Lab 3- Functions of Bone/Skeletal System, Characteristics

Protection

Protects internal organs from injury

6 Functions of Bone/Skeletal System

Support, protection, assistance in movement, mineral storage and release, blood cell production, triglyceride storage

Assistance in Movement

Most skeletal muscles attach to bones (through tendons), when they contract, pull on bone to produce movement

Compact Bone

(Cortical or Dense Bone Tissue) Dense and has smaller spaces, surface of bone but can extend deeper. Makes up bulk of diaphyses of long bones. Contain microscopic spaces and canals, making it porous. Provides protection, support and resists stresses produced by weight and movement.

Spongy Bone

(Trabecular or Cancellous Bone Tissue) Always the interior of bone, protected by covering of compact bone. Consists of lamellae that are arranged in an irregular pattern of thin columns called trabeculae. Also contains osteocytes that lie in lacunae and canaliculi that radiate outward. Helps resist stresses and transfer force without breaking. Light. Provides support and protects red bone marrow. See Page 157 for a pictorial description.

What is the body weight of the bone/skeletal system?

18% of body weight

Red Bone Marrow

A connective tissue. Produces red blood cells, white blood cells and platelets in a process called hemopoises or hematopoiesis. Consists of developing blood cells, adipocytes, fibroblasts, and macrophages, within a network of reticular fibers. With increasing age, red bone marrow will change to yellow.

Mineral Storage and Release

Bone tissues stores several minerals, especially calcium and phosphorous- which contribute to the strength of bone

Yellow Bone Marrow

Consists mainly of adipose cells, which store triglycerides. Stored triglycerides are potential chemical energy reserve.

Blood Cell Production

Contains red bone marrow

Triglyceride Storage

Contains yellow bone marrow

Where is red bone marrow found?

Developing bones of the fetus and some adult bones- hip bones (pelvic), ribs, sternum, vertebrae, skull, ends of humerus (arm) and femur (thigh).

Location of Spongy Bone

Hip bones, ribs, sternum, vertebrae, and the proximal ends of the humerus and femur is the only site where red bone marrow is stored and thus, the site where hemopoiesis (blood cell production) occurs in adults.

Support

Skeleton serves as structural framework for body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles.