Epithellial Tissue Functions
covers body surfaces, lines hollow organs, body cavities, and ducts, forms glands. Protection, Absorbtion, Secretion, Filtration.
Connective Tissue Functions
Protects/Supports body, binds organs together, transports/stores energy, provides immunity.
Muscle Tissue Functions
generates physical force necessary to move.
Nervous tissue functions
detects changes in environment, responds by generating nerve impulses to maintain homeostasis.
Tight junctions
Contact point between adjacent cells that is so tight that it prevents the passage of substances between them. plasma membrane is fused together.
Adherens Junctions
Plaque is used to link cells in adhesion belts. leaves some intracellular space so materials can pass between 2 cells.
Desmosomes
A strong connection of adjacent cells through intermediate fillaments (very strong protein fillaments) that go through spots of plaque (not belts) in each cell, leaving enough intracellular space so material does pass.
Hemidesmosomes
Half a desmosome, anchors cells to underlying basement membrane of extracellular material (does not connect 2 adjacent cells)
Gap Junctions
Fluid filled tunnels between cells in the cytosol that are used for cell to cell communication, such as electrical signals sent by cardiac muscle cells. Cells are not fused, they are seporated by a gap.
Apical Surface
Top surface of epithelial tissue.
Epithelial Tissue Characteristics
tightly connected cells arranged in sheets. has apical, basal, and lateral suraces. attached to a basement membrane. avascular. regenerates readily.
Lateral Surface
Middle layer of epithelial tissue.
Basal surface
the base/bottom of epithelial tissue that is connected to basement membrane.
Basal Lamina
Extracellular material produced by the epithelial tissue that makes up part of the basement membrane.
Reticular Lamina
Makes up part of the basement membrance and is produced by cells of the connective tissue.
The 2 categories of epithelial tissue
covering/lining epithelium and glandular epithelium
Connective Tissue Characteristics
Most abundant tissue type in body. Highly vascular. protects and insulates. major transport system. primary source of energy storage. main source of immune responses.
What are the only types of connective tissue that are NOT vascular?
Cartilage, and tendons are limited.
Fibroblasts
most numerous cells in CT. Produce protein fibers and lay down matrix.
2 basic elements of connective tissue
extracellular matrix and cells
Extracellular Matrix of CT
Consists of protein fibers and ground substance
Ground Substance
May be fluid (like in blood), semifluid, gelatinous, or calcified. Supports cells and binds them together. Contains polysaccharides known as GAGs.
Macrophages
defensive cells. Engulf and destroy pathogens through phagocytosis.
Plasma Cells
Small cells that develop from white blood cells. Secrete antibodies and attack foreign substances in the body. Defensive cells.
Mast Cells
Cells that produce histamine as part of the inflamatory response. Abundant alongside the blood vessels that supply connective tissue.
Adipocytes
Fat cells that store triglycerides (fats)
White blood cells
Protective cells, not that common in CT but can migrate from blood into the tissues to kill infections.
3 types of fibers in CT
collagen, elastic, reticular
Collagen fibers
Impart Strength. Very strong fibers that resist tension but are not stiff, which allows tissue flexability. Often occur in parallel bundles. Made up of the protein collagen whihc is the most abundant protein in the body (25%).
Elastic Fibers
Impart stretchability and elasticity. Rebound to their original shape. Smaller in diameter than collagen fibers.
Reticular Fibers
Network of fibers for strength. Creates a net-like framework for shape and support.
Loose Connective Tissue
Fibers in matrix are loosely arranged between cells. Types are areolar, adipose, and reticular CT.
Dense Connective Tissue
Contain more fibers which are thicker and more densely packed. Have considerably fewer cells than other types of CT. 3 types: regular, irregular and elastic CT.
Cartilage
Consists of a dense network of collagen fibers and elastic fibers embedded in chondoitin sulfate, a gel like component of ground substance. Can endure lots of stress. Resiliency and strength is due to collagen fibers. 3 types: hyaline, fibrocartilage, ela
2 types of membranes
Epithelial and Synovial
2 types of epithelial membranes
Muscous and Serous
Mucous Membrane
Barrier to the outside world where no skin is already covering. Lines body cavities that open directly to the exterior.
Serous Membrane
Line body cavities that do not open to outside world. Consists of simple squamous epithelium (mesothelium) and areolar CT.
Parietal Layer of Membrane
Lines the cavity wall with serous membrane
Viseral Layer
Lines the organs inside a cavity with serous membrane
Synovial membrane
Does not have an epithelium. Located in cavities of freely moving joints. Contains areolar CT, elastic fibers and adipocytes.
Synovial Fluid
nurishes and lubricates the cartilage on the joint surfaces.
Cutaneous Membrane
Skin that covers surface of the body and consists of epidermis (superficial portion) and dermis (deeper portion).