Tissues PDF

Tissues PARA 1002 1 Tissue Types Epithelial – Covers and protects surfaces, lines cavities, transports substances, forms glands Connective – Supports, connects and protects, transports substances throughout the bod...

Tissues PARA 1002 1 Tissue Types Epithelial – Covers and protects surfaces, lines cavities, transports substances, forms glands Connective – Supports, connects and protects, transports substances throughout the body Muscle – Specialized cells that contract and produce most of the body movements Nervous – Most specialized – Communication, integration and coordination of body functions PARA 1002 2 1  Epithelial Tissue Found throughout the body and perform various vital functions (see table 5-4): – Protection from mechanical, biological and chemical factors – Specialized epithelia for sensory roles (skin, olfactory, auditory, visual) – Secretory role in glands – Absorption of nutrients and gas and ion exchange – Excretion such as waste products in body fluids PARA 1002 3 Epithelia Very little extracellular material Cells are closely opposed (cell junctions) Form surface linings and most glands Epithelial tissue is avascular but innervated Cells are polarized (apical-vs-basal) High regenerative capacity (very important!) Cells have various shapes: squamous, cuboidal, columnar Cell layers: simple or stratified May be membranous or glandular PARA 1002 4 2  Epithelial Cells Linings, vessels, membranes Ducts, glands, ion and H2O concentration, Absorptive, digestive, secretory PARA 1002 5 Membranous Epithelial Tissues Alveoli, *Also: pericardial surface Keratinized (skin) Stratified Non-keratinized (vagina) cuboidal Glands, Kidney tubules (ducts of sweat glands) Mucous membranes microvilli bladder Stratified columnar (rare in humans) Respiratory system Male urethra PARA 1002 6 3  Connective tissue: Most diverse and abundant tissue in the body Provides structure and support (connects muscle- muscle, muscle-bone, bone-bone) Stores and carries nutrients Surrounds and protects structures such as blood vessels and nerves Provides defense against infection PARA 1002 7 Connective tissue: Composed of various cell types in a large extracellular matrix Matrix contains: Protein fibres (collagen, reticular, elastic), Ground Substance, Defense Cells and Adipose Cells (fat cells) Connective Tissue proper (fibrous): Loose, Adipose, Reticular, Dense Specialized Connective Tissue: Cartilage, Bone, Blood See text for examples PARA 1002 8 4  Cartilage Cartilage contains only one type of cell (chondrocytes) PARA 1002 9 Types of Cartilage Hyaline - supports, reinforces - resilient cushioning - resists compressive stress Elastic - more elastic than hyaline - flexible but maintains shape Fibrocartilage - great tensile strength - absorbs compressive shock - less firm than hyaline PARA 1002 10 5  Muscle Tissue Referred to as composite tissue (Why?) Responsible for almost all body movements Specialized structure allows contraction of individual muscle fibres Three types: Skeletal, Cardiac, Smooth PARA 1002 11 Types of Muscle Cardiac muscle (myocardium) – forms the walls of the heart chambers – have the ability to contract by themselves – a slightly striated appearance / 1 nucleus per cell Smooth muscle (visceral) – artery walls and various organs – tapered cells with no striations / 1 nucleus per cell Skeletal muscle (striated) – forms all of the muscles attached to bones (a few are attached to the basal surface of the skin) – cells are cylindrical and have several nuclei each – striated appearance (arrangement of protein PARAbands) 1002 12 6  Types of Muscle How are nerves involved in the action of each of these types of muscle? PARA 1002 13 Nervous Tissue Also a composite tissue (Why?) Main component of the brain, spinal cord, and nerves Includes some of the “longest” cells in the body Limited capacity for regeneration PARA 1002 14 7  Membranes 4 different types of membranes in the body are classified as: Epithelial Membranes 1. Cutaneous membranes – cover external body surfaces Composed of a superficial layer of epithelial cells and an underlying layer of supportive connective tissue 2. Serous membranes – line internal body cavities Parietal membrane lines the wall of the cavity Visceral membrane covers the organ surface (pleura, peritoneum, pericardium) PARA 1002 15 Membranes …Epithelial Membranes 3. Mucous membranes – line internal body surfaces that open directly to the outside (such as?) Highly variable epithelial component Specialized cells produce mucous for protection, lubrication and defense. Connective Tissue Membranes (#4) These do not contain epithelial components Smooth and slippery synovial membranes that line the spaces between bone joints Secrete synovial fluid to lubricate joints PARA 1002 16 8  Body Membranes PARA 1002 17 Tissue Regeneration Epithelial and connective tissues have an extremely high capacity for regeneration Consider how quickly damage to mucous membranes and other epithelia / connective tissues heals How is this capacity for regeneration affected by the onset of age? PARA 1002 18 9  Skin – all tissues represented Can you identify examples of all 4 tissue types? PARA 1002 19 10