Histology of Connective Tissues Flashcards

In Marfan syndrome, the primary structural defect involves which connective tissue protein?

Answer: Fibrillin-1

Marfan syndrome results from mutations in the FBN1 gene encoding fibrillin-1, a major component of elastic fiber microfibrils.

Which connective tissue type is found in the stroma of the liver and spleen?

Answer: Reticular

Reticular connective tissue forms the supporting stroma of lymphoid organs and parenchymal organs such as the liver and spleen.

Proteoglycans contribute to tissue hydration primarily because glycosaminoglycan chains are:

Answer: Highly negatively charged and attract cations and water

The high density of negative charges on GAG chains attracts cations and osmotically draws large amounts of water into the matrix.

Which enzyme is primarily responsible for degrading collagen in normal tissue remodeling?

Answer: Matrix metalloproteinase (collagenase)

Matrix metalloproteinases (MMPs), specifically collagenases (MMP-1, MMP-8, MMP-13), cleave native collagen triple helices during remodeling.

Ehlers-Danlos syndrome type VI is caused by a deficiency in which enzyme?

Answer: Lysyl hydroxylase

EDS type VI results from lysyl hydroxylase deficiency, impairing hydroxylysine formation and subsequent cross-linking of collagen fibers.

Which cell type is the primary source of extracellular matrix components in connective tissue?

Answer: Fibroblasts

Fibroblasts are the principal cells of connective tissue, synthesizing and secreting collagen, elastin, and ground substance components.

The lamina densa of the basement membrane is composed primarily of:

Answer: Type IV collagen and laminin

The lamina densa (basal lamina proper) consists mainly of type IV collagen and laminin organized into a dense feltwork.