Interpreting Tissue Polarity Basement Membrane Basal Lamina glycoproteins
Interpreting Tissue
Polarity • ___________ • Basement Membrane • Basal Lamina – glycoproteins • Reticular Lamina – collagen of CT
Epithelia: Simple Squamous Description: Single layer of flattened cells Central nuclei Function: Passage of materials by (diffusion & filtration) Location: Kidney, lungs, heart
Epithelia: Stratified Squamous Description: Thick membrane of several layers Basal cells- Cuboidal / Columnar Apical cells- Squamousal (Keratin) Function: Protects underlying tissues Location: Nonkeratinized- moist lining of esophagus, mouth, vagina Keratinized- epidermis of skin
Epithelia: Simple Cuboidal Description: Single layer of cube-like cells Large central nuclei Function: Secretion and absorption Location: Kidney tubules, ducts, ovaries
Epithelia: Stratified Cuboidal Description: Several cell layers Basal cells- Cuboidal Apical cells- Cuboidal Function: Secretion & Protection Location: Ducts of larger glands (sweat glands, mammary glands)
Epithelia: Simple Columnar Description: Single layer of tall cells Round/Oval nuclei Function: Absorption & Secretion Location: Nonciliated most of digestive, some excretory ducts Ciliated lines small bronchi, uterine tubes
Epithelia: Stratified Columnar Description: Several cell layers Function: Secretion & Protection Location: Pharynx, male urethra
Epithelia: Pseudostratified Columnar Description: Single layer w/ differing heights Nuclei at varying levels Function: Secretion (mainly mucus) Location: Nonciliated in sperm-carrying ducts & large glands Ciliated lines the trachea & upper respiratory
Epithelia: Transitional Description: Several cell layers Basal cells- Cuboidal Apical cells- Squamousal-like Function: Stretches to permit distension Location: Urinary bladder, ureters, and part of the urethra
Modes of Secretion • ________– exocytosis (e. g. , pancreas, sweat, and salivary glands) • ________– rupturing of gland cells (e. g. , sebaceous glands) • _______ –pinching off of the tip of the cell (controversial for humans)
Proteoglycans
Fibers (model)
Connective Tissue: Embryonic Mesenchyme Description: Gel-like ground substance with fibers and star-shaped mesenchymal cells Function: Basis for all connective tissue Location: Primarily in Embryo
Connective Tissue: Wharton’s Jelly Description: Jelly-like tissue Matrix composed of: hyaluronic acid (binds cells / lubricates) chondroitin sulfate (support / adhesive) Function: Stem Cell Production Location: Umbilical Cord
Connective Tissue Proper: Loose (areolar) Description: Gel-like matrix w/ all 3 fiber types Macrophages, mast cells, WBC Function: Wraps & cushions organs Phagocytize bacteria Location: Widely distributed under epithelia (forms lamina propria)
Connective Tissue Proper: Loose (adipose) Description: Matrix like areolar (sparse) Closely packed adipocytes(fat cell) Function: Reserve food fuel Insulates and protects Location: Under skin, around kidneys & eyes Abdomen and breasts
Connective Tissue Proper: Loose (reticular) Description: Loose ground substance w/ reticular fibers Reticular cells lie in a fiber network Function: Forms soft internal skeleton that supports other cells Location: Lymph nodes, bone marrow, spleen
Connective Tissue Proper: Dense Regular Description: Parallel collagen fibers Major cell type is fibroblast Function: Attaches muscle to bone Attaches bone to bone Location: Tendons and most ligaments
Connective Tissue Proper: Dense Irregular Description: Irregular collagen fibers Major cell type is fibroblast Function: Withstand tension in many directions Location: Dermis of skin Submucosa of digestive tract Fibrous capsules of organs / joints
(f) Connective tissue proper: dense connective tissue, elastic Description: Dense regular connective tissue containing a high proportion of elastic fibers. Function: Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration. Elastic fibers Location: Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes. Aorta Heart Photomicrograph: Elastic connective tissue in the wall of the aorta (250 x).
Connective Tissue: Hyaline Cartilage Description: Network lacking shape but held together w/ collagen fibers Function: Supports and reinforces Location: Ends of long bones, ribs, nose Most of embryonic skeleton
Connective Tissue: Elastic Cartilage Description: Similar to hyaline but more elastic fibers Function: Maintains shape w/ flexibility Location: Supports external ear, epiglottis
Connective Tissue: Fibrocartilage Cartilage Description: Similar to hyaline but less firm Thick collagen fibers predominate Function: Tensile strength w/ ability to absorb shock Location: Intervertebral discs Discs of knee joint
Connective Tissue: Bone (Osseous Tissue) Description: Hard, calcified matrix w/ collagen Very well vascularized Function: Bone supports and protects Levers for muscle contraction Stores calcium & minerals Marrow is blood formation Location: Bones
Connective Tissue: Blood Description: Red & White Blood cells in fluid matrix Function: Transport of respiratory gases, nutrients, waste & substances Location: Within blood vessels
Nervous Tissue Description: Branching cells May be quite long Function: Transmit electrical signals Location: Brain, spinal cord & nerves
Muscle Tissue: Skeletal (striated) (a) Skeletal muscle Description: Long, cylindrical, multinucleate cells; obvious striations. Function: Voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control. Location: In skeletal muscles attached to bones or occasionally to skin. Photomicrograph: Skeletal muscle (approx. 460 x). Notice the obvious banding pattern and the fact that these large cells are multinucleate.
Muscle Tissue: Cardiac (b) Cardiac muscle Description: Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs). Intercalated discs Function: As it contracts, it propels blood into the circulation; involuntary control. Location: The walls of the heart. Photomicrograph: Cardiac muscle (500 X); notice the striations, branching of cells, and the intercalated discs.
Muscle Tissue: Smooth (visceral) (c) Smooth muscle Description: Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets. Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control. Location: Mostly in the walls of hollow organs. Photomicrograph: Sheet of smooth muscle (200 x).
Cutaneous Membrane • Cutaneous = _____ • Covers surface of body • _________, stratified squamous epithelium • _________& dense irregular CT • ___________& dry
Mucous Membranes • Line body cavities open to the exterior • Moist epithelia • • • Columnar CT = ______ • • Stratified squamous Lamina propria Absorption, secretion & protection Figure 4. 11
Serous Membranes • Closed ventral body cavities • Simple squamous • Thin areolar CT • Produce watery secretion • _____________: • Parietal lines cavity • Visceral covers organs
Tissue Repair - Inflammation • Trauma causes release of _________ • Capillaries dilate & become very permeable • WBCs, antibodies, clotting proteins • ___________ • • Stop blood loss Hold edges together Isolate injured area Exposed part = scab
Tissue Repair • __________ • • Surface epithelium regenerates • Grows under scab until scab falls off • Gets thicker until resembles ___________________ • Fibrous tissue matures • Never quite matches original
Tissue Repair - Results • Fully regenerated epithelium • Underlying _________
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