Tissues_PPT edited PDF

Tissues By: Dr. Pamela Paynter-Armour  Objectives Identify the four primary types of tissue Describe the structure and function of the four primary types of tissue Describe the four types of epithelial membranes Explain the process of tissue repair Outline the deve...

Tissues By: Dr. Pamela Paynter-Armour  Objectives Identify the four primary types of tissue Describe the structure and function of the four primary types of tissue Describe the four types of epithelial membranes Explain the process of tissue repair Outline the developmental aspects of tissues  Tissues Defined What is a tissue? A group of cells with similar structure and function plus extracellular substance (matrix) Histology: The study of tissues ¹  Extracellular Matrix (ECM) Functions Helps bind tissues together structurally ECM components bind to each other and to integrins (receptors) in plasma membranes of cells In some tissues, it is primarily intercellular junctions that hold cells together Allows local communication among ECM and various cells— through connection via integrins in plasma membranes 5  Extracellular Matrix (ECM) Components Water Proteins  Structural proteins Collagen—strong, flexible protein fiber Elastin—elastic fibers  Includes glycoproteins—proteins with a few carbohydrate attachments Help connect the ECM components to cells by binding with integrins in plasma membranes Glycoprotein attachments also allow local communication within a tissue 5  Types of Tissues 1. Epithelial 2. Connective 3. Muscular 4. Nervous ¹ 6  Epithelial Tissues Location: - cover body (internal and external) - Ex. Skin, kidney, trachea, glands, etc. ¹ 7  2 ² ²  Characteristics of Epithelial Tissues Epithelial Tissues: - cells close together (very little extracellular matrix) - form most glands - have free surface – Apical surface - Basal surface: 10 attaches epithelial cells to underlying tissues  Functions of Epithelial Tissues 1. Protect: Ex. Skin 2. Act as a barrier: Ex. Skin keeps bacteria out 3. Diffusion and Filtration: Ex. Lungs and kidneys 4. Secretion: Ex. Sweat glands 5. Absorption: Ex. Small intestine ¹ 12  Classification of Epithelial Tissue Classified according to number of cell layers and cell shape Simple and stratified = number of cell layers Squamous, cuboidal, columnar, transitional= cell shape 13  Types of Epithelial Tissues-No. of Layers Simple Epithelium Structure: 1 layer of cells Stratified Epithelium Structure: many layers of cells ¹ 14  Types of Epithelial Tissues-Shape of Cells Squamous Cuboidal Columnar  Types of Simple Epithelial Tissues Simple Squamous Structure: 1 layer of flat, tile-like cells Function: diffusion and filtration Location: blood vessels, lungs, kidneys Simple Cuboidal Structure: 1 layer of square-shaped cells Function: secretion Location: glands, ovaries, kidneys ¹ 16 17 18  Types of Simple Epithelial Tissues Simple Columnar Structure: 1 layer of tall, narrow cells Function: secrete mucus and absorption Location: stomach, intestines, resp. tract Pseudostratified Columnar Structure: 1 layer of tall, narrow cells appears stratified but isn’t Function: secrete mucus and propel debris out of resp. tract (cilia) Location: nasal cavity and trachea ¹ 19 20 21 Simple Epithelium  Simple cuboidal  Simple columnar  Single layer of Single layer of elongated cells cube-like cells Nuclei usually near the  Common in basement membrane at same glands and their level ducts Sometimes possess cilia Sometimes possess microvilli  Forms walls of kidney tubules Often have goblet cells Line uterus, stomach,  Covers the intestines ³ ovaries  Types of Stratified Epithelial Tissues Stratified Squamous Structure: many layers of flat, tile-like cells Function: protect and acts as a barrier Location: skin, mouth, throat, esophagus Transitional Structure: special type of stratified epi. changes shape (stretched squamous, not stretched cuboidal) Function: hold fluids Location: urinary bladder ¹ 23 24 25 Types of Stratified Epithelial Tissues Stratified cuboidal 2-3 layers Cube-shaped cells Line ducts of mammary glands, sweat glands, salivary glands, and the pancreas Stratified columnar Top layer of elongated cells Cube-shaped cells in deeper layers Line part of male urethra and part of pharynx 27 28  Free Cell Surfaces Surface not in contact with other cells Smooth to reduce friction, Ex. Blood vessels Microvilli: - increase cell’s surface area - Ex. Small intestine¹ 30  Free Cell Surfaces Cilia: - move materials across cell’s surface - Ex. Trachea Goblet cells: - produce mucus - Ex. Stomach¹ 31  Cell Connections Tight junctions: - bind adjacent cells together - Ex. Intestines Desmosomes: mechanical links that bind cells¹ 32  Cell Connections Hemidesmosomes: bind cells to basement membrane Gap junctions: - small channels that allow molecules to pass between cells - allow cells to communicate¹ 33 Figure 4.2 Connective Tissue Connective Tissue ² Connective Tissue ²  Connective Tissues Characteristics Cells far apart Contain large amounts of extracellular matrix Classified based on type of extracellular matrix and function Ex. Blast cells build, clast cells carve Extracellular matrix contains 3 components (in varying amounts): protein fibers, ground substance, cells¹ Ground substance: mostly water along with adhesion proteins and polysaccharide molecules 38  Connective Tissue Fiber Types Collagenous fibers Thick Elastic fibers Composed of collagen Bundles of microfibrils Great tensile strength embedded in elastin Abundant in dense CT Fibers branch Hold structures together Elastic Tendons, ligaments Vocal cords, air passages Reticular fibers Very thin collagenous fibers Highly branched Form supportive networks 3  Connective Tissue Major Cell Types Macrophages Fibroblasts Wandering cell Fixed cell Phagocytic Most common cell Important in injury or Large, star-shaped infection Produce fibers Other Blasts Mast cells Chondroblast Fixed cell Osteoblast Release heparin Hemocytoblast Release histamine3 40  Functions of Connective Tissue 1. Enclose and separate: Ex. around organs and muscles 2. Connect tissues: Ex. Tendons: connect bone to muscle Ex. Ligaments: connect bone to bone 3. Support and Movement: Ex. bones ¹ 41  Functions of Connective Tissue 4. Storage: Ex. bones store calcium and adipose tissue stores fat 5. Cushion and insulate: Ex. adipose tissue protects organs and helps conserve heat 6. Transport: Ex. Blood 7. Protect: Ex. Immune cells¹ 42  Connective Tissue ConnectiveTissue Proper: Specialized Connective Loose connective tissue Tissue: Areolar connective tissue Cartilage Adipose tissue Bone Reticular connective tissue Blood Dense connective tissue Regular Irregular Elastic³ 43 Connective Tissue Types -Loose connective tissue  Areolar connective tissue  Most widely distributed connective tissue  Soft, pliable tissue  Contains all fiber types  Can soak up excess fluid⁴ Connective Tissue Types -Loose connective tissue  Adipose tissue  Matrix is an areolar tissue in which fat globules predominate  Many cells contain large lipid deposits  Functions  Insulates the body  Protects some organs  Serves as a site of fuel storage⁴  Connective Tissue Types -Loose connective tissue  Reticular connective tissue  Delicate network of interwoven fibers  Forms stroma (internal supporting network) of lymphoid organs  Lymph nodes  Spleen  Bone marrow⁴ 47 48  Connective Tissue Types  Dense connective tissue  Main matrix element is collagen fibers  Regular, Irregular and Elastic  Cells are fibroblasts  Examples  Tendon – attach muscle to bone  Ligaments – attach bone to bone⁴ 50 Specialized Connective Tissue Types  Cartilage Type of connective tissue Composed of chondrocytes Contains collagen Withstands compressions Provides support, flexibility, strength ¹ 52  Types of Cartilage Hyaline cartilage Location: covers ends of bones Structure: some collagen fibers Function: reduces friction (cushion) Fibrocartilage Location: between vertebra Structure: lots of collagen fibers Function: can withstand compression ¹ 53  Types of Cartilage Elastic cartilage Location: ear and tip of nose Structure: elastic fibers Function: can recoil ¹ 54  Bone Hard connective tissue 2 types: compact and spongy Composed of osteocytes¹ 57  Blood Liquid connective tissue Erythrocytes, leukocytes, platelets Transport food, oxygen, waste, hormones¹ 59 Muscular Tissue  Muscular Tissue Muscle type Nucleus/i Nucleus/i location Striated Skeletal (most muscle) many peripheral Yes Cardiac (heart) 1 centrally Yes Smooth (organs) 1 centrally No¹ 62 Skeletal Muscle Cardiac Muscle Table Art 4.11b Smooth Muscle Table Art 4.11c Nervous Tissue  Nervous Tissue Consist of neurons or nerve cells Found in brain, spinal cord, and peripheral nerves Controls and coordinates body movements Includes axons, dendrites, cell bodies¹ 67 68 Epithelial Membranes  Types of Membranes There are four (4) types of epithelial membranes: 1. Serous Membranes 2. Mucous Membranes Line body cavities Line tubes and that do not open to organs that open to the outside outside world Reduce friction Lining of mouth, Inner lining of thorax nose, throat, etc. and abdomen Secrete mucus Cover organs of thorax and abdomen Secrete serous fluid 4. Synovial Membranes 3. Cutaneous Membranes Composed entirely of Covers body connective tissue Skin Lines joints ³ 70 Glands  Glands What are they? Structures that secrete substances onto a surface, into a cavity, or into blood Exocrine glands: - glands with ducts - Ex. Sweat or oil glands Endocrine glands: no ducts (directly into bloodstream) Ex. Thyroid, thymus, pituitary glands, etc. ¹ 75  Types of Exocrine Glands Simple: no branches Compound: many branches Tubular: end of duct Alveolus: sac-like structure¹ 76  Types of Glandular Secretions Merocrine Glands Apocrine Glands Holocrine Glands Fluid product Portions of cells Whole cells Salivary glands Pinches off Rupture Pancreas gland Mammary glands Sebaceous glands³ Sweat glands Ceruminous glands Exocytosis Pinched off Disintegrating cell portion of cell and its contents Intact (secretion) (secretion) cell Secretion New cell forming by mitosis and cytokinesis 77 (a) Merocrine gland (b) Apocrine gland (c) Holocrine gland  Tissue Repair What is it? Substitution of dead cells for viable cells Regeneration: Cells of same type develop (no scar) Replacement: Cells of a different type develop (scar) ¹ 78  Inflammation Occurs when tissues are damaged Signals the body’s defenses (white blood cells) to destroy foreign materials and damaged cells so repair can occur. Chemical mediators: - released after injury - cause dilation of blood vessels¹ 79  Symptoms of Inflammation 1. Redness: blood vessels dilate 2. Heat: due to increased blood flow 3. Swelling: from water and proteins 4. Pain: nerve endings are stimulated by damage and swelling¹ 5. Loss of Function: occurs over joints 80 Developmental Aspects  Developmental Aspects Primary germ layers: ectoderm, mesoderm, and endoderm Figure 4.13 Developmental Aspects of Tissue  Epithelial tissue arises from all three primary germ layers  Muscle and connective tissue arise from the mesoderm  Nervous tissue arises from the ectoderm  With old age there is a decrease in mass and viabililty in most tissues⁴  Developmental Aspects By end of second month of development, all primary tissues have appeared With old age, the amount of collagen declines, making tissue repair less efficient Summary Identify the four primary types of tissue Describe the structure and function of the four primary types of tissue Describe the four types of epithelial membranes Explain the process of tissue repair Outline the developmental aspects of tissues