Tissue Level of Organization Flashcards
what are Tissues?
- a group of cells with common embryonic origin that function together to carry out a specific function
Includes hard (bone), semisolid (fat - stores triglycerides) & liquid (blood, CSF, Lymph)
List the types of tissues
- Epithelial
- Connective (5 classifications)
- Muscular
- Nervous
Epithelial tissue
covers body surfaces, lines hollow organs, cavities ducts & forms glands
(5 classifications)
What type of tissue connects, supports & binds organs?
Connective tissue
What tissue generates physical force needed to move the body and generate body heat?
Muscular tissue
What tissue type detects changes in the body & responds by generating nerve impulses?
Nervous tissue
All tissue types form from which 3 things?
(Germ layers)
- Endoderm (GI tract, internal organs)
- Mesoderm
- Ectoderm
Epithelial tissues develop from all 3 germ layers
all connective and muscle tissue derive from the what?
mesoderm
the ectoderm creates what tissues?
Nervous tissue and skin
What is a biopsy?
A sample of living tissue taken:
-looking for cancer
-infections
-inflammatory processes
-connective tissue disorders
What are the 5 most common types of cell junctions?
- Tight junctions (linkers)
- Adherens junctions
- Desmosomes
- Hemidesmosomes
- Gap junctions
What type of junctions are common in epithelial tissues of the stomach, bladder, urinary & intestines?
Tight junctions
* prevent passage of substances between cells from leaking into surrouding tissues
* Transmembrane proteins fuse cells together (linkers)
Adherens Junction
- dense layer of proteins called plaque form adhesion belts that encircle the cell (found 1 in epithelial cells)
- resists separation of cells during contractile activities
- cadherins are transmembrane proteins that insert into the plaque
- located inside the cell & attach to both membrane proteins and microfilaments of the cytoskeleton
What are desmosomes?
- Contain plaque and
cadherins that extend into
the intercellular space to
attach adjacent cells - the plaque attaches to intermediate filaments that contain the protein keratin
- prevents epidermal cells from separating under tension & cardiac muscle cells from pulling apart during contraction
cell junction
Hemidesmosomes
cell junction
- Connects epithelial tissue to underlying tissue (fascia)
- anchors CELLS to BASEMENT membrane (NOT cells adjacent to cells)
- contains transmembrane glycoprotein integrin
- Integrins attach to intermediat filaments and the protein lamilin present in the basement membrane
resembles half a desmosome
what is a gap junction?
cell junctions
- a tiny, fluid filled tunnel between cells (called a connexon)
- cells are separeted by intracellular gap
- ions, nutrients, wastes, chemical & electrical signals travel through connexons
seen primarily in nerve & muscle (cardiac) cells
What tissues consist of cells arranged in continuous sheets, from single to multiple layers?
Epithelial tissues
- functioning in covering & lining the body
- has a free surface to outside of body or hollow inside
What are the 3 major functions of epithelial tissues?
- Selective barrier - regulates what comes in and out of the body
- Secretory surfaces - release products onto the surface
- Protective surfaces against the environment
What are the 3 general features of epithelial cells
and describe each
Apical (free surface) - the edge of the cell facing the body surface, cavity, lumen or duct
Lateral surface - faces adjacent cells
Basal surface - attached to the basment membrane
what are basal & reticular lamina?
thin double layer that serves as the point of attachment between epithelial cells & underlying tissue
basal: attached to epithelial cells, contains lamilin, collagen, glycoproteins & proteoglycans (glue that holds fascia together)
reticular: attached to connective tissues, contains collagen
BASEMENT MEMBRANES
how is epithelial tissue used in the body?
Outer covering
- skin
Inner linings
-blood vessels, ducts
- respiratory, digestive, urinary & reproductive
Glandular epithelium
- secreting portion of glands
Epithelial tissue is avascular, what does that mean?
it does not have its own blood supply
- has its own nerve
- has a high rate of cell division for regeneration and repair
what tissue regenerates and what tissue repairs?
skeletal muscle repairs with fibrous tissue
smooth cardiac muscle regenerates via mitotic cell division
how is epithelial tissue classified?
by cell shape (simple, pseudostratified & stratified)
and
arrangement of layers (squamous - flat, cuboidal and columnar)
what is simple epithelium?
a single layer of cells that function in diffusion, osmosis, filtration, secretion & absorption
what is psudostratfied epithelium?
cells that appear to have multiple layers because the nucleus are at different levels, but is only one layer
all cells do not reach the apical surface
what is stratified epithelium
two or more layers of cells that protect the underlying tissues in areas of wear & tear
What is the name of the shape of thin cells, arranged like floor tiles, that allow for rapid passage of substances called?
Epithelial
Squamous cells
which epithelial cells apear as tall as they are wide?
And what are their functions?
cuboidal cells that may have cillia
they function in secretions or absorption
what is the name for the shape of epithelial cells that are taller than they are wide?
what are their functions?
what other structures might they have?
columnar
secretion and absorption
may have microvilli
