Veterinary Microscopic Anatomy (Histology) Laboratory - Module 8: Cartilage and Osseous Tissue PDF

HIST101B VETERINARY MICROSCOPIC ANATOMY (Histology) LABORATORY Module 8: Cartilage and Osseous (Bone) Tissue CARTILAGE Mature cartilage – basophilic due to - Connective tissue or supportive tissue which is having a...

HIST101B VETERINARY MICROSCOPIC ANATOMY (Histology) LABORATORY Module 8: Cartilage and Osseous (Bone) Tissue CARTILAGE Mature cartilage – basophilic due to - Connective tissue or supportive tissue which is having accumulation of glycosaminoglycan; cell nests or an enclosing membrane called “perichondrium” isogenous groups are present; territorial matrix is Perichondrium more basophilic than in inter-territorial matrix; - Consists of 2 layers of outer fibrous layer (made up of larger and ovoid lacunae dense white fibrous connective tissue) and an inner ELASTIC CARTILAGE cellular layer or chondrogenic layer - Chondrogenic layer – mesenchymal cells which differentiate into cartilage forming cells called “chondroblasts” FEATURES OF CARTILAGE 1. It is avascular (no blood supply) and nutrition is by diffusion from the periphery to the center of the cartilage 2. Has no nerve supply of its own; it cannot respond to stimulus 3. Grows by two methods: appositional and interstitial - Grossly yellow due to yellow color of elastic fibers in HYALINE CARTILAGE fresh state - Contains predominantly elastic fibers and a little collagen - Found in epiglottis, external auditory canal; corniculate and cuneiform process of the larynx, pinna of ear, Eustachian tube - Elastic fibers give the cartilage the ability to be deformed and returned to shape - Larger chondrocytes; perichondrium is present - Inter-territorial matrix is lessened in volume - Elastic fibers are visible as short fine black (with silver stain) FIBROCARTILAGE - Mechanical supports - Model for formation of tubular bones; repair of fractures - Found on articulating surface of bones in synovial joints - Provides support in the nose, larynx, trachea and bronchi - Forms most of appendicular and axial skeleton in the embryo - White and glassy - Has a feature of both dense white fibrous connective - Intercellular substance: amorphous ground substance tissue and cartilage; an intermediate between these and fine collage fibers two tissues Young cartilage – acidophilic matrix due to lesser - Composed of large bundles of collagen fibers amount of glycosaminoglycan; flattened lacunae separated by isolated groups of cartilage and chondrocytes - Chondrocytes arranged in regular rows CADVB | DVM3E  Module 8: Cartilage and Osseous (Bone) Tissue| HIST101B - Lack a perichondrium - hyaluronic acid – another matrix component, a - Intervertebral disks – a fibrous ring called annulus gelatinous mucopolysaccharide that binds fibrosus; attachment of certain tendons, ligaments proteoglycans together into large aggregates and in menisci; in dogs, found in the cardiac skeleton - other components: cells – osteogenic, osteoblasts, – joins the atrial and ventricular heart muscles osteocytes, osteoclasts - Prominent type I Collagen fibers in the matrix osteogenic – youngest; only capable of mitosis MAINTENANCE AND REPAIR OF osteoblasts – bone-secreting cells; secrete CARTILAGE osteoid; active are cuboidal and polarized; located at the periphery Cartilage is maintained throughout life by the nutritive role of chondrocytes osteocytes – bone cells that have stopped If a growing cartilage is damaged, it is repaired by secreting bone matrix and reduced secretory functions; analogous to chondrocytes; trapped in differentiation of chondrogenic cells in the lacunae; capable of removing bone matrix perichondrium into chondroblasts, which in turn through osteolysis; supplying nutrients from secrete the fibers and the amorphous ground substance that comprise the cartilage matrix. The blood vessels repaired tissues does not have the same osteoclasts – similar to chondroclasts; same cell properties as the original one so the structure line as monocytes; bone resorption; lysosomal and function are not restored. contents (Release); resorption release calcium If the cartilage has stopped growing, repair by and phosphorus; disease, dietary deficiencies formation of new cartilage is not possible. Bone or osseous tissue features BONES OR OSSEOUS TISSUE 1. it is mineralized through deposition of calcium in the - Another type of supportive tissue amorphous and fibrous intercellular substance - Similar to cartilage in its amorphous components 2. bones are highly vascular tissue except that it is mineralized. 3. bone cells are in contact with each other through - Enclosed by a membrane called “periosteum” appear small canals called “canaliculi” similar to perichondrium 4. bones grow by appositional method only Periosteum COMPACT BONE - 2 layers: - contains many cylinder-shaped structural units called Outer fibrous layer (made up of dense white osteons (haversian systems) fibrous connective tissue) - osteon runs lengthwise through the bone – make up Inner cellular layer or osteogenic layer – stellate the structural framework or spindle-shaped - unique composition allows delivery of nutrients and osteon – basic structural unit the removal of waste products produced from the lamellae/lamella – surrounding the osteocytes or metabolically active bone cells the cavity surrounding the osteocytes canaliculi – bones cells are in contact with each other through cellular processes embedded in tiny channels in the hard bone matrix haversian canal/system – central canal endosteum – responsible for internal remodeling of bone; bone cavities and canals are lined by this - principal component of bone: intercellular substance – collagen fibers 20 to 30% organic material gives the bones the ability to resist snapping and breaking; and amorphous gel-like matrix - has more collagen fibers than cartilage; more orderly arrangement - amorphous substance and collagen fibers form the osteoid, the unmineralized matrix of bone - once mineralized, it is called hydroxyapatite – gives bone its hardness and rigidity - mature bone has 65% mineral content and 35% amorphous substance and collagen CADVB | DVM3E 2 HIST101B VETERINARY MICROSCOPIC ANATOMY (Histology) LABORATORY Module 9: THE MAMMALIAN AND AVIAN BLOOD (hematopoietic tissue) HEMATOPOIETIC TISSUE - Specialized tissue in which new blood cells are formed - Single large nucleus and scant blue cytoplasm - Adult hematopoietic tissue is in the flat bones and the - Can live for months to years ends of the long bones  Monocytes  Hematopoiesis - Larger nucleus than lymphocytes; folded - Formation of blood cells; occurs within the spongy - More cytoplasm and grey trabeculae of the bone adjacent to vascular sinuses - Can migrate into tissues and become macrophages - Cells are formed elements of blood that persist for weeks to months - Only the mature forms are found in the circulating blood and the immature forms are found in the blood forming sites which in the adult animals are concentrated in the red bone marrow - Two major types of blood cells:  Erythrocytes or red blood cells  Leukocytes or white blood cells a. Granulocytes: neutrophils, eosinophils, basophils b. Agranulocytes: lymphocytes and monocytes TYPES OF WHITE BLOOD CELLS that circulate:  Neutrophils - Have prominent cytoplasmic granules that are lysosomes containing the enzymes released when neutrophils are recruited into inflammatory reactions - Multilobed nuclei - Circulating last about 12 hours and must constantly be replaced from the marrow - Bacterial infections  Band neutrophils AVIAN BLOOD CELLS - Immature neutrophils; few - Crescent shaped nucleus that has not yet become lobated - Have cytoplasmic granules  Eosinophils - Not numerous - Prominent bright red cytoplasmic granules - Parasitic infections and allergic reactions  Basophils - Granulated; prominent dark purple cytoplasmic - (RBC) Large oval cell that contain oval nuclei inclusions - Thrombocytes in birds are small cells with round - Least numerous of circulating white blood cells nucleus, very condensed chromatin and small rim of  Lymphocytes cytoplasm - Both T and B cells circulate, with about 80% of the peripheral blood lymphocytes being T cells CADVB | DVM3E Module 9: THE MAMMALIAN AND AVIAN BLOOD (hematopoietic tissue) | HIST101B - Heterophil = mammalian neutrophil; have segmented nuclei that are obscured partly by large granules that pack the cytoplasm - Eosinophils – slightly smaller than heterophils and their granules are round; - Basophils – contain many small granules same in mammals - Monocytes and lymphocytes – similar to mammals CADVB | DVM3E 2 HIST101B VETERINARY MICROSCOPIC ANATOMY (Histology) LABORATORY Module 10: MUSCLE TISSUE MUSCLE TISSUE CARDIAC MUSCLE - Group of muscle cells or fibers - Muscle fiber is an entire cell - Muscle makes up most of the flesh or meat - Muscle fibers – composed of organelles and inclusions like ordinary cells  Three types of muscle tissue - Skeletal - Cardiac - Smooth - All have excitability as their plasma membranes can change their electrical state (from polarized to depolarized) and send an electrical wave (action potential) along the entire membrane - Found within the heart - Nervous system can influence the excitability of - Have fibers w one to two nuclei cardiac and smooth muscle; skeletal muscle depends - Physically and electrically connected to each other on signaling from nervous system to work properly so the entire heart contracts as one unit - Both cardiac and smooth can respond to other stimuli - Found only in heart such as hormones and local stimuli - Highly coordinated contractions pump blood into the - Differences: microscopic organization of contractile vessels proteins, location in the body and control mechanism - Organized into sarcomeres – same banding - Actin and myosin proteins are arranged regularly in organization in skeletal the cytoplasm of individual muscle cells (fibers) in - Shorter than skeletal muscle; usually contain only both skeletal and cardiac that creates a pattern or one nucleus located centrally stripes called striation - Possess many mitochondria and myoglobin, as ATP is SKELETAL MUSCLE produced through aerobic metabolism - Extensively branched and connected to one another at their ends by intercalated discs – allows the cardiac muscle cells to contract in a wave-like pattern so the heart an work as a pump SMOOTH MUSCLE - Fibers are multinucleated that compose the skeletal muscle - Attached to bones and voluntary control - Actin and myosin not arranged regularly - Cytoplasm has only one nucleus has a uniform, nonstriated appearance CADVB | DVM3E  Module 10: MUSCLE TISSUE| HIST101B - In the walls of arteries – regulates blood pressure needed to push blood through the circulatory system - Skin, visceral organs, internal passageways – for transportation of materials - Involuntary - Walls of hollow organs like the urinary bladder, uterus, stomach, intestines, arteries, veins, tracts of respiratory, urinary, reproductive systems - Present in the eyes where it functions to change the size of iris and alter the shape of the lens - Present in the kin where it causes the hair to erect in response to cold temperature and fear CADVB | DVM3E 2