Body Tissues and Wound Regeneration Anatomy Unit 3

4 Primary Types of Tissues Groups of cells that are similar in structure and function are called TISSUES 4 Primary Types of Tissues Epithelium Connective Tissue Nervous Tissue Muscular Tissue

Basic Functions of Tissues Covering – Epithelium Support – Connective Movement – Muscle Control – Nervous

Epithelial Tissue Epithelial Tissue or Epithelium Lining Covering and Glandular Tissue Covers all free body surfaces and have versatile cells Functions include: Protection Absorption Filtration Secretion Examples: Skin epithelium protect against bacterial and chemical change Epithelium of the lungs has cilia to sweep dust and debris away from lungs

Special Characteristics of Epithelium Most glandular epithelium fit closely together forming continuous sheets Neighboring cells are bound at many points Membranes have one free surface or edge called an apical surface Apical surface is exposed to the body’s exterior or cavity of an internal organ Lower surface of epithelium rest on a basement membrane Basement Membranes- structure-less material secreted by both epithelial cells and connective tissue cells Epithelial tissues have no blood supply Well nourished epithelial cells may regenerate

Classification of Epithelium Epithelium names 1st – give a number Simple – one layer Stratified – multiple layers 2nd – describe the shapes of the cells

Simple Squamous Epithelia Simple Squamous Epithelium – a single layer of thin squamous cells on a basement membrane Usually form membranes for filtration or exchange of substances by rapid diffusion Ex: found in Air sacs in Lungs – where carbon dioxide and oxygen exchange Capillaries where nutrients and gases pass between tissues and blood Form Serous Membranes, or Serosae

Simple Cuboidal Epithelium One layer of Cuboidal Cells on a basement membrane Commonly found in glands and ducts Forms walls of the kidney tubules and covers the surface of ovaries

Simple columnar Epithelium Single layer of tall cells that fit closely together Goblet cells- produce a lubricating mucus Line the entire length of the digestive tract from stomach to the anus Found in membranes that line body cavities open to the body exterior Called mucosae or mucous membranes

Pseudostratified Columnar Epithelium Pseudostratified Columnar cells rest on a basement membrane Some cells are shorter than others and their nuclei appear at different heights above the basement membrane Gives a false impression that it is stratified Mainly functions in absorption and secretion

Stratified Epithelial Cells Consist of two or more layers of Epithelial Cells More durable that Simple Epithelial Cells Function primarily to protect

Stratified Squamous Epithelium Stratified Squamous Epithelium are the most common stratified epithelium in the body Usually consists of several layers of cells Free edge cells are squamous cells, those closer to the basement are cuboidal or columnar Found in sites that receive a good deal of abuse or friction Example esophagus, the mouth, and outer portion of the skin

Stratified Cuboidal and Stratified Columnar Stratified Cuboidal Epithelium typically have 2 layers with at least the surface yare being cuboidal in shape Stratified Columnar Epithelium are columnar cells, but its basal cells vary in size and shape Both the stratified cuboidal and stratified columnar are rare in the body and found mainly in the ducts of large glands

Transitional Epithelium Transitional epithelium is a highly modified, stratified squamous epithelium that forms the lining of only a few organs Urinary bladder, ureters, and urethra Cells of the basal layer are cuboidal or columnar, and those at the free in vary in appearance Cells are able to slide past one another and change shape

Glandular Epithelium Glands- consist of one or more cells that make and secrete a particular product (secretion) Two major types of glands: Endocrine Glands- Loose connection to the surface Also known as Ductless Glands Secretions diffuse directly blood vessels weaving through the gland Exocrine Glands- retain their duct Secretions empty through ducts directly on the epithelial surface

Connective Tissue Connective Tissue – connects body parts Found everywhere in the body Most abundant and widely distributed of the tissues Have variations in blood supply and have an extracellular matrix Common types of connective tissue: Bones Cartilage (especially Hyaline Cartilage) Dense and Loose Connective Tissue Adipose Tissue Reticular Tissue

Muscular Tissue Muscular Tissue – Highly specialized to contract (shorten) to produce movement 3 Types of Muscular Tissue Skeletal Tissue – packaged by connective tissue which attach to the skeleton. Can be controlled voluntarily When they contract pull on the bones or skin and cause movment Cardiac Muscle – is found only in the heart As the muscle contracts the heart pumps Smooth Muscle – has not visible striations Long cells, found in walls of hollow organs like the stomach, uterus, blood vessels etc.

Nervous Tissue makes us think of neurons Neurons receive and conduct electrochemical impulses from one part of the body to another Irritability and Conductiveness are mayor resources

Tissue Repair Wound Healing

Injury to tissue occurs… Tissue repair has two major responses Regeneration Fibrosis 3 Steps: Inflammation sets the stage for injured cells allow for fluids and clotting proteins to take affect Granulation Tissue Forms- is the delicate pink tissue composed of new capillaries that grow into the damaged area and dispose of the blood clot formed earlier. Regeneration and Fibrosis cause permanent repair