8- Among the constituents of Howship's lacuna we note: A. Osteoclasts. B. Mesenchymal cells. C. Closed-end blood capillary. D. Connective fibers. E. Endosteum. F. Collagen fibers. G. Unmyelinated nerve fiber. H. Osteocytes. I. Lining cells. J. Elastic fibers.

Howship's lacuna, also known as a resorption bay, is a microscopic cavity within bone that is undergoing resorption. It is created by osteoclasts, which are the cells responsible for bone resorption. Therefore, the constituents of Howship's lacuna would include:

A. Osteoclasts - These are the cells that create the lacuna by resorbing bone.

The other options listed are not typically considered constituents of Howship's lacuna:

B. Mesenchymal cells - These are multipotent stromal cells that can differentiate into a variety of cell types, including osteoblasts (which form bone), but they are not part of the lacuna itself.

C. Closed-end blood capillary - While blood supply is necessary for bone health and remodeling, the capillaries themselves are not part of the lacuna.

D. Connective fibers - These are part of the bone matrix, not the lacuna.

E. Endosteum - This is a thin layer of connective tissue that lines the surface of the bony tissue that forms the medullary cavity of long bones, not part of the lacuna.

F. Collagen fibers - These are part of the bone matrix, not the lacuna.

G. Unmyelinated nerve fiber - While nerves are present in bone, they are not part of the lacuna.

H. Osteocytes - These are mature bone cells, housed in lacunae of the bone, but not in Howship's lacuna.

I. Lining cells - These are flattened bone cells derived from osteoblasts that line bone surfaces, but they are not part of the lacuna.

J. Elastic fibers - These are part of the bone matrix, not the lacuna.