anatomy of the human hand is quite complicated.Thus, arteries, veins, nerves and muscle and branched constantly intersect with each other, and the network of tendons and ligaments respond to each command in the brain.Furthermore, they can be easily bent and cut. Structure hands implies a greater load on the muscles, because during the day the person produces a wide variety of movements, and their form depends on the state of his hands.
All this complex structure is covered with hand wheel, which serves as its protection from bacteria, toxic substances and radiation.It should be noted that it is waterproof, has a certain ability to maintain body temperature and collect sensory information that comes from outside, so the structure is hand allows precision to manipulate those objects that the hand contact.
lower layer of the skin with the back of the hand is thin, so the hands are freezing frequently than other bodies.The dermis on the back side has a small amount of sweat and sebaceous glands, which is why the skin dries quickly.This layer of the skin contains more nerves, lymph and blood vessels, as well as elastin and collagen that make it strong and resilient.However, ultraviolet light, which penetrates through the dermis, has a negative influence on these two proteins, so your skin loses its elasticity, and her wrinkles faster.
structure of the human hand has some peculiarities.Thus, the bottom layer of the epidermis are cells that produce melanin.Due to skin it absorbs ultraviolet light, thereby preventing its penetration into the dermis.If the sun's rays have a lasting effect on the skin, it leads to the formation of age spots.
structure of the hand of man, including the wrist, can be regarded as a separate chapter.They consist of twenty-seven bones that perfectly fulfill their function, and tendons, the muscles attached to the bones.
If we consider a skeleton hand, we can distinguish here eight bones forming the wrist, the five bones forming the pastern (wrist), and fourteen bones forming the phalanges.
carpal bones consists of two rows of four bones each.The first series includes the scaphoid and lunate bones, as well as three-edged and pisiform.Second row - trapezoid bone, capitate and hamate bone.
The bones of the hand consists of a base, a head (knuckle) and body.Bones fingers consist of three phalanges, except the thumb (he has two phalanges).
Considering the structure of the hand , it should be noted that the muscles that control the wrist and hand, quite a lot.They are divided into front (responsible for flexion), rear (responsible for the extension) and the intrinsic muscles (helping to carry out the movement of the fingers).
The hand performs the following functions: grasping, clear coordinated movements, tingling.
Thus, the hand attached to the body with the help of bones, muscles and joints, and consists of three parts: the forearm, shoulder and hand.Bending at the elbow provides hands high mobility and functionality, so we can perform a variety of movements.
should be noted that at the ends of the fingers are sensory cells, through which a person learns the world by touch, which is why they are sensitive to pain.To protect them there nails which represent horn plate consisting of keratin, keratin than the skin.So, it is porous, harder and less swells in contact with water there.
structure hand allows a person to know the world around him through touch and manipulate objects, which makes it different from other representatives of mammals.
