Extracellular Matrix and Cell Adhesion

These flashcards cover key concepts relating to the extracellular matrix, its components, functions, and related clinical applications.

What is the Stratum corneum composed of?

Dead cells filled with keratin.

What are the five major components of the basal lamina?

Laminin, type IV collagen, nidogen, fibronectin, and perlecan.

What is the main function of collagen?

Provides structural support and strength to tissues.

What disease is associated with mutations in collagen type IV?

Alport syndrome.

What role do integrins play in the extracellular matrix?

Integrins mediate cell-to-ECM adhesion.

What are glycosaminoglycans (GAGs)?

Long, unbranched carbohydrate chains that attract water and form a hydrated gel.

What is the role of proteoglycans in the ECM?

They form the ground substance in which other matrix components are embedded.

What condition is characterized by collagen synthesis defects leading to easy bruising and joint problems?

Ehlers-Danlos syndrome.

What is the clinical application of glucosamine?

Treatment for osteoarthritis.

What effect does aging have on collagen production?

Decreased collagen production leads to wrinkles and reduced skin firmness.

What is the function of elastin?

Allows tissues to stretch and recoil without tearing.

Which proteins are involved in ECM degradation?

Matrix metalloproteinases (MMPs), transmembrane proteases (ADAMs), and secreted proteases (ADAMTSs).

What is the process of leukocyte extravasation?

The movement of leukocytes from blood into tissues during an immune response.

What is a hemidesmosome?

A junction that anchors intermediate filaments to the basal lamina.

What type of junction seals adjacent epithelial cells together, preventing leakage?

Tight junctions (Zonula occludens).

What is the impact of vitamin C deficiency on collagen?

Causes Scurvy by impairing hydroxylation of prolyl and lysyl residues.

Which condition is characterized by excess collagen deposition, leading to skin hardening?

Scleroderma.

What are the main types of intercellular junctions?

Tight junctions, adherens junctions, desmosomes, gap junctions, and hemidesmosomes.

What is the main function of cadherins?

Mediates cell-cell adhesion in adherens junctions.

What is Marfan syndrome?

A genetic connective tissue disorder affecting fibrillin, leading to skeletal and cardiovascular problems.

What does a deficiency in α1-antitrypsin lead to?

Destruction of elastic fibers in the lung, resulting in emphysema.

How do selectins function in the immune response?

They bind to carbohydrates on leukocytes to mediate adhesion during inflammation.

What is the significance of laminin in the basal lamina?

It connects other components of the basal lamina and provides structural support.

Which type of collagen forms the mesh-like network of the basal lamina?

Type IV collagen.

What are the three classes of intercellular junctions?

Anchoring junctions, occluding junctions, and communicating junctions.

What disease results from defective collagen production characterized by brittle bones?

Osteogenesis imperfecta.

What is the purpose of tissue inhibitors of metalloproteinases?

They regulate the activity of matrix metalloproteinases.

What is the role of the extracellular matrix in the kidney?

Provides filtration and structural integrity.

What are two common diseases related to fibrous proteins?

Scurvy and osteogenesis imperfecta.

How does the ECM contribute to resilience in tissues?

GAGs create a hydrated gel that helps resist compressive forces.

What are the major families of cell adhesion molecules (CAMs)?

Cadherins, selectins, immunoglobulin superfamily, and integrins.

What condition is characterized by a defect in the epidermal cadherin?

Pemphigus vulgaris.

What is the clinical significance of Ehlers-Danlos syndrome?

It results in hyperextensibility of the skin and joints.

Did the excessive action of matrix metalloproteinases contribute to joint disease?

Yes, leading to conditions like osteoarthritis.

What type of intercellular junction allows the passage of small molecules between cells?

Gap junctions.

What binds epithelial cells to the basement membrane?

Hemidesmosomes and integrins.

Which component of the ECM is essential for cell signaling and growth factor storage?

Fibrous proteins like collagen.

What defines a focal contact in cell adhesion?

Adhesion of a cell's basal surface to the ECM through integrins.

How do cadherins function in maintaining tissue structure?

By providing strong cell adhesion through homophilic interactions.

What characterizes the basement membrane?

It is a highly cross-linked layer of ECM anchoring epithelial cells to connective tissue.

What type of collagen is primarily involved in the structure of tendons and bones?

Type I collagen.

What pathophysiological condition can arise from defective ECM protein synthesis?

Various connective tissue disorders.

What role does the extracellular matrix play in wound healing?

It aids in cell migration, differentiation, and tissue repair.

What condition involves collagen abnormalities and leads to easy bruising and joint issues?

Ehlers-Danlos syndrome.

How does dysregulation of cell adhesion contribute to cancer?

It allows for cell detachment and metastasis.

What is the histological appearance of collagen fibers under microscopy?

Characteristic banding pattern due to triple-helix structure.

What is a defining consequence of Scurvy?

Fragile blood vessels due to impaired collagen structure.

Which cellular structure is primarily responsible for collagen synthesis?

Fibroblasts.

What are integrins typically involved in?

Cell-to-cell and cell-to-ECM adhesion.

What is the main role of fibronectin in the ECM?

To facilitate cell adhesion and migration.

What factor contributes to the tensile strength of collagen fibers?

Covalent cross-links formed by lysyl oxidase.

Which junction type is responsible for connecting actin filaments between adjacent cells?

Adherens junctions.

Define the term basement membrane in the context of ECM.

A thin layer of ECM that provides support and anchorage for epithelial tissues.

What are matrix metalloproteinases (MMPs) responsible for?

Degrading components of the extracellular matrix.

Which intercellular junction acts as a barrier to prevent paracellular movement?

Tight junctions.

What do homophilic cadherin interactions help maintain?

Tissue structure and integrity.

What condition can result from abnormal elastin synthesis?

Emphysema due to reduced elasticity in lung tissue.

How do inflammatory cytokines affect cell adhesion?

They can upregulate adhesion molecule expression, worsening inflammation.

What major connective tissue protein provides elasticity?

Elastin.

What is the effect of mechanical stress on desmosomes?

They provide strength and resistance against stress in tissue.

Which disease results from excess proteoglycan degradation?

Scurvy.

What is the clinical relevance of MMPs in cancer treatment?

They may contribute to tumor metastasis by degrading ECM barriers.

What role do tight junctions play in epithelial tissues?

they maintain cell polarity and prevent leakage.

What role does GAGs play in the extracellular matrix?

Provides hydration and structural integrity.