Histology Chapter 4: Epithelial Tissue
A. desmosomes
A 42-year-old woman of Mediterranean descent presents with multiple oral blisters and a few cutaneous blisters on her back and buttocks. The superficial bullae are fragile, some have unroofed to form ulcerated lesions, and there is a positive Nikolsky sign. Blood tests reveal antibodies to a subfamily of cadherins and immunohistochemical staining of a biopsy from the oral mucosa shows distribution of the antigen throughout the epithelium. In what structures is the defect that is causing this patient's condition? a. Desmosomes b. Tight junctions c. Hemidesmosomes d. Gap junctions e. Reticular lamina
A. microvilli
An 11-month-old girl is referred to a pediatric gastroenterology clinic due to a history of generalized weakness, slow growth, and refractory diarrhea. For the past month she has been hospitalized regularly to receive parenteral nutrition. Examination of the epithelium lining her small intestine confirms that the failure to absorb nutrients is most likely due to a significant decrease in which of the following? a. Microvilli b. Gap junctions c. Cilia d. Cell layers e. Basement membrane thickness
A. a material crossing the epithelium between the cells (paracellular movement)
An individual genetically unable to synthesize normal occludin is likely to have epithelia with defective regulation in which of the following? A. material crossing the epithelium between the cells (paracellular movement) B.. Communication between the cells C. Attachment to the basement membrane D. Strong attachment to neighboring cells E. Movement of membrane proteins in the apical domains of cells
E. keratin
An intermediate filament protein found in cytoplasm of most epithelial cells is which of the following? a. Actin b. Vimentin c. Laminin d. Myosin e. Keratin
B. connective
Except in the brain and spinal cord, the stroma is always? A. epithelial B. connective C. muscle D. nervous
C. mucous gland
Exocrine glands in which the acini all produce a secretion of heavily glycosylated, hydrophilic proteins are an example of which type of gland? a. Serous gland b. Mixed gland c. Mucous gland d. Tubuloacinar gland e. Simple gland
B. molecular filtering
Functions of the basement membrane include which of the following? A. contractility B. molecular filtering C. active ion transport D. excitability E. modification of secreted proteins
brush or striated border
In cells such as those lining the small intestine, densely packed microvilli are visible as ________ projecting into the lumen
lamina propria
The connective tissue that underlies the epithelia lining the organs of the digestive, respiratory, and urinary systems is called?
type 3 , type 7
The more diffuse meshwork of the reticular lamina contains type _____ collagen and is bound to the basal lamina by anchoring fibrils of type _______ collagen, both of which are produced by cells of connective tissue.
C. apocrine
The release of lipid droplets from cells is which type of secretion? a. Merocrine b. Serous c. Apocrine d. Mucous e. Holocrine
helicobacter pylori (gastric ulcers)
This bacteria binds the extracellular domains of tight-junction proteins in cells of the stomach and inserts a protein into these cells, which targets ZO-1 and disrupts signaling from the junction.
B. false- cilia contain internal arrays of microtubules
True or False: Cilia are long, highly motile apical structures, larger than microvilli, containing internal arrays of microfilaments. A. true B. false
B. false Small blood capillaries normally never enter epithelia.
True or False: Nerve fibers and small blood capillaries normally penetrate the basement membrane of epithelia. A. true B. false
integrins
Unlike desmosomes, in hemidesmosomes, the clustered transmembrane proteins that indirectly link to cytokeratin intermediate filaments are ___ rather than cadherins.
C. gap junctions
Using immunohistochemistry a population of cells is shown to be positive for the protein connexin. From this we can infer that the cells are connected by what type of junction? A. tight (occluding) junctions B. zonula adherens C. gap junctions D. hemidesmosomes E. desmosomes (macula adherens)
clostridium perfringens (food poisoning)
Which bacteria binds claudin molecules of intestinal cells, prevents insertion of these proteins during maintenance of tight junctions, and causes the loss of tissue fluid into the intestinal lumen via the paracellular pathway?
B. number of cell layers
Which of the following cellular features is used in naming types of epithelia? a. Shape of cells in the basal layer b. Number of cell layers c. Presence of a basal lamina d. Size of the nuclei e. Nature of the cell junctions that are present
B. cilia
With a 5-year history of chronic respiratory infections, a 23-year-old, non-smoking man is referred to an otolaryngologist. A bronchial biopsy indicates altered structures in the epithelial cells. Which of the following, if altered to reduce function, is most likely involved in this patient's condition? a. Hemidesmosomes b. Cilia c. Basolateral cell membrane folds d. Microvilli e. Tight junctions
various blistering (bullous) diseases such as Pemphigus Vulgaris
abnormal desmosome function caused by autoimmune reactions against specific desmogleins that reduce cell-to cell adhesions causes this
apocrine secretion (used by exocrine) -lipid droplets are secreted in mammary glands in this manner
accumulates at the cell's apical ends, portions of which are then extended to release the product together w/ small amount of cytoplasm and cell membrane
epithelial tissue
aggreagted polyhedral cells -lining of surface or body cavities; glandular secretion
gap junction (Nexus)
allows direct transfer of small molecules and ions from one cell to another (communication)
hemidesmosome
anchors cytoskeleton to basal lamina
holocrine secretion (used by exocrine) best seen in sebacreous glands producing lipid-rich material in skin
cells accumulate product continuously as they enlarge & undergo terminal differentiation, culminating in complete cell disruption which releases the product & cell debris into the gland's lumen
celiac disease (gluten-sensitive enteropathy) (sprue)
disorder of small intestine in which one of the 1st pathologic changes is loss of microvilli brush border of the absorptive cells immune reaction against gluten during digestion which produces diffuse enteritis (intestinal inflammation)
nervous tissue
elongated cells with extremely fine processes -transmission of nerve impulses
muscle tissue
elongated contractile cells -strong contraction; body movements
Simple Squamous
facilitates the movement of the viscera, active transport by pinocytosis, secretion of biologically active molecules -lining of vessels and cavities
stratified cuboidal
function as protection, secretion -sweat glands, developing ovarian follicles
Simple cuboidal
functions as covering, secretion -covering the ovary, thyroid , renal collecting tubule
stratified columnar
functions as protection -conjunctiva
stratified transitional
functions as protection, distensibility -bladder, ureters, renal calyces
Simple columnar
functions as protection, lubrication, absorption, secretion -lining of intestine, gallbladder
stratified squamous keratinized
functions as protection, prevents water loss (dry) -epidermis
stratified squamous nonkeratinized
functions as protection, secretion, prevents water loss (moist) -mouth, esophagus, larynx, vagina, anal canal
laminin
large glycoproteins that attach to transmembrane proteins called integrins at the cells' basal surface and project through the network of type IV collagen
Merocrine secretion (used by exocrine)
most common method of protein or glycoprotein secretion & involves typical exocytosis from membrane-bound vesicles or secretory granules
chronic bronchitis
number of goblet cells in lining or airways in the lungs are increased greatly leads to excessive mucus production in areas where there are too few ciliated cells for its rapid removal & contributes to obstruction of the airways
pseudostratified
protection, secretion, cilia-mediated transport of particles trapped in mucus out of air passages -lining of trachea, bronchi, nasal cavity
adherent junction (Zonula Adherens)
provides points linking the cytoskeleton of adjacent cells -strengthens and stabilizes nearby tight junctions
desmosome (macula adherens)
provides points of strong intermediate filament coupling between adjacent cells -strengthens the tissue
tight junction (Zonula occludens)
seals adjacent cells to one another, controlling passage of molecules between them -separates apical & basolateral membrane domains
connecfive tissue
several types of fixed and wandering cells very abundant ECM -support & protection of tissues/organs
immotile cilia syndrome (Karteagener syndrome)
symptoms are chronic respiratory infections caused by the lack of the cleansing action of cilia in the respiratory tract and immotile spermatozoa, causing male infertility
papillae
the area of contact between the two tissues may be increased by small envaginations called ____ projecting from the connective tissue to epithelium
endocrine glands
what glands lose the connection to their original epithelium and therefore lack ducts
Exocrine Glands
what glands remain connected with the surface epithelium, the connection forming the tubular ducts lined with epitheium which deliver the secreted material where it is used