Anatomy - Tissues

Basic funtions are protection, absorption, filtration and secreation.

Epithelial cells fit closely together to form continuous sheets. Neighboring cells are bound together at many pionts by cell junctions, including desmosomes and tight juctions.

The membranes always have one unattached surface or edge. This so called apical surface is exposed to the bodys exterior or to the cavity of an internal organ. The exposed surfaces of some epithelia are slick and smooth, but others exhibit cell surface modifications, such as microvilla or cilia.

The lower surface of an epithelium rests on a basement membrane, a structureless matierial secreted by cells.

Epithelial tissues have no blood supply of thier own (avascular) and depend on diffusion from capillaries in the underlying connective tissue.

If well nourished, regenerate easily.

• Classified by number of cell layers and the shape of the cells.
• Simple: one layer
• Stratified: more than one layer
• Sqaumos: Flat
• Cubiodal: cube like
• Columnar: tall, colunm like

• D: Single layer of thin cells resting on basement membrane
• L: Air sacs in lungs and walls of cappilaries
• F: Forms membranes where filtration and exchange of substances occur. Forms serosae which are slick membranes that line the ventral body cavity and its organs.

• D: Single layer of cuboidal cells resting on basement membrane
• L: Glands and there ducts
• F: Forms walls of kidney tubules and covers surface of ovaries

• D: Single layer of tall cells of basement membrane. Goblet cells: produce lubricating mucus
• L: Entire length of digestive tract
• F: Form mucosae which is epithelial membranes that line body cavities open to body exterior.

• D: All rest on basement membrane. Fake stratified, looks multi layered, is not.  
• F: Focused in absorption ad secreation.

• D: All rest on basement membrane. Fake stratified, looks multi layered, is not. 
• L: Respiratory tract
• F: Mucus produced by goblet cells in this epithelum traps dust and the cilia propel the mucus upward away from the lungs.

• D: Most common, multiple layers, flat cells near surface but cuboidal or columnar near beasement membrane.
• L:Areas with lots of friction: esophogus, mouth, and outerportion of skin.
• F: Protect areas with loys of friction.

• Cubiodal
• D: Two cell layers and the surface ones are cubiodal. Rare.
• Columnar
• D:Surface cells Columnar. Rare.
• L: Ducts of large glands

• D: Highly modified. Subject to cosiderable stretching. Basal layer cubiodal or columnar.
• L: Urinary bladder, ureters, and part of urthera.
• F: To strech when distilled with urine to help more urine get through.

• D: Gland: one or more cells that move and secrete particular product that contains protien molecules in aqueous solution.
• L: Endocrine: Thyriod, adrenals and pituitary. Exocrine: Sweat and oil glands, liver and pancreas.
• Two major types of glands:
• Endocrine: Lose connection to surface of duct. All secreations are all hormones and diffuse directly into blood vessels that weave through the glands.
• Exocrine: Retain ducts, secretions empty through ducts to surface. Internal and external.

To connect body parts. Most distributed and abudant.

• 1. Variations in blood supply. Most connective tissues have good blood supply but there are exceptions such as tendons and ligaments, because of low blood supply they heal slowly.
• 2. Extracellular Matrix: Connective tissue are made up of many different types of cells, plus varying amount of non-living substance found outside cells called extracellular matrix.

• D: Osseous tissue. Bone cells sitting in cavities called Lacunae and surrounded by layers of a very hard matrix that contains calcium salts and collogen fibers.  ◦
• L: Everywhere ◦
• F: Protect and support other organs.

• D: Most abudant. Collogen fibers hidden in rubbery matrix with glassy appearence. ◦
• L: Apart of structure that support larynx, and voice box. ◦
• F: Forms joints, support structures.

• D: Less hard and more flexible than bone. 
• L: Disks between vertebraes 
• F: Forms cushlike disks between vertebraes

• D: Less hard and more flexible than bone 
• L: External Ear  
• F: Support

• D: Collogen fibers are in its main matrix element. Crowded between the collogen fibers are rows of fibroblasts (fiber forming cells) that manufacture the fibers. Ropelike. 
• L: Everywhere 
• F: Attach skeletal muscle to bones

• D: Collogen fibers are in its main matrix element. Crowded between the collogen fibers are rows of fibroblasts (fiber forming cells) that manufacture the fibers. Ropelike.  
• L: Everywhere 
• F: Connect bones to bones

• D: Most widely distributed.  Cobwebby.  
• L: Organs 
• F: Cushion and protect the organ it wraps. Universal packing tissue. "Glue" - helps hold internal organs in place and together.

• D: Fat. Areolar tissueis where fat cells predominate.Fat cells are also called Signet ring cells.  
• L: Protects some orgns individually such as Kidneys and eyeballs. Also fat deposets on hip bones and breasts.  
• F: Forms subcutaneous tissue beneath skin that insulates body and protects from extremes of both hot and cold.

• D: Delicate network of interwoven recticular fibers assoicated with recticular cells which resemble fibroblast.  
• L: Lymphoid organs: Lymphnodes, spleen, and bone marrow.  
• F: Forms stroma , or internal supporting framework which can support many freeblood cells in lymphnode organs.

• D: Vascular Tissue. Is considered connective tissue because it consists of blood cells surrounded by a non living fluid matrix called blood plasma. Fibers of blood are soluble protien molecules that become visible only during blood clotting. 
• L: Everywhere  
• F: Transport vehicle for cardiovascular system carrying nutriets, wastes, respiratory gases and other substances.

Highly specialized to contract and shorten to produced movement.

• Is packaged by connective tissue sheets into organs call skeletal muscle which are attached to the skeleton.  
• Controlled Voluntary 
• When skeletal muscles contract they pull on bones or skin resulting in gross body movement or changes in facial expressions.  
• Long 
• Cylindrical 
• Multinucleic 
• Striations

• Found only in heart 
• As heart contracts it pumps and propels blood through blood vessels through out the body.  
• Striations 
• Unnucleic 
• Branching cells that fit closely together at junctions called intercalated disks which contain gap junctions that allows ions to pass freely from cell to cell resulting in rapid conduction of the exciting electrical impulse across the heart. 
• Involuntary control.

• or viseral muscle. ◦No striations ◦Single nucleus  
• Spindle shaped 
• Found in walls of hollow organs such as stomach, blatter, uterus and blood vessels.  
• When smooth muscle contracts the organ becomes smaller or bigger so that substances are propelled through the organ along a specific pathway.  
• Contracts slower 
• Peristalis: a wave like motion that keeps food moving through small intestine.

• Neurons: All neurons recieve and conduct electrochemical impulses from one part of the body to another: thus irritability and conductivity are thier two major fuctional characterics. 
• Unique Structure: Cytoplasm is drawn out into long extentions which allows a single neuron to conduct an impulse ocer long distances in the body.  
• Neurons and supporting cells that insulate, support, and protect the delecate neurons, make up th structures of the nervous system.

• Regeneration: is the replacement of destroyed tissue by the same kind of cells.   
• Fibrosis: involves repair by dense (fibrous) connective tissue by the formation of scar tissue. Fibrosis depends on: the type of tissue damaged, and severity of injury.  
• When tissue is damaged there is a series of things set into motion: Cappilaries become very permiable (to allow fluid rich in clotting protiens and other substances to seep into injured area through blood stream. These protiens construct a clot which stops loss of blood, holds wounds to together to keep from bacteria to get into the wound, then when exposed to air it quickly dries and hardens forming a scab.) , granulation tissue form (contians phagocytes that eventually diposes of blood clot and fibroblasts that synthesize collogen fibersro perminetly bridge the gap.) and, surface epithelium regenerates. (As it regenerates it makes its way across the granulation tissue just beneath the scab which soon detaches.)

• Cell division is extremly important
• Most cells undergo mitosis tell the end of puberty
• Cell groups completely lose ability to divide when they are fully mature and become amitotic.
• Amitotic cells can become serverly handicapped because if damaged cannot be replaced by the same type of cells but then are instead replaced by scar tissue which cannot cotract and not function prperly because of this.
• Neoplasm: When cells fail to honor normal controls on cell division and multipy wildly and create an abnormal mass.
• Hyperplasia: When certain body tissues enlarge because there is soome local iritant or conditoin taht stimulates cells
• Atrophy: Decrease in size can occur in an organ or body area that loses its normal stimulation