The Tissue Level Of Organization And It's Types Flashcards

Four types of tissues 1. Epithelial tissue - covers exposed surfaces, lines internal passageways and chambers and forms glands. 2. Connective tissue - fills internal spaces, provides srtuctural support for other tissues, transports materials and stores energy reserves. 3. Muscle tissue - spezialized for contraction 4. Neural tisse - carries information in terms of electrical impulses. Epithelial tissue Consists of Epithelia - layers of cells that cover internal or external surfaces. Glands - structures that produce fluid secretions; either attached to or derived from epithelia. Characteristics of epithelia *Cellularity - cells very closely together by cell junctions. *Polarity - *Attachment - epithelia is attached to basal lamina. *Avascularity - lacks blood vessels. *Regeneration - Functions of Epithelial Tissue 1. Provide physical protection - . 2. Control permeability - . 3. Provide sensations - . 4. Produce specialzed secretions - . Microvilli Covers epithelial cells that line internal passageways on their exposed surfaces. Abundant where absorbtion and secretion takes place, digestive and urinary tract. Cilia Moves substances over epithelial surface by synchronized beating - respiratory tract. Factors that help maintain the physical integrity of an epithelium -3 1) Intracellular connections 2) attachment to the basal lamina 3) epithelial maintenance and repair A basal lamina Attaches epithelia to underlying connective tissues. Three major types of cell junctions 1) Occluding junctions (tight) 2) Gap junctions 3) Macula adhernes (desmosomes) Occluding junction (tight junction) Prevents the diffuesion of fluids and solutes between cells. Gap junction Permits the free diffusion of ions and small molecules between two cells. Macula adhernes (desmosomes) Provides durable interconnections. Very strong and can resist stretching and twisting. Formed by two cells. Within each cell is a complex dense area, which is connected to the cytoskeleton - gives epithelium its strenght. Abundant in superficial layers of the skin. As a result skin is lost in sheets rather than cells. Two types: Spot desmosome and Hemidesmosome. Spot desmosome kj Hemidesmosomes Attaches a cell to extracellular filaments in the basal lamina. This helps stabilze the position of the epithelial cell and anchors it to underlying tissues. Epithelial maintenance and repair Continual division of stem cells, also called germinative cells. Located near the basal lamina. The squamos epithelium Very thin, body's most delicate epithelium. Located in protected areas where absorption or diffusion takes place. Alveoli of the lungs, ventral body cavities (mesothelium), lining of the heart and blood vessels (endothelium). A stratified squamos epithelium Located where mechanical stresses are severe - surface of the skin, lining of the mouth, esophagus, anus. urface cells are flat and dead. Keratinized - apical layers of epithelial cells contain keratin, keeps it tough and water resistent. Nonkeratinized - will dry out unless kept moist - oral cavity, anus, vagina. Simple cuboidal epithelium Provides limited protection. Occurs where secretion or absorption takes place - kidney tubules. Stratified cuboidal epthelia Rare, located along ducts of sweat glands and in the larger ducts of the mammary glands. A transitional epithelium An unusual stratified epithelium - tolerates repeated cycles of stretching and recoiling without damage. Occurs in urinary bladder, ureters, part of urethra. Simple columnar epithelium Found where absorption or secretion occurs - small intestine, stomach, large intestine. Pseudostratified columnar epithelium Columnar epithelium that includes several types of cells with varying shapes and functions. Possess cilia. Portions of the respiratory tract - most of the nasal cavity, the trachea, the bronchi and portions of the male reproductive tract. Stratified columnar epithelia Rare. Provides protection along portions of the pharnyx, anus and urethra. Glands Epithelial cells that produce secretions. Endocrine glands - release their secretions into the interestial fluid - hormones. Exocrine glands - release their secretions into passageways called ducts that open into an epithelial surface - tears, milk, perspiration, earwax, saliva, and digestive enzymes. Exocrine glands modes of secretion 1) Merocrine secretion - most common, mucus secretion of the salivary gland coat food and reduce frictionm in the skin produce perspiration. 2) Apocrine secretion - involves the loss of the cytoplasm as well as the secretory product - milk. 3) Holocrine secretion - destroys the gland cell. The entire cell becomes packed with secretion and then bursts, releasing the secretion but killing the cell - hair follicles. Types of secretions 1) Serous gland - secretes watery solution that contain enzymes - parotid salivary gland. 2) Mucous gland - secretes mucins that hydrate to form mucus - sublingual salivary gland, submucosal gland of the small intestine. 3) Mixed exocrine gland - contain more than one type of gland cell - submandibular salivary gland. Connective tissue Connects the epithelium to the rest of the body. Bone, fat, blood, lymph, loose connective, dense connective tissue. Functions of the connective tissue Protects the body and its organs, binds organs together, stores energy reserves as fat, and provides immunity to disease-causing organisms. Connective tissue matrix Part of connective tissue that prevents tissue cells from touching one another. It is made by fibroblasts and can be fluid, semifluid, gelatinous, fibrous, or calcified. Is made up of the ground substance and fibers Ground substance A componant of connective tissue matrix that is between the cells and fibers. It supports and binds, and provides a medium for material exchange between blood and cells. Connective tissue proper Syrupy ground substance. Contains extracellular fibers and a varied cell population - fibroblasts, fibrocytes, adipocytes and mesenchymal cells - function in local maintenance, repair and energy storage - permanent residents. Macrophages, mast cells, lymphocytes, microphages, defend and repair damaged tissues. 1) Loose connective tissues - lets skin move - areolar, adipose and reticular. 2) Dense connective tissues - tendons and ligaments. Fibroblast Component of connective tissue proper. Always present, most abundant. Secrete hyaluronan and proteins. Fibrocytes Component of connective tissue proper. econd most abundant. Maintain the connective tissue fibers of connective tissue proper. Macrophages Component of connective tissue proper. Large, amoeboid cells scattered in the matrix. Engulf pathogens or damaged cells that enter the tissue. Release chemicals that attract large numbers of additional macrophages and other cells involved in tissue defense. 1) Fixed macrophages - spend long periods in tissues. 2) Free macrophages - migrate rapidly through tissues. Adipocytes Component of connective tissue proper. Fat cell, contains a single, enormous lipid droplet. Mesenchymal cells Component of connective tissue proper. Stem cells that are present in many connective tissues. Respond to local injury or infection by dividing to produce daughter cells that differentiate into fibroblasts or macrophages. Melanocytes Component of connective tissue proper. Synthesize and store the brown pigment melanin, which gives tissues dark color. Abundant in epithelium of the skin, eye and the dermis of the skin. Mast cells Component of connective tissue proper. Common near blood vessels. The cytoplasm is filled with histamine (stimulates local inflammation) and heparin. Lymphocytes Component of connective tissue proper. Migrate throughout the body. Numbers increase wherever tissue damage occurs. Some develop into plasmocytes which produce antibodies. Microphages Component of connective tissue proper. Neutrophils and eosinophils - blood cells, normally in low numbers. Infection causes macrophages and mast cells attract numerous microphages to the site. Connective tissue fibers Fibroblasts form all three by secreting protein subunits that interact in the matrix. Fibrocytes are responsible for maintaining therse connecture tissue fibers. Collagen, Reticular, Elastic. Collagen fibers Long, straight and unbranched. Most common, each consists of a bundle of fibrous protein subunits wound together like the strans of rope. Flexible, but it is stronger that steel when pulled from either end. Tendons, ligaments. What connects skeletal muscles to bones? Tendons What connects one bone to another? Ligaments. Reticular fibers Contain the same protein subunits as collagen fibers but arranged differently. Form a branching, interwooven framework (stroma) that is tough, yet flexible. Resist forces applied from many directions.Stabilize the positions of an organ's blood vessels, nerves and other structures. Elastic fibers Contain the protein elastin. Branched and wavy. After stretching, they will return to their original length. Interconnecting of vertebrae. Ground sunstance Fills the spaces between cells and surrounds connective tissue fibers.Dense enough that bacteria have trouble moving through it. Mesenchyme or embryonic connective tissue First connective tissue to appear in a developing embryo. Contains stem cells (mesenchymal cells) separated by a matrix. Gives rise to all other connective tissues. Loose connective tissue Fill spaces between organs, cushion and stabilize specialized cells in many organs, and support epithelia. Provide a route for the diffusion of materials. Areolar tissue, adipose tissue and reticular tissue. Areolar tissue Open framework, very loosly organized array, a viscous ground substance accounts for most of it volume and absorbs shocks. Returns to its original shape after external pressure is relieved. Forms a layer that separates the skin from deeper structures. Extensive blood supply. common injection site. Capillaries in areolar tissue deliver oxygen and nutrients and remone CO2. Adipose tissue Provides paddin, absorbs shocks, acts as an insulator to slow heat loss through skin, and serves as packing or filler around structures. Fills the bony sockets behind eyes, surrounds the kidneys. Metabolically active cells - their lipids are being broken down and replaced. Reticular tissue Reticular fibers create a three-dimentional stroma. The stroma supports the parenchyma (functional cells) of these organs - spleen, liver, lymph nodes and bone marrow. Dense conective tissue or collagenous tissues Occupied by fibers - mostly collagen. 1) Dense regular connective tissue 2) Dense irregular connective tissue Dense regular connective tissue Collagen fibers are parallel to each other, packed tightly and aligned with the forces applied to the tissue. Provides firm attachement; conducts pull of muscles, reduces friction between muscles, stabilizes relative positions of bones - between skeletal muscls and skeleton (tendons and aponeuroses), ligaments, covering skeletal muscles. Dense irregular connective tissue Fibers form interwoven meshwork in no consistent pattern. These tissues stregthen and support areas subjected to stresses from many directions. Gives skin its strenght. Forms a sheat around cartilages and bones and thick fibrous layer called a capsule which surrounds internal organs such as the liver, kidneys and spleen and encloses the cavities of joints. Helps prevent overexpansion - urinary bladder. Fluid connective tissue Blood an lymph. Distinctive populations of cells suspended in a watery matrix that contains dissolved proteins. Aponeurosis Tendinous sheet that attaches a broad, flat muscle to another muscle or to several bones of th skeleton. It can also stabilze the positions of tendons and ligaments. Associated with large muscles of the skull, lower back, abdomen, and with tendons and ligaments of the palms of the hands and the soles of the feet. The matrix of cartilage Firm gel that contains polysaccharide derivatives called chondroitin sulfates. Cartilage cells, or chondrocytes are the only cells in the cartilage matrix. They occupy lacunae. Avascular, so exchange of nutrients and wastes occurs through diffusion. Cartilage growth 1) Interstitial growth - chondrocytes undergo cell division and daughter cells produce additional matrix. Enlarges the cartilage from within. Most important during development. 2) Apositional growh - New layers are added to the surface 3 types of cartilage 1) Hyaline cartilage 2) Elastic cartilage 3) Fibrous cartilage Hyaline cartilage Most common. Provides stiff but somewhat flexible support, reduces friction between bony surfaces - between tips of ribs and bones of sternum. Matrix contains closely packed collagen fibers. Covers bone surfaces at synoival joints, forming part of nasal septum. Elastic cartilage Provides support, but tolerates distortion without damage and returns to original shape. Contains numerous elastic fibers that make it extremely resilient and flexible. Auricle, auditory tube. Fibrous cartilage Resists compression, prevents bone-to-bone contact, limits relative movement. Little ground substance and matrix is dominated by densely interwoven collagen fibers - extremely durable and tough. Heals poorly. Pads within knee joint, between pubic bones of pelvis, intervertebral discs. What is membrane and 4 different types of membrane. Physical barrier. Line or cover body surfaces. Each consists of an epithelium supported by connective tissue - mucous membranes, serous membranes, cutaneous membrane and synoival membrane. Musous membrane Line passageways and chambers that communicate with the exterior - digestive, respiratory, reproductive and urinary tracts. The epithelial surface must be kept wet to reduce friction - mucus, urine, semen. Serous membrane Line the sealed, internal subdivisions of the ventral body cavity - not open to the exterior. Pleura (lungs), peritoneum (peritoneal cavity organs), pericardium (heart). Very thin, Primary function is to minimize friction between the opposing parietal and visceral surfaces. Cutaneous membrane Skin, covers the surface of the body. Thick, relatively waterproof and usually dry. Synoival membrane Lines the joint cavity . Composed of dense connective tissue, loose connective tissue, and adipose. Found in joint cavities; knee, elbow. Excrete synoival fluid. Fasciae Connective tissue layers ad wrappings that support and surround orgas. The superficial fascia, the deep fascia, the subserous fascia. The superficial fascia or hypodermis Layer of areolar tissue and fat separates the skin from underlying tissues and organs, provides insulation and padding and lets the skin and underlying structures move independently. The deep fascia Consiss of dense irregular connective tissue. Fibers are organized in plywood - in each layer all the fibers run in the same direction but orientation changes from layer to layer. Helps the tissue resist forces applied from many directions. The subserous fascia Layer of areolar tissue that lies between the deep fascia and the serous membranes that line body cavities. Skeletal muscle tissue Large cells in lenght, also called muscle fibers, multinucleate, can't divide. New cells are produced through the divisions of mypsatellite cells, stem cells that persist in adult skeletal muscle tissue. Cytoskeleton contains actin and myosin filaments. Moves or stabilizes the position of the skeleton, guards entrances and exits to the digestive, respiratory and urinary tracts, generates heat, protects internal organs. Voluntary. Cardiac muscle tissue Short cells - cardiocyte, branched, usually with single nucleus, the actin and myosin filaments are arranged the same way as in skeletal muscle, Pacemaker cells establish a regular rate of contraction - involuntary, located in heart. Circulates blood, maintaines blood (hydrostatic) pressure. Smooth muscle tissue Located in the walls of blood vessels, around hallow organs - urinary bladder, digestive and reproductive tracts. Cells is small, single nucleus. Can divide.Actin and myosin filaments are arranged differently - no striations. Involuntary. Moves food, urine and reproductive tract secretions, regulates diameter of blood vessels. Neural tissue Specialized for the conduction of electrical impulses from one region of the body to another. Contains two types of cells - neurons ( longest cells in the body, can't divide, has a large cell body with large nucleus and a prominent nucleolus) and neuroglia ( supports neural tissue and helps supply nutrients to neurons). The response to tissue injury involves? Inflammation - swelling, redness, warmth and pain. This stimuli kills cells, damages fibers. Tissue destruction - necrosis, occurs caused by lysosomal enzymes. Mast cells release histamine, heparin and prostaglandins that trigger changes in local circulation. Regeneration - damaged tissues are replaced or repaired to restore normal function. Fibroblasts move in and lay down collagen fibers producing scar tissue which is being remodelled over time. Both are controlled at the tissue level. Abscess The accumulation of pus (debris, fluid, dead and dying cells and neurotic tissue components collectively) within an enclosed tissue space. A type of junction common in cardiac and smooth muscle tissues is the Gap junction The most abundant connections between cells in the superficial layers of the skin are Macula adherens __________ epithelium are found where mechanical and chemical stresses are common Stratified squamous What cell is the most abundant in connective tissue proper? Fibroblasts Which of the following represents the correct order of structures if you are moving from the outside in? cutaneous membrane, superficial fascia, deep fascia, subserous fascia, serous membrane Glandular epithelia contain cells that produce: Exocrine or endocrine secretions The three basic components of all connective tissues are: Specialized cells, extracellular protein fibers, and ground substance Tendons are cords of dense regular connective tissue that Attach skeletal muscles to bones Ligaments are bundles of elastic and collagen fibers that Connect one bone to another bone The three major subdivisions of the extracellular fluid in the body are Plasma, interstitial fluid, and lymph