Musculoskeletal System

PART 1) MUSCULOSKELETAL SYSTEM

The human musculoskeletal system is the organ system that gives humans the ability to physically move, by using the muscles and skeletal system. It consists of the muscular system and the human skeleton. Bones are connected to each other at the joints by ligaments or cartilage and skeletal muscle is attached to bones, usually by tendons. [1]

„« Bones

Bone is a constantly changing tissue that has several functions. Bones serve as rigid structures to the body and as shields to protect delicate internal organs. They provide housing for the bone marrow, where the blood cells are formed. Bones also maintain the body's reservoir of calcium. In children, some bones have areas called growth plates. Bones lengthen in these areas until the person reaches full height, at which time the growth plates close. Thereafter, bones grow very slowly - in thickness far more than in length.

„« Joints

Bones come together to form joints. The configuration of a joint determines the degree and direction of possible motion. Some joints do not move, except in very young children (during and for a short time after birth). Examples of such joints are those located between the plates of the skull. Other joints allow a large and complex range of motion. For example, the shoulder joints, which have a ball-and-socket design, allow inward and outward rotation as well as forward, backward, and sideways motion of the arms. Hinge joints in the elbows, fingers, and toes allow only bending (flexion) and straightening (extension).

„« Ligaments

Ligaments are tough fibrous cords, composed of connective tissue that contains both collagen and some elastic fibers. The elastic fibers allow the ligaments to stretch to some extent. Ligaments surround joints and bind them together; they help strengthen and stabilize joints, permitting movement only in certain directions. Ligaments also connect one bone to another.

„« Muscles

There are three types of muscles: skeletal, smooth, and cardiac (heart). Two of these kinds - skeletal and smooth - are part of the musculoskeletal system.

Skeletal muscle is what most people think of as muscle, the type that can be contracted to move the various parts of the body. Skeletal muscles are bundles of contractile fibers that are organized in a regular pattern, so that under a microscope they appear as stripes (hence, they are also called striped or striated muscles). Skeletal muscles, which are responsible for posture and movement, are attached to bones and arranged in opposing groups around joints. For example, muscles that bend the elbow (biceps) are countered by muscles that straighten it (triceps). Skeletal muscles are controlled by the brain and are called voluntary muscles because they operate with a person's awareness. The size and strength of skeletal muscles are maintained or increased by regular exercise. In addition, growth hormone and testosterone help muscles grow in childhood and maintain their size in adulthood.

„« Tendons and Bursas

Tendons are tough bands of connective tissue made up mostly of a tough protein called collagen. They do not stretch. Tendons firmly attach each end of a muscle to a bone. They are located within sheaths, which are lubricated to allow the tendons to move without disturbing surrounding tissue.

Bursas are small fluid-filled sacs that lie under a tendon, cushioning the tendon and protecting it from injury. Bursas also provide extra cushioning to adjacent structures that otherwise might rub against each other, causing wear and tearЎXfor example, between a bone and a ligament. [2]

PART 2) INTEGUMENTARY SYSTEM

The integumentary system, consisting of the skin, hair and nails, act as a barrier to protect the body from the outside world. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature. [3]

The integumentary system has multiple roles in homeostasis, including protection, temperature regulation, sensory reception, biochemical synthesis, and absorption. All body systems work in an interconnected manner to maintain the internal conditions essential to the function of the body. The skin has an important job of protecting the body and acts somewhat as the bodyЎ¦s first line of defense against infection, temperature change or other challenges to homeostasis.

The integumentary system has numerous functions:

„« Protects the bodyЎ¦s internal living tissues and organs

„« Protects against