The Tissue Level Of Organization

* Epithelia

* Glands

Glands are structures that produce fluid secretions.

1) Cellularity

2) Popularity

3) Attachment

4) Avascularity

5) Regeneration

The term polarity refers to the presence of structural and functional differences between the exposed and attached surfaces.

The base of an epithelium is bound to a thin noncellular basement membrane which is also called the basal lamina.

* Provide Physical Protection

* Control permeability

* Provide sensation

* Produce specialized secretion

1) Epithelial tissue

2) Connective tissue

3) Muscle tissue

4) Neural tissue

* Tight Junctions

* Gap junctions

* Desmosomes

Desmosomes functions like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy keratin proteins anchor desmosomes in the cytoplasm.

Desmosomes attach muscle cells to each other in a muscle Some "muscle tears" involve the rupture of desmosomes.

An epithelium whose cells have many microvilli is probably involved in absorption or secretion. The microvilli greatly increase the surface area available for these processes.

This is a Simple Squamous Epithelium.

It can be found in the pleural, pericardial, and peritoneal cavities, as well as the lining of the heart and blood vessels.

They reduce frictions, controls vessel permeability; performs absorption and secretion.

This is the Stratified Squamous Epithelium.

They can be found in the surface of the skin, the lining of the mouth, throat, esophagus, rectum, anus, and vagina.

They proceed physical protections against abrasion, pathogens, and chemical attack.

Mesothelium.

This is the Simple Cuboidal Epithelium.

They can be found in glands, ducts; portions of kidney tubules; thyroid gland.

They provide limited protection, secretion, and absorption.

This is the Stratified Cuboidal Epithelium.

They are found in the lining of some ducts but very RARE.

They offer protection, secretion, and absorption.

Transitional epithelium is an unusual stratisfied epithelium. Unlike most epithelia, it tolerates repeated cycles of stretching and recoiling without damage.

A transitional epithelium is found in regions of the urinary system, such as the urinary bladder.

This is the Simple Columnar epithelium.

They can be found in the lining of the stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys.

They offer protection, secretion, and absorption.

This is a columnar epithelium that includes several types of cells with varying shapes and functions. The distances between the cell nuclei and the exposed surface vary, so the epithelium appears to be layered, or stratified.

However, it is not truly stratified, though, because every epithelial cell contacts the basement membrane. These cells also typically have cilia.

*Epithelia of this type line most of the nasal cavity, the trachea (windpipe), the bronchi, and portions of the male reproductive tract.

This is the Stratified Columnar Epithelium.

This can be found in small area of the pharynx, epiglottis anus, mammary glands, salivary gland ducts, and urethra.

They offer solely protection.

The simple squamous epithelium lining the inner surface of the heart and all blood vessels.

A gland is a collection of epithelial cells that produce secretions.

Endocrine glands release their secretions into the interstitial fluid. These secretions are called hormones. Because endocrine gland secretions are not released into ducts, they are often called ductless glands.

Exocrine glands release their secretions into passageways called ducts that open onto an epithelial surface.

Examples of exocrine secretions are enzymes entering the digestive tract, perspiration on the skin, tears in the eyes, and milk produced by mammary glands.

1) Merocrine secretion

2) Apocrine secretion

3) Holocrine secretion

The only unicellular exocrine glands in the body are mucous cells, which secrete mucins. Both the pseudo stratified ciliated columnar epithelium that lines the trachea and the columnar epithelium of the small and large intestines have an abundance of mucous cells.

This is the simple tubular gland.

They can be found in intestinal glands.

This is the simple coiled tubular.

They are the merocine sweat glands.

This is the simple branched tubular.

They are the gastric glands, the mucous glands of the esophagus, the tongue, and the duodenum

This is the simple alveolar (acinar).

They are not found in adults; a stage in development of simple branched glands.

This is the simple branched alveolar.

They are the sebaceous (oil) glands.

This is the compound tubular.

They are the mucous glands, bulbourethral glands (in the male reproductive system), and testes.

This is the compound alveolar (acinar).

They are the mammary glands.

This is the compound tubuloalveolar.

They are the salivary glands, the glands of respiratory passages, and the pancreas.

All these regions are subject to mechanical trauma and abrasion - by food (pharynx and esophagus), by feces (anus), and by intercourse or childbirth (vagina).

* Establishing a structural framework for the body

* Transporting fluids and dissolved materials

* Protecting delicate organs

* Supporting surrounding, and interconnecting other types of tissue

* Storing energy, especially in the form of triglycerides

* Defending the body from invading microorganisms.

* Connective tissue proper

* Fluid connective tissues

* Supporting connective tissues

Connective tissue proper includes those connective tissues with many types of cells and extracellular fibers in a syrupy ground substance.

Both adipose tissue (fat) [a loose connective tissue] and tendons [a dense connective tissue] are connective tissue proper, but they have very different structural and functional characteristics.

Fluid connective tissues have distinctive populations of cells suspended in a watery matrix that contains dissolved proteins.

The only two types are blood and lymph.

Supporting connective tissues different from connective tissue proper in having a less diverse cell population and a matrix containing much more densely packed fibers.

They two types of supporting connective tissues are cartilage and bone.

They are

* Fibroblasts

* Fibrocytes

* Adipocytes

* Mesenchymal Cells

These are permanent residents of the connective tissue.

They are

* Macrophages

* Mast cells

* lymphocytes

* Plasma Cells

* Microphages

These are *not* permanent residents; instead they migrate through healthy connective tissues and collect at sites of tissue injury.

Fibroblasts are the only cells that are always present in connective tissue proper. They are also the most abundant permanent, or fixed, residents of connective tissue proper.

Fibroblasts secrete hyaluronan and proteins. Each fibroblast also secretes protein subunits that assemble to form large extracellular fibers.

Fibrocytes are the second most abundant fixed cell in connective tissue proper. They differentiate from fibroblasts. They maintain the connective tissue fibers of connective tissue proper.

Adipocytes are also known as fat cells.

They are stems cells that are present in many connective tissues. These cells response to local injury or infections by dividing to produce daughter cells that differentiate into fibroblasts, macrophages, or other connective tissue cells.

They are large phagocytic cells scattered throughout the matrix. These scavengers engulf damaged cells or pathogens that enter the tissue.

They are small, mobile connective tissue cells that are common near blood vessels. The cytoplasm of mast cell is filled with granules containing histamine and heparin.

They are phagocytic blood cells that normally move through connective tissues in small numbers. They are attracted to the site of an infection or injury by chemicals released by macrophages and mast cells.

They synthesize and store the brown pigment melanin, which gives tissues a dark color.

They are abundant in connective tissues of the eye and the dermis of the skin.

* Collagen

* Reticular

* Elastic

Fibroblasts form all three by secreting protein subunits that interact in the matrix.

They are the most common fibers in connective tissue proper. They are long, straight, and unbranched. They are flexible like a rope, but it is stronger than steel when pulled from either end.

Tendons which connect skeletal muscles to bones, consist almost entirely of collagen fibers.

Typical ligaments are similar to tendons, but they connect one home to another bone.

Reticular ribers contain the same protein subunits as do collagen fibers, reticular fibers form a branching, interwoven framework that is tough, yet flexible.

Reticular fibers stabilize the positions of an organ's blood vessels, nerves, and other structures, despite changing positions and the pull of gravity.

Elastic fibers are branched and wavy. After stretching, they return to their original length.

Ground substance fills the spaces between cells and surrounds connective tissue fibers.

Mucous connective tissue

Loose connective tissues are the packing materials of the body. They fill the spaces between organs, cushion, and stabilize specialized cells in many organs, and support epithelia.

These tissue surround and support blood vessels and nerves, store lipids, and provide a route for the diffusion of materials.

Areolar tissue is the least specialized connective tissue in adults. Areolar tissue forms a layer that separates the skin from the deep structures.

They cushion organs; provides support, but permits independent movement; phagocytic cells provide defense against pathogens.

They are fat. They are deep to the skin, especially at sides, buttocks, and breasts; padding around eyes and kidneys.

They provide padding and cushion shocks; insulates; stores energy.

They are reticular fibers that form a complex three-dimensional storm. The storm supports the functional cells, or parenchyma, of these organs.

They are found in the over, kidney, spleen, lymph nodes, and bone marrow.

Elastic tissue is a dense regular connective tissue made up mainly of elastic fibers. They help stabilize the positions of the vertebrae of the spinal column.

Plasm

Adipose (fat).

Blood and lymph

* interstitial growth enlarges the cartilage from within

* appositional growth adds new layers of cartilage to the surface.

* Hyaline cartilage

* Elastic cartilage

* Fibrocartilage

Hyaline cartilage is the most common type of cartilage. It is tough, but somewhat flexible because its matrix contains closely packed collagen fibers.

They lie between the tips of ribs and bones of the sternum; covering bone surfaces at synovial joints; supporting larynx (voice box), trachea, and bronchi; forming part of nasal septum .

They provide tiff but somewhat flexible support; reduce friction between bony surfaces.

Elastic cartilage is extremely resilient and flexible because it contains numerous elastic fibers.

They are found in the auricle of external ear; epiglottis; auditory canal; cuneiform cartilage of larynx.

They provide support, but tolerates distortion without damage and returns original shape.

Fibrocartilage is extremely durable and tough because it has little ground substance and its matrix is dominated by densely interwoven collagen fibers.

They pad the knee joint; between pubic bones of pelvis; intervertebral discs.

They resist compression; prevents bone to bone contact; limits movement.

Bone

1) Mucous membranes

2) Serous Membranes

3) Cutaneous membrane

4) Synovial membranes

Mucous membranes line passageways and chambers that communicate with the exterior, including those in the digestive, respiratory, reproductive, and urinary tracts.

The cutaneous membrane is the skin that covers the surface of your body. It consists of a *stratified squamous epithelium* and a layer of areolar tissue reinforced by underlying dense irregular connective tissue.

The synovial membrane lines the joint cavity with synovial fluid.

The epithelium has gaps and develops within a connective tissue.

Fasciae are connective tissue layers and wrappings that support and surround organs. When can divide the fasciae into three types of layers:

* The superficial fascia

* The deep fascia

* The subserous fascia

1) Skeletal muscle, which forms the large muscles that produce gross body movements

2) Cardiac muscle, found in the heart, is responsible for circulating the blood

3) Smooth muscle, found in the walls of visceral organs and a variety of tore locations, where it provides elasticity, contractility, and support.

This is also known at the nervous tissue or nerve tissue. It is specialized for the propagation of electrical impulses from one region of the body to another.

They are supporting cells for the neuron cells.

Inflammatory response isolates the injured area while damaged cells, tissue components, and any dangerous microorganisms, which could cause infection are cleaned up.

Regernation is the repair process that restores normal function after inflammation has subsided.

Desmosomes.

Connective tissues contain (1) specialized cells (2) extracellular protein fibers (3) a fluid ground substance

The basement membrane, also called the basal lamina, is a complex structure produced by the basal surface of the epithelium and the underlying connective tissue.

The basement epithelium.

Skeletal.

* Skeletal

* Cardiac

* Smooth Muscle

* Cardiac

* Smooth

* Smooth

Cardiac muscle