skeletal system

The skeletal system is made up of 206 bones. They are attached to each other
at joints. In this chapter you will learn about the location of the major bones,
the structure of bones, and how bones contribute to body function. You will also
learn about the structure of joints and how they function to produce movement.
Major Bones of the Body
Practice for Learning: Major Bones of the Body
Write the words below in the correct spaces on Figure 7-1. To help you, the number
beside the word tells you where it goes on the figure. Be sure to pronounce each word
as you write it. Repeat the pronunciation several times if you find the word hard to say.
The common names and adjectival forms are listed in Table 7-1.
1. cranium (KRAY-nee-um)
2. facial bones (FAY-shal)
3. thorax (THOR-acks)
4. carpals (KAR-palz)
5. metacarpals (met-ah-KAR-palz)
6. phalanges (fah-LAN-jeez)
7. tarsals (TAR-salz)
8. metatarsals (met-ah-TAR-salz)
9. phalanges (fah-LAN-jeez)
10. fibula (FIB-yoo-lah)
11. tibia (TIB-ee-ah)
12. patella (pah-TEL-ah)
13. femur (FEE-mur)
14. pelvis (PEL-vis)
15. ulna (ULL-nah)
16. radius (RAY-dee-us)
17. humerus (HEW-mer-us)
18. vertebra (VER-teh-brah)
19. scapula (SKAP-yoo-lah)
20. clavicle (KLAV-ih-kul)
Bone Structure and Function
Bone Structure
Cells and Minerals
Just like other organs, bones are made up of cells and tissues. Bones grow and renew
themselves. Immature bone cells are called osteoblasts (OS-tee-oh-blasts). They grow
into mature cells called osteocytes (OS-tee-oh-sights). Osteocytes form bone tissue
called
osseous (OS-ee-us) tissue.
Osteoblasts are immature bone cells.
Osteocytes are mature bone cells.
Osteocytes form osseous tissue.
Calcium and phosphorus are minerals that make bone hard.
For bones to properly form and become hard and strong, we need to eat food that
contains two minerals: calcium (KAL-see-um) and phosphorus (FOS-for-us). We also
need plenty of vitamin D to help us absorb the calcium.
Cartilage is similar to bone but it is soft because it lacks the calcium deposits that
make bone hard. Cartilage is found in all joints, the spinal column, and the rib cage.
Bone Function
Bones have many functions. They provide protection and support, and allow movement
to happen because they provide a rigid structure for the muscles to pull on. They
also act as a storehouse for calcium and phosphorus, and release these minerals into
the bloodstream when required. The inner part of the bone is called bone marrow. It
produces
blood cells that are necessary for life. This blood-forming process is called
hematopoiesis (he-mah-toh-poy-EE-sis).
Practice for Learning: Bone Structure and Function
Circle True if the statement is correct. Circle False if the statement is not correct.
1. Calcium is a mineral found in bone. True or False
2. Bone marrow produces blood cells. True or False
3. Osseous is a type of bone cell. True or False
4. Osteoblasts are a type of bone cell. True or False
7.3 Vertebral Column
Practice for Learning: Vertebral Column
Write the bones of the vertebral column in the correct space on Figure 7-3. To help you,
the number beside the bone tells you where it goes on the figure. Be sure to pronounce
each word as you write it. Repeat the pronunciation several times if you find the word
hard to say.
The bones of the vertebral (VER-teh-brahl) column are organized into five groups.
They are illustrated in Figure 7-3. The vertebral column is also called the spinal column,
spine, or backbone.
The vertebral column consists of 33 bones arranged in a column that extends from
the base of the skull to the lower back. Each bone is called a vertebra (VER-teh-brah)
(plural vertebrae [VER-teh-bree]). There are 7 cervical vertebrae (C1 to C7), 12 thoracic
vertebrae (T1 to T12), 5 lumbar vertebrae (L1 to L5), 5 fused bones called the sacrum
(S1 to S5), and 4 fused bones called the coccyx or tailbone. Each vertebra has a round
hole in the middle. The holes line up to form a canal. The spinal cord lies within this
canal. The vertebrae protect the spinal cord, which is made up of nerves
Joints
A joint is where two bones come together. Movement occurs at joints. A joint is usually
named after the bones that it joins. For example, the sternoclavicular (ster-noh-klah-
VICK-yoo-lar) joint is the union between the sternum (stern/o) and clavicle (clavicul/o)
(Figure 7-1).
For joints to work properly and without pain, it is important that the two bones
glide smoothly over each other (Figure 7-4). This is accomplished by articular (ar-TIKyoo-
lar) cartilage and synovial (sih-NOH-vee-al) fluid inside the joint. The synovial
fluid is produced by synovial membrane lining the joint.
Although most of the joints in the body are movable, there are a few immovable
joints in the skull. These immovable joints are called sutures.
Also at joints (but not inside) are tendons (TEN-donz), ligaments (LIG-ah-ments), and
bursae (BUR-see) (Figure 7-5). Tendons attach muscle to bone. Ligaments attach bone
to bone. Bursae are tiny, purse-like sacs lined with synovial membrane and filled with
Joints
A joint is where two bones come together. Movement occurs at joints. A joint is usually
named after the bones that it joins. For example, the sternoclavicular (ster-noh-klah-
VICK-yoo-lar) joint is the union between the sternum (stern/o) and clavicle (clavicul/o)
(Figure 7-1).
For joints to work properly and without pain, it is important that the two bones
glide smoothly over each other (Figure 7-4). This is accomplished by articular (ar-TIKyoo-
lar) cartilage and synovial (sih-NOH-vee-al) fluid inside the joint. The synovial
fluid is produced by synovial membrane lining the joint.
Although most of the joints in the body are movable, there are a few immovable
joints in the skull. These immovable joints are called sutures.
Also at joints (but not inside) are tendons (TEN-donz), ligaments (LIG-ah-ments), and
bursae (BUR-see) (Figure 7-5). Tendons attach muscle to bone. Ligaments attach bone
to bone. Bursae are tiny, purse-like sacs lined with synovial membrane and filled with.