Lab. Act 3 Epithelial, Connective, Muscle, Nerve Tissues PDF

 Is a group of cells with similar structure & function Histology is the microscopic study of tissue structure Surrounded by or embedded in a complex extracellular material called the matrix Knowledge of tissue structure & function is important in under- standing the next hi...

 Is a group of cells with similar structure & function Histology is the microscopic study of tissue structure Surrounded by or embedded in a complex extracellular material called the matrix Knowledge of tissue structure & function is important in under- standing the next higher level of body organizations Four basic types: epithelial, connective, muscle & nervous tissues  epi = upon, over, on top Is the lining, covering & glandular tissue of the body Functions: protection, secretion, absorption, acts as barrier, permits the passage of substances Classified according to : shape & number of layers Shape: squamous, cuboidal, columnar Number of layers: simple & stratified Pseudostratified & transitional SIMPLE SQUAMOUS EPITHELIUM Single layer of thin, flat cells resting on a basement membrane Function: diffusion, filtration, secretion & protection Location: lining of blood vessels, alveoli of the lungs, portions of the kidney tubules, lining of serous membranes of body cavities (pleural, pericardial, peritoneal) SIMPLE CUBOIDAL EPITHELIUM Single layer of cube-shaped like cells resting on a basement membrane (some have microvilli or cilia) Function: secretion, absorption & movement Location: kidney tubules, glands and ducts; lining of terminal bronchioles of the lungs; & surface of the ovary SIMPLE COLUMNAR EPITHELIUM Single layer of tall, thin cells that fit closely together (some have microvilli or cilia) Function: secretion, absorption & movement of particles Location: glands and some ducts, bronchioles of lungs, uterus, uterine tubes, stomach, intestines, gallbladder, bile ducts & ventricles of the brain PSEUDOSTRATIFIED COLUMNAR EPITHELIUM pseudo = false Appears stratified or layered but not A layered effect occurs because the cell nuclei are at two or more levels in the row or aligned cells touching the basement membrane Cells are almost always ciliated and are associated with Goblet cells that secrete mucus onto the free surface Function: synthesize & secrete mucus Location: lines the passages of respiratory system STRATIFIED SQUAMOUS EPITHELIUM A thick epithelium consists of several layers of cell The deepest cells are cuboidal or columnar & are dividing & producing new cells that are pushed to the surface that becomes flat & thin Keratinized squamous epithelium Location: keratinized - outer layer of the skin; non-keratinized – mouth, throat, larynx, esophagus, anus, vagina, inferior urethra, & corneas Function: protects against abrasion, forms a barrier against infection & reduce loss of water from the body STRATIFIED CUBOIDAL EPITHELIUM Consists of two or three layers of cuboidal cells that form the lining of the lumen Function: absorption, secretion & protection Location: sweat glands, ovarian follicular cells, the salivary glands, pancreas & larger ducts of mammary glands STRATIFIED COLUMNAR EPITHELIUM one or more layer of epithelial cells; but the surface cells are columnar and the deeper layers are irregular or cuboidal in shape Function: absorption, secretion & excretion Location: mammary gland ducts, larynx, and portion of the male urethra TRANSITIONAL EPITHELIUM Special type of stratified epithelium that can be greatly stretched Specialized to change in response to tension Function: accommodate fluctuation of volume of the liquid in an organ Location: urinary bladder, ureter, urethra  Is the most abundant & widely distributed tissue Is found throughout the body Usually characterized by large amounts of extracellular material Tissue that bind structures, provides support & protection, serve as frameworks, fill spaces, store fat, produce blood cells, protect against infections & help repair tissue damage; they can divide Three types: connective tissue proper (loose & dense), supporting connective tissue (cartilage & bones) & fluid connective tissue (blood)  Cells are either fixed cells (resides in the tissue for an extended period of time) like fibroblasts & mast cells; and wandering cells (move through & appear in tissues temporarily, usually in response to an injury or infection) like macrophages  Major cell types: fibroblasts (large star-shaped cells produce fibers by secreting proteins) are the most common type of fixed cells; macrophages or histiocytes (originate as white blood cells specialized on phagocytosis) and mast cells (located near blood vessels; releases heparin that prevents blood clotting & histamine associated with inflammation and allergies) LOOSE CONNECTIVE TISSUE Consists of relatively few protein fibers that form a lacy network, with numerous spaces filled with ground substances & fluid This is where the basement membrane of the epithelial tissues often rest Three subdivisions: areolar, adipose, reticular LOOSE CONNECTIVE TISSUE Areolar Tissue Areolar – means “spacious” Forms delicate, thin membranes Has extracellular matrix consisting mostly of collagen fibers & a few elastic fibers The most common cells is fibroblasts (responsible for producing the matrix) Function: support & nourishment Location: glands, muscles & nerves in the skin LOOSE CONNECTIVE TISSUE Adipose Tissue Large cells that are closely packed & a small amount of extracellular matrix Consists of adipocytes or fat cells Contains large amounts of lipid for energy storage mostly of collagen and reticular fibers & a few elastic fibers Acts a s a thermal insulator Function: thermal insulator, energy storage & protection Location: mesenteries, renal pelves, around kidneys, colon surface, mammary glands LOOSE CONNECTIVE TISSUE Reticular Tissue It has a branched and mesh-like pattern, often called reticulum, due to the arrangement of reticular fibers (reticulin) Function & location: forms the framework of lymphatic tissue, such as in the spleen, lymph nodes, and as well as in bone marrow & liver DENSE CONNECTIVE TISSUE Consists of many closely packed, thick, collagenous fibers & a fine network of elastic fibers; it has relatively few cells mostly fibroblasts Two major categories: collagenous & elastic DENSE CONNECTIVE TISSUE Dense Regular Collagenous Connective Tissue The collagen fibers are oriented in the same direction like in tendons and ligaments Dense Irregular Collagenous Connective Tissue The fibers are oriented in many different directions as in the dermis and organ capsules DENSE CONNECTIVE TISSUE Dense Regular Elastic Connective Tissue Matrix of collagen fibers & elastic fibers are oriented in the same direction like in the vocal cords SUPPORTING CONNECTIVE TISSUE Cartilage Composed of chondrocytes (cartilage cells) located in spaces called lacunae (small spaces) Resilient & relatively rigid Provides support Three types: hyaline cartilage, fibrocartilage & elastic cartilage SUPPORTING CONNECTIVE TISSUE Cartilage Hyaline Cartilage Clear or glassy; the most abundant type of cartilage Covers the ends of bones where they come together to form joints Fibrocartilage Has more collagen than hyaline cartilage Found in the disks between vertebrae and some joints (knee and jaw) SUPPORTING CONNECTIVE TISSUE Cartilage Elastic Cartilage Contains elastic fibers in addition to collagen & proteoglycans Able to return to its original shape after being stretched Provides rigidity with even more flexibility; found in the external ears, epiglottis & auditory tubes SUPPORTING CONNECTIVE TISSUE Bone Hard connective tissue that consists of living cells & mineralized matrix Osteocytes, bone cells within the lacunae Supports & protects tissues & other organs Two types: compact bone & spongy bone Spongy or Cancellous bone SUPPORTING CONNECTIVE TISSUE Blood A specialized form of connective tissue made up of blood cells & is surrounded by a non-living fluid called plasma Conveyed by the arteries & veins & pumped by the heart; it is usually generated in the bone marrow It functions to deliver nutrients & oxygen to the cells & transports waste away from the same cells  Is a specialized tissue which functions for contraction Controls the movements of an organism as well as many other contractile functions Composed of long, cylindrical cells called muscle fibers or muscle cells or myocytes Muscle cells are living cells Three types: skeletal muscle tissue, cardiac muscle tissue and smooth muscle tissue SKELETAL MUSCLE TISSUE Striated (alternating series of bands or stripe), voluntary muscle Muscle fibers are long cylindrical & multinucleated Are usually attached to the skeletal system via tendons to maintain posture & control movement CARDIAC MUSCLE TISSUE Striated, involuntary muscle Muscle fibers are short branching fibers; have a single centrally located nucleus ONLY found in the heart where cardiac contractions pump blood throughout the body & maintain blood pressure are fused end-to-end by intercalated disks SMOOTH MUSCLE TISSUE Non-striated, involuntary muscle Muscle fibers are spindle-shaped (fusiform); have a single centrally located nucleus; and are generally parallel with one another Involved in many “housekeeping” functions of the body. For example aiding the movement of food through the digestive system via peristalsis Found in the walls of the hollow organs like intestines, stomach & uterus  Is the main tissue component of the nervous system controls the body's movements, sends and carries signals to and from the different parts of the body, and has a role in controlling bodily functions such as digestion Types of cell: neuron (impulse- conducting cell) which transmits impulses & the structural unit of the nervous system; and, neuroglia (or glia or glial cells & smaller than neurons) support cells & provide protection to the neurons