You look under a microscope at 400X and see a tissue with few cells, but large amounts of short, branched fibers with cells clinging to them. You are looking at:
A adipose connective tissue
B reticular tissue
C elastic cartilage
D areolar connective tissue
The correct answer and explanation is :
The correct answer is: B. Reticular tissue
Explanation (300 words):
Reticular tissue is a specialized type of loose connective tissue that is characterized by a delicate network of thin, branched reticular fibers (a type of collagen, specifically type III collagen) forming a supportive framework (stroma) for soft organs. These fibers are short, fine, and form a mesh-like structure that supports the parenchyma (functional cells) of organs such as the spleen, lymph nodes, bone marrow, and liver.
When viewed under a microscope at 400X magnification, reticular tissue appears as a loose network of dark-stained, branched fibers, with relatively few cells dispersed throughout. The reticular fibers provide structural support, and reticular cells (a type of fibroblast) may be seen clinging to or aligned along these fibers. These cells synthesize the reticular fibers and support immune functions by interacting with blood and immune cells.
Let’s contrast this with the other options:
- A. Adipose connective tissue consists mostly of large, lipid-filled adipocytes, with very little extracellular matrix or fiber. It appears as large, empty-looking cells under the microscope.
- C. Elastic cartilage contains chondrocytes within lacunae and a dense matrix of elastic fibers. It is more solid and dense, found in the ear and epiglottis, and doesn’t have a meshwork appearance.
- D. Areolar connective tissue is also a loose connective tissue but contains a mix of collagen, elastic, and reticular fibers loosely arranged with many different cell types. It is more cellular and less uniform than reticular tissue.
In summary, based on the histological appearance described — few cells and abundant short, branched fibers with cells clinging to them — the tissue is reticular connective tissue, which forms the supportive meshwork of soft, lymphoid organs.