Chapter 4: TISSUES IX. Tissues Intro Epithelial Tissue lining, covering, glandular tissue > Function protect, absorption, filtration, secretion, excretion Connective Tissue most widespread tissue type of the body > Function protect, support, binding connects body parts Muscle Tissue > Function contracts & shortens (movement) Nervous Tissue makes up brain, spinal cord, and nerves > Function communication/control cell - basic unit of life 1
X. Epithelial Tissue > Characteristics 1. Cells fit closely together (desmosomes & tight junctions) 2. One free surface or edge (apical); covered with microvilli, cilia, or smooth surface 3. Lower surface rests on a basement membrane 4. Avascular, it depends on diffusion from capillaries in underlying connective tissue for food & O 2 5. Regenerate quickly X. Epithelial Tissue cont'd Classification: by arrangement & shape > Arrangement: Simple: 1 layer of cells Stratified: more than 1 layer > Shape: Squamous: flattened Cuboidal: cube shape "like dice" Columnar: shaped like columns 2
X. Epithelial Tissue cont'd Simple Epithelium for absorption, secretion, & filtration A. Simple Squamous absorption, secretion, filtration - Air sacs of lungs, capillaries, serous membranes B. Simple Cuboidal lines glands and ducts (secretion & absorption) - Salivary glands, pancreas, kidney tubules C. Simple Columnar tall cells fit closely together (secretion&absorption) - In addition: Goblet cells line the digestive tract, mucus membranes D. Pseudostratified Ciliated Columnar "false impression" of being stratified Secretion of mucus (goblet cells) and lined with cilia - Line the respiratory tract 3
X. Epithelial Tissue cont'd Stratified Epithelium for protective purposes A. Stratified Squamous "most common" Several layers of squamous found on top of cuboidal or columnar on the basement membrane S kin, esophagus B. Stratified Cuboidal very rare C. Stratified Columnar very rare Transitional Epithelium highly modified, stratified squamous Cells have the ability to slide past one another (allows for stretching) F ound in Urinary System Glandular Epithelium make and secrete specific products Endocrine no ducts, produce hormones, diffuse into bloodstream Exocrine ducts are present, sweat and oil glands 4
XI. Connective Tissue > Characteristics 1. Most are vascularized tissue, having it's own blood supply Exceptions tendons, ligaments, cartilage 2. Have non living substances secreted outside the cells called extracellular matrix (ECM) 3. Heal slowly ground substance proteins fibers: collagen, elastic, reticular fibers... **Depending on the type of connective tissue the matrix can be liquid, gel like, semi solid, or very hard XI. Connective Tissue cont'd A. Bone Tissue cells are found in cavities called lacunae Surrounded by hard matrix, with large amounts of collagen fibers B. Cartilage Tissue rubbery matrix & also consists of large amounts of collagen fibers - Types: hyaline, elastic, fibrocartilage - Found where ribs connect to the sternum, ends of long bones C. Dense Connective Tissue made of almost exclusively collagen fibers - Types: dense regular, dense irregular, dense elastic - Makes up tendons & ligaments, dermis of skin D. Loose Connective Tissue: 1. Areolar Tissue fluid type of matrix Helps cushion and protect body organs 2. Adipose Tissue stores "fats", insulates, protects, & energy storage Found in subcutaneous layer under skin 3. Reticular Tissue major component of lymphatic system Found in lymph nodes, spleen, bone marrow E. Blood fluid matrix, referred to as our vascular tissue Consists of plasma, RBCs, WBCs, and blood clotting proteins 5
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XII. Muscle Tissue > Characteristics 1. Elongated cells = fibers 2. Highly specialized cells that have ability to contract/shorten to produce movements A. Skeletal Muscle (voluntary) Multi nucleated, striated, long cylinder shaped, arranged in bundles Cells that are attached to bones B. Cardiac Muscle (involuntary) Single nucleus, striated, long cylinder shaped but with branching ends, arranged in a figure 8 Connected by intercalated disks Cells that are only found making up the heart C. Smooth Muscle (involuntary) Non striated, spindle shaped that are pointed at ends, arranged in pairs Found surrounding hollow organs *Slow controlled contractions called peristalsis 7
XIII. Nervous Tisssue > Characteristics 1. Cells are called neurons 2. Irritability and conductivity functions 3. Cytoplasm extensions can be drawn out up to 3 feet long 4. Make up nerves, brain, and spinal cord XIV. Tissue Repair Regeneration replacement by same type of cells (no scar tissue) Fibrosis replacement by connective tissue (scar tissue) **The type of repair that occurs is dependent upon: > Type of tissue that is damaged > Severity of injury Steps to Repair: 1. INFLAMMATION a. Injured cells release inflammatory chemicals b. Capillaries dilate, become permeable to WBCs which will clean up mess (phagocytosis) c. Clotting proteins rush to injured area causing formation of a scab *Signs of inflammation: swelling, heat, redness, pain 2. ORGANIZATION a. Clot is replaced by granulation tissue (delicate pink tissue rich in capillaries and contains fibroblasts, collagen, phagocytes) b. Fibroblasts produce dense network of collagen fibers "scar tissue" aka "fibrous tissue" c. Phagocytes/Macrophages: "Janitors" eat blood clot 3. REGENERATION and/or FIBROSIS a. Depends on tissue b. Skin regenerates quickly c. Cardiac muscle replaced by fibrosis connective tissue 8
Epithelial Tissue Fibrous Connective Tissue Bone Tissue Skeletal Muscle Tissue Cardiac Muscle Tissue Nervous Tissue good regeneration good regeneration good regeneration poor regeneration, if at all replaced only by scar tissue replaced only by scar tissue 9
Attachments Cell Organelle & Transport Quiz 2015 16 2.docx