Unit 1: Lesson 3 Tissue Level of Organization

Unit 1: Lesson 3 Tissue Level of Organization tissue level of organization Tissues •A tissue is a collection of specialized cells and cell products that performs a specific function •A combination of tissues that perform complex functions are known as organs •The study of tissues is histology •4 basic tissue types: 1.Epithelial tissue 2.Connective tissue 3.Muscle tissue 4.Nervous tissue Epithelial tissue Epithelial Tissue •Made up of closely bound cells that form a continuous sheet •Cover exposed surfaces, line internal passageways and chambers, and form glands •Examples: skin, lining of esophagus, lining of bladder, lining of blood vessels, lining of cornea, mammary glands •Includes epithelia (layers of cells that cover external or line internal surfaces) and glands (structures that produce fluid secretions) •An epithelium has an exposed apical surface and attached basal surface •Epithelia are further classified by the shape of their cells and the number of cell layers that exist •Avascular tissue Functions of Epithelial tissue: 1. Provides physical protection 2. Controls permeability 3. Provides sensation → neuroepithelium 4. Provides specialized secretions → glandular epithelia Functions of Epithelial Tissue Classifying Epithelial Tissue 1.By the arrangement of the cells (layers) in the tissue: •Simple- one cell layer •Stratified- several cell layers •Pseudostratified- one cell layer that appears stratified due to uneven nuclei and varied cell shape 2.By the shape of the cells that compose the tissue: •Squamous •Cuboidal •Columnar •Transitional On goodnotes there is a picture test epithelial tissue functions and locations To be an effective barrier, epithelial tissue depends on 3 factors: 1.Intercellular connections 2.Attachment to the basement membrane 3.Epithelial maintenance and repair Intercellular Connections - supplemental documents on eclass Epithelial cells are firmly attached to each other by way of specialized intercellular connections. 1.Cell Adhesion Molecules (CAMs) •Transmembrane proteins 2.Cell Junctions •Specialized areas of the plasma membrane: - Gap Junctions - Tight junctions - Desmosomes cell junctions MAKE SURE YOU LOOK AT SUPPLEMENTAL REVIEW FOR OVERALL INFORMATION Connective tissue •A diverse group of tissues that share 3 basic components: 1. Specialized cells ● Blast cells, plasma cells, macrophages 2. Extracellular protein fibers ● Collagen, reticular fibers, elastic fibers 3. A fluid known as ground substance ● A syrupy solution that surrounds cells and connective tissue fibers •Connective tissues are found throughout the body but are never exposed to the outside environment Functions of Connective tissue: 1. Provides structural framework for the body 2. 3. 4. 5. 6. Transport fluids and dissolved materials Supports and protects organs Interconnect other types of tissues Store energy Defend against invading microorganisms Classification of Connective Tissue 1.Connective Tissue Proper •Includes a range of tissues, divided into 2 categories: loose connective tissue and dense connective tissue •Examples: adipose tissue (loose) and tendons (dense) 2.Fluid connective tissues •Distinctive collections of cells suspended in a fluid matrix •Two types: blood and lymph 3.Supporting connective tissues •Densely packed matrix •Two types: cartilage and bones On goodnotes there is a activity for connective tissue cells based on supplemental review as well as a diagram labelling activity****** Connective Tissue Proper Cells of Connective Tissue Proper •Cells that function locally: - Fibroblasts, fibrocytes, adipocytes, mesenchymal cells •Mobile cells: - Macrophages, mast cells, lymphocytes, plasma cells, microphages Connective Tissue Fibers •Collagen fibers, reticular fibers, elastic fibers Loose vs Dense Connective Tissue Loose connective tissues fill the spaces between organs, offering cushioning, support, and stability 1.Areolar tissue 2.Adipose tissue 3.Reticular tissue Dense connective tissue (collagenous tissues) 1.Dense regular connective tissue 2.Dense irregular connective tissue 3.Elastic tissue Supportive Connective Tissue - refer to pg 138 fig 4-15, 4-16 •Offer support and structure •Includes cartilage and bone •Cartilage - Firm gel matrix containing chondroitin sulfates - Cartilage cells are the only cells in the cartilage matrix - Avascular - Separated from other tissues by a two-layer fibrous perichondrium - Types of cartilage: hyaline cartilage, elastic cartilage, fibrous cartilage MEMBRANES What about Membranes? •Tissue membranes form a barrier by lining or covering surfaces •Consist of an epithelial layer over a connective tissue layer •4 types of tissue membranes: - Mucous membrane - Serous membrane - Cutaneous membrane - Synovial membrane •Mucous membranes are moist membranes that line passages to the exterior •Serous membranes line the ventral body cavity (parietal) and the organs (visceral) therein. Includes the pleura, peritoneum, and pericardium. •Cutaneous membrane is a thick, dry, water-resistant membrane. The skin that covers the surface of the body. •Synovial membranes line joint cavities and produce synovial fluid. Muscle Tissue MUSCLE TISSUE •Tissue that is specialized for contraction and movement •Three types of muscle tissue: - Skeletal Muscle - Cardiac Muscle - Smooth Muscle •Functions: - Movement - Heat - Posture Muscle Tissue CONT 1.Skeletal muscle tissue - Long multinucleated cells - Striated (actin and myosin in parallel so muscle appears to have bands across it) - Large skeletal muscles under voluntary nervous system control (striated voluntary muscle) 2.Cardiac muscle tissue - Smaller cells with only one nucleus - Striated involuntary muscle (heart has own pacemaker) 3.Smooth muscle tissue - Small cells with one nucleus - Surround hollow organs and passageways to exterior (resp tract, digestive tract, etc.) - Nonstriated involuntary muscle Nervous Tissue Nervous Tissue •Tissue specialized for the conduction of electrical impulses from one area of the body to another •Contains two basic cell types: - Neurons - Neuroglia (glial cells) •Found throughout the body, but 98% of nervous tissue exists in the brain and spinal cord Discussion •Why is it important for nurses to know about the different types of tissues? •How does aging impact these tissues? External Resources: - cell membrane and transport crash course epithelial tissue crash course connective tissue crash course connective tissue Readings: - Chapter 4 (pp.115-147) Mastering AP: - Dynamic study modules - Practice questions (go to chapter, practice tests) - Questions in the textbook Can also draw Look at registerednursern questions