2.1/2.2 bones

Bones come in several basic shapes, including __________, flat, short, and irregular.

long

Bones are made up of multiple layers of superficial solid and dense __________ bone and deep loosely organized sponge-like __________ bone.

compact; spongy

The basic organizational and functional unit of osseous tissue is the __________.

osteon

Compact bone contains numerous, densely-packed __________, while the osteons in spongy bone are scattered throughout its trabeculae.

osteons

A single osteon is comprised of multiple circular and spiral layers of concentric __________.

lamellae

In between each lamella sit the __________, which are mature bone cells found in small gaps or pits.

osteocytes

The gaps or pits in which osteocytes reside are called __________.

lacunae

The channels through the hard bone matrix that allow communication between osteocytes are known as __________.

canaliculi

The cylindrical bones of the limbs that are longer than they are wide are called __________ bones.

long

The long central portion of each long bone is called the __________.

diaphysis

The complex endpiece of each long bone is referred to as the __________.

epiphysis

Living bone tissue is encased by a superficial thin layer of dense connective tissue called __________.

periosteum

Flat bones lack a medullary cavity and are structured like a __________.

sandwich

The deep layer of spongy bone in a flat bone is referred to as __________.

diploë

Bone tissue plays a critical role in the maintenance of __________ homeostasis throughout the body.

calcium

According to Wolff’s Law of Bone, bone grows stronger to better withstand regular __________.

forces

The regulation of free calcium availability in the bloodstream is primarily controlled by __________ hormones.

3

Parathyroid Hormone (PTH) promotes __________ of the matrix of osseous tissue, returning minerals to the bloodstream.

bone resorption

Calcitonin promotes __________ of the mineral components of bone, lowering blood calcium levels.

bone deposition