Bone Notes

Bones are organs because they contain different types of tissues. A bone is mostly made of __________ connective tissue.

osseous

All bone has a dense outer layer consisting of __________ bone that appears smooth and solid.

compact

Inside the compact bone is __________ bone, which consists of honeycomb, needle-like, or flat pieces, called trabeculae.

spongy

Open spaces inside spongy bone are filled with red bone marrow (full of __________ cells) or yellow bone marrow (full of __________ cells).

blood; adipocytes

The __________ is a long tubular shaft of bone. It is made of an outer layer of compact bone around a central medullary cavity filled with yellow bone marrow in adults.

diaphysis

The __________ are the ends of long bones that consist of compact bone around spongy bone filled with red marrow.

epiphyses

The __________ is the transition between the diaphysis and the epiphysis.

metaphysis

The __________ of the bone is covered by the periosteum membrane.

external surface

The __________ surface of the bone is lined by a delicate connective tissue membrane called the endosteum.

internal

The periosteum and endosteum each contain an __________ layer, the inner layer in contact with bone that contains osteoprogenitor stem cells.

osteogenic

Osteogenic cells are __________ active stem cells found on the periosteum and endosteum membranes.

mitotically

Osteoblasts secrete un-mineralized bone matrix called __________.

osteoid

Osteocytes are mature bone cells in lacunae that no longer divide. They maintain bone matrix and act as stress or strain __________.

sensors

Osteoclasts are derived from the same __________ stem cells that produce macrophages.

hematopoietic

They have ruffled borders that increase __________ for the degradation of bone.

surface area

Bone-lining cells are flat cells that work with osteocytes to help maintain bone __________.

matrix

Bone-lining cells aren’t inside __________ because they are on the edges of the bone structure.

lacunae

List the six important functions of bones.

Support, movement, protection, mineral storage, blood cell production, and energy storage.

The __________ cartilage covers the ends of long bones at joints, providing a smooth surface for articulation.

articular

The __________ is a dense connective tissue membrane covering the outer surface of bones, providing protection and nourishment.

periosteum

The __________ is a thin membrane lining the internal surfaces of bones, including the medullary cavity and the surfaces of trabecular bone.

endosteum

Red bone marrow is primarily located in the __________ of long bones, where it produces blood cells.

epiphysis

Yellow bone marrow is found in the __________ cavity of long bones and serves as a fat storage area.

medullary

Osteogenic cells are found in the periosteum and endosteum and develop into __________ or osteoblasts, contributing to bone formation.

osteoblasts

Osteoblasts are responsible for the secretion of __________, which is the organic component of bone matrix.

osteoid

Osteocytes, which are mature bone cells, act as __________ for the bone matrix, detecting mechanical strain and signaling to osteoblasts and osteoclasts.

sensors

Osteoclasts are responsible for the __________ of bone tissue, ensuring proper bone remodeling and calcium mobilization.

resorption

Periosteal cells are similar to osteoblasts and are involved in the __________ of the bone surface, responding to mechanical stress.

maintenance