Ch. 5.1 Tissues Organization Flashcards
Tissue
Groups of similar cells the work together towards a common function
histology
the study of tissue
What is the function of epithelial tissue?
Cover the bodies surface, lines body and organ cavities, and forms glands.
Define cellularity as it relates to epithelial tissue
Tightly packed cells with minimal extracellular matrix.
Polarity as it relates to epithelial cells
having an apical or basal surface
Apical Surface
the side of epithelial cells that is exposed to the outside or some internal body space. these surfaces might have microvilli or cilia on them.
Basal surface
Fixed surface that is attached to the basement membrane of connective tissue.
What are the three parts of the basement membrane?
Lamina lucida, lamina densa, and reticular lamina. Only visible with an electron microscope.
What are the three basement lanes made of?
Collagen, glycoproteins, and proteoglycans.
Avascularity
all epithelial tissue lacks blood vessels.
How much nervous tissue does epithelial tissue have?
Lots!
Stem cells- what do they do?
They are responsible for cell division at the base of epithelium, closest to the basement membrane. This cell division provides for the replacement cells necessary as the epithelium takes wake and tare on its apical surface.
What makes up glands?
Epithelial cells. May be one cell, or a group of cells.
what type of epithelial cells can be keratinized?
stratified squamous
endothelium- composition and location
simple squamous epithelium- lines blood vessels and lymph vessels.
mesothelium
simple squamous epithelium that forms the serous membranes of body cavities.
endon
within
mesos
middle
attributes of simple columnar epithelium
Good for absorptive and secretary functions. Two types. Ciliated, and non-ciliated.
Non-Ciliated simple columnar attributes
Have microvilli and often have some goblet cells.
Define brush border
A bright fuzzy structure that is made up of microvilli and can only be seen under a microscope.
musin
a glycoprotein secreted by goblet cells that forms mucus when hydrated.
Where are non-ciliated columnar epithelium located?
The lining of the intestinal tracts and the stomach.
where is simple squamous epithelium located?
Alveoli, lining of blood vessels, and serous membranes
Where are serous membranes located? What do they secrete?
Coving body organs. They secrete serous fluid.
Where are non-keratinized stratified squamous epithelium located?
The linings of the mouth, part of the pharynx, part o of the larynx, the esophagus, the vagina, and the anus.
What is generally the purpose of stratified cuboidal epithelium? What does it form?
Protection and secretion.
Forms tubes and ducts. (forms the walls of the ducts of most exocrine glands)
Where is stratified columnar epithelium located?
What is its function?
Large ducts of salivary glands, conjunctiva, and segments of the male urethra.
Function: To protect and secrete.
Describe endocrine glands
lack ducts. Secrete hormones directly into the blood.
I.E. Thyroid and adrenal glands.
Describe exocrine glands
Maintain connection with the epithelium by means of a duct.
Sweat glands, mammary glands, salivary glands.
Describe unicellular exocrine glands and their body locations
Usually ductless
Located close to the surface of the epithelium they reside in.
Most common type is the goblet cell
Found in simple columnar epithelium and pseudo stratified ciliated columnar epithelium
Describe multicellular exocrine glands and their body locations
Gland often consists fo acini.
These acini have ducts that connect to form a larger duct and transport secretions the surface of the epithelial tissue.
Often surrounded by a fibrous capsule.
Portions of the capsule called septa partition these glands into lobes.
Define acini
clusters of cells in exocrine glands that produce secretions and one or more smaller ducts.
define acinus
grapes
Merocrine
Glands that pack their secretions into vesicles and secrete them through exocytosis.
I.E. Tear glands, salivary glands, sweat glands, pancreatic glands, and stomach glands
Meros
share
Apocrine
Secretion occurs when apical surface of cells pinch off and release cytoplasmic contents.
I.E. Mammary glands and ceruminous glands of the ear
Apo
away from, off
Halocrine
Cells that accumulate a product and then disintegrate.
I.E. Sebacious (oil producing cells of the skin) glands
Holos
whole
