Hole’s Human Anatomy and Physiology 1 Chapter 5 Tissues Four major tissue types 1. Epithelial 2. Connective 3. Muscle 4. Nervous 2 Epithelial Tissues General characteristics - • cover organs and the body • line body cavities • line hollow organs • have a free surface • have a basement membrane • avascular • cells readily divide • cells tightly packed • cells often have desmosomes • function in protection, secretion, absorption, and excretion • classified according to cell shape and number of cell layers 3 Epithelial Tissues Simple squamous – Simple cuboidal – • single layer of flat cells • single layer of cube-shaped • substances pass easily through cells • line air sacs • line kidney tubules • line blood vessels • cover ovaries • line lymphatic vessels • line ducts of some glands 4 Epithelial Tissues Simple columnar – Pseudostratified columnar – • single layer of elongated cells • single layer of elongated cells • nuclei usually near the basement • nuclei at two or more levels membrane at same level • appear striated • sometimes possess cilia • often have cilia • sometimes possess microvilli • often have goblet cells • often have goblet cells • line respiratory passageways • line uterus, stomach, intestines 5 Epithelial Tissues Stratified squamous – Stratified cuboidal – • many cell layers • 2-3 layers • top cells are flat • cube-shaped cells • can accumulate keratin • line ducts of mammary glands, • outer layer of skin sweat glands, salivary glands, • line oral cavity, vagina, and and the pancreas anal canal 6 Epithelial Tissues Stratified columnar – Transitional – • top layer of elongated cells • many cell layers • cube-shaped cells in deeper • cube-shaped and elongated layers cells • line part of male urethra and • line urinary bladder, part of pharynx ureters, and part of urethra 7 Glandular Epithelium Composed of cells that are specialized to produce and secrete substances Endocrine glands are ductless Exocrine glands have ducts Unicellular exocrine gland • composed of one cell • goblet cell Multicellular exocrine gland • composed of many cells • sweat glands, salivary glands, etc. • simple and compound 8 Structural Types of Exocrine Glands 9 Types of Glandular Secretions Merocrine glands Apocrine glands Holocrine glands • fluid product • cellular product • secretory products • salivary glands • portions of cells • whole cells • pancreas • mammary glands • sebaceous glands • sweat glands • ceruminous glands 10 Connective Tissues General characteristics - • most abundant tissue type • many functions • bind structures • provide support and protection • serve as frameworks • fill spaces • store fat • produce blood cells • protect against infections • help repair tissue damage • have a matrix • have varying degrees of vascularity • have cells that usually divide 11 Connective Tissue Major Cell Types Fibroblasts Macrophages • fixed cell • wandering cell • most common cell • phagocytic • large, star-shaped • important in injury • produce fibers or infection Mast cells • fixed cell • release heparin • release histamine 12 Connective Tissue Fibers Collagenous fibers Elastic fibers • thick • bundles of • composed of collagen microfibrils embedded • great tensile strength in elastin • abundant in dense CT • fibers branch • hold structures together • elastic • tendons, ligaments • vocal cords, air passages Reticular fibers • very thin collagenous fibers • highly branched • form supportive networks 13 Connective Tissues Connective tissue proper Specialized connective tissue • loose connective tissue • cartilage • adipose tissue • bone • reticular connective tissue • blood • dense connective tissue • elastic connective tissue 14 Connective Tissues Loose connective tissue Adipose tissue • mainly fibroblasts • adipocytes • fluid to gel-like matrix • cushions • collagenous fibers • insulates • elastic fibers • store fats • bind skin to structures • beneath skin • beneath most epithelia • behind eyeballs • blood vessels nourish • around kidneys and heart nearby epithelial cells • between muscles 15 Connective Tissues Reticular connective tissue Dense connective tissue • composed of reticular fibers • packed collagenous fibers • supports internal organ • elastic fibers walls • few fibroblasts • walls of liver, spleen, • bind body parts together lymphatic organs • tendons, ligaments, dermis • poor blood supply 16 Connective Tissues Elastic connective tissue Bone (Osseous Tissue) • abundant in elastic fibers • solid matrix • some collagenous fibers • supports • fibroblasts • protects • attachments between bones • forms blood cells • walls of large arteries, airways, heart • attachment for muscles • skeleton • osteocytes in lacunae 17 Connective Tissues Hyaline cartilage • most abundant Cartilage • ends of bones • rigid matrix • nose, respiratory passages • chondrocytes in lacunae • embryonic skeleton • poor blood supply • three types Elastic cartilage • hyaline • flexible • elastic • external ear, larynx • fibrocartilage Fibrocartilage • very tough • shock absorber • intervertebral discs • pads of knee and pelvic girdle 18 Connective Tissues Three types of cartilage Hyaline Cartilage Elastic Cartilage Fibrocartilage 19 Connective Tissues Blood • fluid matrix called plasma • red blood cells • white blood cells • platelets • transports • defends • involved in clotting • throughout body in blood vessels • heart 20 Muscle Tissues Skeletal muscle • attached to bones • striated General characteristics • voluntary • muscle cells called Smooth muscle muscle fibers • walls of organs • contractile • skin • three types • walls of blood vessels • skeletal • involuntary • smooth • not striated • cardiac Cardiac muscle • heart wall • involuntary • striated • intercalated discs 21 Muscle Tissues Skeletal Muscle Smooth Muscle Cardiac Muscle 22 Nervous Tissues • found in brain, spinal cord, and peripheral nerves • basic cells are neurons • neuroglial cells support and bind nervous tissue components • sensory reception • conduction of nerve impulses 23 Types of Epithelial Membranes Mucous Serous • line tubes and organs • line body cavities that open to outside world that do not open to • lining of mouth, nose, the outside throat, etc. • reduce friction • secrete mucus • inner lining of Cutaneous thorax and abdomen •covers body • cover organs of • skin thorax and abdomen • secrete serous fluid Synovial • composed entirely of connective tissue • lines joints 24 Clinical Application The Extracellular Matrix: The Body’s Glue Cancer Heart Failure and Atherosclerosis • fibroblasts become more • imbalances of collagen production contractile, take on cancer and degradation cell characteristics and secrete • ECM buildup may block blood flow abundant collagen in the arteries and the heart Liver Fibrosis • collagen deposit increases • ECM exceeds normal 3% value and may block blood flow 25 Clinical Application Collagen Disorders Chondrodysplasia Dystrophic epidermolysis bullosa • collagen chains too wide • breakdown of collagen that attaches • stunted growth skin layers • deformed joints • stretchy skin • lax joints Hereditary osteoarthritis • change in amino acid in collagen • painful joints 26.