Homework 10 Questions 6.4-6.12

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

16 weeks

What type of bone growth is the doctor most likely looking for in the example above? (scoliosis) Intramembranous ossification Ossification and remodeling around an external callus Appositional ossification Endochondral ossification

Endochondral ossification

In what area of a long bone would it probably be easiest to observe the cartilage the orthopedic doctor refers to? Metaphysis Nutrient foramen Surface of epiphysis at articulations Medullary cavity

Metaphysis

All of the following result in decreased calcium levels in the bloodstream, except: PTH stimulation of osteoclasts. decreased PTH or calcitriol levels. increased calcitonin levels. calcitonin inhibition of osteoclasts.

PTH stimulation of osteoclasts.

The cartilage the doctor is referring to (scoliosis) will disappear when Mesenchymal cells cluster around ossification centers The cartilage deteriorates and is eliminated The osteoblasts work faster than cartilage producing cells Chondrocytes accelerate their activities in the bone

The osteoblasts work faster than cartilage producing cells

Remnants of osteons whose matrix components have been almost completely recycled by osteoclasts are known as which of the following? interstitial lamellae concentric lamellae circumferential lamellae perforating canals

interstitial lamellae

The process of osteolysis is performed by which cell population? osteoclasts osteocytes osteoprogenitor cells osteoblasts

osteoclasts

The trabeculae of spongy bone are concentrated in the cortex of the diaphysis. are composed mostly of cartilage. are organized along stress lines. will collapse under stress. are organized parallel to the long axis of the bone.

are organized along stress lines.

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

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

The following are major steps in the process of intramembranous ossification. 1. Clusters of osteoblasts form osteoid that becomes mineralized. 2. Osteoblasts differentiate within mesenchymal connective tissue. 3. Spicules of bone radiate out from the ossification centers. 4. Mesenchymal cells aggregate. What is the correct order for these events? 4, 2, 1, 3 2, 3, 1, 4 4, 1, 2, 3 2, 1, 3, 4

4, 1, 2, 3

Which of the following is the intestinal response to PTH stimulation? Calcium is absorbed slowly. Calcium is released. Calcium is conserved. Calcium is absorbed quickly.

Calcium is absorbed quickly.

Bill, age 15, is still growing, but his older sister Andrea, age 19, has stopped. What has changed in Andrea's bones? Her osteoblasts have died. Her epiphyseal plates have ossified. They have more cartilage than Bill's. Sex hormones are no longer telling them to grow.

Her epiphyseal plates have ossified.

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

It is an incomplete cellular layer that lines the medullary cavity.

Bone plays a central role in the regulation of blood levels of iron. potassium. sodium. calcium. sulfate.

calcium.

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

circumferential lamellae

Which type of fracture occurs in vertebrae that are subjected to extreme stresses? compression fracture epiphyseal fracture Pott fracture Colles fracture

compression fracture

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

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

Cells that secrete the organic components of the bone matrix are called osteoblasts. osteocytes. osteoclasts. chondrocytes. osteoprogenitor cells.

osteoblasts

Cells of the perichondrium need to take on a new role as ossification begins. They will become __________. fibroblasts, to coat the model in collagen osteoclasts and dissolve cartilage matrix osteoblasts and begin to deposit bone matrix new chondrocytes, so the model can continue to grow

osteoblasts and begin to deposit bone matrix

At puberty: - decreasing thyroid hormones stimulate bone growth dramatically. - osteoblasts begin producing bone faster than chondrocytes are producing new epiphyseal cartilage. - epiphyseal cartilage thickens. - chondrocytes begin producing bone faster than osteoblasts are producing new epiphyseal cartilage.

osteoblasts begin producing bone faster than chondrocytes are producing new epiphyseal cartilage.

Which component is not present in spongy bone? osteons canaliculi trabeculae lamellae

osteons

Blood is distributed from the surface of a bone to deeper central canals through channels known as concentric lamellae. osteons. trabeculae. lamellae. perforating canals.

perforating canals.

As blood vessels extend into the spaces left by dying chondrocytes, the models begin to ossify internally. Where does internal ossification begin? the secondary ossification centers in the epiphyses the epiphyseal lines the primary ossification centers in the epiphyses the primary ossification center in the diaphysis

the primary ossification center in the diaphysis