Epithelium I, II Flashcards by Alison Butler

The apical and basolateral surfaces are segregated by a specialized junctional complex called the __________________.

A. gap junction

B. tight junction

C. junctional complex

D. glycocalyx

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The red box in this image features an apical specialization that is often associated with the ________.

A. Respiratory tract

B. Urogenital tract

C. Intestinal tract

D. Proximal tubule cells

E. Epididymis

C - Glycocalyx (shown in the image) is featured in the intestinal tract.

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One feature that separates the glycocalyx from other apical specializations (i.e. is UNIQUE to the glycocalyx layer) is:

A. mechanotransduction

B. control of tissue hydration

C. protection against mechanical damage

D. protection against pathogen damage

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Mucous in the mucous layer is secreted by:

A. goblet cells

B. proximal tubule cells

C. microplicae

D. none of the above

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The tissue in the following image is found in the:

A. Respiratory tract

B. Urogenital tract

C. Trachea

D. Hard palate

D - this image features the microplicae surface, which is present in the cornea, GI tract, fallopian tubes, bladder, and hard palate

*Note: hard palate example is featured in the powerpoint but not syllabus ~tricky~

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“Umbrella cells” (pictured) are a characteristic feature of which apical specialization?

A. Glycocalyx

B. Mucous Layer

C. Microplicae

D. Microvilli

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The image displayed here predominantly features which apical specialization?

A. Stereocilia

B. Motile cilia

C. Non-motile cilia

D. Microplicae

E. Microvilli

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One particular apical specialization is prevalent in the brush border of small intestinal enterocytes due to its ability to increase surface area 30-fold, as well as its mechanotransduction and sensory perception functions. What other body location would we expect to see this cell?

A. Mucociliary escalator

B. Cells of the primitive node

C. Oviducts

D. Embryonic node

E. Proximal tubule cells (kidney)

E - the specialization being described is the microvilli layer of the apical surface.

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At the center of each stereocilium is a core of _________.

A. actin filaments

B. microtubules in a 9+2 organization

C. microtubule pairs in a 9+0 organization

D. none of these

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Stereocilia are found on the _________ cells that line the epididymis and vas deferens.

A. Simple cuboidal

B. Stratified squamous

C. Simple squamous

D. Simple columnar

E. Pseudostratified columnar

E (see image)

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At the center of each motile cilia is a core of _________.

A. actin filaments

B. microtubules in a 9+2 organization

C. microtubule pairs in a 9+0 organization

D. none of these

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The image here is an example of:

A. Stereocilia

B. Motile cilia

C. Primary cilia

D. Nodal cilia

B - motile cilia feature whip-like projections and a core of microtubules in a 9+2 organization

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These cilia function specifically to promote the movement of fluid, substances, and cells. Where might they be found?

A. Trachea

B. Brain ventricles

C. Oviducts

D. Embryonic node

E. All of the above

E - the cilia being described are motile cilia, which are found in all of these locations!

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Most non-motile cilia show a configuration of _________.

A. actin filaments

B. microtubules in a 9+2 organization

C. microtubule pairs in a 9+0 organization

D. none of these

C - note that non-motile or primary cilia also lack central microtubules and dynein

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Primary cilia are also known as:

A. Stereocilia

B. Motile cilia

C. Non-motile cilia

D. Nodal cilia

E. Pseudocilia

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The cilium on the LEFT in the image displayed is an example of: ___________.

A. Stereocilium

B. Primary cilium

C. Motile cilium

D. Not enough information to tell - the 9+0 configuration is characteristic of more than one type of cilia!

B - note that while D is true, the other type of cilia with “9+0” architecture is nodal cilia, which is not featured here.

Polycystic kidney disease is linked to:

A. Microvilli dysfunction that creates an inability to recover nutrients or solutes from the lumen

B. Disruption of the glycocalyx, creating an imbalance in cell hydration

C. Loss of primary cilia involved in sensory transduction

D. Mutation in the gene encoding nodal cilia, which causes pathology linked to left-right asymmetry during embryogenesis

The apical component of the junctional complex is the:

A. Tight junction

B. Desmosome

C. Adherence junction

D. Gap junction

A - see image

The Adherins junction is found beneath the tight junction. It contains a transmembrane component - Ca2+ dependent cadherins. However, it also contains an attachment protein which is ______.

A. Claudins

B. Occludins

C. Zonulins

D. Catenins

D - alpha, beta, and gamma catenins provide links from cadherins to the cytoskeleton in adherens junctions. Note - the other three options are part of the tight junction component of the cell.

The box in the image below displays a component of the junctional complex which functions to:

A. Provide mechanical strength

B. Tether the cytoskeleton

C. Allow ions and small molecules to pass between cells

D. Limit the passage of toxins and microbes

A - this image features a desmosome, which mediates adhesion in cells exposed to high mechanical stress

Consider the component of the junctional complex within box in this image. Where are these components most likely to be found ?

(Hint: they are also prevalent in the epidermis)

A. Skeletal muscle cell

B. Central nervous tissue cell

C. Intercalated discs between adjacent cardiac muscle cells

D. Hair cells of inner ear

C - the box features a desmosome

Gap junctions:

A. are found along the basal surfaces of epithelial cells

B. are gated closed by low Ca2+ or high pH

C. are common in muscle cells and the nervous system

D. feature a single connexin assemblage that creates a pore between adjacent cells

C - gap junctions are found along the lateral surfaces of epithelial cells, are gated closed by high Ca2+ or low pH, and feature 6 connexins assembled into a connexon that forms a pore between cells.

The brackets in the image feature:

A. Large gap junctions

B. Desmosomes

C. Tight junctions

D. Small gap junctions

A - the brackets are pointing to large gap junctions, characterized by the appearance of multiple connexons

Laminins:

A. is the major component of the basal lamina

B. consists of three disulfide linked polypeptide chains

C. has binding sites for type IV collagen and midogen

D. All of the above

Which component of the basement membrane is rich in **Collagen I and III**? A. Basal lamina B. Reticular lamina C. Integrins D. Laminins E. Fibronectin

B - reticular lamina is rich in collagen I, collagen III, and fibronectin.

Fibronectin: A. Comes in one form - plasma fibronectin B. is formed by two identical chains joined by disulfide linkages close to the N-terminal C. has binding sites for collagen and integrins D. All of the above

C - note that A is incorrect because fibronectin comes in two forms (plasma and cellular), while B is incorrect because the disulfide linkages are close to the **C-terminal.**

A 21-year old man was diagnosed as having end-stage renal disease during his first consultation with a nephrologist. The reason for referral was hypertension associated with high level of urea and creatinine. He was born with post-axial polydactyly. During childhood, cognitive deficit and visual deficiency were noted. He was treated since then as a case of idiopathic mental retardation. At the consultation with the nephrologist, hypogenitalism and obesity were noted besides cognitive deficit and blindness. What is this patient's diagnosis? A. Barde-Biedl Syndrome (BBS) B. Kartagener syndrome C. Famial adenomatous polyposis-1 D. Bronchial asthma E. Cystic fibrosis

A - **BBS** is an example of a rare recessive disorder with complex symptomalogy reflecting disruptions of primary cilia. Note that this disease features a disruption in hedgehog signaling, causing postaxial polydactaly.

A 24 year old man presents with productive cough, headache, and fever. Sinus radiographs showed mucosal thickening, opacified sinus cavities, and other features of chronic sinusitis. Contrast Enhanced Computed Tomography (CECT) showed sinusitis, bronchiectasis and situs inversus. What is this patient's diagnosis? A. Barde-Biedl Syndrome (BBS) B. Kartagener syndrome C. Famial adenomatous polyposis-1 D. Bronchial asthma E. Cystic fibrosis

B - considering the clinical picture of the patient, sinusitis, bronchiectasis and situs inversus, the clinical diagnosis of **Kartagener’s Syndrome** was made.

Patients with **familial adenomatous polyposis-1:** A. have dysfunctional keratin intermediate filaments, meaning they often do not survive past 5 years of age B. show abnormal E-cadherin expression, leading to a predisposition to cancer C. suffer from renal failure due to leaky gap junctions caused by a mutation in the gene encoding connexons D. None of these

B - familial adenomatous polyposis-1 is an autosomal dominant disorder caused by problems in E-cadherin expression. **E-cadherin** is both a tumor suppressor and a sink for B-catenin (an element in **Wnt** signaling).

A 45-year-old male was present with the presence of multiple blisters in the trunk. Oral cavity is normal. Autoantibodies to which of the following has resulted in the present scenario? A. Hemidesmosomes B. Zonula adherens C. Macula occuldens D. Zonula occludens E. Gap junctions

A - autoantibodies to components in the basement membrane, such as **hemidesmosomes, collagen type XVII, or dystonin,** is known as **bullous pemphigoid -** this disease matches the patient's symptoms.

A 22-year-old female presents for an annual screening exam. She was ordered a pap test. She is sexually active and uses protection during intercourse. The type of epithelium found in the cervix is? A. Stratified squamous keratinized B. Simple cuboidal C. Simple columnar D. Pseudostratified columnar E. Transitional epithelium

A - **stratified squamous epithelial cells** are found in the epithelium of the cervix.