A&P Test 2 6.4-6.12

compact bone formation

A swelling initially marks the location of the fracture. Over time, this region with be remolded by osteoblasts and osteoclasts, and little evidence of the fracture will remain

A) it is an incomplete cellular layer that line the medullary cavity

All of the following are characteristics of periosteum except: A) it is an incomplete cellular layer that lines the medullary cavity B) it provides a route for the blood and nervous supply C) it actively participates in bone growth and repair D) it has two layers, an inner layer and an outer layer

A) PTH stimulation of osteoclasts

All of the following result in decreased calcium levels in the bloodstream except: A) PTH stimulation of osteoclasts B) increased calcitonin levels C) calcitonin inhibtion of osteoclasts D) decreased PTH or calcitriol

D) osteoblasts are producing bone faster than chondrocytes are producing new epiphyseal cartilage

At puberty: A) chondrocytes begin producing bone faster than osteoblasts are producing new epiphyseal cartilage B) epiphyseal cartilage thickens C) decreasing thyroid hormones stimulate bone growth dramatically D) osteoblasts begin producing bone faster than chondrocytes are producing new epiphyseal cartilage

systems to maintain normal blood calcium levels

Digestive, skeletal, and urinary systems

periosteum

Except within joint cavities, the superficial layer of compact bone that covers all bones is wrapped by a ____________, which has a fibrous outer layer and a cellular inner layer. 1) isolates the bone from surrounding tissues 2) provides a route for the blood and nervous supply 3) actively participates in bone and growth repair

greenstick fracture

In a ______ _________ only one side of the shaft is broken, and the other is bent. This type generally occurs in children

endosteum

The ___________ is an incomplete cellular layer that lines the medullary cavity. This layer, which is active during bone growth, repair, and remodeling, covers the trabeculae of spongy bone and lines the inner surfaces of the central canals. It consists of a simple flattened layer of osteogenic cells that covers the bone matrix, generally without any intervening connective tissue fibers

epiphyseal closure

The completion of epiphyseal growth is called _________ _______

trabeculae

The matrix in spongy bone forms struts and plates called _______. The thin _____ branch, creating an open network. There are no capillaries or venules in the matrix of spongy bone.

A) osteoclasts

The process of osteolysis is performed by which cell population? A) osteoclasts B) osteoblasts C) osteocytes D) osteoprogenitor cells

C) are organized along stress lines

The trabeculae of spongy bone: A) are concentrated in the cortex of the diaphysis B) are composed mostly of cartilage C) are organized along stress lines D) will collapse under stress E) are organized parallel to the long axis of the bone

enchondral ossification

When the hyaline cartilage are gradually replaced by bone. The process begins with a small cartilage that is basically a miniature model of the corresponding bone of the adult skeleton.

C) metaphysis

Where does growth in length occur? A) hyaline cartilage B) epiphysis C) metaphysis D) periosteum E) compact bone

roof of skull, lower jaw & clavicle

Where does intramembranous ossification occur?

A) osteons

Which component is NOT present in spongy bone? A) osteons B) canaliculi C) lamellae D) trabeculae

A) fractures that are produced by twisting stresses that spread along the length of the bone

Which of the following describes spiral fractures? A) fractures that are produced by twisting stresses that spread along the length of the bone B) fractures in which only one side of the shaft is broken and the other is bent C) fractures that break the bone shaft across its long axis D) fractures that produce new and abnormal bone arrangements

B) calcium is absorbed quickly

Which of the following is the intestinal response to PTH stimulation? A) calcium is conserved B) calcium is absorbed quickly C) calcium is absorbed slowly D) calcium is released

C) compression fracture

Which type of fracture occurs in vertebrae that re subjected to extreme stresses? A) Pott fracture B) colles fracture C) compression fracture D) epiphyseal fracture

spiral fractures

______ ________ are produced by twisting stresses that spread along the length of the bone

osteoblasts

_______ produce new bone matrix in a process called ossification or osteogenesis. They make and release the proteins and other organic components of the matrix. They also assist in elevating local concentrations of calcium phosphate to the point where this calcium salt is deposited in the organic matrix

ratio of inorganic to organic components

ratio 33%:67%

endochondral ossification process

1) As the hyaline cartilage enlarges, the chondrocytes of the shaft of the bone increase in size, which then die and leave cavities within the cartilage 2) Blood vessels then begin to grow around the edges of the cartilage. The cells of the perichondrium convert to osteoblasts. The shaft of the hyaline cartilage then becomes surrounded by a superficial layer of bone 3) Those blood vessels then penetrate the cartilage and invade the diaphysis. Fibroblasts differentiate into osteoblasts and begin producing spongy bone at a primary ossification center. Bone formation then spreads along the shaft toward both epiphysis 4) Remodeling occurs as growth continues, creating the medullary cavity. Cartilage near each epiphysis is replaced by shafts of bone. 5) Growth in length occurs at the metaphysis. Capillaries and osteoblasts migrate into the epiphyses, creating the secondary ossification centers. Which has blood vessels entering and bone formation 6) The epiphyses are filled with spongy bone because of the osteoblasts. Articular cartilage remains and will be reduced to a thin superficial layer. At each metaphysis, an epiphyseal cartilage (or plate) separates the epiphysis from the diaphysis 7) Osteoblasts now being producing bone faster than chondrocytes are producing new cartilage. The osteoclasts "catch up" and the epiphyseal cartilage gets narrower and narrower until it disappears.

intramembranous ossification process

1) Mesenchymal cells cluster and start to secrete organic components of the matrix. The osteoid becomes mineralized and mesenchymal cells differentiate into osteoblasts. The location where ossification begins is ossification center 2) The developing bone grows outward from the ossification center in small struts called spicules. It traps some osteoblasts inside bony pockets and they differentiate into osteocytes. 3) Blood vessels begin to grow into the area. As the spicules meet and fuse together, some of these blood vessels become trapped within the developing bone 4) Continued deposition of bone by osteoblasts located close to blood vessels results in a plate of spongy bone with blood vessels weaving throughout. Osteocytes develop 5) Intramembranouse bone consists of spongy bone only. Subsequent remodeling around trapped blood vessels can produce osteons typical of compact bone. The connective tissue around the bone organizes into the fibrous layer of the periosteum. The osteoblasts closest to the bone surface become less active but remains at the inner cellular layer of the periosteum

colles fracture

A ____ _________ a break in the distal portion of the radius, is typically the result of reaching out to cushion a fall

pott's fracture

A _____ ________ also called a bimalleolar fracture, occurs at the ankle and affects both the medial malleolus of the distal tibia and the lateral malleolus of the distal fibula

C) the primary ossification center in the diaphysis

As blood vessels extend into the spaces left by dying chondrocytes, the models begins to ossify internally. Where does internal ossification begin? A) the epiphyseal line B) the secondary ossification centers in the epiphyses C) the primary ossification centers in the diaphysis D) the primary ossification centers in the epiphyses

perforating fibers

As the bone grows, the collagen fibers from tendons, ligaments, and joint capsules are cemented into the circumferential lamellae by osteoblasts from the cellular layer of the periosteum.

spongy bone formation

As the repair continues, osteoblasts replace the central cartilage of the external callus with spongy bone, which then unites the broken ends. The ends of the fracture are now held firmly in place and can withstand normal stresses from muscle contractions

D) 16 weeks

At which point during embryonic development can most of the bones of the adult skeleton be identified? A) 4 weeks B) 8 weeks C) 10 weeks D) 16 weeks

A) her epiphyseal plates have ossified

Bill, age 15 is still growing, but his older sister Andrea, age 19, has stopped. What has changed in Andrea's bones? A) her epiphyseal plates have ossified B) her osteoblasts have died C) sex hormones are no longer telling them to grow D) they have more cartilage than Bill's

E) perforating canals

Blood is distributed from the surface of a bone to deeper central canals through channels known as: A) lamellae B) concentric lamellae C) osteons D) trabeculae E) perforating canals

E) calcium

Bone plays a central role in the regulation of blood levels of A) sulfate B) iron C) potassium D) sodium E) calcium

minerals stored in the bones

Calcium, potassium, sodium, magnesium, carbonate, phosphorus

B) osteoblasts and being to deposit bone matrix

Cells of the perichondrium need to take a new role as ossification begins. They will become: A) new chondrocytes, so the model can continue to grow B) osteoblasts and begin to deposit bone matrix C) fibroblasts, to coat the model in collage D) osteoclasts and dissolve cartilage matrix

C) osteoblasts

Cells that secrete the organic components of the bone matrix are called: A) osteocytes B) osteoclasts C) osteoblasts D) osteoprogenitor cells E) chondrocytes

perforating canals

Central canals generally run parallel to the surface of the bone. Other passageways, known as ___________ _____, extend perpendicular to the surface. Blood vessels in these canals supply blood to osteons deeper in the bone and to tissues of the medullary cavity

calcium levels

If calcium concentration in blood increases or decreases by more than 30-35%, neuron and muscle cell function is disrupted with potentially lethal results

fracture hematoma formation

Immediately after the fracture, extensive bleeding occurs. Over a period of time, a large blood clot, or _________ ________, soon closes off the injured vessels and leaves a fibrous meshwork in the damaged area

epiphyseal line

In adults, the former location of the epiphyseal cartilage is often detectable in x-rays as a distinct __________ ____, which remains after epiphyseal growth has ended

organs involved in calcium homeostasis

In the intestines, calcium and phosphate ions are absorbed from the diet Within the skeleton, osteoblasts continuously deposit new bone matrix. At the same time, osteoclasts erode existing matrix, releasing calcium and phosphate ions into the circulation. In the kidneys, the levels of calcium and phosphate ions lost in urine are hormonally regulated

appositional growth

In this process, osteogenic cells in the inner layer of the periosteum differentiate into osteoblasts and add bone matrix to the surface. Osteoblasts trapped between these lamellae differentiate into ostecytes

B) metaphysis

In what area of a long bone would it probably be easiest to observe the cartilage the orthopedic doctor refers to? A) Nutrient foramen B) Metaphysis C) surface of epiphysis at articulations D) medullary cavity

osteocytes

Mature bone cells called _______ maintain protein and mineral content of the surrounding matrix through the turnover of matrix of components

callus formation

Next, cells of the intact endosteum and periosteum undergo rapid cell division, and the daughter cells migrate into the fracture zone. An internal callus forms as a network of spongy bone unites the inner edges of the fracture. An external callus of cartilage and bone encircles and stabilizes the outer edges of the fracture

factors that increase blood calcium levels

Parathyroid Gland: Signaled to secrete the parathyroid hormone (PTH) Bone response: The PTH causes the osteoblasts to release a factor that stimulates immature osteoclasts to differentiate into mature osteoclasts. Which accelerate the erosion of bone matrix and thereby releasing stored calcium ions Intestinal response: PTH enhances the calcium absorbing effects of calcitriol on the intestine. As a result, the rate of intestinal calcium absorption increases Kidney response: PTH increases renal production of the hormone calcitriol, which is continuously secreted by the kidneys at low levels. This hormone stimulate calcium reabsorption by the kidneys and calcium absorption in the intestines

D) intersitial lamellae

Remnants of osteons whose matrix components have been almost completely recycled by osteoclasts are known as which of the following? A) perforating canals B) circumferential lamellae C) concentric lamellae D) intersitial lamellae

C) 4,1,2,3

The following are major steps in the process of intramembranous ossification: 1. Clusters of osteoblasts form osteiod that becomes mineralized 2. Osteoblasts differentiate within mesenchymal connective tissue 3. Spicules of bone radiate out from the ossification centers 4. Mesenchymal cells aggregate A) 2,1,3,4 B) 2,3,1,4 C) 4,1,2,3 D) 4,2,1,3

calcitonin

This hormone decreases calcium ion concentrations in blood through two different mechanisms: -Less calcium enters the blood because osteoclasts leave the mineral matrix alone -More calcium is removed from the blood because osteoblasts continue to produce new bone matrix while calcium ion excretion qt the kidneys accelerates

factors that decrease blood calcium levels

Thyroid gland: C cells in the thyroid gland secrete calcitonin Bone response: Calcitonin inhibits osteoclasts but does not affect osteoblasts, which continue to deposit calcium ions within the bone matrix Intestinal response: Decreasing PTH or calcitriol levels result in a decrease in the rate of calcium ion absorption from the intestines Kidney response: Increased calcitonin levels have an inhibitory effect on the kidneys and suppress calcium ion reabsorption

D) circumferential lamella

To form perforating fibers, osteoblasts from the cellular layer of the periosteum cement collage fibers from tendons, ligaments, and joint capsules into which structures? A) central canal B) interstitial lamellae C) concentric lamellae D) circumferential lamellae

B) genetic mutation that affects the structure of connective tissue throughout the body

What characteristic may cause life-threatening issues in individuals with Mafran syndrome? A) abnormal epiphyseal activity B) genetic mutation that affects the structure of connective tissue throughout the body C) genetic mutation that involves the deposition of bone around skeletal muscles D) overproduction of growth hormone

Bone growth

While bone is being added to the outer surface through appositional growth, osteoclasts are removing and recycling lamellae at the inner surface. As a result the medullary cavity gradually enlarges as the bone increases in diameter. -Bone matrix is removed by osteoclasts

osteogenic cells

______ ____ also called osteoprogenitor cells are Mesenchymal (stem) cells that produce cells that differentiate into osteoblasts. They are found in the inner, cellular layer of the periosteum; in an inner layer, or endosteum, that lines medullary cavities; and in the vascular passageways, which contain blood vessels that penetrate the matrix of compact bone.

structure of spongy bone

_______ ____ makes up most of the mass of short, flat, and irregular bones and is also found at the epiphyses of long bones; it stores marrow and provides some support

transverse fracture

_______ _____ break a bone shaft across its long axis

structure of compact bone

_______ ______ which lies over spongy bone and makes up most of a bone's diaphysis, consists of compactly arranged osteons; it protects supports, and resists stress. Circumferential lamellae are added through appositional growth

osteolysis

_______ or resorption is important in regulating calcium phosphate ion concentrations in blood and other body fluids. Acids and proteolytic enzymes secreted by osteoclasts dissolve the matrix and release the stored minerals. (The process)

comminuted fractures

_________ _______ shatter the affected area into a multitude of bony fragments

displaced fractures

_________ ________ produce new and abnormal bone alignments. Nondisplaced fractures retain the normal alignment of the bones or fragments

circumferential lamellae

_________ _________ are found at the outer and inner surfaces of the bone, where they are covered by the periosteum and endosteum.

osteoclasts

_________ are cells that remove and recycle bone matrix. These are large cells with 50 or more nuclei. They are derived from the same stems cells that produce monocytes and macrophages, cells involved in the body's defense mechanisms. Acids and proteolytic enzymes secreted by ________ dissolve the matrix and release the stored minerals.

epiphyseal fractures

__________ _______ tend to occur where the bone matrix is undergoing calcification and chondrocytes are dying. A clean transverse fracture along this line generally heals well

interstitial lamellae

__________ ________ fill in the spaces between the osteons in compact bone. These lamellae are remnants of osteons whose matrix components have been almost completely recycled by osteoclasts

compression fractures

____________ ________ occur in vertebrae subjected to extreme stresses, such as the forces produced when you land on your butt in a fall. Often associated with osteoporosis

intramembranous ossification (definition)

_________________ ________________ is bone formation within connective tissue without the prior development of a cartilaginous model. Mesenchymal cells or fibrous connective tissue is replaced by bone