Microvilli are small finger-like projections that greatly increase the surface area of epithelial cells (thus epithelial tissues), an important attribute of tissues that have a role in absorption and secretion.
*Endothelium provides a slick surface lining all hollow cardiovascular organs.
*Stratified epithelia are associated with filtration.
*Pseudostratified epithelia are commonly keratinized.
*Simple epithelia are commonly found in areas of high abrasion
*Holocrine cells are slightly damaged by the secretory process, but repair themselves.
*These glands are ductless.
*Apocrine cells are destroyed, then replaced, after secretion.
*Merocrine glands are not altered by the secretory process
-simple cuboidal epithelium
-Simple squamous epithelia consist of tall, narrow cells.
-Simple epithelia form impermeable barriers to viruses.
-Stratified squamous epithelia are present where protection from abrasion is important.
-Pseudostratified epithelia consist of at least two layers of cells stacked on top of one another
Goblet cells are found within pseudostratified ciliated columnar epithelium.
Epithelial tissues always exhibit apica-basal polarity; meaning that cell regions near the apical surface differ from those near the basal surface.
Depending on the functional state of the bladder, transitional epithelium may resemble stratified squamous or stratified cuboidal epithelium.
Merocrine glands produce their secretions by accumulating their secretions internally until the cell ruptures.
Salivary glands exhibit simple tubuloalveolar glandular arrangement.
Squamous cells are flattened and scalelike when mature.
Endocrine glands are often called ducted glands.
-Fibers are not normally visible.
-It is more vascularized.
-It contains less nuclei.
-It is more harder and rigid.
-primarily concerned with secretion
-typically arranged in a single layer of cells
-usually lines a body cavity
-usually contains a large amount of matrix
-ground substance and cells
-all organic compounds
-cells and fibers
-fibers and ground substance
Cell type not found in areolar connective tissue.
– hyaline cartilage
-are mature cartilage cells located in spaces called lacunae
-within the cartilage divide and secrete new matrix
-never lose their ability to divide
-remain in compact bone even after the epiphyseal plate closes
-collagen fibers enlarge as they change from dehydrated to hydrated shape
-reticular connective tissue invades the area
-areolar tissue soaks up excess fluid in an inflamed area
-adipose cells enlarge by pinocytosis
-collagen, elastin, and reticular fibers
-ground substance, fibers, and cells
-fibroblasts, chondroblasts, and osteoblasts
-alveoli, fibrous capsule, and secretory cells
-When connective tissue is stretched, collagen gives it the ability to snap back.
-Reticular fibers form thick, ropelike structures.
-Elastin fibers are sometimes called white fibers.
-Collagen fibers provides high tensile strength.
-Chondroblasts are the main cell type of connective tissue proper.
-Connective tissue cells are nondividing.
-Connective tissue does not contain cells.
-“Blast” cells are undifferentiated, actively dividing cells.
-It is composed mostly of extracellular matrix.
-Mature adipose cells are highly mitotic.
-Its primary function is nutrient storage.
-Most of the cell volume is occupied by the nucleus.
The shock-absorbing pads between the vertebrae are formed of fibrocartilage.
The role of brown fat is to warm the body; whereas, the role of white fat is to store nutrients.
Tendons and ligaments are composed mainly of dense irregular connective tissue.
Macrophages are found in areolar and lymphatic tissues.
Aging tends to increase bony spread within the body as chondrocytes die.
Connective tissues that possess a large quantity of collagen fibers often provide the framework for organs such as the spleen and lymph nodes.
The basic difference between dense irregular and dense regular connective tissues is in the amount of elastic fibers and adipose cells present.
A major characteristic of fibrocartilage is its unique amount of flexibility and elasticity
Cartilage tissue tends to heal less rapidly than bone tissue.
Cartilage has good regenerative capacity, while most epithelial tissues do not.
Functions of connective tissues include binding, support, insulation, and protection.
Healing of a surgical incision through the body wall will tend to increase the amount of areolar tissue.
Blood is considered a type of connective tissue
-contains contractile units made of collagen
-cuboidal shape enhances function
-highly cellular and well vascularized
-is a single-celled tissue
Intercalated discs and striations are found in skeletal muscle.
Smooth muscle cells possess central nuclei but lack striations.
Nervous tissue consists mainly of neurons and collagen fibers.
-formation of scar tissue
-replacement of destroyed tissue by the same kind of cells
-proliferation of fibrous connective tissue
-The clot is formed from dried blood and transposed collagen fibers.
-Inflammation causes capillaries to dilate and become permeable.
-Granulation tissue is highly susceptible to infection.
-Granulation tissue is another name for a blood clot.
-Formation of new stem cells
-Restoration of blood supply
-Regeneration and fibrosis.
-(1) fixation, (2) sectioning, (3) staining
-(1) fixation, (2) staining, (3) sectioning
-(1) sectioning, (2) staining, (3) fixation
-(1) staining, (2) fixation, (3) sectioning (1) sectioning, (2) fixation, (3) staining
-digestive tract: absorption
The keratinized stratified squamous epithelium of skin is designed for protection, not absorption from the external environment.
-Epithelial tissue is innervated.
-Epithelial tissue is typically unable to regenerate.
-Epithelial tissue contains blood vessels.
-Epithelial tissue does not exhibit polarity.
Epithelial tissue is an innervated, avascular tissue that exhibits polarity. Epithelial tissue is also highly regenerative.
-Stratified squamous epithelia are found in areas subjected to wear and tear.
-Simple squamous epithelia are associated with filtration and exchange.
-Simple columnar epithelia are associated with absorption and secretion.
-Simple cuboidal epithelia are found in areas that stretch.
This is incorrect; transitional (not simple cuboidal) epithelia are found in areas that stretch, in particular the ureters and urinary bladder. Simple cuboidal epithelia are designed for absorption and secretion (not stretching).
-in areas involved in filtration
-in areas subjected to stretching
-in areas subject to wear and tear
-in areas involved in absorption
Transitional epithelium is found in the urinary system. It lines the ureters, bladder and proximal part of the urethra-organs that are subjected to distention or stretching as urine passes through or fills them
-secrete substances into blood
-are only unicellular in structure
-secrete substances onto body surfaces
Exocrine glands use ducts to secrete substances into the external environment (onto the surfaces of the cutaneous and mucous membranes). Note: “exo” means outside. Endocrine glands are ductless; they secrete hormones into the extracellular fluid of our internal environment. Note: “endo” means inside.
-multicellular compound gland
-multicellular simple gland
-unicellular compound gland
-unicellular simple gland
Multicellular exocrine glands with unbranched ducts are “simple”; those with branched ducts are “compound”.
Unicellular exocrine glands do not have ducts.
-Holocrine glands secrete their products by endocytosis.
-Holocrine glands secrete their products by rupturing.
-Holocrine glands secrete their products by pinching off the apex of the cell.
-Holocrine glands secrete their products by exocytosis.
Holocrine glands secrete their products by rupturing. Sebaceous (oil) glands are the only example of holocrine glands in the body.
-unicellular exocrine glands
-multicellular exocrine glands
Mucous cells are unicellular exocrine glands that secrete mucin, a protein that combines with water to form mucus.
– Golgi bodies
-a rich vascular supply
-aids in digestion
-lines most of the respiratory tract
-is not an epithelial classification
-possesses no goblet cells
Simple cuboidal epithelia are usually found in areas where secretion and absorption occur.
All epithelia have two surfaces, an apical surface and a basal surface, that differ in both structure and function.
All epithelia exhibit polarity, which is defined by the presence of an apical surface and a basal surface that differ in both structure and function.
-An amino acid
Like mucous cells, goblet cells are unicellular exocrine glands that secrete mucin, a protein that combines with water to form mucus. In goblet cells, the cuplike accumulation of mucin distends the top of the cell, making these cells look like a glass with a stem, thus “goblet” cell. This distortion does not occur in mucous cells.
Pseudostratified epithelium consists of multiple cell layers.
While pseudostratified epithelium has the illusion of being a multi-layered tissue, it is in fact made up of only one cell layer. The irregular heights of the cells in pseudostratified epithelia give the tissue a layered appearance. In reality, all of the cells in this tissue rest on the basement membrane (i.e., their basal surfaces are in contact with the basement membrane).
Epithelial tissue is a sheet of cells that covers a body surface or lines a body cavity (epithe = laid on, covering). In addition to coverings and linings, epithelial cells can also form glands, called glandular epithelium.
-stratified squamous epithelium
-simple squamous epithelium
-simple columnar epithelium
Transitional epithelium forms the lining of hollow urinary organs, which stretch as they fill with urine. The ability of transitional cells to change their shape (undergo “transitions”) allows a greater volume of urine to flow through the tube-like ureters and allows more urine to be stored in the urinary bladder.
-unicellular exocrine glands
-multicellular exocrine glands
Endocrine glands, which are ductless glands, secrete hormones into the interstitial fluid surrounding them. The hormones then diffuse toward and pass through a nearby capillary wall to enter the blood. Circulating throughout the body in the blood stream is how hormones eventually reach their target cells.
-primarily consist of extracellular matrix
-are delicate tissues, not designed to bear weight or withstand abrasion or tension
-are all avascular
-arise from different types of embryonic tissue; therefore, they have little relationship or kinship to one another
All other primary tissues are composed mainly of cells, but connective tissues are largely nonliving extracellular matrix, which separates, often widely, the living cells of the tissue.
-provide tensile strength
-form delicate networks around blood vessels and support the soft tissue of organs
Collagen fibers are extremely tough and provide high tensile strength (that is, the ability to resist being pulled apart) to the matrix. Stress tests show that collagen fibers are stronger than steel fibers of the same size!