Skeletal System in the Human Body - Assignment Example

Skeletal SystemThe bones in the human body are usually classified into four categories according to their shapes. Name these four categories and give an example of each.Long bones: humerus (in the upper arm), radius and ulna (in the forearm), femur (in the high), tibia and fibula (in the lower leg), and phalanges (finger bones, metacarpals in the palm of the hands, toe bones and metatarsals in the feet)Short bones: carpals (wrist bones) and tarsals (ankle bones)Flat bones: scapulae, ribs, and the skullIrregular bones: vertebrae, sacrum, coccyx, mandible (the lower jaw), and the hyoid bone.

What critical functions are performed by the skeletal system?Supporting the body's framework (structure), preventing the entire body from collapsing .into a heap of soft tissuesProviding shells to protect vital organs for example, the ribcage protects the heart and lungs, and the skull protects the brainAllowing movement of the body. The skeletal system provides the mechanical levers for certain groups of muscles whose contraction moves the bodyHousing bone marrow which produces red blood cellsStoring calcium and phosphorus.

The bones are the greatest calcium and phosphorus reserves of the body, constantly being drawn upon and added to.Describe why cartilages are said to be avascular.The cartilages are said to be avascular there is no canal system or blood vessel penetrating the cartilage structureBriefly describe the diarthroses and synarthroses types of joint. articulations and give an example of each.Diarthroses joint are a small space that exists between the articulating surfaces of the two joined bones. Since no other tissues grow in this cavity, the surfaces move freely against one another.

Hence, they are functionally defined as freely movable joints. Some examples include ball and socket joints and hinge joints.Synarthroses joint does not have a joint cavity. Fibrous cartilage 'or bone tissues grow between the articulating surfaces of the two joined bones and make them unable to move freely against one another. Therefore, they are functionally defined as immovable (or slightly movable) joints that do not allow free movement. Examples include the skull joints.Muscular System handoutWhat is motor unit?

Motor nerves supply signals from the nervous system to the muscle system. A single motor nerve fiber that supplies to a group of muscle fibers within a muscle is called a motor unit.What type of muscles is of greatest interest to the ergonomist? Why?Skeletal muscles are more rapid in contracting than cardiac and smooth muscles. Skeletal muscles are important in locomotion and movement, and consequently are of greatest interest to the ergonomist.What are the fuel sources normally used for aerobic glycolysis?

What are the amount of energy potentials and capacities for each fuel source?Glucose stored in the cell or diffused into the cell from the circulatory system can be broken down anaerobically to generate ATP for muscle contractions.Describe the all-or-none law of physiologyThe all-or-none law, states that once the threshold has been reached, an action potential will continue to completion where the membrane will depolarize and then re-polarize. The all-or-none law also applies to muscle fibers.

For muscles, the law states that once adequately stimulated, a muscle fiber will contract completely.What is the effect of fatigue on the muscle contraction?Not all the muscle fibers are necessarily stimulated at the same time stated earlier, smaller motor units are recruited first and then aggressively larger motor units until the desired strength is attained. Thus, not all the muscle fibers are necessarily contracted at the same time. Fatigue results in failure of a muscle to contract in response a stimulus.

Describe the terms force arm and resistance arm, and mechanical advantage.The segment of the lever between the point of force exertion and the fulcrum is called the force arm and, likewise, the segment between the resistance and the fulcrum is called the resistance arm.