Cells and Tissues PDF

CELLS AND TISSUES Body Tissues ❑Group of similar cells 4 PRIMARY TISSUES thar are similar in 1. EPITHELIA/EPITHELIUM structure and function 2. CONNECTIVE 3. MUSCULAR 4. NERVOUS Simple Epithelia TYPES ❑Absorptio...

CELLS AND TISSUES Body Tissues ❑Group of similar cells 4 PRIMARY TISSUES thar are similar in 1. EPITHELIA/EPITHELIUM structure and function 2. CONNECTIVE 3. MUSCULAR 4. NERVOUS Simple Epithelia TYPES ❑Absorption, secretion and 1. Simple squamous epithelium filtration ❑Usually forms membranes, where ❑Selective barrier filtration or exchange of substances by rapid diffusion occurs. ❑Usually very thin, protection ❑Air sacs of the lungs, forms the is not one of their specialty wall of capillaries ❑Forms serous membrane or serosae that slick membranes that line the ventral body cavity and cover the organs in that cavity TYPES 2. Simple cuboidal epithelium 3. Simple columnar epithelium ❑Common in gland and their ❑Goblet cells which produce a ducts lubricating mucus ❑Walls of the kidney tubules and ❑Lines the entire length of the covers the surface of ovaries digestive tract from stomach to anus ❑Nonciliated ❑Ciliated simple columnar epithelium TYPES 4. Pseudostratified columnar epithelium ❑Absorption and secretion ❑Pseudostratified ciliated columnar epithelium STRATIFIED EPITHELIA TYPES ❑Protection 1. Stratified squamous epithelium ❑Most common ❑The cells at the free edge are squamous, where those close to the basement membrane are cuboidal or columnar ❑Esophagus, mouth, vagina and outer portion of the skin  TYPES 2. Stratified cuboidal epithelium and stratified columnar epithelium ❑Fairly rare in the body , found mainly in ducts of large glands 3. Transitional epithelium ❑Highly modified stratified squamous epithelium that forms the lining of only a few organs- urinary bladder, ureters, and part of urethra ❑Cells of the basal layer – cuboidal or columnar ❑Slide past one another and change their shape  TYPES OF CONNECTIVE TISSUE A. loose connective tissue fibers in the extracellular matrix are loosely arranged. Collagen, elastic, and reticular fibers in this tissue provide strength, elasticity, and support. Ground substance is semi-fluid (viscous), but interstitial fluid can easily diffuse through it. Fibroblasts and adipocytes (lipid-storing cells) permanently reside in the tissue. TYPES OF CONNECTIVE TISSUE B. Dense connective tissues The extracellular matrix of dense connective tissue is packed with fibers and contains very little ground substance and few fibroblasts. A. Loose Connective Tissue a.1. areolar - is the most abundant connective tissue type. It contains fibroblasts, all three fiber types, a semi-fluid (viscous) ground substance, and a variety of cells involved in body defenses. a.2. reticular - Reticular (reticulo- = net-like) fibers are the dominant fiber type in reticular connective tissue. a.3. adipose tissues- Adipose (adipo- = pertaining to fat) tissue adipose tissue has a greater number of adipocytes (lipid storing cells) and very little extracellular matrix. Checkpoint!  B. Dense Connective Tissue 1. Dense regular connective tissue, the extracellular matrix is packed with parallel bundles of collagen fibers Fibroblasts are squeezed between the bundles Often called white fibrous tissue 2. Dense irregular connective tissue, like dense regular connective tissue, has little ground substance and few fibroblasts. The extracellular space is also packed with bundles of collagen fibers with fibroblasts squeezed between these bundles. the bundles of collagen fibers are irregularly arranged. B. Dense Connective Tissue 3. In elastic connective tissue, the extracellular matrix is packed with elastic fibers, and fibroblasts are found in the spaces between these fibers. Elastic fibers allow the tissue to be stretched and then regain its original size and shape (recoil). Specialized form of connective tissue. Cartilage Its extracellular matrix consists of collagen and elastic fibers embedded in a firm gelatinous ground substance. Chondroblasts (chondro- = cartilage) secrete the fibers and ground substance, become isolated in spaces called lacunae (little lakes), and transform into chondrocytes. avascular  Three Types of Cartilage a. hyaline (hyalos = glass) - the most predominant cartilage in the body and contains fine collagen fibers in the extracellular matrix. It contains collagen fibers that are thin and not visible with a compound microscope b. elastic - similar to hyaline cartilage, except the matrix is packed with elastic fibers. The many elastic fibers allow this cartilage to be much more flexible. a. Fibrocartilage- has fewer lacunae and chondrocytes, and its extracellular matrix is packed with thick collagen fibers that give it tensile strength similar to dense connective tissue. Under the microscope, collagen fibers are the most prevalent structures seen.  B. Connective tissue Bone The extracellular matrix is organized in layers called lamellae and consists of collagen fibers, ground substance, and inorganic salts. Osteocytes (mature bone cells) are trapped in spaces called lacunae. Small canals called canaliculi connect lacunae to each other and to larger canals that contain blood vessels. Nutrients diffuse from a blood vessel through the canaliculi to the osteocytes, and waste materials diffuse back to the blood vessel for removal. The two types of bone tissue 1. compact (cortical) bone - The extracellular matrix of compact bone is organized into repeating structural units called osteons. In the center of each osteon is a large central canal. 2. spongy (cancellous or trabecular) bone -has large spaces compared to compact bone and does not have osteons. Instead, the extracellular matrix of spongy bone is arranged in trabeculae (little beams)—flat plates with a lattice-like network of thin, bony columns. B. Connective Tissue Blood - composed of red blood cells, white blood cells, platelets, and plasma. Plasma is the extracellular matrix, and its fibers C. Muscle Tissue causes movement -very cellular, with three types of muscle tissue most of the tissue consisting of muscle A. Skeletal muscle cells cells B. Cardiac muscle cells All muscle tissues are highly vascularized and are innervated. C. Smooth muscle cells Muscle cells are elongated cells called fibers that shorten (contract) when stimulated, causing movement.  D. Nervous Tissue forms the brain, spinal cord, and nerves, is very cellular two basic types of nervous tissue cells 1. Neurons receive and send information 2. Neuroglia support the neurons and help them to function. Neurons have one or more processes (cellular extensions) that receive or send information as nerve impulses. Inflammatory Response