BSMLS_HAPP_Basic-Types-of-Tissues.pdf

BASIC TYPES OF TISSUES Dr. Nehemiah B. Mula HISTOLOGY Microscopic examination of tissue structure Tissue has a cell and an extracellular matrix Four primary tissue types ○ Epithelial Tissue ○ Connective Tissue ○ Muscle Tissue ○ Nervous...

BASIC TYPES OF TISSUES Dr. Nehemiah B. Mula HISTOLOGY Microscopic examination of tissue structure Tissue has a cell and an extracellular matrix Four primary tissue types ○ Epithelial Tissue ○ Connective Tissue ○ Muscle Tissue ○ Nervous Tissue 01 EPITHELIAL TISSUE EPITHELIAL TISSUE Also known as epithelium Covers, protects surfaces, both outside and inside the body, and forms glands Has an exposed surface called the apical surface Has a surface that is anchored or held in place – basal surface ○ Anchored through attachment to a noncellular material called basement membrane Basal lamina + Reticular lamina It is avascular – blood vessels in the underlying connective tissue does not penetrate the basement membrane Capable of regeneration EPITHELIAL TISSUE Functions of the Epithelial tissue ○ Protection for underlying structures ○ Acting as a barrier ○ Permitting the passage of substances ○ Secreting substances ○ Absorbing substances CLASSIFICATION Classified based on SHAPE OF CELLS ○ Squamous Cells are flat or scale-like ○ Cuboidal Cube-shaped , as wide as they are tall ○ Columnar Tall and thin, taller than wide CLASSIFICATION Classified based on NUMBER OF CELL LAYERS ○ Simple Epithelium Single layer of cells,each cell extending from the basement membrane to the free surface ○ Stratified Epithelium Consist of more than one layer of cells but only the basal layer attaches to the basement membrane ○ Pseudostratified Epithelium Special type of simple epithelium; consists of one layer of cells that appear to be 2 or more because cells are varying in size ○ Transitional Epithelium Special type of stratified epithelium. Shape of cells changes from cuboidal to columnar to squamous-like when stretched CLASSIFICATION SIMPLE EPITHELIUM Simple Squamous Epithelium ○ Single layer of flat cells ○ Best adapted for areas where filtration and diffusion are common SIMPLE EPITHELIUM Simple Cuboidal Epithelium ○ Has a greater secretory capacity ○ Most glands in the body and other secretory structures are frequently composed of this type of epithelium SIMPLE EPITHELIUM Simple Columnar Epithelium ○ Single layer of tall, rectangular cells ○ Secrete digestive enzymes, absorbs nutrients, and secretes mucus ○ Acts as barrier against bacterial penetration SIMPLE EPITHELIUM Pseudostratified Columnar ○ Single layer of tall cells but appear to be layered due to height difference of adjacent cells ○ Found in the respiratory tract STRATIFIED EPITHELIUM Stratified Squamous ○ Multiple layers of flat cells about 30 - 40 cells thick ○ One type forms the outer layer of skin - keratinized stratified squamous epithelium ○ Non-keratinized type is found in the mouth and throat, and other mucosal surface STRATIFIED EPITHELIUM Stratified Cuboidal ○ Multiple layers of cuboidal shape cells ○ Rare; can be found in sweat glands, ovarian follicular cells, salivary gland ducts STRATIFIED EPITHELIUM Stratified Columnar ○ Multiple layers of tall, thin cells ○ Found in mammary glands STRATIFIED EPITHELIUM Transitional Epithelium ○ Found in the lining of the urinary tracts ○ Cuboidal when not stretched, squamous when stretched GLANDS Composed of epithelium supported by a network of connective tissue 2 major types of glands in the body ○ Endocrine glands Produce chemicals called hormones Thus not have ducts into which their secretions empty Associated with extensive network of blood vessels ○ Exocrine glands Produce wide variety of products (saliva, sweat, digestive tract secretions) Secretions enter ducts, which are continuous with the epithelial tissue surface Classified based on structure and mode of secretion UNICELLULAR AND SIMPLE GLANDS COMPOUND GLANDS GLANDS ACCORDING TO MODE OF SECRETION 02 CONNECTIVE TISSUE CONNECTIVE TISSUE Tissues that connect, support, and help bind other tissues It consists of cells separated from each other by abundant extracellular matrix Functions of Connective Tissue ○ Enclosing and Separating other Tissues ○ Connecting tissues to one another ○ Supporting and moving parts of the body ○ Storing compounds ○ Cushioning and Insulating ○ Transporting ○ Protecting CONNECTIVE TISSUE CLASSIFICATION Embryonic Connective Tissue ○ Mesenchymal ○ Mucous Connective Tissue Adult Connective Tissue ○ Connective Tissue Proper Loose Dense ○ Supporting Connective Tissue Cartilage Bone ○ Fluid Connective Tissue Blood EMBRYONIC CONNECTIVE TISSUE CONNECTIVE TISSUE PROPER: LOOSE C.T. Cushions most organs and other tissues It attaches the skin to underlying tissues CONNECTIVE TISSUE PROPER: LOOSE C.T. Consist of adipocytes which contain large amounts of lipids Composed of large cells and small amount of extracellular matrix Usually arranged in clusters or lobules separated by loose connective tissue Signet ring apearance Has 2 types: Brown and Yellow Adipose CONNECTIVE TISSUE PROPER: LOOSE C.T. Provides structural support for lymphatic and other blood-related tissues Usually found in spleen, lymph nodes, and bone marrow  CONNECTIVE TISSUE PROPER: DENSE REGULAR C.T. DENSE REGULAR COLLAGENOUS C.T. Has abundant collagen fibers Forms structures such as tendons and most ligaments  CONNECTIVE TISSUE PROPER: DENSE REGULAR C.T. DENSE REGULAR ELASTIC C.T. Has abundant elastic fibers Forms structures such as ligaments between vertebrae and vocal cords  CONNECTIVE TISSUE PROPER: DENSE IRREGULAR C.T. DENSE IRREGULAR COLLAGENOUS C.T. Forms most of the dermis of the skin Forms organ capsules surrounding kidney and spleen  CONNECTIVE TISSUE PROPER: DENSE IRREGULAR C.T. DENSE IRREGULAR ELASTIC C.T. Has abundant elastic fibers Forms the walls of arteries  SUPPORTING CONNECTIVE TISSUE: CARTILAGE CARTILAGE Composed of cartilage cells within an extensive and rigid matrix Surface of the cartilage is surrounded by a layer of dense irregular connective tissue called perichondrium Cartilage cells arise from perichondrium and secrete matrix. Once surrounded by matrix, cartilage cells are called chondrocytes Has 3 types: ○ Hyaline Has abundant collagen fibers; has a glassy appearance ○ Fibrocartilage Has more collagen fibers and are arranged in thick bundles ○ Elastic Consist of elastic fibers SUPPORTING CONNECTIVE TISSUE: CARTILAGE SUPPORTING CONNECTIVE TISSUE: CARTILAGE SUPPORTING CONNECTIVE TISSUE: CARTILAGE  SUPPORTING CONNECTIVE TISSUE: BONE BONE Hard connective tissue that consists of living cells and mineralized matrix Has an organic and inorganic portion ○ Organic is composed of proteins such as collagen ○ Inorganic portion consists of crystals call hydroxyapatite (calcium and phosphate) Has 2 types: ○ Spongy Bone ○ Compact Bone SUPPORTING CONNECTIVE TISSUE: BONE  SUPPORTING CONNECTIVE TISSUE: FLUID C.T. BLOOD Matrix between the cells is liquid Blood cells move freely within a fluid matrix which allows it to flow rapidly ○ Carrying nutrients, oxygen, waste products 3 types of cellular structures ○ Red blood cells ○ White blood cells ○ Platelets 03 MUSCLE TISSUE MUSCLE TISSUE Main characteristic of muscle tissue is its ability to contract 3 types of muscle tissue ○ Skeletal Muscle ○ Cardiac Muscle ○ Smooth Muscle SKELETAL MUSCLE Attaches to the skeleton and enables the body to move Skeletal muscles are long, cylindrical, each has a nuclei located at the periphery Striated or banded due to the contractile proteins CARDIAC MUSCLE Muscle of the heart; responsible for pumping blood Cylindrical but shorter than skeletal muscles Striated and usually have 1 nucleus per cell ; branched and connected to one another by intercalated disks SMOOTH MUSCLE Forms the walls of hollow organs; can also be seen in skin and eyes Responsible for moving food through digestive tract and emptying the urinary bladder Tapered at each end, has a single nucleus, and are not striated 04 NERVOUS TISSUE NERVOUS TISSUE Found in the brain, spinal cord, and nerves Characterized by the ability to conduct electrical signal called action potentials Nervous tissue consists of: ○ Neurons ○ Glial Cells NEURONS Aka Nerve Cells are the conducting cells of the nervous tissue Composed of 3 major parts: ○ Cell body Contains the nucleus and is the site of general cell function ○ Dendrites Receive action potentials ○ Axon Conducts action potentials away from the cell body Group based on Structure: ○ Multipolar ○ Bipolar ○ Pseudo-unipolar GLIAL CELLS Supporting cells of the brain, spinal cord, and peripheral nerves Nourish, protect, and insulate neurons Thank you! 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