Thursday, July 3, 2008

Compendium Review Chapter 11


Full Skeleton: Note Appendicular Skeleton


Interesting pic of rib cage! :)



Vertebral Column



Bones of Skull


Axial Skeleton

Spiral Fracture


Bone Remodeling


Epiphyseal Plate 2


Epiphyseal Plate

Long Bone


Skeletal System

I. Overview of Skeletal System
II. Bone Growth, Remodeling and Repair
III. Bones of the Axial Skeleton
IV. Bones of the Appendicular Skeleton
V. Articulations


I. Overview of Skeletal System
A. Consists of the bones, cartilage, and fibrous connective tissue, found in ligaments at the joints.
(Insert Skeletal System picture / hsc.csu.edu.au / http://rds.yahoo.com/_ylt=A0S020uaM21In60AXlSjzbkF/SIG=12ni7sovr/EXP=1215202586/**http%3A//hsc.csu.edu.au/senior_science/core/bionics/9_3_3/933net.html)
B. Functions of the Skeleton
- Supports the body.
- Protects soft parts of body.
- Produces blood cells.
- Stores minerals and fats.
-Permits flexible body movement (w/ muscles.)
C. Anatomy of Long Bone
A. Main portion (shaft) is the diaphysis.
- Diaphysis has a large medullary cavity, (a hollow tube- Frolich PowerPoint Slide 19) whose walls are made of compact bone.
- Lined with thin, vascular membrane (endosteum).
- Filled with yellow bone marrow that stores fat.
B. Epiphyses: Expanded region at end of long bone.
- Composed mostly of spongy bone that contains red bone marrow, where blood cells are made.
- Coated with thin layer of hyaline cartilage, called articular cartilage, because it occurs at joint.
- Periosteum: A layer of fibrous connective tissue that covers all of a long bone except the articular cartilage on end of bone. Covering contains blood vessels, lymphatic vessels, and nerves.
C. Bone:
1c. Compact Bone: Highly organized and made of tubular units called osteons.
- Osteocytes: Bone cells that lie in the lacunae within the osteon.
2c. Spongy Bone: Unorganized appearance. Contains numerous thin plates (trabeculae)separated by unequal spaces.
- Lighter than compact bone, but still designed for strength.
- Trabeculae follow lines of stress, as supporters.
- Spaces are often filled with red bone marrow, a tissue that makes all types of blood cells.
D. Cartilage:
1d. Not as strong as bone.
- More flexible because the matrix is gel-like and contains collagen and elastic fibers.
- Chondrocytes: Cells of cartilage that like within lacunae that are irregularly grouped.
- No nerves.
- Suited for padding joints.
- No blood vessels, so it is slow to heal.
2d. Three types:
- Hyaline Cartilage: Firm and somewhat flexible. Matrix is uniform and glassy, but has a good supply of collagen fibers. Found at end of long bones, in nose, ends of ribs, and in larynx and trachea.
- Fibrocartilage: Stronger than hyaline, because matrix has rows of thick collagen fibers. Can withstand pressure and tension. Found in disks located between vertebrae and in cartilage of the knees.
- Elastic Cartilage: More flexible than hyaline, because matrix has mostly elastin fibers. Found in ear flaps and epiglottis.
E. Fibrous Connective Tissue: Contains rows of cells called fibroblasts separated by bundles of collagenous fibers. (Mader 208)
- Organized in layers around blood vessels. (Frolich PowerPoint Slide 16)
1e. Ligaments: Made of fibrous connective tissue. Connects bone to bone.
2e. Tendons: Made up of fibrous connective tissue. Connect muscles to a bone at joints (articulations.) (Mader 208)
(Insert Anatomy of Long Bone picture / pathologyoutlines.com / http://rds.yahoo.com/_ylt=A0S0200ORG1Iw3gB8qyjzbkF/SIG=11q06s9k7/EXP=1215206798/**http%3A//pathologyoutlines.com/bone.html )
II. Bone Growth, Remodeling and Repair
A. Bones are made up of living tissues, and they can grow, remodel, and repair. (Mader 208)
- Has nerves, blood supply, cells. (Frolich PowerPoint Slide 16)
1a. Types of cells involved in growth, remodeling and repair:
- Osteoblasts: Bone-forming cells. Secrete organic matrix of bone and promote the deposition of calcium salts into the matrix.
- Osteocytes: Mature bone cells derived from osteoblasts. Maintain structure of bone.
- Osteoclasts: Bone-absorbing cells. Break down bone and assist in depositing calcium and phosphate in blood.
B. Remodeling: Bones can grow throughout an entire lifetime by changing size, shape, and strength in response to stress.
C. Bone Repair: If a bone fractures, it can heal.
D. Bone Development and Growth:
1d. Ossification: Formation of bone.
2d. Skeleton begins forming at 6 weeks gestation, through intramembranous ossification and endochondal ossification.
* Intramembranous Ossification: Ex. Flat bones, like those of the skull.
- Bones develop between sheets of fibrous connective tissue.
- Cells that are made from connective tissue cells become osteoblasts, and they are housed in ossification centers.
- Osteoblasts secrete the organic matrix of bone. They also promote calcification.
- Periosteum forms outside the spongy bone and osteoblasts, and they carry out further ossification.
- Trabeculae form and fuse to become compact bone.
* Endochrondral Ossification: Most bones of human skeleton are formed by this method.
- Bone replaces cartilaginous models of bones.
- Cartilage is gradually replaced by calcified bone matrix.
- Bone formation spreads from center to ends.
3d. The Cartilage Model:
- Chondrocytes lay down hyaline cartilage, in the shape of future bones.
- As the models calcify, chondrocytes die.
4d. The Bone Collar:
- Osteoblasts (from periosteum) secrete the organic bone matrix, which undergoes calcification, resulting in bone collar.
- Bone collar (made of compact bone) covers the diaphysis.
5d. The Primary Ossification Center:
- Blood vessels bring osteoblasts to the interior, and they lay down spongy bone. Called the primary ossification center.
6d. The Medullary Cavity and Secondary Ossification Sites:
- Spongy bone of diaphysis is absorbed by osteoclasts, and the cavity created becomes the medullary cavity.
- Shortly after birth, secondary ossification centers form in the epiphyses.
- Red bone marrow is present in spongy bone in epiphyses.
- Cartilage is present in the epiphyseal (growth) plate and articular cartilage.
7d. The Epiphyseal (Growth) Plate:
- Band of cartilage remains between primary ossification center and each secondary center. (Mader 211)

- "Bone growth occurs at cartilaginous growth plate between diaphysis and epiphysis at either end of bone." (Frolich PowerPoint Slide 18)
(Insert Epiphyesal Plate pictures 1 & 2 / oregonstate.edu / http://rds.yahoo.com/_ylt=A0S0207MT21I9HMBZfyjzbkF/SIG=136pqoher/EXP=1215209804/**http%3A//oregonstate.edu/~peila/Pharmstuff/Projector%2520Slides/Projector%2520Slides & http://www.kort.com/ / http://rds.yahoo.com/_ylt=A0S020r2UG1IPxwBI8ajzbkF/SIG=13m4s38mn/EXP=1215210102/**http%3A//www.kort.com/cond_injuries_topic.aspx%3FtID=192c44869f07e0f9a0099b5f676b60d4%26amp;catID=46)
- When the epiphyseal plates close, growth in bone length stops. For women, this happens around age 18, age 20 for men.
E. Hormones Affect Bone Growth:
1e. Growth Hormone: A chemical messenger that affects bone growth.
- Directly stimulates growth of the epiphyseal plate, and bone growth in general.
- Works in conjunction with the metabolic activity of cells.
- Thyroid hormone promotes the metabolic activity of cells.
F. Bone Remodeling and Its Role in Homeostasis
1f. Bone is constantly broken down by osteoclasts and rebuilt by osteoblasts in an adult.
- Approx. 18% of bone is recycled per year. = Bone remodeling.
- Keeps bones strong.
- Allows body to regulate amount of calcium in blood, which is required for blood clotting.
- Bones are storage sites for calcium. (Mader 210-212)
- Calcium is needed for many aspects of cell metabolism, but is especially crucial to muscle cells. (Frolich PowerPoint Slide 20)
- Hormones involved in regulating blood calcium level: Parathyroid hormone, which accelerates bone recycling and increases blood calcium level, and Calcitonin that acts opposite to PTH. (Mader 210-212)
- Osteoporosis: Result of calcium need outweighing bone support role. Most common in women, and the elderly. Bone is broken down by osteoclasts faster than it is formed by osteoblasts. (Frolich PowerPoint Slide 21)
- Exercise keeps bones strong because they stimulate the work of osteoblasts instead of osteoclasts. (Mader 210-212)
(Insert Bone Remodeling picture / http://www.octusa.com/ / http://rds.yahoo.com/_ylt=A0S020umVG1IZ9UAqqejzbkF/SIG=123mm20gh/EXP=1215211046/**http%3A//www.octusa.com/product/Osteoporosis.html)
G. Bone Repair:
1g. Required after break or fracture.
- Fracture Repair: Takes several months, in four steps:
1. Hematoma: After a fracture, blood escapes from ruptured blood vessels and forms a hematoma, a mass of clotted blood, between the broken bones within 6-8 hours.
2. Fibrocartilaginous Callus: Tissue repair begins, and a fibrocartilaginous callus fills the space between ends of broken bone for approx. 3 weeks.
3. Bony Callus: Osteoblasts produce trabeculae of spongy bone and changes the fibrocartilage callus to a boney callus that joins the broken bones together. Approx. 3-4 months.
- Remodeling: Osteoblasts build new compact bone at the periphery, and osteoclasts absorb the spongy bone, creating a new medullary cavity.
2g. Types of Fractures:
- Complete Fracture: Bone is broken clear through.
- Incomplete Fracture: bone is not separated into two parts.
- Simple: Does not pierce the skin.
- Compound: Does pierce the skin.
- Impacted: Broken ends are wedged into each other.
- Spiral: Break is ragged due to twisting of bone. (Mader 214)
(Insert Spiral Fracture picture http://www.flickr.com/ / http://rds.yahoo.com/_ylt=A0S0200uWG1IHIYBeomjzbkF/SIG=127bmguvs/EXP=1215211950/**http%3A//www.flickr.com/photos/spurkatory/1085629545/
III. Bones of the Axial Skeleton
A. All 206 bones of the skeleton are either in the axial skeleton or the appendicular skeleton.
B. Axial Skeleton:
1b. Lies in midline of the body and consists of skull, hyoid bone, vertebral column, and rib cage.
(Insert Axial Skeleton picture academic.wsc.edu / http://academic.wsc.edu/faculty/jatodd1/351/ch4outline.html)
C. Skull: Formed by the cranium and facial bones.
D. Cranium: Protects the brain.
- 8 bones that fit tightly together (in adults).
- In newborns, bones are not completely formed and are joined by fontanels.
1d. Some bones contain sinuses: air spaces lined by mucous membrane.
- They reduce the weight of the skull and give a resonant sound to the voice.
- Mastoid sinuses drain into middle ear. (Mastoiditis in inflammation of these sinuses.)
2d. Major bones of cranium have same names as lobes of the brain:
- Frontal (forms forehead), parietal (extend to the sides), occipital (forms base of skull, and has opening called foreamen magnum that allows the spinal cord to pass and become the brain stem), and temporal (opening that leads to middle ear).
- Sphenoid bone is shaped like a bat and extends across the floor of the cranium from one side to the other. Keystone of cranial bones because all others articulate with it. Completes side of skull and is part of forming the orbits.
- Ethmoid bone In front of sphenoid. Helps for orbits and nasal septum.
(Insert Bones of Skull picture / svhrad.com / http://rds.yahoo.com/_ylt=A0S0202QgG1IITIASQWjzbkF/SIG=11v1r1obr/EXP=1215222288/**http%3A//svhrad.com/DigLib/digitallibrary.htm)
E. The Facial Bones:
- Mandible: Lower jaw. Only movable portion of skull. Also forms chin and contains teeth sockets.
- Maxillae: Bones that form the upper jaw and the anterior portion of hard palate. Also contains tooth sockets.
- Zygomatic Bones: Cheekbone.
- Nasal Bones: Form bridge of nose.
F. Hyoid Bone:
- Not part of skull, but it is part of the axial skeleton.
- Only bone in body that does not articulate with another bone.
- Attached to temporal bones by muscles and ligaments and to the larynx by a membrane.
- Anchors the tongue. (Mader 216-217)
G. Vertebral Column:
1g. Consists of 33 vertebrae.
- Normal vertebral column has four curvatures to provide resilience and strength in posture.
- Spinal cord passes through the vertebral canal.
- Spinal nerves control skeletal muscle contractions.
- Spinous processess of vertebrae and the transverse processess are attachment sites for the muscles that move the vertebral column.
(Insert Vertebral Column picture / people.emich.edu / http://rds.yahoo.com/_ylt=A0S0202Hhm1IITIAE3WjzbkF/SIG=12ro09un5/EXP=1215223815/**http%3A//people.emich.edu/pbogle/PHED_200/outlines/chapter_07/outline.htm)
H. Types of Vertebrae:
1h. Named according to location in vertebral column.
- Cerebral- in neck.
- Atlas- holds up head.
-Axis- Allows rotation in head.
- Thoracic- ribs., etc.
I. Intervertebral Disks:
- Between vertebrae. Composed of fibrocartilage that act as padding so vertebrae don't grind together.
- Absorbs shock caused by movement.
- Degenerate with age.
J. Rib Cage (Thoracic Cage):
1j. Composed of thoracic vertebrae, ribs, cartilage and sternum.
- Protects heart and lungs.
- Moves with respiration.
K. Ribs:
1k. Flattened bone beginning in thoracic vertebrae and goes toward anterior thoracic wall.
- 12 pairs.
- Articulates with body and transverse process of it's thoracic vertebra.
- Upper 7 (true) ribs connect to sternum by costal cartilage.
- "False ribs", the next three pairs, connect to sternum by a common cartilage.
- "Floating ribs", the last two pairs, do not connect to sternum at all.
L. Sternum: Lies in midline of body.
-Helps protect heart and lungs.
-Flat, knife-shaped.
1l. Composed of three bones: manubrium (handle / joins with body of sternum at angle), body (blade), and the xiphoid process (point of blade / attachment site for diaphragm). (Mader 218-219)
IV. Bones of the Appendicular Skeleton
A. The bones in the pectoral and pelvic areas and their attached limbs.
1a. Pectoral Girdle and Upper Limb:
-Specialized for flexibility.
- Left and right pectoral girdles: each has a scapula (shoulder blade / visible bone in back.) and a clavicle (collarbone that extends across top of thorax. Articulates with sternum.)
2a. Glenoid cavity of scapula articulates with head of humerus.
- Allows arm to move easily in different directions, thus most prone to dislocation.
3a. Rotator Cuff: Formed by tendons that extend to humerus from four small muscles beginning in scapula.
4a. Humerus: Single long bone in arm. Fits into glenoid cavity of scapula.
5a. Capitulum and Trochlea: protuberances at far end of humerus that articulate with the radius and the unla at the elbow.
6a. Wrist has 8 carpal bones, that look like pebbles. Five metacarpal bones fan out to make palm.
- Phalanges: Bones of fingers and thumb.
B. Pelvic Girdle and Lower Limb:
1b. Pelvic Girdle is two heavy, large bones- hip bones.
2b. Pelvis: Basin made of pelvic girdle, sacrum, and coccyx.
- Bears weight of body, protects organs, and is the place of leg attachment.
3b. Coxal Bone: 3 parts:
- Ilium: largest part of coxal bones. Hips come from its flareout.
- Ischium: What we sit on. Hips occurs where it flares out.
- Pubis: Anterior part of coxal bone.
4b. Pubic Symphysis: Where the two pubic bones connect in fibrocartilaginous joint.
5b. Femur: Longest and strongest bone in body.
- Articulates with tibia.
- Patella: kneecap.
6b. Fibula: Slender bone in leg.
- Articulates with tibia and a distal lateral malleolus.
7b. Ankle has many tarsal bones.
- Instep has five elongated metatarsal bones.
- Phalanges: Bones of toes. (Mader 220-221)
V. Articulations
A. Bones joined at joints, which are either fibrous, cartilaginous, or synovial.
1a. Joints are classified according to their degree of movement. (ARIS Mader Text Website Chapter 11 Review)
- Fibrous joints, such as the sutures between bones in cranium, are not able to move.
- Cartilaginous joints are connected by hyaline cartilage, like those that joind the ribs to sternum. Slightly movable.
- Synovial joints are freely movable.
- Synovial fluid acts as lubricant.
- Ball and socket joints at hips and shoulders allow movement in all ways, even rotational.
- Elbows and knees: synovial but hinged: movement in one direction only.
B. Movements Permitted by Synovial Joints:
- Skeletal muscles are attached to bones by tendons that span joints.
- When a muscle contracts, one bone moves in relation to another bone. (Mader 222)

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