Lecture Test #2 Study Guide PDF

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Study Guide Lecture Test #2: Ch.6 and Ch.8 Histology, Anatomy, and Physiology of Bones and Joints 1.

Describe the two main divisions of the skeleton. 1. Divisions 1. Axial skeleton (126 bones) 1. Bones of skull, thorax, and vertebral column 2. Form longitudinal axis of body 2. Appendicular skeleton (80 bones) 1. Bones of the limbs and girdles that attach them to the axial skeleton

2.

List five functions of the skeletal system. • •

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Support: structural support for the body and framework for attachment of soft tissues and organs Storage: – Minerals: reservoir for calcium and phosphorus – Lipid (triglyceride) storage Blood cell production: hematopoiesis occurs within the marrow cavities of bones Protection: provide a protective case for the brain, spinal cord, and vital organs Leverage – As levers, bones change magnitude and direction of skeletal muscle forces – Produce movements ranging from delicate fingertip motion to positional changes of the entire body

3.

Classify bones according to shape

4.

Describe the anatomy of a typical long bone. Define diaphysis, epiphysis, epiphyseal plate, medullary cavity, periosteum, and endosteum

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Diaphysis (shaft) • Composed of compact bone • Metaphysis (connects epiphysis to shaft) Epiphysis • Enlarged ends of the bones • Compact bone covering spongy bone • Red bone marrow Medullary cavity • Cavity of the shaft • Contains yellow marrow (mostly fat) in adults • Contains red marrow (for blood cell formation) in infants • Lined by endosteum Articular cartilage • Covers the external surface of the epiphyses • Made of hyaline cartilage

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• Decreases friction at joint surfaces Periosteum • Dense irregular connective tissue on bone surface (not on articular surface) • Inner surface contains bone forming cells

Describe the functions of osteoblast, osteocytes, and osteoblasts. Osteocytes are cells that form the bones themselves, osteoblasts are responsible for the formation of new osteocytes, whereas osteoclasts are responsible for the resorption of old bone matter. Thus, between them, the three types of bone cells regulate the formation, sustenance, and decay of bones. It is a constant process and is carried out for an individual’s entire lifetime. A disorder related to either one of the three is disastrous for bone health, since all three, even the osteoclasts, are vital. These three are part of an osteon, which is a functional unit of compact bone matter. Bones have two types of tissues: the hard, strong exterior and the spongy interior marrow. Osteocytes, osteoblasts, and osteoclasts are found on the outer side of bones. Osteocytes are formed from osteoblasts, and become part of the bone (and, as discussed above, ‘become’ osteocytes) when they mature. They send out long tendrils (as seen in the figure) which connect numerous osteocytes to each other. They produce bone matrix, including collagen and calcium/phosphorus compounds, that eventually covers them. The space occupied by each osteocyte and its matrix is known as a lacuna. Osteocytes maintain bone mass, and are also speculated to act as the command centers of the bones when experiencing stress, using their connection with other osteocytes. The osteocytes direct osteoclasts to the site of the damage, hastening healing. While osteoblasts and osteocytes have the same source, and are, in fact, different stages of the same cells, osteoclasts are derived from cells in the bone marrow. Osteoclasts perform the job of breaking down the composite material in bones, with the help of an acid and collagenase proteins. The calcium in the bones acted on by osteoclasts is then sent back into the bloodstream. Osteoclast production is regulated mainly by the thyroid gland. They are produced when more blood calcium is needed, and suppressed when there is no deficiency of calcium in the body. They are also vital in repairing mechanical breaks (fractures) to the bone.

6.

Name the components of the matrix and explain their contribution to bone flexibility and the ability of bones to bear weight.

• Components: • Organic (1/3) and inorganic component (2/3) • Organic component secreted by the osteoblasts: • Collagen fibers and Proteoglycans provide the bone with resilience and the ability to resist stretching and twisting •

7.

Describe the structure of cancellous bone. •

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8.

Inorganic component of bone matrix • Mainly calcium phosphate and calcium hydroxide. These 2 salts interact to form a compound called hydroxyapatite • Also smaller amounts of magnesium, fluoride, and sodium • These minerals give bone its characteristic hardness and the ability to resist compression

Bone can be classified according to the amount of bone matrix relative to the amount of space present within the bone • Cancellous bone (spongy) has many spaces • Internal layer which is a honeycomb of trabeculae filled with red or yellow bone marrow • Compact bone is dense with few spaces • External layer Cancellous bone Located where bones are not heavily stressed or stress is in many directions Lamellae form struts and plates (trabeculae) creating an open network • Reduces weight of skeleton • No blood vessels in matrix • Nutrients reach osteons through canaliculi open to trabeculae surfaces • Red bone marrow is found between trabeculae

Describe the process of appositional bone growth. While bones are increasing in length, they are also increasing in diameter; growth in diameter can continue even after longitudinal growth ceases. This growth by adding to the free surface of bone is called appositional growth. Appositional growth can occur at the endosteum or peristeum where osteoclasts resorb old bone that lines the medullary cavity, while osteoblasts produce new bone tissue. The erosion of old bone along the medullary cavity and the deposition of new bone beneath the periosteum not only increase the diameter of the diaphysis but also increase the diameter of the medullary cavity. This remodeling of bone primarily takes place during a bone’s growth. However, in adult life, bone undergoes constant remodeling, in which resorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone to replace that which is resorbed. Injury, exercise, and other activities lead to remodeling. Those influences are discussed later

in the chapter, but even without injury or exercise, about 5 to 10 percent of the skeleton is remodeled annually just by destroying old bone and renewing it with fresh bone. 9.

Where do primary and secondary ossification centers appear during endochondral ossification. Intramembranous Ossification: primary (Powerpoint)

Secondary ossification centers occur in the epiphyses

10.

What is intramembranous ossification? What bones in the body developed by intramembranous ossification? •

11.

Intramembranous ossification: bone develops from a fibrous membrane • Flat bones of the skull, part of the mandible, and the diaphysis of the clavicles

What causes pituitary dwarfism, achondroplasia, gigantism, acromegaly, Marfan’s syndrome, congenital talipes equinovarus, FOP, rickets, and osteomalacia? PG 226 A variety of endocrine (hormonal) or metabolic problems can results in atypical skeletal growth A. Pituitary Dwarfism:

12.

List the major steps in bone repair. Pg 232 • 1. Fracture hematoma formation • 2. Callus Formation • 3. Spongey Bone Formation • 4. Compact Bone Formation

13.

Name the hormone that is the major regulator of Ca2+ levels in the body. What stimulates the secretion of this hormone?

Parathyroid hormone, calcitriol, and calcitonin When blood calcium ion concentration falls below normal, cells of the parathyroid glands, embedded in the thyroid gland in the next, release parathyroid hormone into the bloodstream.

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Necessary for physiological process • Nerve conduction • Muscle contraction 2+ • Ca necessary for heart (too high it stops) • Breathing (too low it stops) muscle contraction • Blood clotting 2+ If Ca levels too low —parathyroid (in neck) releases parathyroid hormone (PTH) 2+ • Activates osteoclasts to breakdown bone matrix and release Ca ions into blood 2+ 2+ • PTH decreases Ca loss in urine and increased blood Ca 2+ • PTH stimulates production of calcitriol—increases GI absorption of Ca 2+ When Ca too high calcitonin (thyroid gland) inhibits osteoclasts and increases 2+ deposition of Ca

What are the effects of PTH on osteoclast number, the formation of vitamin D, and the reabsorption of Ca 2+ from urine? Pg 236 and pg 231 Osteoclast activity is decreased. In pregnant and nursing women calcitonin and Vitamin D3 are increased

15.

What stimulates calcitonin secretion? When blood calcium ion concentration rises above normal. Increased blood calcium. How does calcitonin affect osteoclast activity? Calcitonin, a calcium regulatory hormone, strongly inhibits bone-resorbing activity of osteoclasts

16.

Define fibrous joint, describe the three types, and give an example of each. Pg 289

Joi nt s: Aj oi nti swher et wobonesi nt hesk el et als ys t em connectt ohav eashar edf unct i on.Di ffer entj oi nt s, al socal l edanar t i c ul at i on,al l owf ordi ffer entdegr eesandt ypesofmot i on.

There are three kinds of fibrous joints: sutures, gomphosis, and syndesmoses. These types of joints strongly unite adjacent bones. Sutures, such as the coronal suture, are most commonly seen in the skull. Gomphoses are joints between teeth and their sockets. Syndesmosis (Fibrous) joints hold the tibia and the fibula together.

17. List the 3 functional categories of joints. Pg 289 1. Synarthrosis 2. Amphiarthrosis 3. Diarthrosis

18. List the major types of joints according to their structure. Give examples of each. 1. Immovable or fibrous joints – Synarthrosis

Skull, teeth, ribs, sternum • • • • • •

Joint by hyaline cartilage Little or no movement Some are temporary and are replaced by synostoses Some are permanent Some like costochondral joints develop into synovial joints Examples: st – 1 true rib – Epiphyseal plates – Ilium, ischium, and pubis, before fussing together

2. Slightly Movable (Cartilaginous) Joints – Amphiarthrosis Distant joint between tib/fib, pubic symphysis • • •

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Bones connected by ligament Most movable fibrous joint E.g.-interosseus membranes of radius/ulna and tibiofibular ligament

Joint by fibrocartilage Amphiarthrosis (slightly movable) Examples: – Symphysis pubis – Intervertebral disks Between the manubrium and the body of the sternum

3. Freely Movable (Synovial) Joints – Diarthrosis Long bones, upper and lower extremities Most common joints in body Joints in which bones are separated by a space called a joint cavity Most are freely movable (diarthrosis)

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19. Describe the structure of a synovial joint.

Articular cartilage: – Hyaline cartilage that covers epiphysis – Absorbs compression of joint, reduces friction Joint cavity (synovial cavity) – Unique to synovial joints – Cavity is a potential space that holds small amount of fluid Joint (Articular) Capsule - a 2 layered capsule – Fibrous capsule • Strengthens joint – Synovial membrane • Lines joint capsule and covers internal joint surfaces • Functions to make synovial fluid Synovial fluid: – Viscous fluid similar to raw egg white – Viscosity due to high concentration of hyaluronan (hyaluronic acid) – Provides oxygen and nutrients to chondrocytes – Carries away metabolic wastes – A Nerves in capsule help brain know position of joints (proprioception)

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20. List and describe the accessory structures in the joints.

A. Bursae • • • •

Small, thin, fluid-filled pocket filled with synovial fluid and lined by synovial membrane Forms in connective tissue outside a joint capsule Often form where tendons or ligaments rub against other tissue Reduces friction Acts as shock absorber

B. Fat pads • • • •

Localized masses of adipose tissue covered by a layer of synovial membrane Usually superficial to joint capsule Protect articular cartilage Fill in spaces created as joint moves and joint cavity changes shape

C. Menisci • • • •

Pad of fibrocartilage between opposing bones in a synovial joint May subdivide a synovial cavity May channel synovial fluid flow Allows variations in the shapes of the articular surfaces

D. Accessory ligaments • Capsular • Cruciate •

Support, strengthen, and reinforce synovial joints • Capsular ligaments or intrinsic ligaments • Localized thickenings of the joint capsule • Extrinsic ligaments • Separate from the joint capsule • Extracapsular ligaments (pass outside the joint capsule) • Example: patellar ligament • Intracapsular ligaments (pass inside the joint capsule) • Example: cruciate ligaments

21. Describe the 6 types of joints and give examples of each.

22. Compare the general relationship between joint stability and ROM for axial and appendicular joints. Pg 299

Axial Joints have less range of motion than appendicular joints but are stronger Most of the joints of the axial skeleton are strong and permit little movement Joints of the appendicular skeleton allow for extensive range of motion but are often weaker or less stable. 23. Define the following movements and give example of each. a. b. c. d. e. f. g. h. i. j. k. l.

Flexion and extension pg 294 Lateral flexion (head) pg 294 Dorsiflexion/plantar flexion -pg 294 Abduction and adduction pg 295 Circumduction pg 295 Rotation – pg 296 Supination and pronation – pg 296 Elevation and depression pg 297 Opposition and reposition pg 297 Protraction and retraction pg 297 Inversion and eversion pg 297 Elevation/depression

24. List the most common joint disorders. Rheumatism Arthritis Osteoarthritis Gouty Arthritis Rheumatoid arthritis...