Question

The medullary cavity in the center of an adult bone would contain...

A. mostly compact bone

B. red bone marrow

C. mostly spongy bone

D. haversian canals

E. yellow bone marrow

Answer 1

Option (e) yellow bone barrow

There are five types of bones according to morphology: long, short, flat, irregular, and sesamoid. Long bones are so named because they are longer than they are wide. Example- Femur (upper region of leg) and tibia (lower region of leg). They experience most of the load during physical activities so these bones are important for skeletal mobility . Each long bone consists of two parts-

1) Diaphysis, the middle long shaft

2) Epiphysis, present at each end of the bone

Epiphyseal plates are present beneath the epiphysis which is the area responsible for growth of bone from age 16 to 25 years, after which this plate closes and no more bone growth occurs. The epiphysis together with the epiphysial plate is known as metaphysis

The hard-outer layer of long bone consists of densely populated osteocytes and matrix known as compact bone. This is covered by another outer membrane of connective tissue called periosteum. There is another inner lining of connective tissue known as endosteum is found inside the bone. There is second layer of less dense bone tissue called spongy or cancellous bone. Beneath the spongy layer lies the medullary cavity which consist of red bone marrow in young  responsible for producing blood cells where as yellow bone marrow in adult.