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Epithelial Tissue (Epithelium)
Forms large continuous sheets.
Helps form the skin and covers the entire outer surface of the body.
Lining for internal organs.
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Epithelial tissue functions
- Protection/barrier (sun, water)
- Filtration (O2/CO2)
- Absorption (intestines)
- Secretion (sweat, mucus glands)
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Epithelial tissue characteristics
- Forms continuous sheets (ex. fish scales)
- Has two surfaces, 1)unattached and 2) attached.
- Avascular; has NO blood supply of its own
- Depends on blood supply of underlying connective tissue for nurishment
- Able to regenerate or repair itself quickly
- Classified according to cell shape and layers
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Epithelial tissue Shapes
- Squamos epithelium; cells are thin and flat like fish scales
- Cuboidal epithelium; cells are cube-like and look like dice
- Columnar epithelium; cells are tall and narrow and look like columns
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Epithelial tissue layers
- Simple epithelium; One layer of cells
- Stratified epithelium; Two or more layers of cells
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Simple Epithelia
Because they are so thin, they're concerned primarily with movement or transport of various substances across the membranes from one body compartment to another.
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Simple Squamous epithelium
A single layer of squamous cells with an underlying basement of membrane.
Found where substances move by rapid diffusion or filtration.
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Simple Cuboidal epithelium
Rests against basement membrane
Often found in glands & Kidney tubules
Functions in the transport and secretion of various substances
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Simple Columnar epithelium
Rests on basement membrane
Tall tightly packed cells line entire stomach (digestive tract)
Goblet cells-modified columnar cells
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Pseudostratified columnar
"falsely stratified", appear multilayered
Facilitate absorption and secretion
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Stratified epithelia
- Multilayered (2-20 layers)
- Stronger than simple epithelium
- Protection function
- Found in tissue exposed to everyday wear and tear (ex. mouth, esophagus, skin)
Stratified Squamous=most widespread epithelial tissue
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Transitional Epithelium
- Found primarily in organs that stretch (bladder)
- Cells slide past one another when tissue stretched
- Appear stratified when unstretched, simple when stretched
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Glandular Epithelia
- Secretion
- Much is composed of simple cuboidal epithelium
- Exocrine glands
- Endocrine glands
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Exocrine Glands
Have ducts, tiny tubes, into which the exocrine secretions are released
Secretions include: mucus, sweat, saliva, and digestive enzymes
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Endocrine Glands
- Secrete hormones directly into blood, such as insulin
- Ductless glands
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Connective Tissue
- The most abundant of tissues
- Widely distributed throughout body
- Binds together the parts of the body
- Supports, protects, fat storage, and transport of substances
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Connective Tissue Characteristics
- Good blood supply (except ligaments, tendons, and cartilage)
- Abundance of intercellular matrix (may be liquid, gel-like/hard that fills btwn cells)
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Blast Cells
- found in connective tissue
- secrete matrix that is characteristic of that matrix
- ex. Fibroblasts (cells found in dense fibrous cells); Chondroblasts (found in cartilage)
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(3) Types of connective tissue
- 1. Loose connective tissue; Areolar, Adipose, Reticular
- 2. Dense fibrous; Tendons, ligaments, cartilage, Bone tissue
- 3. Liquid tissue; Blood (plasma) and lymph
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Loose Connective Tissue
- Contains fibers that are loosely arranged around cells.
- Areolar tissue; made up of collagen and elastin fibers, "Tissue glue", most widely distributed connective tissue
- Adipose tissue; fat, composed of adipocytes (cells that store fat)
- Reticular tissue; (fine collagen) loose fibers
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Dense Fibrous Connective Tissue
- Composed of fibroblasts and intercellular matrix, containing Collagen and Elastic Fibers
- Tendons; cordlike structures that attach muscles to bones
- Ligaments; cross joints and attach bone to bone. Ability to stretch easily.
- Fascia; sheets of tissue that covers, supports and anchors organs to nearby structures
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Cartilage
(Dense Fibrous connective tissue)
- Formed by chondroblasts that eventually mature into chondrocytes (cartilage cells)
- Three types of cartilage
- Hyaline; found in the larynx, end of long bones at joints, the nose, and area between breastbone and ribs
- Elastic
- Fibrocartilage
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Bone
(Dense Fibrous connective tissue)
- AKA Osseous tissue
- formed by Osteocytes (bone cells)-hard intercellular matrix: collagen, calcium salts, and other minerals.
- Protects organs and supports weight of the body
- Storage site for mineral salts (calcium)
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Blood and Lymph
(Liquid Connective Tissue)
- Watery intercellular matrix
- Blood=plasma
- Lymphatic vessels=lymph
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Nervous tissue
- Makes up the brain, spinal cord, and nerves
- Two types of cells: Neurons and Neuroglia
- Neurons; transmit electrical signals, has dendrites, cell body, and axons
- Neuroglia; supports and takes care of neurons, ability to bind and form vast network of neurons
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Muscle Tissue
- Cells that shorten or contract thereby causing movement.
- Fibers not cells b/c they are long and slender
- Three types: Skeletal, smooth, and cardiac
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Tissue Repair
- Regeneration; replacement of tissue by cells that undergo mitosis (Skin)
- Fibrosis; formation of scar tissue
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Membranes
- Thin sheets of tissue that cover surfaces, line body cavities, and surround organs.
- Epithelial and Connective tissue
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Epithelial Membranes
- Cutaneous Membrane; the skin
- Mucous Membrane; epithelial membranes that line all body cavities that open to the exterior of the body, secrete mucus (mouth, eyes, anus)
- Serous Membranes; epithelial membranes that line the ventral body cavities which are not open to the exterior of the body.
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Serous membranes
- Parietal layer; lines the wall of the cavity
- Visceral layer; covers the outside of an organ
- Three serous membranes: Pleura, pericardium, peritoneum
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Connective tissue Membranes
- synovial membranes
- perisoteum
- perichondrium
- meninges
- fascia
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Quiz QUESTION HELP
http://quizlet.com/14133953/chapter-6-tissues-and-membranes-flash-cards/
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