SC 1232 Study Guide Exam 2 Fall 2009

Chapter 7: skeletal system.

Introduction.
Individual bones are the organs of the skeletal system.
A bone contains very active tissues.
Bone support and protect soft tissues, provide attachments for muscles, house blood producing cells, and store inorganic salts.

Bone structure.
Bones are grouped according to their shapes-long, short, flat, irregular, or round (sesamoid).
The epiphysis is the bone and which is covered by articular cartilage.
The shaft of the bone is also called the diaphysis.
Except for the articular cartilage, bone is covered by a periosteum.
Compact bone as a continuous extracellular matrix with no gaps.
Spongy bone has irregular interconnecting spaces between bony plates.
Both compact and spongy bone are strong and resist bending.
The diaphysis contains a medullary cavity filled with marrow.
Compact bone contains osteons cemented together.
The osteons contains a central canal which contain blood vessels that nourish the cells of the osteons.
Perforating canals connect central canals transversely and communicate with the bones surface and the medullary cavity.
Diffusion from the surface of thin tiny plates nourishes cells of spongy bones.
Intramembranous bones develop from layers of connective tissue.
Osteoblasts within the membranous layers form bone tissue.
Mature bone cells are called osteocytes.
Most of the bones of the skeleton are endochondral.
Endochondral bones develop from cartilaginous skeletons.
Endochondral bone forms from primary ossification centers that appear in the diaphysis.
Secondary ossification centers appear in the epiphyses.
Epiphyseal plates are responsible for lengthening the bone.
Long bones continue to lengthen until the epiphyseal plates are ossified.
Growth in thickness of the bone is due to ossification beneath the periosteum.
The action of osteoclasts forms the medullary cavity.
Osteoclasts and osteoblasts continually remodeled bone.
The total mass of bone remains nearly constant.

Bone function.
Bones shape and form body structures.
Bones support and protect his softer, underlying tissues.
Bones and muscles interact, producing movement.
Red bone marrow houses developing red blood cells, white blood cells and blood platelets.
The extracellular matrix of bone tissue contains abundant calcium phosphate in the form of hydroxyapatite.
When blood calcium ion concentration is high, osteoblasts are stimulated to form bone tissue and store calcium salts.

Skeletal organization.
Usually a human skeleton has 206 bones, but the number may vary.
The extra bones in sutures are called central bones.
The skeleton can be divided into axial and appendicular portions.
The axial skeleton consists of the skull, hyoid bone, vertebral column, and thoracic cage.
The appendicular skeleton consists of the pectoral girdle, upper limbs, pelvic girdle, and lower limbs.
The skull.
The skull consists of 22 bones, which include eight cranial bones and 14 facial bones.
The cranium encloses and protects the brain and provide attachments for muscles.
Some cranial bones contain error filled paranasal sinuses that help to reduce the weight of the skull.

Lifespan changes.
Gradually bone loss exceeds bone replacement.
Aging increases risk of bone fractures.

Diagram labeling.
Please be prepared to label the following: figure 7.1 which is found on page 194 of your textbook.
Please be prepared to label the following: figure 7.2 which is found on page 194 of your textbook.
Please be prepared to label the following: figure 7.4 which is found on page 196 of your textbook.
Please be prepared to label the following: figure 7.13 which is found on page 204 of your textbook.
Please be prepared to label the following: figure 7.15 which is found on page 207 of your textbook.
Please be prepared to label the following: figure 7.19 which is found on page 210 of your textbook.
Please be prepared to label the following: figure 7.34 and figure 7.36 which is found on pages 222 and 223 of your textbook.
Please be prepared to label the following: figure 7.41 which is found in page 228 of your textbook.
Please be prepared to label the following: figure 7.42 which is found on page 229 of your textbook.
Please be prepared to label the following: figure 7.47 a which is found on page 234 to textbook.
Please be prepared to label the following: figure 7.50 which is found on page 237 of your textbook.

Chapter 8: joints of the skeletal system.

Introduction.
1.A joint forms wherever two or more bones meet.
2.Joints are the functional junctions between bones.

Classification of joints.
3.Joints are classified according to the type of tissue that binds the bones together.
4.Bones at fibers joints are tightly fastened to each other by a layer of dense connective tissue with many collagenous fibers.
5.There are three types of fibers joints.
6.A syndesmosis has bones bound by along connective tissue fibers.
7.A suture is where flat bones are united by a thin layer of connective tissue.
8.A gomphosis is formed by the union of a cone shaped bony process with a bony socket.
9.A layer of cartilage holds together bones of cartilaginous joints.
10.There are two types of cartilaginous joints.
11.A synchondrosis occurs where bones are united by hyaline cartilage that may disappear as a result of growth.
12.A symphysis occurs where articular surfaces of the bones are covered by hyaline cartilage and the cartilage is attached to a pad of fibrocartilage.
13.Synovial joins have a more complex structure than other types of joints.
14.Synovial joints include articular cartilage, a joint capsule, and a synovial membrane.

General structure of a synovial joint.
15.Articular cartilage covers the articular ends of bones in a synovial joint.
16.Synovial joints have a joint capsule strengthen by ligaments which hold bones together.
17.A synovial membrane that secrete synovial fluid lines the inner layer of the joint capsule of the synovial joint.
18.Synovial fluid moistens, provides nutrients, and lubricates the articular surfaces of the synovial joint.
19.Menisci divide some synovial joints into compartments.
20.Bursa cushion and aid movement of tendons over bony parts.

Types of synovial joints.
21.Ball and socket joints.
22.Condyloid joints.
23.Gliding joints.
24.Hinge joints.
25.Pivot joints.
26.Saddle joints.

Types of joint movements.
27.Muscles acting at synovial joints produce movements in different directions and different planes.

Lifespan changes.
28.Joint stiffness is often the earliest sign of aging.
29.Collagen changes causes the feeling of stiffness.
30.Regular exercise can lessen the effects of aging.
31.Fibers joints are the first to begin to change and strengthen overall lifetime.
32.Synchondroses of the long bones disappear with the growth and development.
33.Changes in the symphysis joints of the vertebral column diminish flexibility and decrease height with aging.
34.Over time, synovial joints lose elasticity.

Be prepared to label the following diagram from your textbook:
35.figure 8.7
36.figure 8.8
37.figure 8.9 entirely
38.figure 8.10
39.figure 8.12
40.figure 8.13 a
41.figure 8.15 a
42.figure 8.18 a
43.figure 8.21 a