Anatomy Exam Histology of Connective Tissues 4 — Questions and Answers
Question 1: In Marfan syndrome, the primary structural defect involves which connective tissue protein?
- Type I collagen
- Elastin
- Fibrillin-1 (Correct answer)
- Fibronectin
Correct answer: Fibrillin-1
Marfan syndrome results from mutations in the FBN1 gene encoding fibrillin-1, a major component of elastic fiber microfibrils.
Question 2: Which connective tissue type is found in the stroma of the liver and spleen?
- Dense regular
- Dense irregular
- Loose areolar
- Reticular (Correct answer)
Correct answer: Reticular
Reticular connective tissue forms the supporting stroma of lymphoid organs and parenchymal organs such as the liver and spleen.
Question 3: Proteoglycans contribute to tissue hydration primarily because glycosaminoglycan chains are:
- Hydrophobic and repel water
- Highly negatively charged and attract cations and water (Correct answer)
- Covalently cross-linked to collagen
- Degraded by hyaluronidase only
Correct 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.
Question 4: Which enzyme is primarily responsible for degrading collagen in normal tissue remodeling?
- Elastase
- Matrix metalloproteinase (collagenase) (Correct answer)
- Hyaluronidase
- Lysyl oxidase
Correct answer: Matrix metalloproteinase (collagenase)
Matrix metalloproteinases (MMPs), specifically collagenases (MMP-1, MMP-8, MMP-13), cleave native collagen triple helices during remodeling.
Question 5: Ehlers-Danlos syndrome type VI is caused by a deficiency in which enzyme?
- Prolyl hydroxylase
- Lysyl oxidase
- Lysyl hydroxylase (Correct answer)
- Collagen peptidase
Correct answer: Lysyl hydroxylase
EDS type VI results from lysyl hydroxylase deficiency, impairing hydroxylysine formation and subsequent cross-linking of collagen fibers.
Question 6: Which cell type is the primary source of extracellular matrix components in connective tissue?
- Macrophages
- Mast cells
- Fibroblasts (Correct answer)
- Adipocytes
Correct answer: Fibroblasts
Fibroblasts are the principal cells of connective tissue, synthesizing and secreting collagen, elastin, and ground substance components.
Question 7: The lamina densa of the basement membrane is composed primarily of:
- Type I collagen and fibronectin
- Type IV collagen and laminin (Correct answer)
- Type III collagen and elastin
- Heparan sulfate and dermatan sulfate only
Correct 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.
Anatomy Exam Histology of Connective Tissues 4
In Marfan syndrome, the primary structural defect involves which connective tissue protein?