Histology Stuff Flashcards
What type of epithelium lines body walls, cavities, tubes, and vascular channels?
Surface Epithelium
What type of epithelium forms glands and secretory ducts?
Glandular Epithelium
What is a major difference in endocrine and exocrine glands?
endocrine glands have ducts
Exocrine glands do not
What are some features of epithelium?
Cells closely opposed Polarized Present at cell surface Rest on the basement membrane avascular Form continuous sheets
What two criteria are used to classify epitheilia?
number of layers (simple, stratified)
Shape of cells (squamous, cuboidal, columnar)
Where can simple squamous endothelium be found?
Lines the blood vessels and heart, shows as a thin layer with a stretched nucleus.
Where can simple squamous mesoderm be found?
Closed body cavities. Looks like tiles on a floor
Where can simple cuboidal epithelium be found?
kidney tubules. (nuclei is at the center and they are evenly spaced)
Where can simple columnar epithelium be found?
Gallbladder and Small intestine (has goblet cells intersperced) [nuclei typically in base]
What are the two types of stratified squamous epithelium?
non-keritinized and keritinized
What formes the lining of larger glandular ducts?
stratified columnar and cuboidal epithelium
Where can pseudostratified columnar epithelium be found?
Male reproductive tract (have stereocillia and a large lumen)
Respiratory (ciliated, intersperced with goblet cells)
What type of epithelium is made for stretching?
transitional epithelium
Is transitional epithelium stratified?
yes
What is the basement membrane of epithelium made of?
reticular lamina, and collagen fibrils
lamina densa and reticular layer
What are the components of the basal lamina?
collagen type 4 (for strength), proteoglycans (increase permeability of the basal lamina)
What is laminin?
glycoprotein with 3 large binding domains, 1 for collagen type 4, one for perlean, one for integrin receptors in the epithelial cell membrane
What do terminal bars consist of?
Zona occludens, zonula adherens, Macula adherins
What does the zona occludens do?
prevents passage of molecules, prevents passage of proteins using claudin (occludin is also there)
What layer does becterial toxin break down?
decomposes proteins and allows fluid in = food poisoning
What is the job of the zonula adherens?
like a zipper and helps dissipate mechanical forces
What proteins make up zonula adherins?
actin (from within cell to dissipate shock) and E-cadherin ( two of these touch to join two cells)
What ion is cadherin dependent on?
Ca2+
How do macula adherins work?
like spot welds. Desmocolins and desmogleins attach to keratin in the cytoskeleton
What side of the cell do gap junctions exist on?
The lateral side of the cell
What protein makes up gap junctions?
Connexon- makes a little tunnel
What are gap junctions important for?
coordination of movment like the beating of cilia
Spinous processes showing as an artifact may indicate what?
That the cells are joined by tight junctions
What is pemphigus vulgaris?
autoimmune disorder where antibodies are produced against desmosomes
What is the symptom of pemphigus vulgaris?
severe blistering
Where are the only two places to find microvilli?
the brush border of the kidney and striated border of the small intestine
What creates microvilli?
Vertical parallel microvilli and a terminal web that they insert into below
What is ciliac disease?
villi become inflammed and shortened, causes a decreased absorption in nutrients
What are stereocillia?
long MICROVILLI - can be found in sensory cells of the ear and in ductus epidymus
What structures is commonly found the in respiratory tract to move mucous?
Cilia
Describe the arragement of tubules in cillia
9 pairs of 2 in a circle with dyeinin arms, 2 tubules in the middle, 9 triplets at the base
What is dynein?
a motor protein
What is Kartagam?
a disease where you don’t produce dynein arms and makes are infertile, also lots of respiratory tract infections
