Chapter 4: The Tissue Levle of Organization Flashcards
4 types of tissue in the human body
epithelial, connective, muscluar, nervous
points of contact between two cells
cell junctions
junctions that form fluid-tight seals between cells
tight junctions
junctions that are made of plaque and anchor cells together
adherens junctions
junctions that arecomposed of plaque and are linked by transmembrane glycoproteins that extend across a gap between adjacent cell membranes and link the cytoskeletons of cells together
desmosomes
connect cells to extracellular material such as the basement membrane
hemidesmosomes
allow cells in a tissue to rapidly communicate through connexins, transmembrane protein channels that connect cells together
gap junctions
What are the major structual differences between epithilial and connective tissues?
- number of cells in the matrix
- prescence of blood vessels
- epithilial is almost never covered by another tissue
how are epithelial cells arranged
in sheets
a single layer of flat, scale-like epithelial cells with a centered nucleus
simple squamous epithelium
function of simple squamous epithelium
present at sites of diffusion and filtration and secreation in serous membranes
a single layer of cube shaped cells with a central nucleus
simple cubiodal epithelium
function of simple cubiodal epithelium
secreation and absorption
single layer of column like cells with oval nuclei near the base
simple columnar epithelium
What are the two variations of simple columnar epithelium
non-ciliates (have microvilli) and ciliated
single layer of column like cells that may appear as several layers die to the fact that some do not reach the apical surface
pseudostratified epithelium
function of pseudostratified epithelium
absorption and secreation
which type of pseudostratified epithelium contains golblet cells that secrete mucous or sweep away mucous
cilated
epithelium that consists of several layers of cells in which the top layer of cells is flat, and the deeper layers of cells vary in shape from cuboidal to columnar
- Stratified squamous epithelium
what does karatin do instratified squamous epithelium?
karantinized epithelium becomes tough, resisting friction and repelling bacteria
is a rare tissue consisting of two or more layers of cube-shaped cells whose function is mainly protective.
stratified cubiodal epithelium
consists of several layers of cells of which only the top layer is columnar. It is somewhat rare and functions in protection and secretion.
- Stratified columnar epithelium
type of epithilium with several layers of varying cells. Capable of stretching permiting distention of organs such as the bladder
Transitional epithiulium
is a single cell, or a mass of epithelial cells adapted for secretion.
gland
ductless glands that secrete hormones into extracellular fluid
endocrine glands
glands that secrete products into ducts that empty at the epithelial surface
exocrine
how are multicellular glands classified
the shapes of the secretory portion with the degree of branching of the duct
glands that form the secretory products and discharge it by exocytosis
merocrine glands
glands that accumulate their secretary product at the apical surface of the secreting cell; that portion then pinches off from the rest of the cell to form the secretion with the remaining part of the cell repairing itself and repeating the process
apocrine
glands that accumulate the secretory product in the cytosol; when the cell dies, it and its products are discharged as the glandular secretion
holocrine glands
what are the two basic elements of connective tissue?
Cells and extracellular matrix that can be liqued, gelatenous, calcified, etc
connective tissue cells are derived from what?
mesenchyme
how are immature and mature cells in the extracellular matrix of connective tissue named?
immature- “blast”
mature- “cyte”
cells that secrete fibers and matrix
fibroblasts
cells that devolop from monocytes and are phagocytic
macrophages
cells that develop into anti-body producuing B cells
plasma cells
cells that poduce histamine; abundant along blood vessels
mast cells
fat cells that store energy in the form of triglycerides
adipocytes
white blood cells which are involved in immunity; easily migrate from one tissue to another
leukocytes
what are glycosaminoglycans
substances found in the ground substance of the extrecellular matrix. Ex: hyularonic acid, keratin sulfate
what is the funcation of ground substance in the extracellular matrix
it supports, binds, and provides a medium for the exchange of materials between the blood and cells, and is active in influencing cell functions.
fucntion of fibers in the matrix
provide tissue strength and support
tough fibers that are resistant to stretching; found in bones, cartilage, tendons and ligaments
collagen fibers
fibers that provide both strengh and stretching capacity; found in skin, blood vessels and lungs
elastic fibers
fibers that provide support in the walls of blood vessels and form a strong, supporting network around fat cells, nerve fibers, and skeletal and smooth muscle fibers
reticular fibers
found almost exclusively in the embryo, is the tissue form from which all other connective tissue eventually arises
mesenchyme
tissue that is found in the umblical cord of the fetus
mucoid connective tissue (whartons jelly)
classifications of mature connective tissue
loose, dense, cartilage, bone and blood
tissue consists of fine interlacing reticular fibers and reticular cells. It forms the stroma of certain organs. It helps to bind together the cells of smooth muscle.
Reticular connective tissue
consists of bundles of collagen fibers in a regular and orderly, parallel arrangement that confers great strength along long axis of fibers
dense regular connective tissue
tissue contains collagen fibers that are irregularly arranged and is found in parts of the body where tensions are exerted in various directions
dense irregular connective tissue
consists of elastic fibers and fibroblasts. It is quite strong and can recoil back to its original shape after being stretched. It is found in lung tissue and elastic arteries.
Elastic connective tissue
consists of a dense network of collagen fibers and elastic fibers embedded in chondroitin sulfate. Typically has no blood or nerve supply
cartilage
weakest type of cartilage that has fine collagen fibers embedded in a gel-type matrix. It provides flexibility and support, and at joints it reduces friction and absorbs shock
Hyaline cartilage
the strongest type of cartilage that does not contain a perichondrium. strong and rigid
Fibrous cartilage
contains a threadlike network of elastic fibers within the matrix. A perichondrium is present. It provides strength and elasticity and maintains the shape of certain organs
elastic cartilage
consists of a matrix containing mineral salts and collagenous fibers and cells called osteocytes
Bones (osseous tissue)
concentric rings of matrix that consist of mineral salts that give bone its hardness and collagen fibers that give bone its strength
lamella
are small spaces between lamellae that contain mature bone cells called osteocytes
lacunae
canals containing processes of osteocytes that provide routes for nutrient and waste transport
canaliculi
canal within bones that contains blood vessels and nerves
Haversian canal
Spongy bones have what in place of osteons?
trabeculae
consists of a liquid matrix called plasma and formed elements.
Blood (vascular tissue)
Red blood cells that function mainly in transporting respiratory gases.
erythrocytes
white blood cells that are involved in phagocytosis, immunity and allergic reactions
leukocytes
blood cells that aid in clotting
platelets (thrombocytes)
flat sheets of pliable tissue that cover or line a part of the body
membranes
membranes that line joints and contain only connective tissue
synovial membranes
the connective tissue layer of a mucous membrane
lamina propria
membranes that line cavities that open to the exterior, such as the gastrointestinal tract
mucous membranes
membranes that line a body cavity that does not open directly to the exterior and covers the organs that lie within the cavity
serous membranes
membrane that covers the outside of the body (skin)
cutaneous membrane
consists of fibers (cells) that are modified for contraction and thus provide motion, maintenance of posture, and heat production
muscle tissue
muscle tissue that is striated, voluntary and attached to bones
skeletal
muscle tissue that is striated, involuntary and forms the heart wall
cardiac
muscle found in the walls of hollow internal structures (blood vessels and viscera), is nonstriated, and is usually involuntary
smooth (visceral)
consist of a cell body and two types of processes called dendrites and axons
neuron
protect and support neurons and are often the sites of tumors of the nervous system
neuroglia
the process of scar formation on a tissue
fibrosis
what two types of tissue have a poor capacity for renewal
nervous and muscle
what is granulation tissue
actively growing connective tissue that forms after an extensive injury
