Medic14HistologyCh4

Study of tissues

Epithelial, connective, muscle and neural

Includes epithelia and glands. Epithelia are layers of cells that cover internal or external surfaces. Glands are composed of secreting cells derived from epithelia. Four basic functions: provide physical protection, control permeability, provide sensation and produce specialized secretions.

Secretions that are discharged onto the surface of the epithelium. Ex: enzymes within digestive tract, perspiration on the skin, and milk produced in mammary glands. 

Secretions that are released into the surrounding tissue fluid and blood. These secretions are called hormones and act as chemical messengers and regulate or coordinate the activities of other tissues, organs and organ systems. Mainly produced in organs such as pancreas, thyroid and pituitary gland. 

CAM's and Intercellular Cement (a protein-polysaccharide mixture) are specialized transmembrane proteins that form effective barriers in undamaged epithelia

The lipid layers of adjacent cell membranes are tightly bound together by interlocking membrane proteins. Ex: lining of stomach to keep contents from damaging underlying tissue

Two cells are held together by embedded membrane proteins. THey are channel proteins, forming a narrow passageway that lets small molecules and ions pass from cell to cell. Most abundant in cardiac muscle and smooth muscle tissue.

The cell membranes of two cells are locked together by intercellular cement and by membrane proteins connected to a network of intermediate filaments. Abundant between cells in the superficial layers of the skin.

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• Simple- secretions or absorption 
• Stratified- protection

Most common mode of secretion. The product is released from secretory vesicles by exocytosis. Ex: Mucus

Involves the loss of both cytoplasm and the secretory product. The outermost portion of the cytoplasm becomes packed with secretory vesicles before it is shed. Ex: Milk from mammary glands

Entire cell becomes packed with secretions and then bursts apart and dies. Ex: sebaceous glands.

Secrete a watery solution that contains enzymes. Ex: parotid salivary gland

Secrete mucins that form a thick, slippery mucus. Ex: sublingual salivary gland

• Support and protection. Ex: Bone
• Transportation of materials. Ex: Blood
• Storage of energy reserves. Ex: Adipose cells
• Defense of the body. Ex: Antibody production

Consists of many types of cells and fibers within a matrix that conns a syrupy ground substance. Ex: tendons and ligaments

Distinctive population of cells suspended in a matrix of water ground substance that contains dissolved proteins. Ex: blood and lymph

Less diverse cell population than connective tissue proper and a matrix of dense ground substance and closely packed fibers. Ex: cartilage and bone

Most abundant cells in CTP. Produce and maintain the connective tissue fibers and ground substance.

Scattered throughout the matrix. 'Big eaters' that phagocytize damaged cells or pathogens that enter the tissue. Also release chemicals that mobilize the immune system. 

Also called adipocytes. Contain such a large droplet of lipid that nucleus and organelles are squeezed to one side of the cell. 

Small, mobile connective tissue cells often found near blood vessels. Cytoplasm is packed with vesicles filled with chemicals that are released to begin the body's defensive activities after and injury or infection.

Long, straight and unbranched that form strong but flexible fibers. Are the most common fiber in connective tissue proper. 

Contain the protein elastin. Branched and wavy and after stretching will return to original length. 

Least common of connective tissue fibers. Thinner than collagen fibers and commonly form a branching, interwoven framework in various organs. 

Similar in consistency to maple syrup found in interstitial space. Dense consistency slows the movement of bacteria and other pathogens. 

Loose: Least specialized CT in body. Forms a layer that separates the skin from underlying muscles, and provides both padding and a considerable amount of independent movement. 

Dense: Consist mostly of collagen fibers. Collagen fibers are parallel to each other, packed tightly, and aligned with the forces applied to the tissue. Ex: tendons and ligaments. 

Loose connective tissue that contains large numbers of adipocytes. Provides another source of padding and shock absorption for the body. 

Blood and lymph are FCT's that contain distinctive collections of cells in a fluid matrix. In blood, the watery matrix is called plasma. 

Bone and cartilage

Avascular matrix containing embedded fiber. Chondrocytes, which are the only cells found in the matrix, live in small pockets known as lacunae. 

Hyaline Cartilage: Most common type of cartilage. Tough but somewhat flexible. Ex: connects ribs to sternum, keeps trachea open and covers bone surfaces within joints. 

Elastic Cartilage: Extremely resilient and flexible. Ex: Forms external flap of the outer ear, the epiglottis and an airway to the middle ear. 

Fibrocartilage: Dominated by collagen fibers. Resist compression, absorb shocks and prevent damaging bone-to-bone contact. Ex: Lie between the vertebrae in the spinal column, between the pubic bones in the pelvis and around or within a few joints and tendons. 

Matrix of bone consists mainly of hard calcium compounds and flexible collagen fibers. Composed of osteocytes. Diffusion cannot occur through the bony matrix; cytoplasmic extensions provide osteocytes with nutrients.

Also called mucosae. Line cavities that communicate with the exterior including the digestive, respiratory, reproductive and urinary tracts. 

Line the sealed, internal subdivisions of the ventral body cavity. Three types: pleura, peritoneum and pericardium. Parietal lines inside of cavity, visceral lines outside. 

Skin. Consists of stratified squamous epithelium and the underlying dense connective tissue. 

Consists primarily of loose connective tissue and an incomplete layer of epithelial tissue. Lines joint cavity in joints that allow free movement. THe synovial fluid helps lubricate the joint and permits smooth movement. 

Large and have prominent striations, multiple nuclei, and an unbranched arrangement.

Smaller than skeletal fibers, branching and typically mononucleated.

Small and spindle-shaped, have a central nucleus and lack branches or striations. 

Two basic types: neurons and neuroglia, or supporting cells.

Provide physical support for neural tissue, maintain the chemical composition of the tissue fluids, supply nutrients to neurons, and defend the tissue from infection.

Consists of two steps: inflammation and regeneration.

Inflammation: Area is isolated from neighboring healthy tissue while damaged cells, tissue components, and any dangerous microorganisms are cleaned up. 

Regeneration: Tissue is replaced or repaired to restore normal function.