Bones

with the muscular system. It provides a framework of stiff levers and stable plates that permits a
multitude of movements. The skeleton also integrates functionally with the cardiovascular system – as every second, millions of fresh blood cells pour out of the bone marrow. A healthy diet that provides enough minerals, especially calcium, along
with regular moderate exercise, can reduce the risks of many bone and and teeth break.
INTERESTING FACTS ABOUT THE SKELETON
 The skeleton makes up almost one-fifth of a healthy body’s weight.
 This flexible inner framework supports all other parts and tissues, which would collapse
without skeletal reinforcement.
 It also protects certain organs, such as the delicate brain inside the skull.
 Bones are reservoirs of important minerals, especially calcium, and also make new cells
for the blood.
 About one person in 20 has an extra rib.
 Bone is an active tissue, and even though it is about 22 per cent water, it has an
extremely strong yet lightweight and flexible structure.
 A similar frame made of high-technology composite materials could not match the
skeleton’s weight, strength, and durability. It’s as strong as steel but light as aluminum.
 It can repair itself if damaged and can remodel its bones to thicken and strengthen them
in areas of extra stress, when persons do extreme sports.

32 teeth stand out.
But look closer and you’ll see even more structures.
The human skeleton also includes ligaments and cartilage.
Ligaments are bands of dense and fibrous connective tissue that are key to the function of joints.
Cartilage is more flexible than bone but stiffer than muscle.
Cartilage helps give structure to the larynx and nose. It is also found between the vertebrae and at the ends of bones like the femur.
LIGAMENTS
Ligaments are strong bands or straps of fibrous tissue that provide support to bones and link bone ends together in and around joints.
They are made of collagen – a tough, elastic protein.
A large number of ligaments bind together the complex wrist and ankle joints.
The foot ligaments store energy as they stretch when the foot is planted and then impart it again as they recoil and shorten to put a “spring in the step”. This saves an enormous amount of energy when walking.

are arranged to form structures.
 The skull protects the brain and gives shape to the face.
 The thoracic cage surrounds the heart and lungs.
 The vertebral column, commonly called the spine, is formed by over 30 small bones.
 Then there are the limbs (upper and lower) and the girdles that attach
the four limbs to the vertebral column.
THE SKELETON PROTECTS VITAL ORGANS
The brain is surrounded by bones that form part of the skull. The heart and lungs are located within the thoracic cavity, and the vertebral column provides structure and protection for the spinal cord.
INTERACTIONS BETWEEN THE SKELETON, MUSCLES, AND NERVES MOVE THE BODY
How does the skeleton move? Muscles throughout the human body are attached to bones. Nerves around a muscle can signal the muscle to move. When the nervous system sends commands to skeletal muscles, the muscles contract. That contraction produces movement at the joints between bones.

of the appendicular skeleton facilitate movement - girdles and limbs.
Bones of the axial skeleton protect internal organs – skull, vertebral column and thoracic cage.
Of the 206 bones, 80 are in the axial skeleton, with 64 in the upper appendicular and 62 in the lower appendicular skeleton.
BONES CAN BE CLASSIFIED INTO FIVE TYPES
Bones of the human skeletal system are categorized by their shape and function into five types.
The femur is an example of a long bone.
The frontal bone is a flat bone.
The patella, also called the knee cap, is a sesamoid bone.
Carpals (in the hand) and tarsals (in the feet) are examples of short bones.
Vertebrae are classified as irregular shaped bones.

long bone consists of a layer of compact bone surrounding spongy bone.
Red bone marrow contains haemopoietic tissue, the chief function of which is to produce all three main kinds of blood cell: red; white; and platelets.
At birth, red marrow is present in all bones, but with increasing age, in the long bones it gradually becomes yellow marrow and loses its blood-making capacity.

located in networks of spongy bone tissue inside some bones. (shown in blue in the image)
In adults the red marrow in bones produce blood cells of the:
 Cranium (skull)
 Vertebrae
 Scapulae (shoulder bones)
 Sternum (bone in the center of the chest)
 Ribs
 Pelvis
 The epiphyseal ends of the large long bones

(occipital [затылочная кость], parietal [теменная кость], frontal [лобная кость], nasal [носовая кость], lacrimal [слёзная кость] and vomer [сошник]),
 the thoracic cage (sternum [грудина] and ribs [рёбра])
 the pelvis (ilium [подвздошная кость], ischium [седалищная кость], and pubis [лобковая кость]).
The function of flat bones is to protect internal organs such as the brain, heart, and pelvic organs.
Flat bones can provide protection, like a shield and can also provide large areas of attachment for muscles.

they are wide, include:
The femur [бедренная кость] (the longest bone in the body)
Relatively small bones in the fingers.
Long bones are mostly located in the appendicular skeleton and include:
The lower limbs
Bones in the upper limbs

are wide.
Located in the wrist and ankle joints, short bones provide stability and some movement.
Examples of short bones are:
The carpals [кости, образующие скелет запястья] in the wrist
The tarsals [предплюсна] in the ankles

and structure and therefore do not fit into any other category (flat, short, long, or sesamoid). They often have a fairly complex shape, which helps protect internal organs. For example, the vertebrae, irregular bones of the vertebral column, protect the spinal cord. The irregular bones of the pelvis protect organs in the pelvic cavity.

small, round bones are commonly found in the tendons of the hands, knees, and feet.
Sesamoid bones function is to protect tendons from stress and wear.
The patella (надколенник), commonly referred to as the kneecap, is an example of a sesamoid bone.

BODY
The skull consists of the cranial bones and the facial skeleton. The cranial bones [кости черепа] compose the top and back of the skull and enclose the brain. The facial skeleton, as its name suggests, makes up the face of the skull.

or simply “the backbone”. This strong yet flexible central support holds the head and torso upright yet allows the neck and back to bend and twist.
Spine function
The spine consists of 33 ring-like bones called vertebrae. With the S shape, it acts like a spring and can flex when we are young and jump off of something. If it was straight up and down, it could break easily. The bottom nine vertebrae are fused
into two larger bones termed the sacrum and the coccyx, leaving 26 movable components within the spine.

formed by the ribs and sternum, protects internal organs and gives attachment to muscles involved in respiration and upper limb movement. The sternum consists of the manubrium [рукоятка грудины], body of the sternum [тело грудины], and xiphoid process [Мечевидный отросток грудины]. Ribs 1-7 are called true ribs because they articulate directly to the sternum. Ribs 8-12 are known as false ribs.