HUMAN ANATOMY

   1. The human body is a complex machine. It takes in and absorbs oxygen through the respiratory
   system. Then the  blood is distributed through the cardiovascular system to all tissues. The
   digestive system converts food to energy and disposes of the rest. The skeletal-muscular
   system gives form to the body. And the skin covers the mass. It is the largest organ of the
   body. The science of the structure of this complicated "machine" is called anatomy.

   

   2. One of the major systems is the skeletal-muscular system. It consists of more than 200
   bones and the muscles and tendons which are connected to them. They are strong but can bend at
   their joints. They also protect the vital internal organs from injury.

   

   3. Bones are as strong as steel but much lighter and more flexible. They are composed of
   minerals, organic matter, and water, held together by a substance called collagen, and are
   filled with red and yellow bone marrow. The red marrow produces the red blood cells which
   transport oxygen, while the yellow marrow consists primarily of fat cells. The bones are
   covered by  periosteum.

   

   4. human skeletonHUMAN SKELETON

   The human skeleton consists of 206 bones. We are actually born with more bones (about 300),
   but many fuse together as a child grows up. These bones support your body and allow you to
   move. Bones contain a lot of calcium (an element found in milk, broccoli, and other foods).
   Bones manufacture blood cells and store important minerals.

   The longest bone in our bodies is the femur (thigh bone). The smallest bone is the stirrup
   bone inside the ear. Each hand has 26 bones in it. Your nose and ears are not made of bone;
   they are made of cartilage, a flexible substance that is not as hard as bone.

   Joints: Bones are connected to other bones at joints. There are many different types of
   joints, including: fixed joints (such as in the skull, which consists of many bones), hinged
   joints (such as in the fingers and toes), and ball-and-socket joints (such as the shoulders
   and hips).

   5. Muscles control movement and many organic functions. Skeletal muscles are called voluntary
   because they can be consciously controlled. Other muscles, such as the stomach muscles and the
   heart, are involuntary and are operated automatically by the central nervous system.

   

   6. The most important muscle in the body is the heart. Its rhythmic contractions are called
   the pulse rate. Without the heart and its cardiovascular (circulatory) system, human life
   would not be possible

   

   7. The human heart consists of four chambers, two atria  and two ventricles. It functions in
   two phases - the contraction phase, called the systole, and  relaxation phase called  the
   diastole .

   

   8. The rest of the system consists of vessels which are: arteries, veins, arterioles (small
   arteries), venules (small veins), and capillaries.

   

   9. The cardiovascular system also carries hormones which are secreted by glands of the
   endocrine system.

   

   11. The respiratory system starts at the nose, where air is breathed in during inspiration. It
   then passes through the larynx (voice box) and trachea (windpipe) into the bronchi and
   bronchioles, and ends in little air pockets called alveoli  within the lungs. The process is
   called respiration.

   

   12. The largest organ in the body is the outer covering called skin  plus its structures
   (hair, nails, sebaceous and sweat glands, and specialized sensory  receptors). They altogether
   make up the integumentary system. Skin protects the body from microbes and other impurities,
   prevents the loss of body fluids, and regulates body temperature. It consists of the
   epidermis, the dermis, and the subcutis (subcutaneous layer).

   13. Another major body complex is the digestive system, which processes the food so that it
   can be used for energy. The process begins in the mouth, where food is chopped and crushed by
   the teeth.

   14. The food then passes through the esophagus in the stomach. From there the food passes into
   small intestine, where it is absorbed. What cannot be absorbed is passed out through the large
   intestine as feces. Liquid wastes are eliminated through the urinary ystem. They are picked up
   by the blood and removed by the kidneys. From there they pass through the ureter, bladder, a
   urethra, and are excreted from the body as urine.

   15. Closely associated with the urinary system is the reproductive system, by which human life
   is carried on to future generations.

   

   16. The nervous system controls all other systems and bodily movements.

   

   17. The nervous system is divided into the central nervous system (the brain and spinal cord)
   and the peripheral nervous system, which consists of the nerves that connect muscles and
   sensory organs with the central nervous system.

   18. The brain is not only the most important component of the nervous system; it is also the
   controller of all bodily activities, thoughts, and emotions.

   English terms denoting parts of the human body:

   

   

   +--------------------------------------------------------------------------------------------+
   |ankle                  |ear               |hand          |leg            |shoulder          |
   |arm                    |elbow             |head          |mouth          |thigh             |
   |belly button           |eye               |heel          |nose           |toes              |
   |chest                  |fingers           |hip           |neck           |waist             |
   |chin                   |foot              |knee          |shin           |wrist             |
   +--------------------------------------------------------------------------------------------+