Tissues: Biology Definitions, Types, and Functions PDF

Chapter 4: Tissues What is a Tissue? Tissues are group of cells similar in structure working together to perform a common function  Epithelial Tissue  Epithelial tissue  Covers exposed surfaces such as skin  Lines internal passageways  Forms glands ...

Chapter 4: Tissues What is a Tissue? Tissues are group of cells similar in structure working together to perform a common function  Epithelial Tissue  Epithelial tissue  Covers exposed surfaces such as skin  Lines internal passageways  Forms glands  Epithelial Tissues  Cover surfaces and provide protection: – skin and lining of cavities  Cell junction is tightly packed to make a barrier  Apical and basal surface: cells are different in structure and function  Apical: They are always on top – Goblet cells: a unicellular gland for secretion – Cilia to move substances – Microvilli to increase surface area for absorption and secretion – Keratinized: dead cells filled with protein Keratin to help against abrasion, such as skin  Epithelial Tissues  Basal surface: They have a basement membrane – Basement membrane: - Made of collagen and glycoprotein - Helps attach the epithelium to the connective tissue underneath - Gives room for cell to go through mitosis - Determines what gets into epithelium from the connective tissue below  Avascularity: no blood vessels. They get blood from connective tissue below through basement membrane  Regeneration : very fast  Nerve endings: usually a lot  Classification of Epithelia  Classes of Epithelia: How do we name them?  Based on shape  Based on layers  Cell Shapes Based on shape - Squamous epithelia: thin and flat - Cuboidal epithelia: square shaped - Columnar epithelia: tall, slender rectangles  Cell Layers Based on layers - Simple epithelium: single layer of cells - Stratified epithelium: several layers of cells - Named according to the cells at the free surface  Classification of Epithelia  Squamous Epithelia  Simple squamous epithelium  Absorption, diffusion, reduce friction: lung, kidney tubules  Mesothelium  Lines body cavities  Endothelium  Lines heart and blood and lymphatic vessels  Simple Squamous Absorption, diffusion, reduce friction  Simple Squamous Absorption, diffusion, reduce friction  Simple Cuboidal  Secretion and absorption – Gland, ducts, kidney tubules  Simple Columnar  Absorption and secretion – Lining of stomach, intestine, uterine tubes  Stratified Squamous Protects against attacks and abrasions Skin, inside the mouth Keratin protein adds strength and water resistance: skin Figure 4–3 Squamous Epithelia.  Stratified cuboidal epithelia  Sweat ducts and mammary ducts Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Transitional Epithelium  Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage  Appearance changes as stretching occurs  Pseudostratified Columnar  Looks like stratified  Each cell attaches to basement membrane  Not all cells make it to free surface  Respiratory tract  Quiz Epithelial tissues A. lines body cavities B. has a basement membrane at the free surface C. can have blood vessels D. contain cells that do not undergo mitosis  Quiz Epithelial tissues A. lines body cavities B. has a basement membrane at the free surface C. can have blood vessels D. contain cells that do not undergo mitosis  Quiz If an epithelial tissue has cuboidal at basement membrane, cuboidal in the middle, and columnar at the top, this tissue would be called ______ A. Stratified cuboidal B. Stratified columnar C. Simple columnar D. Simple cuboidal  Quiz If an epithelial tissue has cuboidal at basement membrane, cuboidal in the middle, and columnar at the top, this tissue would be called ______ A. Stratified cuboidal B. Stratified columnar C. Simple columnar D. Simple cuboidal  Classification of Epithelia  Glandular Epithelia  Endocrine glands  Release hormones: – into interstitial fluid – no ducts  Exocrine glands (Merocrine)  Produce secretions: – onto epithelial surfaces – through ducts  Classification of Epithelia  Merocrine secretion  Is released by vesicles (exocytosis)  sweat glands, salivary glands, pancreas  Apocrine secretion  Is released by shedding cytoplasm  mammary gland  Holocrine secretion  Is released by cells bursting, killing gland cells  Gland cells replaced by stem cells  sebaceous gland Glands  Quiz Exocrine glands are made up of A. epithelial B. connective C. muscle D. nervous  Quiz Exocrine glands are made up of A. epithelial B. connective C. muscle D. nervous  Connective Tissues Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Connective Tissues  Connect epithelium to the rest of the body (basal lamina)  Provide structure (bone)  Store energy (fat)  Transport materials (blood)  Have no contact with environment Characteristics of Connective Tissue  They have  scattered cell  Matrix – Ground substance – Fibers » Collagen: strong & flexible » Elastic: stretch » Reticular: network of fine collagen fibers  Connective Tissue  Ground substance determines the characteristics of connective tissue. There are few cells in the ground substance.  Blood: ground substance like water  Areolar (always below epithelium tissue) : ground substance has hyaluronic acid that makes it viscous (joint fluid)  Cartilage: ground substance of chondroitin & glucosamine  Bone: ground substance has calcium salt that makes it hard Characteristics of Connective Tissues  Characteristics of Connective Tissues  Vascular (except in cartilage)  Nerve ending  Connective Tissues  Classification of Connective Tissues  Connective tissue proper  Connect and protect  Fluid connective tissues  Transport  Supportive connective tissues  Structural strength Scattered Cells in the Connective Tissues  Fibroblasts – connective tissue proper  Chondroblasts – cartilage  Osteoblasts – bone  Hematopoietic stem cells – blood -White blood cells, plasma cells, macrophages, and mast cells Plasma cells develop from B lymphocytes (B cells), a type of white blood cell that is made in the bone marrow. Normally, when bacteria or viruses enter the body, some of the B cells will change into plasma cells. The plasma cells make antibodies to fight bacteria and viruses, to stop infection and disease. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Lymphocytes Lymphocytes are responsible for many functions, including: Antibody production: B cells produce antibodies that attack bacteria, viruses, and toxins Cell-mediated killing: T cells destroy virus-infected and cancerous cells Immune response regulation: T cells help control immune responses Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Connective Tissues  Connective Tissue Proper Cells  Fibroblasts  The most abundant cell type: – found in all connective tissue proper  Fibrocytes  The second most abundant cell type: – found in all connective tissue proper – maintain the fibers of connective tissue proper  Connective Tissues  Connective Tissue Proper Cells  Macrophages  Large, cells of the immune system: – eat pathogens and damaged cells  Adipocytes  Fat cells  Mesenchymal Cells  Stem cells that respond to injury or infection: – differentiate into fibroblasts, macrophages, etc.  Connective Tissues  Connective Tissue Proper Cells  Melanocytes  Synthesize and store the brown pigment melanin  Mast Cells  Stimulate inflammation after injury or infection: – release histamine and heparin Mast cells play an important role in how the immune system responds to certain bacteria and parasites and they help control other types of immune responses. They contain chemicals such as histamine, heparin, cytokines, and growth factors.  Connective Tissues  Connective Tissue Fibers  Collagen fibers  Most common fibers  Strong and flexible  Resist force in one direction – tendons and ligaments  Connective Tissues  Connective Tissue Fibers  Reticular fibers  Network of interwoven fine collagen fibers  Resist force in many directions  sheaths around organs  Connective Tissues  Connective Tissue Fibers  Elastic fibers  Contain elastin  Return to original length after stretching – elastic ligaments of vertebrae  Connective Tissues  Embryonic Connective Tissues  Are not found in adults  Mesenchyme (embryonic stem cells)  The first connective tissue in embryos  Mucous connective tissue  Loose embryonic connective tissue  Connective Tissues  Loose Connective Tissues  Three types in adults  Areolar  Adipose  Reticular  Areolar Viscous ground substance (hyaluronic acid) Collagen, elastic, and reticular fibers Scattered cells of fibroblast and mast cells Found under epithelial tissue Figure 4.9a  Adipose Ground substance (hyaluronic acid) Prevent heat loss Found around organs and under skin White fat (adults, one droplet of fat per cell) Brown fat (newborn, several fat droplets per cell) Figure 4.9b  Reticular Provides support Supportive fibers (stroma) Support functional cells (parenchyma) Reticular organs: Spleen, liver, lymph nodes, and bone marrow Figure 4.9c  Connective Tissues  Dense Connective Tissues  Dense regular connective tissue  Dense irregular connective tissue  Elastic tissue  Dense Regular Tightly packed, parallel collagen fibers with fibroblast cells Tendons attach muscles to bones Ligaments connect bone to bone Aponeuroses attach in sheets to large, flat muscles Withstands great tensile stress when pulling force is applied in one direction Figure 4.9d  Dense Irregular Interwoven networks of collagen fibers with fibroblast cells Layered in skin, Around cartilages, Around bones Provide strength to resist forces applied from many direction Figure 4.9e  Elastic Tissue Made of elastic fibers Elastic arteries such as Aorta True vocal cords Elastic ligaments of spinal vertebrae Cushion shocks Supportive Connective Tissues  Cartilage  Gel-type ground substance  For shock absorption and protection  No blood vessels or nerve ending  Bone  Calcified (made rigid by calcium salts, minerals)  For weight support  Cartilage  Cartilage Matrix: Chondroitin sulfates  Scattered cells: Chondrocytes in lacunae  Perichondrium: 2 Layers Dense irregular connective tissue covering cartilage Cellular layer  Hyaline cartilage (most common)  Stiff, flexible support  Reduces friction between bones  Found in embryonic skeleton, synovial joints, rib tips, nose, sternum, and trachea Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Fibrous Cartilage (fibrocartilage)  Limits movement, resists compression  Prevents bone-to-bone contact  Pads knee joints (menisci of the knee), between pubic bones and intervertebral discs Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Elastic Cartilage  Supportive but bends easily  Found in external ear and epiglottis Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Supportive Connective Tissues Bone or osseous tissue Strong (calcified: calcium salt deposits) Bone cells or osteocytes Periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces (i.e. the parts within a joint space) of long bones. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fluid Connective Tissues: Blood  Plasma a watery matrix with dissolved proteins  No fibers unless it clots Formed elements of blood RBC (erythrocytes) WBC (leukocytes) platelets  Fluid Connective Tissues: Blood Types of white blood cells Monocytes. They have a longer lifespan than many white blood cells and help to break down bacteria. Lymphocytes. They create antibodies to fight against bacteria, viruses, and other potentially harmful invaders. Neutrophils. They kill and digest bacteria and fungi. They are the most numerous type of white blood cell and your first line of defense when infection strikes. Basophils. These small cells seem to sound an alarm when infectious agents invade your blood. They secrete chemicals, such as histamine, a marker of allergic disease, that help control the body's immune response. Eosinophils. They attack and kill parasites and cancer cells and help with allergic responses. Fluid Connective Tissues: Lymph  In lymph vessels  Immunity  Watery matrix  No fibers  WBC  Quiz Name two types of tissues that don’t have blood vessels A. Epithelial tissues B. Connective tissues C. Dense regular D. Cartilage E. A & D F. A & B Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Quiz Name two types of tissues that don’t have blood vessels A. Epithelial tissues B. Connective tissues C. Dense regular D. Cartilage E. A & D F. A & B Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Muscle Tissue Three types of muscle tissue Skeletal muscle Cardiac muscle Smooth muscle  Muscle Tissue: Skeletal Striated and voluntary Are long and cylindrical Are multinucleated Don’t regenerate well Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Muscle Tissue: Cardiac Striated and involuntary Single nucleus Form branching networks connected at intercalated discs Don’t regenerate Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Muscle Tissue: Smooth Non-striated and involuntary Single nucleus Are small and tapered Regenerates well Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Neural Tissue (Nervous or nerve Tissue) Specialized for conducting electrical impulses Neural tissue is concentrated in the central nervous system Brain Spinal cord  Neural Tissue Two Kinds of Neural Cells Neurons Perform electrical communication Amitotic Neuroglia Supporting cells Repair (mitosis) supply nutrients to neurons  Neural Tissue Mitosis is the process of nuclear division in which chromosomes replicate Become equally distributed into two daughter cells so that these daughter cells have the same number and type of chromosomes as was present in the parent cell. Spindle formation occurs in mitosis. Amitosis is a simple method of cell division Also called direct cell division which occurs without formation of spindle fibers and appearance of chromosomes By 'appearance of chromosomes’ the chromatin network, which is initially present in the form of long threads does not condense to form distinct structures called chromosomes. Neural Tissue Neural Tissue  Membranes Membranes Are physical barriers That line or cover portions of the body Consist of An epithelial tissue Supported by connective tissues: Areoler  Membranes Four Types of Membranes Mucous membranes Serous membranes Cutaneous membrane Synovial membranes  Mucous Membranes (mucosa) Line passageways that have external connections with an different epithelial tissue Always have Goblet cells Epithelial surfaces must be moist: To reduce friction & facilitate absorption and excretion Lamina propria is areolar tissue  Mucous Membrane Mucous – lines passage-ways that open to the exterior (e.g., digestive and respiratory tracts) Figure 4.12b  Serous Membranes  Secretes watery fluid  Always has simple squamous epithelial and Areolar  Line cavities not open to the outside  Reduce friction  Have a parietal portion covering the cavity  Have a visceral portion (serosa) covering the organs  Membranes  Three Serous Membranes  Pleura:  Lines pleural cavities  Covers lungs  Peritoneum:  Lines peritoneal cavity  Covers abdominal organs  Pericardium:  Lines pericardial cavity  Covers heart Serous Membranes Serous – moist membranes found in closed ventral body cavity Figure 4.12c  Synovial Membranes  Mostly areolar tissue with few cells on top  Line moving, articulating joint cavities  Produce synovial fluid (lubricant) /Hyaluronic acid  Protect the ends of bones  Cutaneous Membrane Cutaneous – skin It is an organ system consisting of keratinized stratified squamous epithelium. It is a dry membrane  Tissue Repair Inflammation and migratory phase- bleeding and dilation of the blood vessels to increase blood flow. Mast cells release histamine. Brings in plasma with antibodies and clotting factors. Signs of inflammation: Swelling Redness Heat Pain  Tissue Repair  Granulation (proliferation) phase- building of new blood vessels, and layers of connective tissue.  Fibroblasts lay down new collagen fibers  Tissue Repair  Maturation (Regeneration/Scarring) phase Regeneration: same type of cells replaced. Restores normal function to tissue. Surface of a cut is regenerated.  Tissue Repair  Fibrosis: damaged tissue replaced with scar tissue, mainly collagen. Normal function not restored.  Parenchyma vs. stroma Parenchyma: lead to functional, regenerated cells Stroma: Fibroblast cells make the tissue causing Fibrosis.