1Biology: Human Anatomy and PhysiologyCH. 4: THE TISSUE LEVEL OF ORGANIZATION1.Define the term tissue, and classify the tissues of the body into four major types.A.tissue●A tissue is a group of cells that usually have a common origin and function, andthey work together to carry out a specific activity.B.histology●The science that deals with the study of tissuesI.epithelial tissue●covers body surfaces and lines hollow organs, body cavities, and ducts; italso forms glands. This tissue allows the body to interact with both itsinternal and external environments.●Most common type of tissueII.connective tissue●protects and supports the body and its organs. Various types ofconnective tissues bind organs together, store energy reserves as fat, andhelp provide the body with immunity to disease-causing organisms.III.muscular tissue●is composed of cells specialized for contraction and generation of force.In the process, muscular tissue generates heat that warms the body.IV.nervous tissue●detects changes in a variety of conditions inside and outside the body andresponds by generating electrical signals called nerve action potentials(nerve impulses) that activate muscular contractions and glandularsecretions.2.What are some key differences in function among thefour tissue types?●Epithelial tissuecovers the body, lines various structures, and forms glands.●Connective tissueprotects, supports, binds organs together, stores energy, and helpsprovide immunity.●Muscular tissuecontracts and generates force and heat.●Nervous tissuedetects changes in the environment and generates nerve impulses thatactivate muscular contraction and glandular secretion3.What is abiopsy?●A biopsy is the surgical removal of a sample via a needle or syringe of living tissue formicroscopic examination.●This is used to help diagnose many disorder, especially cancer.4.Describe the structure and functions of the five principal types of cell junctions.A.cell junction
2●Cell junctions Are contact points between the plasma membranes of the tissuecells. There are five different types of cell junctions:1.tight junction➔Web like strands of transmembrane proteins.they fused togetherthe outside surfaces of the adjacent plasma membrane➔they allow the passage of substances between cells and preventthe contents of the organs from leaking into the blood orsurrounding tissue.➔tissues that line the stomach,intestines,urinary bladder.2.adherens junction➔These contain plaque,which is a dense layer of protein on theinside of the plasma membrane,this attaches both to themembrane protein and to the microfilaments of the cytoskeleton.➔Cadherins join the cells➔These Junctions are known for zones called “adhesion belts”because they encircle the cell.