Types of Human Tissues I PDF

Types of human tissues I - Cell - basic unit of all organisms which can reproduce itself exactly - There are about 75 000 000 000 000 (75 x 1012 ) cells in an adult human body - 200 types of cells 4 main types: - neurons - muscle cells -...

Types of human tissues I - Cell - basic unit of all organisms which can reproduce itself exactly - There are about 75 000 000 000 000 (75 x 1012 ) cells in an adult human body - 200 types of cells 4 main types: - neurons - muscle cells - epithelial cells - connective tissue cells - Tissue - collection of cells performing similar functions - Organ - 2 or more tissues combined to perform particular functions Epithelial tissue - covers the body - lines cavities, ducts - reproduces quickly - tightly packed cells - little of matrix connective tissue epithelial tissue Epithelial tissue subtypes: - surface epithelium - glandular epithelium - sensory epithelium Functions of the epithelial tissue - examples: - protection - skin, gastro-intestinal system - secretion - glands - absorption - gastro-intestinal system - excretion - kidneys - filtration - kidneys - diffusion - lungs - sensory reception - olfactory epithelium squamous epithelium cuboidal epithelium columnar epithelium simple epithelium stratified epithelium basement membrane Simple squamous epithelium Stratified squamous epithelium Stratified squamous epithelium subtypes: - keratinized - skin - not keratinized - vagina Stratified squamous epithelium - not keratinized Stratified squamous epithelium - keratinized keratin Simple cuboidal epithelium Simple columnar epithelium Columnar epithelium cilia microvilli Pseudostratified columnar epithelium Pseudostratified columnar epithelium Transitional epithelium Transitional epithelium Glands Types of glands: - unicellular - e.g. goblet cells - produce mucus - necessary in: - digestive - respiratory - urinary - reproductive system - multicellular glands Multicellular glands - structural classification: - simple - compound - tubular - alveolar (acinar) e.g. simple tubular, simple alveolar, compound tubular, compound alveolar Classification of glands by types of secretion: - merocrine - apocrine - holocrine Classification of glands – by place of secreting: - endocrine - secrete directly to blood stream, have no ducts - exocrine - secrete to ducts leading to surface ducts blood endocrine glands exocrine glands Connective tissue - bind structures together - form a framework and support for organs - store fat - cells usually separated by large amount of extracellular (nonliving) matrix - matrix consists of amorphous jelly in which are embedded long, slender fibers Connective tissue - intercellular matrix: - ground substance - fibers: - collagenous - yellow (elastic) - reticular - cells - fibroblasts - mast cells - macrophages - lymphocytes - plasma cells - eosinophiles - reproduces less rapidly than epithelial tissue Fibroblasts: - producing components of the matrix collagen fibers fibroblasts, collagen fibroblast Mast cells: - promoting inflamation - producing heparin, histamine - degranulating during contact with antigen mast cell mast cell, lymphocytes mast cell, collagen Macrophages : - killing bacteria - cleaning-up garbage - old cells - foreign particles macrophage macrophage monocyte Adipose cells : - have ability to take up fat - energy storage plasma cell lymphocytes Connective tissue subtypes: -Loose connective tissue -Adipose (fat) tissue -Dense fibrous connective tissue -Cartilage -Bone Loose connective tissue - soft -collagenous and elastic fibers are embedded in a gel-like matrix - between muscles, beneath the skin, binds organs together loose Adipose (fat) tissue -cells are filled with fat droplets so that nucleus and cytoplasm are pushed to the periphery -little intercellular matrix - cushions, insulates, stores energy - beneath the skin, around the kidneys, heart, eyeballs Dense fibrous connective tissue - matrix filled with paralell bundles of collagenous fibers (greater number, densely packed) - binds structures together - tendons, ligaments, capsules of organs tendon Supporting connective tissues: =Cartilage and Bone Cartilage - hyaline – solid matrix with fibers and scattered cells , chondrocytes in lacunae - end of long bones, tracheal rings - fibrocartilage – numerous collagenous fibers in matrix - intervertebral disks - elastic – numerous elastic fibers - auricle of the ear hyaline cartilage elastic cartilage Bone (osseus connective tissue) -hard matrix with mineral salts -matrix arranged in lamellae around haversian canal -osteocytes in lacunae -Compact bone – shafts of long bones, parralell plates of flat bones - structural unit – Haversian system -Haversian canals -Volkmann’s canals - matrix arranged in lamellae around Haversian canal -Spongy bone – ends of long bones, center of irregular bones - no Haversian system bone marrow Bone formation -Intramembranous ossification - bones of the skull, clavicle - concentration of mesenchyme - cells producing collagenous fibers and osteoid - later deposition of salts -Enchondral ossification - cartilage model - formation of primary ossification center - blood vessels enter the ossification center - formation of secondary ossification center - formation of bone marrow cavity