Mov 1 exam 3

What is the structural unit of compact bone? >osteon >Haversian canal >osteoid >canaliculus

> Osteon. The structural unit of compact bone is the osteon, an elongated cylinder oriented parallel to the long axis of the bone.

Flat bones consist of spongy bone sandwiched between compact bone. Is this statement true or false? >True >False

> True.

Which event has to precede all others during endochondral ossification? Which event has to precede all others during endochondral ossification? >A nutrient artery invades the diaphysis. >A cartilage model is formed. >Bone trabeculae appear in the epiphyses. >An epiphyseal plate is trapped between the diaphysis and either epiphysis.

>A cartilage model is formed. This event precedes all others in endochondral ossification.

Which of the following statements is true? Which of the following statements is true? >After 21, most people will not experience longitudinal growth of bones. >PTH will increase calcium deposits in the bone matrix. >Increasing levels of calcium in the blood will trigger calcium deposition in the bone. >By 21, the width of the bones stops changing.

>After 21, most people will not experience longitudinal growth of bones. This is correct. By 21, most people have experienced the process that seals the epiphyseal plates.

In which of the labeled parts of the adult long bone would hematopoietic tissue be located? (Refer to Image 1) >A >B >C >D >E

>B. Hematopoietic tissue is found in the spaces within the red bone marrow found within certain body locations consisting of spongy bone. Examples include the diploe of flat bones and the proximal epiphyses of the femur and humerus (pictured).

Which of the labeled parts of the bone is composed primarily of compact bone? (Refer to Image 1) >A >B >C >D >E

>D.

Which of the following statements is true? >Endochondral ossification occurs within fibrous connective tissue membranes. >Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). >Most bones in the body are formed by intramembranous ossification. >Endochondral ossification leads to the formation of the clavicles and cranial bones.

>Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). Endochondral ossification is the formation of bone within hyaline cartilage. Hyaline cartilage "bones" are used as templates for the formation of true bone. Most bones below the base of the skull form by endochondral ossification.

__________ bones are generally thin and have a layer of spongy bone between two layers of compact bone. >Long >Flat >Irregular >Short

>Flat.

During infancy and childhood, the most important stimulus of epiphyseal plate activity is __________. >estrogen >testosterone >growth hormone >thyroid hormones

>Growth Hormone. During infancy and childhood, the single most important stimulus for bone growth is growth hormone. It directly stimulates growth of the hyaline cartilage that forms the epiphyseal plates in long bones, causing the bones to lengthen.

Which of the following most directly controls bone remodeling? >the nervous system and hormones >hormones and diet >mechanical stress and hormones >mechanical stress and diet

>Mechanical stress and Hormones. Remodeling goes on continuously in the skeleton, regulated by genetic factors and two control loops that serve different "masters." One is a negative feedback hormonal loop that maintains Ca2+ homeostasis in the blood; the other involves responses to mechanical and gravitational forces acting on the skeleton.

Which description of bone cells is INCORRECT? >Osteoclasts secrete digestive enzymes and hydrogen ions. >Bone lining cells on the internal surfaces of bone are also called endosteal cells. >Osteoblasts secrete collagen and calcium-binding proteins. >Osteogenic cells can differentiate into osteoclasts.

>Osteogenic cells can differentiate into osteoclasts. Osteoclasts are derived from the same hematopoietic stem cells that differentiate into macrophages; they are not derived from osteogenic cells. Osteogenic cells can differentiate into osteoblasts.

In addition to supporting and protecting the body, the skeleton provides this function as well. >Its muscles provide movement. >The bones store fat, red marrow, and calcium. >Its cartilages produce blood.

>The bones store fat, red marrow, and calcium.

Which statement is NOT true about the osteon? >The osteon is not brittle because of the organic collagen in the matrix. >The more osteons in a bone, the stronger the bone is. >The osteon absorbs stress in all directions equally. >Strength of the osteon comes from the inorganic salts secreted into the bone matrix.

>The osteon absorbs stress in all directions equally. This is not a true statement. In fact, the reason that bones break is because a stress is placed on the osteons at an angle opposite to the direction that the osteons run.

Which of the following statements is true regarding the future actions of the vessels in the medullary cavity and the vessels in the epiphyses of the bone? >They will grow and encourage bone formation until the epiphyseal plate eventually ossifies. >They will eventually degrade and die, leaving the bone with little or no blood supply. >They will grow and encourage bone formation until all cartilage in the bone is ossified. >They will grow to a certain size and then maintain all of the cartilage seen in the figure.

>They will grow and encourage bone formation until the epiphyseal plate eventually ossifies. The loss of the epiphyseal plate will seal the epiphysis and diaphysis and eventually end the lengthening of the bone.

The main role of the axial skeleton is to protect and support vital organs. Is this statement true or false? >True >False

>True. The main role of the appendicular skeleton involves locomotion; it also allows us to manipulate our environment. The axial skeleton is mostly involved in supporting other body parts and protecting vital organs.

The collagen in the osteoid bone matrix makes the overall bone matrix stronger by allowing flexibility. Is this statement true or false? >True >False

>True. The matrix is one-third organic osteoid. This portion includes a large amount of collagen that allows the bone to stretch and absorb shock without being too brittle.

Which of the following diseases would most likely be associated with a disorder at A? (Refer to Image 2) >osteosarcoma >osteomalacia >achondroplasia >osteoarthritis

>achondroplasia. This genetic disease can lead to shortening of the long bones due to premature closure of the epiphyseal plate.

What would be the physical sign that a bone CANNOT continue longitudinal growth? >the presence of hyaline cartilage on the ends of the bone >the presence of osteons >the presence of osteoblasts >an epiphyseal line

>an epiphyseal line. The epiphyseal plate is a zone of hyaline cartilage between the epiphysis and diaphysis of a long bone. When the cartilage is replaced with bone and the plate closes, the bone has reached its maximum length. This is called the epiphyseal line.

During bone growth, which significant event occurs at the surface indicated by the letter C? (Refer to image 2) >bone resorption >expansion of the articular cartilage >conversion of spongy bone to compact bone >appositional growth

>appositional growth. Growth in width involves the adding of layers of lamellar (compact) bone along the bone's outer surface. This process of growth by "layering" is termed appositional growth and is distinct from growth by expansion of the interior matrix (interstitial growth).

Bones of the skeleton are connected at junctions called ________. >articulations >associations >appendiculars >axials

>articulations

Which structure is seen at the arrow? >periosteal bud >bone collar >diaphysis >epiphyseal plate

>bone collar. A collar of ossified tissue forms around the bone in the early stages of ossification.

During bone growth, which significant event occurs at the surface indicated by the letter D? (Refer to Image 2) >bone resorption >interstitial growth >production of hyaline cartilage >production of compact bone

>bone resorption. As the bone widens, the matrix at the endosteal surface is resorbed to maintain the proper thickness of the walls surrounding the medullary cavity.

Which of the following are correctly matched? >linear fracture; the break is perpendicular to the bone's long axis >compound fracture; the fractured bone ends penetrate the skin >nondisplaced fracture; the fractured bone ends are misaligned >incomplete fracture; the bone is broken through

>compound fracture; the fractured bone ends penetrate the skin. In a compound (open) fracture, the fractured bone ends penetrate the skin. Such open injuries carry a higher risk of infection.

Which bone-forming process is shown in the figure? (Refer to Image 4) >intramembranous ossification >endochondral ossification >bone remodeling >bone fracture repair

>endochondral ossification. The figure illustrates a step in the embryonic formation of a bone from a cartilage model.

This membrane lines the shaft of long bones, and covers the trabeculae of spongy bone. >epiphysis >endosteum >periosteum >perforating fibers

>endosteum

Longitudinal bone growth occurs at this location in long bones. >midshaft >epiphyseal plates >diaphyseal plates >heads

>epipyhsial plates

The epiphyses of long bones are ________. >solid >filled with spongy bone >hollow

>filled with spongy bone

What is the first stage in the healing of a bone fracture? >formation of a hematoma >bone remodeling >formation of a bony callus >formation of a fibrocartilaginous callus

>formation of a hematoma. This is the first stage in the healing of a bone fracture. In order, here are the stages of bone fracture healing: (1) formation of a hematoma, (2) formation of a fibrocartilaginous callus, (3) formation of a bony callus, and (4) bone remodeling.

Bones do NOT have a role in __________. >fat storage >movement >blood cell formation >glycogen production >support

>glycogen production. Glycogen production (glycogenesis) is not a role of bone; it takes place primarily in muscle and liver cells.

The area where blood vessels are penetrating the center of the bone used to be occupied by which tissue? (Refer to Image 4) >hyaline cartilage >fibrocartilage >adipose tissue >dense connective tissue

>hyaline cartilage. In this type of ossification, the bone is first modeled from cartilage and then replaced by bone as blood vessels invade the model.

The structure indicated by the arrow is composed primarily of what tissue? >mesenchyme >hyaline cartilage >dense connective tissue >fibrocartilage

>hyaline cartilage. The cartilage models used to form bones are composed of hyaline cartilage. This tissue persists within the epiphyseal plate at the boundary between primary and secondary ossification centers until early adulthood.

There are several components to a functional osteon. Changes to which of the following components would make the bones less strong overall and cause the bones to bend under a person's body weight? >periosteum >articular cartilage >hydroxyapatite >osteoid

>hydroxyapatite. The hydroxyapatite is the rigid portion of the bone matrix. As hydroxyapatite is removed from the bone, more of the body's weight would be transferred to the collagen of the osteoid, which would bend under the weight.

Vertebrae belong to this category of bones. >short >irregular >long >flat

>irregular

Which of the following disorders is only associated with the type of bone shown in the figure? (Refer to Image 6) >lack of formation of certain skull bones and the clavicle (cleidocranial dysostosis) >weakening of the bones through failure in deposition/absorption balance (osteoporosis) >bowed legs and pelvic deformities (rickets) >excessive and random bone deposition (Paget's disease)

>lack of formation of certain skull bones and the clavicle (cleidocranial dysostosis). This genetic disorder of the processes of intramembranous ossification can result in these bones being deformed or even missing.

of the following are short bones except ________. >tarsals >phalanges >patella >carpals

>phalanges.

Osteoid-producing osteoblasts must rely upon this organelle to produce primary structures leading to the formation of collagen and calcium-binding proteins. >peroxisomes >ribosomes >centrioles >mitochondria

>ribosomes.

Which type of cartilage is NOT properly matched with its function? >skeletal cartilage; reinforce airways >fibrocartilage; withstand pressure and stretch >hyaline cartilage; cover the ends of bones >elastic cartilage; withstand repetitive bending

>skeletal cartilage; reinforce airways. Skeletal cartilage is not a specific cartilage type but rather a description of the collection of cartilage in the body.

Which of the following is a characteristic of the bone material at D but NOT of the material at B? (Refer to image 1) >vascularity >an origin in mesenchyme >osteocytes >lamellae

>vascularity. The compact bone at D would contain blood vessels as well as nerves in the central canals of its osteons. The spongy bone at B would be nourished by the surrounding fluids.

In adults, ________ marrow fills the central canal of long bones, and ________ marrow is found in the epiphyses of long bones. >yellow, yellow >yellow, red >red, yellow >red, red

>yellow, red.

The blood vessels and nerve in the figure are found within which type of space? >central (Haversian) canal >marrow cavity >canaliculi >perforating (Volkmann's) canal

A central (or Haversian) canal runs lengthwise at the center of each osteon.

Which of the following is a site for a muscle or ligament attachment? >foramen >fossa >sinus >trochanter >groove

A trochanter is a bone projection; projections often protrude from the bone because of the interaction forced upon them by muscle or ligaments.

Which of the following statements is true? >Most bones in the body are formed by intramembranous ossification. >Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). >Endochondral ossification occurs within fibrous connective tissue membranes. >Endochondral ossification leads to the formation of the clavicles and cranial bones.

Endochondral ossification is the formation of bone within hyaline cartilage. Hyaline cartilage "bones" are used as templates for the formation of true bone. Most bones below the base of the skull form by endochondral ossification.

When chondrocytes in lacunae divide and form new matrix, it leads to an expansion of the cartilage tissue from within. This process is called __________. >calcification >hematopoiesis >appositional growth >interstitial growth

Interstitial growth occurs when chondrocytes divide and form new matrix, thereby expanding the cartilage tissue from within. This causes the cartilage to lengthen.

When chondrocytes in lacunae divide and form new matrix, it leads to an expansion of the cartilage tissue from within. This process is called __________. >hematopoiesis >interstitial growth >calcification >appositional growth

Interstitial growth occurs when chondrocytes divide and form new matrix, thereby expanding the cartilage tissue from within. This causes the cartilage to lengthen.

What is the term for the layers of bony matrix surrounding the cell at A? (Refer to Image 3) >endosteum >lamellae >periosteum >lacunae

Lamellae are layers of bony matrix synthesized by osteoblasts during bone growth and maintenance.

What is the term for the layers of bony matrix surrounding the cell at A? (Refer to Image 3) >lacunae >periosteum >endosteum >lamellae

Lamellae are layers of bony matrix synthesized by osteoblasts during bone growth and maintenance.

Classify the cells seen at the arrow in A. (Refer to Image 6) >osteoclasts >chondroblasts >osteocytes >osteoblasts

Osteoblasts ("bone makers") begin bone formation by secreting the bone matrix.

Which of the following cells are NOT matched with its appropriate function? >osteoblasts create new bone matrix >osteoclasts; bone reabsorption >bone lining cells; maintain matrix >osteocytes; produce new bone cells.

Osteocytes are mature bone cells that monitor and repair mature bone tissues.

What type of cell is shown at A? (Refer to Image 5) >mesenchymal >osteoclast >osteoblast >osteocyte

Osteocytes, literally "bone cells," are the primary structural and maintenance cells found in bone.

What material makes up most of the structure at A? (Refer to Image 1) >fibrocartilage >elastic cartilage >hyaline cartilage >dense irregular connective tissue

The articular cartilage at the ends of long bones is formed from hyaline cartilage.

What is the weakest part of a developing, adolescent long bone? >the epiphyseal plate >the diaphysis >the medullary cavity >the epiphyses

The epiphyseal plate is a weak point because of the lack of calcification.

What is intramembranous ossification? >the formation of bone from preexisting elastic cartilage models >the formation of bone from fibrous membranes >the formation of bone from preexisting hyaline cartilage models >the formation of bone from preexisting fibrocartilage models

The formation of bone from fibrous membranes is called intramembranous ossification.

What is intramembranous ossification? >the formation of bone from preexisting hyaline cartilage models >the formation of bone from preexisting fibrocartilage models >the formation of bone from fibrous membranes >the formation of bone from preexisting elastic cartilage models

The formation of bone from fibrous membranes is called intramembranous ossification.

There are several components to a functional osteon. Changes to which of the following components would make the bones less strong overall and cause the bones to bend under a person's body weight? >articular cartilage >hydroxyapatite >osteoid >periosteum

The hydroxyapatite is the rigid portion of the bone matrix. As hydroxyapatite is removed from the bone, more of the body's weight would be transferred to the collagen of the osteoid, which would bend under the weight.

Which of the following correctly pairs the structure at C with its primary component? >endosteum; areolar tissue >periosteum; dense irregular connective tissue >endosteum; dense regular connective tissue >periosteum; cuboidal epithelium

The periosteum is composed of dense irregular connective tissue along with a layer of simple squamous epithelium.