Lesson 4 Tissues PP.pdf

9/20/2023 TISSUES Chapter 3 1 Body Tissues  Cells are specialized for particular functions  Tissues  Groups of cells with similar structure and function  Four primar...

9/20/2023 TISSUES Chapter 3 1 Body Tissues  Cells are specialized for particular functions  Tissues  Groups of cells with similar structure and function  Four primary types  Epithelium  Connective tissue  Nervous tissue  Muscle 2 1  9/20/2023 3 EPITHELIAL TISSUE  Forms boundaries between different environments  Epithe = laid on, covering,  Found in different body areas  Body coverings  Body linings  Glandular tissue 4 2  9/20/2023 5 EPITHELIAL TISSUE Functions Covers and lines all – Protection (skin) free body surfaces, – Absorption (GI) inside and out. – Filtration (Renal) – Secretion (glands) 6 3  9/20/2023 Epithelium Characteristics  Cells fit closely together, glands are exception. Bound by junctions.  Tissue layer always has one free (unattached) surface  The lower surface is bound by a basement membrane  Avascular (have no blood supply, rely on diffusion from nearby capillaries)  Regenerate easily if well nourished 7 Classification of Epithelium  Number of cell layers  Simple – one layer  Stratified – more than one layer  Pseudostratified – appears layered – is not! 8 4  9/20/2023 Classification of Epithelium  Shape of cells  Squamous – flattened  Cuboidal – cube- shaped  Columnar – column- like 9 Simple Epithelium  Simple squamous  Single layer of flat cells  Usually forms membranes  Lines body cavities  Lines lungs and capillaries 10 5  9/20/2023 Simple Epithelium  Simple cuboidal  Single layer of cube-like cells  Common in glands and their ducts  Forms walls of kidney tubules  Covers the ovaries 11 Simple Epithelium  Simple columnar  Single layer of tall cells  Often includes goblet cells, which produce mucus  Lines digestive tract 12 6  9/20/2023 Simple Epithelium  Pseudostratified columnar  Single layer, but some cells are shorter than others  Often looks like a double cell layer  Sometimes ciliated, such as in the respiratory tract  May function in absorption or secretion 13 Stratified Epithelium  Stratified squamous  Cells at the free edge are flattened  Found as a protective covering where friction is common  Locations  Skin  Mouth  Esophagus 14 7  9/20/2023 Stratified Epithelium  Stratified cuboidal  Two layers of cuboidal cells  Stratified columnar  Surface cells are columnar, cells underneath vary in size and shape  Stratified cuboidal and columnar  Rare in human body  Found mainly in ducts of large glands 15 Stratified Epithelium  Transitional epithelium  Shape of cells depends upon the amount of stretching  Lines organs of the urinary system 16 8  9/20/2023 Glandular Epithelium  Gland – one or more cells that make & secrete a particular product  Two major gland types  Endocrine gland  Ductless (bloodstream for transport)  Secretions are hormones  Exocrine gland  Empty through ducts to the epithelial surface  Include sweat and oil glands 17 CONNECTIVE TISSUE  Found everywhere in the body  Includes the most abundant and widely distributed tissues  Functions  Binds body tissues together  Supports the body  Provides protection  Cushioning  Insulation 18 9  9/20/2023 Connective Tissue Characteristics  Variations in blood supply  Some tissue types are well vascularized  Some have poor blood supply or are avascular  Extracellular matrix  Non-living matrix that surrounds living cells  Matrix: produced by connective tissue cells, secreted to exterior. (ground substance + fibers) 19 Connective Tissue Types  Bone (osseous tissue)  Cartilage  Flexible, 3 varieties  Hyaline – most abundant – rubbery with glassy appearance.  Dense connective tissue  Tendons & Ligaments, dermis  Loose connective tissue  Areolar connective tissue  Adipose tissue  Reticular connective tissue 20 10  9/20/2023 Connective Tissue Types  Blood  Blood cells surrounded by fluid matrix  Fibers are visible during clotting  Functions as the transport vehicle for materials 21 MUSCLE TISSUE – Three types  Function is to produce movement  Skeletal muscle - Can be controlled voluntarily  Cells are striated - Cells have more than one nucleus  Cardiac muscle - Involuntary control  Found only in the heart & function is to pump blood  Cells are striated - One nucleus per cell  Smooth muscle - Involuntary muscle  Surrounds hollow organs  No visible striations  One nucleus per cell 22 11  9/20/2023 NERVOUS TISSUE  Neurons and nerve support cells  Function is to send impulses to other areas of the body  Irritability  Conductivity 23 Tissue Repair (Wound healing) Injury occurs Inflammatory response activated – Capillaries become leaky – Brings hormones and nutrients to the area – Clot & scab form Granulation tissue forms – Fragile tissue forms, capillaries Regeneration: Surface epithelium – New tissue is formed 24 12  9/20/2023 Wound Repair www.Ipmc.epfl.ch 25 13