Animal Tissues PDF

ANIMAL TISSUES Biology Department, CNSM MSU Main Campus Animal structure has a hierarchy Structure in the living world Is organized in a series of hierarchical levels A Cellular level Muscle cell B Tissue level...

ANIMAL TISSUES Biology Department, CNSM MSU Main Campus Animal structure has a hierarchy Structure in the living world Is organized in a series of hierarchical levels A Cellular level Muscle cell B Tissue level Muscle tissue C Organ level Heart D Organ system level Circulatory system E Organism level Many organ systems functioning together Figure 20.2A–E METAZOANS Consists of cellular components derived from the 3 Embryonic Germ Layers: ECTODERM MESODERM ENDODERM and extracellular components EXTRACELLULAR COMPONENTS 2 IMPORTANT NONCELLULAR COMPONENTS: (1) Body Fluids (2)Extracellular Structural Elements EUMETAZOANS Body fluids are subdivided into 2 fluid compartments:  1. INTRACELLULAR SPACE – inside cells  2. EXTRACELLULAR SPACE – outside cells  2 Types of Extracellular fluid (In animals with closed vascular system)  a. Blood plasma  b. Interstitial fluid EXTRACELLULAR STRUCTURAL ELEMENTS Supportive material of the organisms including: Loose Connective Tissue (in all Metazoans) Cartilage (Molluscs & Chordates) Bone (Vertebrates) Cuticle (Artropods, Nematodes, Annelids, & Others) Functions: (1) Provide mechanical stability & protection (2) Act as depot of materials for exchange between cells & interstitial fluid (3) Serve as medium for extracellular reactions  CELL JUNCTIONS Four major classes of cell junctions Tight junctions Gap junctions Cell-cell junctions Cell-matrix junctions Tight Junctions Connect epithelial cells that line the intestine and prevent passage of fluids through cell layers http://de.wikipedia.org/wiki/Tight_junction Gap Junctions Distributed along the lateral surfaces of adjacent cells. Allow the cells to exchange small molecules for metabolic coupling among http://cellbio.utmb.edu/cellbio/membrane3.htm Cell-Cell Junctions Performs the primary function of holding cells to cells http://cellbio.utmb.edu/cellbio/membrane3.htm http://cellbio.utmb.edu/cellbio/membrane3.htm TISSUE Group of similar cells (together with associated cell products) Specialized for a perrformance of common function. HISTOLOGY – “histos” – tissue + “logos” – discourse  TYPES OF TISSUES 1. EPITHELIUM 2. CONNECTIVE 3. MUSCLE 4. NERVOUS  EPITHELIUM Lines, covers, protects other tissues and organs. Characterized by: Cells are held tightly together by tight junctions The presence of a cell secretion called the basement membrane  a condensed region of ground substance of connective tissue Named by: Cell shape Other characteristics of the cell Squamous, Cuboidal, and Columnar  SQUAMOUS EPITHELIUM Cells very thin, much wider than they are thick. SIMPLE SQUAMOUS EPITHELIUM Air sacs of respiratory Lining of blood vessels, heart and lymphatic tubes Found in all metazoans STRATIFIED SQUAMOUS EPITHELIUM Skin, vagina, esophagus, mouth SIMPLE SQUAMOUS EPITHELIUM SIMPLE SQUAMOUS EPITHELIUM STRATIFIED SQUAMOUS EPITHELIUM STRATIFIED SQUAMOUS EPITHELIUM CUBOIDAL EPITHELIUM cubed-shaped cells secretion and absorption  Kidney tubules  Duct and small glands  Surface of ovary CUBOIDAL EPITHELIUM COLUMNAR EPITHELIUM Elongated cells, much longer than they are wide SIMPLE COLUMNAR EPITHELIUM Lines the digestive tract, gall bladder, and excretory ducts of some glands. With microvilli at surface for absorption PSEUDOSTRATIFIED CILIATED COLUMNAR EPITH Lines the bronchi, trachea, uterine tubes, and some of the uterus.  COLUMNAR EPITHELIUM COLUMNAR EPITHELIUM COLUMNAR EPITHELIUM Glands Secretory organs that are derived from epithelium Exocrine glands secrete products onto free epithelial surface via ducts or tubes Endocrine glands are ductless and release hormones into the  pore that opens at skin surface mucous gland poison gland pigmented cell Frog Epithelium Cell Junctions Tight junctions prevent leaks Gap junctions connect abutting cytoplasms Adhering junctions cement cells CONNECTIVE TISSUE Characterized by the cells widely separated from each other in a matrix that is produced by the cells. Tissue that protects and supports. Cell Matrix composed of two regions Ground Liquid (sol), Gel, Gum or solid Fibers Non-elastic (white or Collagen) Elastic (yellow fibers) CONNECTIVE TISSUE FIBERS Three Kinds of Connective Tissue Fibers (which are made of protein) 1. Collagenous Fibers 2. Elastic Fibers 3. Reticular Fibers 1. COLLAGENOUS FIBERS made of collagen, probably the most abundant protein in the animal kingdom non-elastic and do not tear easily when pulled lengthwise e.g. If you pinch and pull some skin on the back of your hand, it is mainly collagen that keeps the 2. ELASTIC FIBERS long threads made of a protein called ELASTIN it provides a rubbery quality that compliments the non-elastic strength of collagenous fibers. e.g. When you pinch the back of your hand and then let go, elastic fibers quickly restore your skin to its original shape. 3. RETICULAR FIBERS very thin and branched It is composed of collagen and continuous with collagen fibers, they form a tightly woven fabric that joins connective tissue to adjacent tissue. TYPES OF CONNECTIVE TISSUE LOOSE CONNECTIVE TISSUE (AREOLAR) DENSE CONNECTIVE TISSUE ADIPOSE CARTILAGE BONE BLOOD  LOOSE CONNECTIVE TISSUE (AREOLAR) Gel like ground with both elastic and non-elastic fibers running though the ground in many directions. Wraps and cushions organs  LOOSE CONNECTIVE TISSUE (AREOLAR) LOOSE CONNECTIVE TISSUE (AREOLAR)  LOOSE CONNECTIVE TISSUE the most widespread connective tissue in the vertebrate body it binds epithelia to underlying tissues and functions as packing material, holding organs in place it gets its name from the loose weave of its fibers it has all three fiber types: collagenous, elastic, and reticular among the cells scattered in the fibrous  LOOSE CONNECTIVE TISSUE 2 Types Predominate:  1a. FIBROBLASTS – secrete the protein ingredients of the extracellular fibers  1b. MACROPHAGES amoeboid cells that roam the maze of fibers, engulfing bacteria and the debris of dead cells by phagocytosis.  DENSE CONNECTIVE TISSUE Nuclei and fibers arranged in parallel rows. Tendons, ligaments, and fascia Fibers mostly non-elastic  DENSE CONNECTIVE TISSUE dense due to its large numbers of collagenous fibers the fibers are organized into parallel bundles, an arrangement that maximizes non-elastic strength Tendons (attach muscle to bones) ligaments (attach bones together at joints) fascia (attach muscle to muscle)  ADIPOSE TISSUE a specialized form of loose connective tissue that stores fat in adipose cells distributed throughout its matrix function: adipose tissue pads and insulates the body stores fuel as fat molecules each adipose cell contains a large fat droplet that swells when fat is stored  ADIPOSE TISSUE (FAT) Adipose cells contain a large vacuole which in the live cell contains lipids. Cell nucleus and cytoplasm are pushed out to edge of cell membrane. ADIPOSE TISSUE (FAT)  CARTILAGE has an abundance of collagenous fibers embedded in a rubbery matrix made of a substance called: CHONDROITIN SULFATE – a protein- carbohydrate complex CHONDROCYTES – the cells that secrete chondroitin sulfate and collagen the composite of collagenous fibers and chondroitin sulfate makes cartilage a strong yet somewhat flexible support material.  CARTILAGE Ground of matrix is gum like. Cells are found in Lacunae within the matrix. Fibers may be elastic or non-elastic, or a form of non-elastic called reticular(where the non-elastic fibers of very thin) HYALINE CARTILAGE – e.g. ends of the bones ELASTIC CARTILAGE – e.g. ear NON-ELASTIC CARTILAGE – e.g. nose HYALINE CARTILAGE ELASTIC CARTILAGE  cartilage on end of a CARTILAGE long bone and BONE TISSUE Cartilage is a solid but pliable intercellular material Bone is a compact bone tissue hardened connective tissue with living cells spaces in spongy imprisoned in their bone mineralized tissue secretions  BONE Ground of matrix is Solid (Calcium carbonate). Has blood supply and nerves running through the Haversian canal systems.  BONE the skeleton supporting the body of most vertebrates. it is a mineralized connective tissue calcium, magnesium, and phosphate ions combine and harden with in the matrix into the mineral HYDROXYAPATITE. the combination of hard mineral and flexible collagen makes bone harder  BONE  OSTEOBLASTS bone forming cells deposit a matrix of collagen they become trapped in their own secretions and are called OSTEOCYTES (mature bone cell) OSTEONS (Haversian System)  the microscopic structure of hard mammalian bone each has concentric layers of the mineralized matrix, which are deposited BONE  BLOOD (VASCULAR TISSUE) Plasma (Liquid Matrix) 90% water 10%Plasma proteins, electrolytes, hormones, oxygen, glucose etc. Cellular Elements ERYTHROCYTES (RBCs) – for gas transport. Mammals are enucleated while rest of the vertebrates they have nuclei LEUCOCYTES (WBCs) – for defense THROMBOCYTES (Platelets) - blood clotting  MUSCLE TISSUE it is composed of long cells called muscle fibers that are capable of contracting when stimulated by nerve impulses arranged in parallel with in the cytoplasm of muscle fibers are large numbers of myofibrils made of contractile proteins ACTIN and MYOSIN it is the most abundant tissue in most animals, and muscle contraction accounts for much of the energy consuming cellular work in an active animal  1. SKELETAL MUSCLE attached to bones by TENDONS, responsible for voluntary movements of the body adults have a fixed number of muscle cells; weight lifting and other methods of building muscle do not increase the number of cells but simply enlarge those already present it is also called STRIATED MUSCLE because the arrangement of overlapping filaments gives the cells a striped (striated)  2. SMOOTH MUSCLE it lacks striations, it is found in the walls of the digestive tract, urinary bladder, arteries, and other internal organs except the heart the cells are spindle-shaped they contract more slowly than skeletal muscles but can remain contracted longer it is controlled by different kinds of nerves than those controlling skeletal muscles smooth muscles are responsible for involuntary body activities, such as churning of stomach or contraction of arteries  3. CARDIAC MUSLCE it forms the contractile wall of the heart (involuntary contraction) it is striated like skeletal muscle, but cardiac cells are branched the end of cells are joined by structures called INTERCALATED DISCS which relay signals from cell during heartbeat  NERVOUS TISSUE It senses STIMULI and transmit signals from one part of the animal to another It is located in brain and nerve extensions that carry impulses or signals NEURON – the functional unit of nervous tissue or nerve cell which is uniquely specialized to transmit signals called NERVE IMPULSES  NERVOUS TISSUE DENDRITES transmit impulses from their tips toward the rest of the neuron it is one of numerous, short, highly branched processes of a neuron that conveys nerve impulses toward the cell body AXONS  transmit impulses toward another neuron or towards an effector it carries impulse away from the cell body toward target cells Neurons - The functional unit of the Nervous System. Signal direction Dendrites Cell body Cell body Node of Ranvier Myelin sheath Signal Axon pathway Schwann cell Nucleus Nucleus Nodes of Ranvier Schwann cell Myelin sheath Synaptic knobs Figure 28.2  2 Basic Types of Cells in Nervous Tissue (1) Neurons (Gr. Nerve) Basic functional unit of nervous system (2) Neuroglia (Gr. Nerve + glia – glue) Non-nervous cells that insulate neuron membrane Supporting Cells (Glia) Glia are supporting cells That are essential for the structural integrity of the nervous system and for the normal functioning of neurons In the CNS, astrocytes Provide structural support for neurons and regulate the extracellular concentrations of ions and neurotransmitters 50 µm Figure 48.7  Oligodendrocytes (in the CNS) and Schwann cells (in the PNS) Are glia that form the myelin sheaths around the axons of many vertebrate neurons Node of Ranvier Layers of myelin Axon Schwann cell Schwann cell Nodes of Nucleus of Axon Myelin sheath Ranvier Schwann cell Figure 48.8 0.1 µm Tissue Type Epithelial Connective Muscle Nerve Cell Shape Flattened, Irregular or Elongated Cell cuboidal, round appendages columnar branched Cell Single  Scattered in In sheets or Isolated or Arrangement multilayered matrix bundles networked Location Body covering Supports other Lining internal Concentrated in or lining organs organs organs, make brain and spinal or cavities skeletal cord + all over muscles the body Surface Cilia, microvilli - - - Feature of Cells Matrix Type Basement Varied – protein - - membrane fibers + liquid, gelatinous, firm to calcified Matrix Minimal Extensive Absent Absent Amount Unique No direct blood Cartilage has Can generate Can generate Feature supply, except no blood supply electrical electrical signal for glands signals, force and movement