Chapter 4 Flashcards
Tissues
collections of specialized cells and the extracellular substances surrounding them.
extracellular matrix
noncellular substances surrounding the cells
Histology
microscopic study of tissues.
endoderm
inner layer, forms the lining of the digestive tract and its derivatives.
mesoderm
middle layer, forms tissues such as muscle, bone, and
blood vessels.
ectoderm
the outer layer, forms the skin
neuroectoderm
portion of the ectoderm that becomes the nervous system
neural crest cells
Groups of cells that break away from the neuroectoderm during development that give rise to parts of the peripheral
nerves, skin pigment, the medulla of the adrenal gland, and many tissues of the face.
Epithelial tissue or epithelium
covers and protects surfaces, both outside and inside the body.
free or apical
surface not attached to other cells
lateral surface
attached to other epithelial cells
basement membrane
The basal surface of most epithelial tissues is attached
to a basement membrane, a specialized type of extracellular material secreted by epithelial and connective tissue cells.
Simple epithelium
consists of a single layer of cells, with each cell extending from the basement membrane to the free surface.
Stratified epithelium
consists of more than one layer of cells, but only the basal layer attaches the deepest layer to the basement membrane.
Pseudostratified columnar epithelium
special type of simple epithelium; appears to be stratified but is not; It consists of one layer of cells, with all the cells attached to the basement membrane.
Squamous
flat or scalelike.
Cuboidal cells
cube-shaped—about as wide as they are tall.
Columnar
(tall and thin, similar to a column) cells are taller than they are wide.
Nonkeratinized (moist) stratified squamous epithelium
found in mouth, esophagus, rectum, and vagina, consists of living cells in the deepest and outermost layers. A layer of fluid covers the outermost layers of cells, makes moist.
keratinized stratified squamous epithelium
found in the skin, gums and hard palate of the mouth; consists of living cells in the deepest layers, and the outer layers are composed of dead cells containing the protein keratin. The dead, keratinized cells give the tissue a dry, durable, moisture-resistant character.
transitional epithelium
type of stratified epithelium that lines the urinary bladder, ureters, kidney, urethra; structures where considerable expansion can occur/ stretch cells
goblet cells
specialized columnar epithelial cells that are responsible for secreting; found in endocrine glands; unicellular
desmosomes
disk-shaped structures with especially adhesive glycoproteins that bind cells to one another and intermediate filaments that extend into the cytoplasm of the cells
Hemidesmosomes
attach epithelial cells to the basement membrane.
Tight junctions
hold cells together and form a permeability barrier
adhesion belt
belt of glycoproteins is found just below the tight junction; acts as a weak glue that holds cells together.
gap junction
small, specialized contact region between cells containing protein channels that aid intercellular communication by allowing ions and small molecules to pass from one cell to
another
exocrine glands
Glands with ducts
endocrine glands
separate from the epithelium of their origin and have no ducts
hormones
cellular products of endocrine glands
simple
Glands that have a single duct
compound
glands with ducts that branch
tubular
Glands with secretory regions shaped as tubules
acinar or alveolar
glands shaped in saclike structures
merocrine secretion
products are released, but no actual cellular material is lost; Secretions are either actively transported or packaged in vesicles and then released by the process of exocytosis at the free surface of the cell. Merocrine secretion is used by water-producing sweat glands
and the exocrine portion of the pancreas.
apocrine secretion
the secretory products are released as fragments of the
gland cells; they are retained within the cell, and portions of the cell are pinched off to become part of the secretion. The milk-producing mammary glands release milk by a
combination of apocrine and mostly merocrine secretion.
Holocrine secretion
involves the shedding of entire cells; Products accumulate in the cytoplasm of each epithelial cell, the cell ruptures and dies, and the entire cell becomes part of the secretion. Holocrine secretion is used by the sebaceous (oil) glands of the skin.
Blasts
create the matrix
cytes
maintain the matrix
clasts
break the matrix down for remodeling
Mast cells
lie beneath membranes in loose connective tissue and along small blood vessels of organs; contain chemicals, such as heparin, histamine, and proteolytic enzymes, that are released in response to injury, such as trauma and infection, and play important roles in inflammation.
Macrophages
derived from monocytes, a type of white blood cell; phagocytize foreign and injured cells, and they play a
major role in protecting against infections.
Undifferentiated mesenchymal cells
type of adult stem cell that persist in connective tissue; have the potential to form multiple cell types in response to injury.
Hyaluronic acid
long, unbranched polysaccharide chain composed of repeating disaccharide units; good lubricant
mesenchyme
Embryonic connective tissue
mucous connective tissue or Wharton’s jelly
major source of remaining embryonic connective tissue in the newborn is in the umbilical cord; stem cells
loose connective tissue
consists of relatively few protein fibers that form a lacy network, with numerous spaces filled with ground substance and fluid.
Areolar tissue
“loose packing” material of most organs and other tissues; support and nourishment for the structures with which it is associated
adipose tissue
Packing material, thermal insulation, energy storage, and
protection of organs against injury from being bumped or jarred
reticular tissue
Provides a superstructure for lymphatic and hemopoietic tissues
Dense connective tissue
has a relatively large number of protein fibers that form thick bundles and fill nearly all of the extracellular space.
Dense regular connective tissue
has protein fibers in the extracellular matrix that are oriented predominantly in one direction.
Dense regular collagenous connective tissue
has abundant collagen fibers, which give this tissue a
white appearance; forms structures such as tendons and ligaments, considerable strength in the direction of the fiber orientation.
Dense regular elastic connective tissue
consists of parallel bundles of collagen fibers and abundant elastic fibers; forms some elastic ligaments, such
as those in the vocal folds and the nuchal ligament
Dense irregular connective tissue
contains protein fibers arranged as a meshwork of randomly oriented fibers; have strength in many directions but less strength in any single direction than does regular connective tissue.
Dense irregular collagenous connective tissue
forms most of the dermis and connective tissue capsules that surround organs such as the kidney and spleen.
Dense irregular elastic connective tissue
found in the walls of elastic arteries.
chondrocytes
cartilage cells
lacunae
spaces where cartilage cells are located
Hyaline cartilage
Allows the growth of long bones; provides rigidity with some flexibility in the trachea, bronchi, ribs, and nose; forms rugged, smooth, yet somewhat flexible articulating
surfaces; forms the embryonic skeleton
Fibrocartilage
Somewhat flexible and capable of withstanding considerable pressure; connects structures subjected to great pressure
Elastic cartilage
Provides rigidity with even more flexibility than hyaline cartilage because elastic fibers return to their original shape after being stretched
hydroxyapatite
specialized crystals in the mineral, or inorganic, portion of bone consists which contain calcium and phosphate.
Spongy bone
has spaces between trabeculae, or plates, of bone and therefore resembles a sponge; Acts as a scaffolding to provide strength and support without the greater weight
of compact bone
Compact bone
more solid, with almost no space between many thin layers, or lamellae of bone; Provides great strength and support; forms a solid outer shell on bones that keeps
them from being easily broken or punctured
Hemopoietic tissue
forms blood cells; found in bone marrow
muscle tissue
contracts, or shortens, with a force and therefore is responsible for movement.
Skeletal muscle
what we normally think of as “muscle”; Skeletal muscle cells are striated, or banded; under voluntary (conscious) control
Cardiac muscle
muscle of the heart; responsible for pumping blood; under
involuntary (unconscious) control
intercalated disks
contain specialized gap junctions and are important in coordinating cardiac muscle cell contractions
smooth muscle
Regulates the size of organs, forces fluid through tubes, controls the amount of light entering the eye, and produces “goose flesh” in the skin; is under involuntary (unconscious) control
Nervous tissue
found in the brain, spinal cord, and nerves and is characterized by the ability to conduct electrical signals called action potentials.
multipolar neurons
Neurons that possess several dendrites and one axon
bipolar neurons
Neurons that possess a single dendrite and an axon
Pseudo-unipolar neurons
have only a single, short process that extends from the cell body; Conducts action potentials from the periphery to the brain or spinal cord
Neuroglia
support cells of the brain, spinal cord, and peripheral nerves
mucous membrane
consists of epithelial cells, their basement membrane, a thick layer of loose connective tissue called the lamina propria, and sometimes a layer of smooth muscle cells.
serous membrane
consists of three components: a layer of simple squamous epithelium called mesotheliumits, basement membrane, and a delicate layer of loose connective tissue.
Serous membranes
fluid serous membranes secrete which lubricates the membranes, making their surfaces slippery; serous membranes do not contain glands
synovial membrane
consist of modified connective tissue cells, either intermixed with part of the dense connective tissue of the joint capsule or separated from the capsule by areolar
or adipose tissue.
synovial fluid
rich in hyaluronic acid, making the joint fluid very slippery, and facilitating smooth movement within the joint.
chemical mediators
After a person is injured, chemical substances are released or activated in the tissues and the adjacent blood vessels. The mediators include histamine, kinins, prostaglandins, leukotrienes, and others.
Tissue repair
the substitution of viable cells for dead cells. Tissue
repair can occur by regeneration or replacement.
regeneration
when the new cells are the same type as those that were destroyed, and normal function is usually restored.
replacement
when a new type of tissue develops that eventually produces a scar and causes the loss of some tissue function.
Labile cells
continue to divide throughout life; adult stem cells and other cells of the skin, mucous membranes, and hemopoietic and lymphatic tissues. Damage to these cells can be repaired completely by regeneration.
Stable cells
connective tissues and glands, including the liver, pancreas, and endocrine glands, do not divide after growth ceases, but they retain the ability to divide and are capable of regeneration in response to injury.
Permanent cells
have a very limited ability to replicate and, if killed, are usually replaced by a different type of cell. Some permanent cells, such as neurons, are postmitotic-can recover if the cell body is not destroyed
primary union or primary intention
If the edges of the wound are close together, as in a surgical incision, the wound heals by this process
secondary union or secondary intention
If the edges are not close together, or if tissue loss has been extensive a wound heals this way
fibrin
The clot contains this threadlike protein, which binds the edges of the wound together.
scab
The surface of the clot dries to form this, which seals the wound and helps prevent infection.
chronic inflammation
if the agent responsible for an injury is not removed or if the healing process is disrupted, the inflammatory response persists
neutrophils
phagocytic cells of the white blood cells that move into the tissue to ingest bacteria, thus helping fight infection, they ingest tissue debris and clear the area for repair.
granulation tissue
a delicate, granular-appearing connective tissue that consists of fibroblasts, collagen, and capillaries.
scar
A large amount of granulation tissue is converted to a scar, which consists of dense irregular collagenous connective tissue.
wound contracture
contraction of fibroblasts in the granulation tissue leads to
this, resulting in disfiguring and debilitating scars.
sarcoma
cancer derived from connective tissue
carcinoma
cancer derived from epithelial tissue
apoptosis
A self-destruction mechanism that destroys cells with abnormal DNA.
oncogenes
Mutations in proto-oncogenes can give rise to these abnormal regulatory genes which increase the rate of cell division.
Tumor suppressor genes
normal genes that slow or stop cell division.
