Patho Chapter 38: Structure and Function of the Musculoskeletal System

Which inorganic components are major elements of bone? (select all that apply) Select all that apply. a. Calcium b. Phosphate c. Magnesium d. Sodium e. Potassium

a,b Phosphate and calcium are present in sufficient quantities to be considered the major inorganic components in bone matrix.

Which statements regarding the Haversian system are correct? (select all that apply) Select all that apply. a. There is a central canal. b. There are concentric layers of bone matrix called lamellae. c. There are tiny spaces between the lamellae called lacunae. d. Spongy bone contains this system. e. Its presence results in a compact bone.

a,b,c Spongy bone is less complex than compact bone and does not contain the Haversian system. The remaining statements are true.

Which terms are used to identify a stage of wound healing in bone? (select all that apply) Select all that apply. a. Hematoma formation b. Procallus formation c. Callus formation d. Hematoma reabsorption e. Remodeling

a,b,c,e The steps, in order, for bone wound healing are hematoma formation, procallus formation, callus formation, callus replacement, and remodeling. Hematoma reabsorption is not a recognized stage of bone healing.

Which type of joint has two bony surfaces that are united by a ligament or membrane? a. Syndesmosis b. Gomphosis c. Fibrous joint d. Synchondrosis

a. Syndesmosis Syndesmosis is a joint that has two bony surfaces united by a ligament of membrane. Gomphosis is a special type of fibrous joint in which a conical projection fits into a complementary socket and held by a ligament. A fibrous joint describes when bone is connected to bone by fibrous connective tissue. Synchondrosis is a joint in which hyaline cartilage connects the two bones (instead of fibrocartilage).

Which portion of the bone is the narrow tubular portion that merges into the neck of the bone? a. Long bone b. Diaphysis c. Metaphysis d. Epiphysis

b. Diaphysis The diaphysis is the narrow tubular midportion that merges into the neck (metaphysis). The broad end of a bone is the epiphysis. Long bone is a classification of bone.

The phase of bone remodeling during which the osteoclasts resorb bone and leave a resorption cavity is referred to as: a. Phase 1. b. Phase 2. c. Phase 3. d. Phase 4.

b. Phase 2. Phase 1 is activation of the osteoclasts. Phase 2 is osteoclast resorption of bone and creation of resorption cavities. Phase 3 occurs when osteoblasts line the walls of the resorption cavity and lay new bone. Phase 4 does not exist.

The deltoid muscles are examples of: a. fusiform muscles. b. pennate muscles. c. fascia. d. epimysium.

b. pennate muscles. Pennate muscles are broad, flat, and slightly fan shaped, and the fibers run obliquely to the muscle's long axis. Fusiform muscles are elongated muscles shaped like straps and can run from one joint to another. Fascia is the connective tissue framework of skeletal muscle. Epimysium is the outermost layer of fascia.

During muscle contraction, which location shortens? a. Z band b. Actin c. I band d. Myosin

c. I band The I band is the distance between two myosin molecules and decreases length during contraction. The Z band is located between the sarcomeres and does not change length. Actin and myosin do not change length.

An elderly woman is diagnosed with osteoporosis. Which cells would be most active in her bones? a. Osteocytes b. Osteoblasts c. Osteoclasts d. Lacunae

c. Osteoclasts Osteoclasts are the cells that resorb or break down bone and subsequently cause osteoporosis. Osteocytes are osteoblasts that became entrapped in the osteoid and become relatively nonfunctional. Osteoblasts are the cells that form bone. Lacunae are the spaces in hardened bone where osteocytes are located.

What are the major resorptive cells found in bone? a. Osteoblasts b. Osteoids c. Osteoclasts d. Osteocytes

c. Osteoclasts Osteoclasts are the major resorptive cells of bone. Osteoid is the nonmineralized bone matrix. Osteoblasts are cells derived from mesenchymal stem cells that produce type I collagen. An osteocyte is a transformed osteoblast that is trapped in osteoid and has little function.

What is the function of osteocalcin? a. Forms compression-resistant networks between collagen fibrils b. Controls collagen interactions that lead to fibril formation c. Plays a part in bone resorption by recruiting osteoclasts d. Transports essential elements such as hormones

c. Plays a part in bone resorption by recruiting osteoclasts Osteocalcin is a calcium-binding protein that binds preferentially to calcium that has already crystallized. The roles include the inhibition of calcium phosphate precipitation and a part in bone resorption by recruiting osteoclasts. Proteoglycans are responsible for forming compression-resistant networks between the collagen fibrils. Glycoproteins control the collagen interactions that lead to fibril formation. Bone albumin is identical to serum albumin.

Which statement regarding the different types of bone tissue is accurate? a. There are three types of bone. b. Compact bone makes up approximately 10% of the skeleton. c. The major difference between the types of bones is the organization of elements. d. The different types of bones have different structural elements.

c. The major difference between the types of bones is the organization of elements. Bone is composed of two types of osseous tissue: compact and spongy bone. Compact bone makes up 85% of the skeleton, and spongy, the remaining 15%. They have similar structural elements, and the organization of elements is what makes them different.

The bones of the wrist would be classified as: a. long bones. b. flat bones. c. cuboidal bones. d. irregular bones.

c. cuboidal bones. Short or cuboidal bones include those of the wrist and ankle. Long bones are longer than they are wide. Flat bones are those such as the ribs and scapulae. Irregular bones include the vertebrae, mandibles, and other facial bones.

What is the term for the gelatinous material found in bone? a. Collagen b. Calcium c. Protein d. Ground substance

d. Ground substance Mature rigid bone is composed of rigid connective tissue consisting of cells, fibers, ground substance, and minerals. The ground substance is the gelatinous material.

During which stage of muscle contraction does actin bind to myosin? a. Coupling b. Relaxation c. Discharging d. Excitation

ANS: A During coupling, depolarization of the transverse tubules occurs. This triggers the release of calcium ions from the sarcoplasmic reticulum, exposing binding sites on the actin molecule. In the presence of calcium, actin is free to bind with myosin. Relaxation is the last step. It begins as calcium ions are actively transported back into the sarcoplasmic reticulum, removing ions from interaction with troponin. Discharging is not a step in the process. Excitation is the first step of muscle contraction and it begins with the spread of an action potential from the nerve terminal to the neuromuscular junction. REF: p. 985

Which characteristic of a postural muscle is a result of having substantial amounts of type I muscle fibers? a. Resists fatigue b. Rapid response time c. Little contractibility d. Lacks a fascia lining

ANS: A Postural muscles have more type I fibers, allowing them the high resistance to fatigue that is necessary to maintain the same position for extended periods. The ocular muscles have more type II muscle fibers, allowing them to respond rapidly to visual changes. Little contractibility or lacking a fascia lining is associated with type I muscle fibers. REF: p. 980

What is the major difference between compact and spongy bone? a. Organization of the structural elements b. Location within the body c. Activating chemicals in each d. Types of minerals in the bone matrix

ANS: A The major difference between the two types of tissue is the organization of the elements. The differences in location in the body, chemical activation, or types of minerals contained are not as relevant. REF: pp. 972-973

How do blood vessels penetrate into the inner structures of the bone? a. Volkmann canals b. Canaliculi c. Sharpey fibers d. Lamellae

ANS: A The outer layer of the periosteum contains blood vessels and nerves, some of which penetrate to the inner structures of the bone through channels called Volkmann canals. Canaliculi are small channels or canals. Sharpey fibers also help hold or attach tendons and ligaments to the periosteum of bones. Concentric layers of bone matrix are called lamellae. REF: p. 973

Which terms are used to describe skeletal muscle? (select all that apply) a. Voluntary b. Striated c. Extrafusal d. Fibrotic e. Epithelial

ANS: A, B, C Skeletal muscle has been termed voluntary, striated, or extrafusal. REF: p. 979

The shapes that represent bone classifications include: (select all that apply) a. long. b. flat. c. short. d. irregular. e. round.

ANS: A, B, C, D Bones can be classified by shape as long, flat, short (cuboidal), or irregular. REF: p. 974

The nursing student has a good understanding of glycoproteins when he states which of the following glycoproteins are present in the bone? (select all that apply) a. Osteocalcin b. Sialoprotein c. Bone albumin d. Alpha-glycoprotein e. Collagen

ANS: A, B, C, D Four glycoproteins are present in bone: sialoprotein, which binds easily with calcium; osteocalcin, which binds preferentially to crystallized calcium; bone albumin, which is identical to serum albumin and possibly transports essential nutrients to and from bone cells and maintains the osmotic pressure of bone fluid; and alpha-glycoprotein (-glycoprotein). Collagen is not a glycoprotein. REF: p. 972

Which molecules are parts of the bone matrix? (select all that apply) a. Collagen fibers b. Elastin fibers c. Proteoglycans d. Glycoproteins e. Epithelial cells

ANS: A, C, D Bone matrix is composed of collagen fibers, proteoglycans, and glycoproteins. REF: p. 969, Table 38-1 | p. 972

When describing a freely movable joint, which term should be used? a. Synarthrosis b. Amphiarthrosis c. Fibrous d. Diarthrosis

ANS: D A diarthrotic joint is freely moveable. A synarthrotic joint is immovable. An amphiarthrotic joint is slightly movable. A fibrous joint has little, if any, movement. REF: p. 975

The structures present in compact bone include the: (select all that apply) a. haversian canals. b. trabeculae. c. canaliculi. d. lamellae. e. lacunae.

ANS: A, C, D, E Compact bone is highly organized, solid, and extremely strong. The basic structural unit in compact bone is the haversian system. Each haversian system is made up of haversian canals, lamellae, and canaliculi. Trabeculae are found in spongy bone. REF: p. 973

A nurse recalls fibrous joints generally are: a. rotating. b. slightly movable. c. freely movable. d. calcified.

ANS: B A fibrous joint has little, if any, movement. REF: p. 975

Hydroxyapatite found in bone matrix contains a combination of which molecules in its crystalline structure? a. Calcium and magnesium b. Calcium and phosphate c. Phosphate and magnesium d. Magnesium and hydrogen

ANS: B Calcium and phosphate form amorphous (fluid) calcium phosphate compounds that are converted, in stages, to solid hexagonal crystals of hydroxyapatite. Hydroxyapatite does not contain magnesium or hydrogen. REF: p. 972

Which molecule prevents a muscle contraction from occurring when the muscle is at rest? a. Calcium b. Troponin-tropomyosin c. Actin d. Myosin

ANS: B Contraction begins as the calcium ions combine with troponin, a reaction that overcomes the inhibitory function of the troponin-tropomyosin system. Calcium, actin, and myosin all facilitate muscle contraction. REF: p. 985

The nurse observed the patient's muscle contracted, but the limb did not move. How should the nurse chart this muscle contraction? a. Isotonic contraction b. Isometric contraction c. Eccentric contraction d. Concentric contraction

ANS: B During isometric contraction, the muscle contracts, but the limb does not move. During isotonic contraction, the muscle maintains a constant tension as it moves. Eccentric contraction is a form of isotonic contraction. Concentric contraction is a form of isotonic contraction. REF: p. 986

Once their initial function is complete, what do osteoblasts become? a. Osteoclasts b. Osteocytes c. Chondroblasts d. Osteoids

ANS: B Osteoblasts are the bone-forming cells. Their primary function is to lay down new bone. Once this function is complete, osteoblasts become osteocytes. Osteoclasts reabsorb bone. Chondroblasts are a part of mature bone. Osteoids are part of nonmineralized bone matrix that the osteoblasts work on. REF: p. 970

Between which structures will you find a joint that contains synchondrosis costal cartilage? a. Vertebrae b. Ribs and sternum c. Sutures of the skull d. Facial bones

ANS: B Synchondrosis costal cartilage is located between the ribs and the sternum. This type of cartilage is not found between the vertebrae, sutures of the skull, or between the facial bones. REF: p. 975

A nurse recalls the freely moveable joint is an example of which type of joint? a. Amphiarthrosis b. Diarthrosis c. Synarthrosis d. Symphysis

ANS: B The elbow joint is freely moveable and is an example of a diarthrosis joint; amphiarthrosis joints are only slightly moveable. Synarthrosis joints are immoveable. A symphysis is a cartilaginous joint in which bones are united by a pad or disk of fibrocartilage. REF: p. 975

After puberty, the epiphyseal plate calcifies, and the epiphysis and _____ merge. a. epiphyseal line b. diaphyseal plate c. metaphysis d. articular cartilage

ANS: C After puberty, the epiphyseal plate calcifies, and the epiphysis and metaphysis merge. None of the other options merges with the epiphysis after puberty. REF: p. 974

What does the term "sarcopenia" describe? a. Absence of muscle cells b. Fatigue of muscle cells c. Age-related loss in skeletal muscle d. Muscles that are unable to contract

ANS: C Age-related loss in skeletal muscle is referred to as sarcopenia and is a direct cause of the age-related decrease in muscle strength. The term is not used to describe the absence or fatigue of muscle cells or their inability to contract. REF: p. 988

Which ions directly control the contraction of muscles? a. Sodium b. Potassium c. Calcium d. Magnesium

ANS: C Contraction begins as the calcium ions combine with troponin, a reaction that overcomes the inhibitory function of the troponin-tropomyosin system. The release of intracellular calcium ions is the critical link between a nerve impulse (electrical excitation) and muscle contraction. The critical link that allows for the contraction of muscles is not reliant upon sodium, potassium, or magnesium. REF: p. 985

The skeletal muscles are encased in a connective tissue framework made of: a. bone. b. epithelium. c. fascia. d. cartilage.

ANS: C Each skeletal muscle is a separate organ, encased in a three-part connective tissue framework called fascia. This framework is not made of bone, epithelium, or cartilage. REF: p. 979

What type of joint normally exists between the teeth and the maxilla or mandible? a. Symphysis b. Diarthrosis c. Gomphosis d. Syndesmosis

ANS: C Gomphosis joints exist between the teeth and the maxilla or mandible. None of the other options fulfills that function. REF: p. 975

Clusters of which type of bone cells are responsible for bone remodeling? a. Trabeculae b. Osteoclastic cutting cones c. Basic multicellular units d. Haversian system cells

ANS: C Remodeling is carried out by clusters of bone cells termed basic multicellular units. The basic multicellular units are made up of bone precursor cells that differentiate into osteoclasts and osteoblasts. Trabeculae are plates found in spongy bone. The osteoclasts form a "cutting cone," which gradually resorbs bone, not remodels it. Haversian canals are part of compact bone. REF: pp. 974-975

What is the main energy source or fuel for skeletal muscle contraction? a. Potassium b. Lactic acid c. Adenosine triphosphate (ATP) d. Actin

ANS: C Skeletal muscle requires a constant supply of ATP and phosphocreatine. These substances are necessary to fuel the complex processes of muscle contraction. Neither potassium, lactic acid, nor actin is the main energy source for muscle contraction. REF: p. 985

Which of the following should the nurse include when discussing the different types of cartilaginous joints? a. Sutures and gomphosis b. Syndesmosis and gomphosis c. Symphysis and synchondrosis d. Gomphosis and synchondrosis

ANS: C There are two types of cartilaginous joints: symphysis and synchondrosis. REF: p. 975

Which component of the bone matrix gives bone its tensile strength? a. Calcium b. Phosphate c. Collagen d. Magnesium

ANS: C While calcium, phosphate, and magnesium all play a role in bone formation, collagen is the component of bone matrix that gives bone tensile strength. REF: p. 969, Table 38-1

Which layer forms the fascicles in skeletal muscle? a. Tendon sheath b. Endomysium c. Epimysium d. Perimysium

ANS: D The perimysium further subdivides the muscle fibers into bundles of connective tissue called fascicles. None of the other options forms fascicles. REF: p. 979

The structure of the contractile subunit of the myofibril is called the: a. sarcoplasmic reticulum. b. actin. c. motor end plate. d. sarcomere.

ANS: D The sarcomere is the contractile portion of the myofibril. In response to a nerve impulse, RyR1 (found in skeletal muscle cells) releases intracellular calcium and initiates muscle contraction at the sarcomere, a portion of the myofibril. The sarcoplasmic reticulum is made like the endoplasmic reticulum in other cells. Actin is a protein of the sarcomere. It is at the motor nerve end plate where the nerve impulse is transmitted. REF: p. 982

What term identifies a muscle acting as a contraction's prime mover? a. Flexor b. Recruiter c. Antagonist d. Agonist

ANS: D When a muscle contracts and acts as a prime mover, or agonist, its reciprocal muscle, or antagonist, relaxes. Neither the term flexor nor recruiter identifies this action. REF: p. 986