contains protein elastin; coiled yellow fibers; rubberband quality • Reticular – least common; fine, branching fibers that form networks of fibers; support soft tissue of organs.

  27. Connective Tissue

  28. Cells of Connective Tissue Proper • Fibroblasts- produce fibers and ground substance • Macrophages – engulf bacteria and other foreign bodies (phagocytize) • Mast Cells – mark substances for destruction by secreting chemicals (histamine) that start the immune response • Adipocytes (fat cells) – stores fat, nucleus and organelles are pushed to the side.

  29. Fixed macrophage Mast cell Reticular fibers Elastic fibers Melanocyte Free macrophage Plasmocyte Collagen fibers Blood in vessel Fibroblast Free macrophage Adipocytes (fat cells) Mesenchymal cell Ground substance Lymphocyte

  30. Areolar: C: loose matrix with all three fiber types; contains macrophages, mast cells and WBC’s F: cushion organs; phagocytize bacteria, (assists when infections are present. L: distributed under epithelia; packages organs Elastic fibers Collagen fibers Fibroblast macrophage

  31. C: closely packed cells; nucleus pushed off to side by fat droplet; vascular F: reserve fuel; insulates; supports and protects organs. L: under skin; around kidneys and eyeballs; in bones, abdomen and breasts Adipose: LOCATIONS: Deep to the skin, especially at sides, buttocks, breasts; padding around eyes and kidneys FUNCTIONS: Provides padding and cushions shocks; insulates (reduces heat loss); stores energy Adipocytes Adipose tissue

  32. C: network of reticular fibers in lots of extracellular matrix; composed of reticular cells and blood cells F: form a soft internal skeleton for organs L: lymph nodes; bone marrow and spleen Reticular: Reticular fibers Reticular tissue

  33. C: mainly consists of parallel collagen and some elastin fibers; main cell is fibroblast. L: tendons and ligaments F: Attach muscle to bone; bone to bone; withstands pulling forces; (wavy fibers enable the tissue to stretch) Dense Regular Collagen fibers Fibrocyte nuclei Tendon

  34. Characteristics of Cartilage • Avascular and lacks nerve fibers (diffusion thus cartilage is rarely thick) • Ground substance consists of chondroitin sulfate • Chondrocytes are the working cells • Lacunae (small cavities) surround cells

  35. C: matrix appears glossy (amorphous); collagen fibers most common; but not visible L: tip of nose trachea, larynx, rib’s costal cartilage, soft spot, bones of synovial joints, and nasal septum F: offers support with a little flexibility; absorbs; resists compressive stress LOCATIONS: Between tips of ribs and bones of sternum; covering bone surfaces at synovial joints; supporting larynx (voice box), trachea, and bronchi; forming part of nasal septum Chondrocytes in lacunae FUNCTIONS: Provides stiff but somewhat flexible support; reduces friction between bony surfaces Matrix Hyaline cartilage

  36. C: little ground substance with lots of collagen fibers dominating the matrix. Fibers are interwoven which offers more strength L: discs between vertebra, pubic symphysis, knee meniscus F: shock absorber, resist compressions, prevents bone to bone contact. Fibrocartilage Collagen fibers in matrix Chondrocyte in lacuna Fibrous cartilage

  37. C: contains more elastin fibers making tissue very flexible L: ear, epiglottis F: maintains shape of structure but offers more flexibility and stretch. Elastic Cartilage Chondrocyte in lacuna Elastic fibers in matrix Elastic cartilage

  38. C: matrix similar to cartilage but contains more collagen fibers; ground substance is Ca and PO4; vascular, vessels travel thru canaliculi; Lacunae (free space) may be present F: support, protect, store Ca and PO4; forms blood cells L: Bone Bone Canaliculi Osteocytes in lacunae Central canal Matrix

  39. Blood (k) Others: blood Description: Red and white blood cells in a fluid matrix (plasma), proteins are not in fiber Form but are dissolved in plasma, Contains cell fragments called platelets Plasma Neutrophil Function: Transport of respiratory gases, nutrients, wastes, and other substances. Helps fight off disease, blood clotting Location: Contained within blood vessels. Red blood cells Lymphocyte Photomicrograph: Smear of human blood (1860x); two white blood cells (neutrophil in upper left and lymphocyte in lower right) are seen surrounded by red blood cells.

  40. Comparison of Classes of Connective Tissues (1 of 2)

  41. Comparison of Classes of Connective Tissues (2 of 2)

  42. Muscular Tissue Characteristics • Contain many cells • Contains lots of vascular tissue • Elongated shape; cells are called fibers • Possess myofilaments, proteins that enable the muscle to contract.

  43. C: long parallel cells with many nuclei; banded or striated; voluntary L: attach to bones of skeleton F: large movements; walking, moving extremities Skeletal Tissue Nuclei Muscle fiber Striations Skeletal muscle

  44. C: striated only one nuclei per cell; branching cells join at junctions called intercalated discs; involuntary F: intercalated disc enable to heart to beat as one unit. Cardiac muscle contracts together and relaxes together. L: walls of heart Cardiac Muscle Nucleus Cardiac muscle cells Intercalated discs Striations Cardiac muscle

  45. C: not striated; each cell contains one nucleus; fibers appear to taper at ends; not exactly parallel; involuntary F: moves substances through hollow organs L: found in walls of digestive organs, urinary tract and blood vessels Smooth Muscle Smooth muscle cell Nucleus Smooth muscle

  46. C: contains cells called neurons and supporting cells F: neurons transmit electrical impulses; supporting cells are nonconducting cells that support, insulate and protect neurons. L: nervous system: brain, spinal cord, nerves Nervous tissue Nervous Nuclei of supporting cells Cell body of a neuron Neuron processes Photomicrograph: Neurons (350x)

  47. Nuclei of neuroglia • Maintain physical structure of tissues • Repair tissue framework after injury • Perform phagocytosis • Provide nutrients to neurons • Regulate the composition of the interstitial fluid surrounding neurons Cell body Axon Dendrites Nucleolus Nucleus of neuron Dendrites (contacted by other neurons) Axon (conducts information to other cells) Microfibrils and microtubules Mitochondrion Contact with other cells Nucleolus Nucleus Cell body (contains nucleus and major organelles) A representative neuron (sizes and shapes vary widely)

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