Animal Tissues and Cell Junctions

Which type of intercellular junction forms a continuous band around epithelial cells near their apical end and is primarily responsible for preventing passive flow of materials between cells?

Adherens junctions are primarily responsible for preventing the passive flow of material between cells.

What is the primary function of gap junctions in epithelial tissues?

__________ bind epithelial cells to the underlying basal lamina.

Match each type of junction with its primary role:

Which tissue type is characterized by having several types of fixed and wandering cells with an abundant extracellular matrix, primarily providing support and protection?

Epithelial cells are characterized by a moderate amount of extracellular matrix.

What is the primary function of muscle tissue, as indicated in the provided content?

The region of an epithelial cell that contacts the ECM and connective tissue is called the ______ pole.

Match the tissue types with their corresponding main functions:

Which type of epithelial cell is likely to have flattened nuclei?

The apical and basal poles of epithelial cells have similar structures and functions.

What is the primary component that the basal surface of all epithelia rests on?

Which of the following best describes the function of gap junctions in epithelial tissue?

Tight junctions, or zonulae occludens, are located at the basal end of epithelial cells.

What two transmembrane proteins are primarily responsible for creating the tight seal in tight junctions?

The term 'zonula' in zonula occludens indicates that the junction forms a ______ completely encircling each cell.

Match the following:

Which of the following is NOT a primary function of the basement membrane?

Nidogen and perlecan primarily function to degrade laminins within the basal lamina.

What is the main role of laminin in the basement membrane?

The porosity of the basal lamina, which determines the size of molecules able to filter through it, is regulated by the proteins __________ and ___________.

Match the components of the basement membrane with their primary function:

Why are intercellular junctions particularly numerous and prominent in epithelia?

External laminae are exclusively found surrounding epithelial cells and have a distinctly different composition from basal laminae.

What is the primary purpose of tight junctions in epithelial cells?

What is the primary function of gap junctions in mammalian tissues?

Desmosomes create a belt-like structure around the entire cell.

What are the transmembrane proteins that form gap junctions called?

At their cytoplasmic ends, cadherins bind __________ that link to actin filaments with actin-binding proteins.

In blistering diseases like pemphigus vulgaris, the abnormal desmosome function is caused by autoimmune reactions against which specific molecules?

What cytoskeletal feature forms at the apical pole of many epithelial cells as a result of adherens junctions?

Match the following junction types with their primary function:

Which of the following best describes the structure of connexons within gap junctions?

Which of the following is the primary function of tight junctions in epithelial cells?

Adherens junctions mediate cell adhesion through cadherins, which require the presence of $Mg^{2+}$ for binding.

What type of cell junction is located immediately below the tight junction in the junctional complex?

In adherens junctions, transmembrane glycoproteins called ______ bind to each other in the presence of $Ca^{2+}$ to mediate cell adhesion.

What is the function of the protein strands observed in tight junctions after cryofracture?

Which of the following cell junctions is associated with intermediate Filaments (IF)?

Match the following cell junctions with their primary function:

Epithelial cells have only one membrane domain; the apical domain.

Which junction type primarily contributes to the mechanical stability and integrity of the epithelium by forming strong attachment points linked to intermediate filaments?

What is the key structural difference between desmosomes and zonula adherens in epithelial cells?

Which of the following best describes the functional relationship between tight junctions and adherens junctions in epithelial cells?

A mutation disrupts the function of connexons in a layer of epithelial cells. Which of the following processes would be most directly affected?

Given that both desmosomes and hemidesmosomes utilize intermediate filaments for anchoring, what is the most critical distinction in their respective functions within epithelial tissue?

What is the primary mechanism by which epithelial cells receive nutrients, given their relationship to the basement membrane and blood capillaries?

Which of the following structures is normally excluded from entering the epithelial tissue itself?

In kidney glomeruli, what additional crucial function does the basement membrane perform besides providing support?

What is the main component of the basal lamina?

Which staining method is used to visualize the renal glomerulus in the figure?

Considering the dual role of the basement membrane in the kidney glomeruli, what might be a consequence of damage to the heparan sulfate proteoglycans within this structure?

Which cytoskeletal component is directly linked to cadherins via catenins in adherens junctions?

What is the primary function of connexons in gap junctions?

A researcher is investigating a novel drug designed to enhance nutrient delivery to epithelial cells. Given the information provided, which of the following mechanisms would be the MOST effective target for this drug?

In the context of epithelial cells, what is the 'terminal web'?

If a toxin specifically targeted and destroyed laminin, but not collagen, within the basement membrane of the kidney glomerulus, what immediate physiological consequence would MOST likely be observed?

Which of the following junctions does NOT primarily function in cell adhesion?

What is the structural characteristic of desmosomes that distinguishes them from zonula adherens?

Which component of the basal lamina primarily mediates the attachment of epithelial cells to the lamina through transmembrane integrin proteins?

What is the diameter of the hydrophilic pore formed by connexons in gap junctions?

Which condition is associated with autoimmune reactions against desmogleins, leading to reduced cell-to-cell adhesion in epithelial tissues?

What role do nidogen and perlecan play in the structure and function of the basal lamina?

Besides epithelial cells, where else can external laminae (basal laminae with similar composition) be found?

Epithelial cells are held together by tight and adherent junctions. Imagine a mutation that disrupts the structure of the proteins in the tight junctions and adherens junctions. Considering that tight junctions are located more apically than the adherent junctions, what is the mostly likely functional consequence of those mutations?

What is the primary function of the external laminae surrounding nerve cells?

Which of the following is LEAST likely to be a function of the basement membrane?

How do tight junctions contribute to the overall function of epithelial tissue?

Considering the roles of laminin, nidogen/perlecan, and type IV collagen within the basal lamina, if an epithelial tissue were subjected to a treatment that selectively disrupted the cross-linking function of nidogen and perlecan, what immediate effect would be MOST likely observed?

A researcher is studying a novel mutation that affects the structure of the basal lamina. They observe that despite normal expression levels of laminin and type IV collagen, the epithelial cells exhibit significantly reduced adhesion and increased rates of apoptosis (programmed cell death). Furthermore, the porosity of the basal lamina is abnormally high, allowing larger molecules to pass through. Based on these observations, which protein is MOST likely affected by the mutation?

What is the primary function of the basement membrane in relation to epithelial cells?

Which cellular feature is most useful for determining the number of cell layers in an epithelium using light microscopy?

What distinguishes the lamina propria from other types of connective tissue?

In epithelial tissues subject to high friction, such as the skin and tongue, which structural feature is commonly observed at the interface of the epithelium and connective tissue?

How are nutrients and oxygen typically supplied to epithelial cells in thick epithelia?

What is the primary distinction between the basal lamina and the reticular lamina of the basement membrane, as observed under a transmission electron microscope (TEM)?

Given that cuboidal and pyramidal epithelial cells generally have spherical nuclei, what nuclear morphology would most likely be observed in squamous epithelial cells?

Consider an epithelium with damaged papillae due to chronic injury. Which of the following compensatory mechanisms would be LEAST likely to occur in the affected tissue?

Which junction type directly facilitates communication between adjacent cells by allowing the passage of small molecules and ions?

What is the primary role of occludins and claudins in epithelial cell junctions?

Which of the following cytoskeletal components is associated with adherens junctions?

Autoimmune reactions against desmoglein I, a cadherin family protein, primarily disrupt cell cohesion in which type of junction, leading to dyshesive skin disorders?

Which of the following proteins is directly associated with hemidesmosomes?

Loss of E-cadherin function is most directly implicated in which of the following pathological processes?

Mutations affecting connexin genes have been associated with:

Which of the following junctions utilizes a cadherin family protein to provide strong intermediate filament coupling between adjacent cells, strengthening the tissue?

A researcher is investigating a novel epithelial tissue and observes defects in the proper formation of the fetal blood-brain barrier. Dysfunction in which of the following transmembrane link protein families is MOST likely the cause?

A patient presents with epidermolysis bullosa due to mutations in a gene affecting hemidesmosome function. Targeted therapy aims to enhance the expression of a protein to stabilize adhesion of epithelial cells to the basal lamina. Which protein would be the MOST appropriate target for increasing expression?

Laminins

Nidogen

Perlecan

External Laminae

Intercellular Junctions

Epithelial Adhesion

Tight Junctions

Junctional Complexes

Epithelial Tissue

Connective Tissue

Muscle Tissue

Nervous Tissue

Function of Epithelial Cells

Basal Pole

Apical Pole

Basement Membrane

Microvilli

Tight Junction (Zonula Occludens)

Adherens Junction (Zonula Adherens)

Desmosome

Gap Junction

Zonula Occludens (Tight Junctions)

Claudin and Occludin

Apical Cell Membrane

Basolateral Domain

Cadherins

Apical

Basolateral

Tight and Adherent Junctions

Pemphigus Vulgaris

Catenins

Connexins

Connexons

Terminal Web

What are Microvilli?

What is a tight junction?

What is a Desmosome?

What is a Gap Junction?

What is a Hemidesmosome?

Basal Laminae

Occluding Junctions

Staining Basement Membranes

Lamina Propria

Papillae

Epithelial Cell Polarity

Reticular Lamina

Cell Shape and Nuclei

Laminin Function

Epithelial Nutrient Supply

Basement Membrane Role

Nidogen Function

Perlecan Function

Desmosome (Macula Adherens)

Desmosome Structure

Gap Junction Function

Gap Junction Structure

Bullous Diseases

Connexon Pore Size

Desmogleins

Tight Junction Function

Adherens Junction Function

Desmosome Function

Hemidesmosome Function

Tight Junction Proteins

Adherens Junction Proteins

Desmosome Proteins

Hemidesmosome Proteins

Gap Junction Protein