Transcript Notes #2
Tissue Notes Types of Tissue 1. Epithelial Tissue - lines all surfaces of the body including organs. Protects, secretes, absorbs, excretes. Ex: outer layer of skin, inside of mouth and stomach, tissue surrounding the body's organs, vessels, ducts. Characteristics of Epithelium • All have one exposed surface • Lack blood vessels-get nutrients by diffusion • Divide rapidly • Tightly packed to form barriers • Classified by shape and # of layers Shapes Layers Squamous-flattened Simple-one layer Cuboidal-cube shaped Stratified-multiple layers Columnar-column shaped Psuedo-stratified-looks layered TYPES OF EPITHELIAL TISSUE • Simple squamous epithelium-One layer, flattened shape, lines air sacs of lungs, capillaries, diffusion occurs easily. Easily damaged. • Simple cuboidal epithelium- one layer, cube shaped, covers ovaries, lines ducts of kidneys and other glands. Nuclei are central.(Free surface faces a lumen or hollow channel). Secretes and absorbs. • Simple columnar epithelium- One layer, elongated shape, some have cilia, made for absorption, secretion, lines uterus and digestive tract organs. ( contain goblet cells to secrete mucus to protect). Thick tissue protects underlying layers. • Pseudostratified columnar epithelium- appear layered but are not. Line respiratory system passages and have cilia to sweep away dust etc. (Goblet cells-also secrete mucus to trap particles). Protects and secretes. Moves things along. • Stratified squamous epithelium -thick multi-layered, forms outer layer of skin (which keratinizes-hardens), line oral cavity, esophagus, vagina, and anal canal ( all which are moist and don’t keratinize). Protects. • Stratified cuboidal epithelium -lines lareger ducts, salivary and sweat glands, mammary glands, ovarian follicles and seminiferous tubules ( all have lumen). Protects. • Stratified columnar epithelium -urethra of males, pharynx. Protects and secretes. Glandular Epithelium -secretes substances into ducts or body fluids. Exocrine glands-secrete products into ducts that open onto surfaces. Example: skin, lining of digestive tract. Endocrine glands-secrete products into tissue or blood. Transitional Epithelium- specialized to change shape in response to increased tension. Found in bladder, urethra, ureters (all stretch and prevent a barrier) 2. Connective Tissue - adds support and structure to the body. Contains fibrous strands of the protein collagen that add strength to connective tissue. Examples: inner layers of skin, tendons, ligaments, cartilage, bone, blood and fat tissue. Types of Connective Tissue • • • • • • • Loose connective Dense connective Hyaline cartilage Elastic cartilage Fibrocartilage Bone Blood 3. Muscle Tissue – specialized tissue that can contract. Contains actin and myosin filaments. Examples: Heart muscle, muscles lining digestive canal and muscles throughout your body. Cardiac muscle Smooth muscle Striated muscle 4. Nerve Tissue -nerve tissue that has the ability to generate and conduct electrical signals in the body. Examples: neurons and glial cells