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Chapter 3

Chapter 3. Body Tissues. Body Tissues. Human body starts out as one cell Cell division occurs to create millions of cells Cellular Specialization results Anytime you have a group of cells working together for the same purpose TISSUES result. Four Main Tissue Types. Connective- Support

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Chapter 3

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  1. Chapter 3 Body Tissues

  2. Body Tissues • Human body starts out as one cell • Cell division occurs to create millions of cells • Cellular Specialization results • Anytime you have a group of cells working together for the same purpose TISSUES result.

  3. Four Main Tissue Types • Connective- Support • Nervous- Control • Muscle- Movement • Epithelium- Covering

  4. Tissues • Most organs are composed of several tissue types. • The Type of tissue will determine the function of the organ.

  5. Epithelial Tissue • The lining, covering, and glandular tissue of the body. • Covers all free body surfaces and contains versatile cells. • Nearly all substances given off or received by the body must pass through the epithelium.

  6. Epithelial Functions • Protection • Absorption • Filtration • Secretion Examples: Epithelium of the skin-protects against bacterial and chemical damage. -Epithelium that lines the digestive tract absorbs food into the body.

  7. Characteristics of Epithelium • Cells fit closely together and form continuous sheets. • The membranes always have one free (unattached) surface or edge. This Apical Surface is exposed to the body’s exterior or tot eh cavity of an internal organ

  8. Characteristics Cont. • The lower surface rest on a basementmembrane • Epithelial tissues have no blood supply of their own(avascular) and depend on diffusion from capillaries to provide oxygen and food. • If well nourished, epithelial cells will regenerate easily.

  9. Classification of Epithelium • Given two names: the 1st= number of cell layers, 2nd= shape of the cells Number of cells 1) Simple= one layer of cells 2) Stratified= more than one cell layer

  10. Classification Cont. ShapesofCells • Squamous- flattened like fish scales • Cuboidal- cube shaped like dice • Columnar- cells shaped like columns * The terms describing the shape and the arrangement are then combined to describe the epithelium completely.

  11. Simple Epithelia • The simple epithelia are most concerned with; -absorption - secretion - filtration **because they are thin protection is not a function**

  12. Simple Squamous Epithelium • A single layer of thin squamous cells. • Cells fit closely together • Forms membranes where filtration or exchange of substances by rapid diffusion occurs. • Found in the following areas: -air sacs of the lungs, forms walls of capillaries, forms serous membranes

  13. Simple Cuboidal Epithelium • One layer of cuboidal cells • Forms: - glands and their ducts(salivary glands and the pancreas), walls of kidney tubules, covers the surface of the ovaries,

  14. Simple Columnar Epithelium • Made up of a single layer of tall cells that fit closely together. • Forms; - Goblet Cells(produce lubricating mucus), lines the entire length of the digestive system

  15. Pseudostratified Columnar Epithelium • Pseudo=false or fake • The appearance of the cells arrangement leads to the look of multiple layers when in fact there is only one. • Function; absorption and secretion • Ciliated version lines the respiratory tract, goblet cells produce mucus to trap dust and debris while the cilia push the mucus away from the lungs

  16. Stratified Epithelium • Consists of two or more cell layers • Considerably more durable then simple epithelia • Functions to Protect

  17. Stratified Squamous Epithelium • Most common stratified epithelium in the body. • Consists of several layers • Found in sites that receive a good amount of abuse or friction like the esophagus, the mouth, and the outer portion of the skin

  18. Stratified Cuboidal Epithelium • Two layers with the cells being cuboidal in shape • Very rare along with stratified columnar epithelium

  19. Stratified Columnar Epithelium • Very rare found only in the ducts of large glands

  20. Transitional Epithelium • Highly modified, stratified squamous epithelium that forms the lining of only a few organs- the urinary bladder, the ureters, and the urethra. • All of these organs are a part of the urinary system and subject to considerable stretching. • The ability of transitional cells to slide past one another and to change shape allows for the urinary system to function properly

  21. Glandular Epithelium • A gland consists of one or more cells that make and secrete a particular product. • This product is called an secretion. • Two major types of glands are formed from epithelial sheets. • Endocrine Glands • Exocrine Glands

  22. Endocrine Glands • Lose their connection to the duct • Their secretions(all hormones) diffuse directly onto the blood vessels that weave through the gland. • Examples include; thyroid, adrenals, and pituitary

  23. Exocrine Glands • Retain their ducts • Secretions empty through the ducts to the epithelial surface • Include; sweat and oil glands, liver and pancreas

  24. Connective Tissue • Connects body parts • Found everywhere in the body • It is the most abundant and widely distributed of the tissue types.

  25. Common Characteristics of Connective Tissue • Variations in blood supply (well vascularized) Exceptions: tendons and ligaments poor blood supply, cartilages are avascular. • Extracellular Matrix-made up of many types of cells and a non-living substance found outside those cells

  26. Extracellular Matrix • Makes connective tissue different then all other tissues. • The matrix is produced by the connective tissue cells and secreted to there exterior. • Matrix may be liquid, semi-solid, gel-like, or very hard

  27. Extracellular Matrix • Because of the matrix, connective tissue can bear weight, withstand stretching, and other abuses that no other tissue could withstand. • One extreme-fat with lots of cells and a soft matrix • Another extreme-bone with few cells and hard matrix

  28. Extracellular Matrix • Various types and amounts of fibers are deposited in and form a part of the matrix. • Examples: Collagen Fibers ( white) • Elastic Fibers (yellow) • Reticular Fibers ( Fine collagen)

  29. Connective Tissue Functions • Protecting, Supporting, and Binding together other body tissues.

  30. Types of Connective Tissues • Bone • Cartilage (3) • Dense connective tissue (2) • Loose connective tissue (2) • Adipose tissue • Reticular connective tissue • Blood

  31. Muscle Tissue • Highly specialized to CONTRACT AND SHORTEN.

  32. Types of Muscle Tissue • Skeletal Muscle • Cardiac Muscle • Smooth Muscle

  33. Skeletal Muscle

  34. Cardiac Muscle

  35. Smooth Muscle

  36. Nervous Tissue • Composed of cells called neurons • All neurons receive and conduct electrochemical impulses from one part of the body to another

  37. Nervous Tissue Function • Irritability and conductivity are two major functions of nervous tissue.

  38. Neuron Structure • Very unique • Cytoplasm stretches out into long extensions that can carry impulses over large areas in the body. • Work with a group of supporting cells that: • Insulate • Support • Protect the delicate structures of the neurons

  39. Tissue Repair • The body has many protective features put into place to help prevent damage or injury. • When injury does occur, it stimulates the body’s inflammatory and immune responses and the healing immediately begins.

  40. Inflammation • A nonspecific response to try and prevent further injury.

  41. Immune Response • An extremely specific response that mounts a vigorous attack against a recognized invader.

  42. 2 Major Ways That Tissue Repair Occurs • Regeneration-the replacement of destroyed tissue by the same kind of cell • Fibrosis- repair by dense connective tissue or the formation of scar tissue

  43. Tissue Repair • The type of tissue repair depends on: • The type of tissue damaged • The severity of the injury **Clean cuts(incisions) heal more quickly than ragged tears(lacerations).

  44. Tissue Injury Events • Capillaries become very permeable which allows fluids rich in clotting proteins to seep into the injured area. • A clot is constructed which stops the bleeding and holds the edges of the wound together.

  45. Events • Clot walls off the injured area preventing bacteria and other harmful substances from getting into the tissue. • The clot that is exposed to air will dry and form a scab. • Granulation Tissue Forms

  46. Events • Granulation tissue is a delicate pink tissue composed largely of capillaries that grow into the damaged area from surrounding healthy blood vessels. • The clot is disposed of and the connective tissue synthesizes collagen fibers(scar tissue) to form

  47. Events 8. Surface epithelium begins to regenerate. 9. Surface epithelium will cover the scar. **the ability for different tissues to regenerate varies widely**

  48. Regeneration • Easily: skin epidermis and mucous membranes, fibrous connective tissue, and bone • Poorly: skeletal muscle • Not at all: cardiac muscle and nervous tissue-replaced only by scar tissue

  49. Developmental Aspects of Cells and Tissues

  50. Developmental • Neoplasm- an abnormal mass of proliferating cells . • Benign • Malignant

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