Unit 2: Ossification Questions

The central canals connect the lacunae to one another.

False canaliculi

Which of the following statements regarding factors that regulate bone growth is FALSE?

THE CORRECT ANSWER (correct)The active form of vitamin C, calcitriol, must be obtained from the diet. Normal bone growth requires a constant dietary source of calcium and phosphate salts, as well as other ions such as magnesium, citrate, carbonate, and sodium. Vitamins A and C are essential for normal bone growth and remodeling. YOU WERE SURE AND INCORRECT Hormones regulate the pattern of growth by changing the rates of osteoblast and osteoclast activity. I DON'T KNOW YET It is false that the active form of vitamin C, calcitriol, must be obtained from the diet. The active form of vitamin D, calcitriol, is synthesized in the kidneys; this process ultimately depends on the availability of a related steroid, cholecalciferol, that may be absorbed from the diet or synthesized in the skin in the presence of UV radiation. Vitamins A and C are essential for normal bone growth and remodeling. These vitamins must be obtained from the diet. Normal bone growth cannot occur without a constant dietary source of calcium and phosphate salts, as well as other ions such as magnesium, citrate, carbonate, and sodium. Hormones regulate the pattern of growth by changing the rates of osteoblast and osteoclast activity.

Which of the following describes how bones are innervated?

The periosteum, endosteum, medullary cavity, and epiphyses are innervated by sensory nerves.

Calcium phosphate interacts with ________ to form hydroxyapatite.

calcium hydroxide

Because they are strong and relatively inflexible, ________ enable bone to withstand the stress of compression.

calcium phosphate crystals

Which of the following describes a central canal?

contains a vein also called Haversian canal contains an artery runs parallel to osteons (correct)All of the answers are correct.

A prominent ridge on a bone is called a(n) ________.

crest

While taking an anatomy practical, Joey looks at an x-ray film of the hand and sees epiphyseal lines. He can correctly say that the x-ray film is from an individual who __________.

had metacarpals and phalanges that weren't going to grow any longer

During the process of endochondral ossification, a major step occurs when the centers of the epiphyses begin to calcify. Capillaries and osteoblasts migrate into these areas, creating sites called __________.

secondary ossification centers

Osteogenesis refers to __________.

site - the development of osteocytes from osteoblasts? Text - Osteobasts are respondible for the production of new bone?

A sharp or pointed process is a _____.

spine

Small, flat, oddly shaped bones that develop between the flat bones of the skull are called ________.

sutural bones

Spongy bone is made up of a network of bony spicules arranged into parallel struts or thick, branching plates called ________.

trabeculae

Processes that form where tendons or ligaments attach to a bone include ________.

trochanters, tuberosities, and tubercles

A smooth, grooved articular process, shaped like a pulley, is a(n) ________.

trochlea

Which of the following is correctly matched?

trochlea - a grooved process that is shaped like a pulley

Which of the following is an example of an irregular bone?

vertebra

Put the steps in endochondral ossification in order from beginning to end of the process.

1) As the cartilage enlarges, chondrocytes near the center of the shaft increase greatly in size, the matrix is reduced to a series of small struts that soon begin to calcify, and the enlarged chondrocytes die and disintegrate, leaving cavities within the cartilage. 2) Blood vessels grow around the edges of the cartilage, and the cells of the perichondrium convert to osteoblasts. The shaft of the cartilage then becomes ensheathed in a superficial layer of bone. 3) Capillaries and osteoblasts penetrate the cartilage and invade the central region; osteoblasts begin producing spongy bone at the primary center of ossification; bone formation then spreads along the shaft toward both ends of the cartilaginous model. 4) Remodeling occurs as growth continues, and osteoclasts erode the central portion, creating a medullary cavity. The bone of the shaft becomes thicker, and the cartilage near each epiphysis is replaced by shafts of bone. 5) Capillaries and osteoblasts migrate into the epiphysis, creating secondary ossification centers. 6) Epiphyses are filled with spongy bone. Articular cartilage remains exposed to the joint cavity; over time it will be reduced to a thin superficial layer. At each metaphysis, an epiphyseal cartilage separates the epiphysis from the diaphysis.

Place the steps of appositional bone growth in order. 1) The osteon is complete with new central canal around blood vessel. Second blood vessel becomes enclosed. 2) Ridges meet and fuse, trapping the vessel inside the bone. 3) Additional circumferential lamellae are deposited, and the bone continues to increase in diameter. 4) Bone formation at the surface of the bone produces ridges that parallel a blood vessel. 5) Ridges enlarge and create a deep pocket. 6) Bone deposition proceeds inward toward the vessel, beginning the creation of a typical osteon.

1) Bone formation at the surface of the bone produces ridges that parallel a blood vessel. 2) Ridges enlarge and create a deep pocket. 3) Ridges meet and fuse, trapping the vessel inside the bone. 4) Bone deposition proceeds inward toward the vessel, beginning the creation of a typical osteon. 5) Additional circumferential lamellae are deposited, and the bone continues to increase in diameter. 6) The osteon is complete with new central canal around blood vessel. Second blood vessel becomes enclosed.

In the formation of blood and lymphatic supply, which vessels supply blood to the diaphyseal surface of each epiphyseal cartilage, where bone is replacing cartilage?

All of the listed responses are correct. THE CORRECT ANSWER (correct)Metaphyseal vessels YOU WERE SURE AND INCORRECT Periosteal vessels Epiphyseal vessels I DON'T KNOW YET Osseous tissue is very vascular, and the bones of the skeleton have an extensive blood supply. Metaphyseal vessels supply blood to the inner (diaphyseal) surface of each epiphyseal cartilage, where bone is replacing cartilage. The epiphyseal ends of long bones often contain numerous smaller foramina. The epiphyseal vessels that use these foramina supply the osseous tissue and medullary cavities of the epiphyses. Periosteal vessels from the periosteum are incorporated into the developing bone surface. These vessels provide blood to the superficial osteons of the shaft. Figure showing the circulatory supply to a mature bone

Endochondral Ossification

1) Cartilage enlarges. Surrounding matrix begins to calcify. Chondrocytes die and disentegrate leaving cavities. 2) Blood vessels grow around cartilage edges. Perichondrium becomes osteoblasts (periosteum) Bone collar forms 3) Increase blood supply. Capillaries and osteoblasts migrate into the heart of cartilage invading cavities. Osteoblasts replace calcified cartilaginous matrix with spongy bone. Bone development proceeds from this primary ossification center in shaft, towards both ends of th cartilaginous model. 4) While small, entire shaft is filled with spongy bone, as it enlarges, osteoclasts erode the central portion and create a medullary cavity. Shaft becomes thicker and cartilage of metaphysis is invaded by osteoblasts that produce columns of bone. Further growth involves two distinct processes. An increase in length and an enlargement in diameter. 5) Capillaries and osteoblasts then migrate into the centers of epiphyses, creating secondary ossification centers. 6) Epiphyses eventually becomes filled with spongy bone. Epi and dia seperated by epiphyseal cartilage (plate) within metaphyses. Osteoblasts invade the shaft side of the epiphyseal cartilage, replacing the cartilage with bone, at the same rate that the epiphyseal cartilage enlarges through interstitial growth. This enlargement pushes the epiphysis away from the diaphysis, and the length of the bone increases. 7) maturity

Put the steps of intramembranous ossification in the correct order: 1) Entrapment of blood vessels within the bone 2) Differentiation of osteoblasts within the mesenchyme 3) Formation of spongy bone 4) Formation of bony spicules

1) Differentiation of osteoblasts within the mesenchyme 2) Formation of bony spicules 3) Entrapment of blood vessels within the bone 4) Formation of spongy bone

In the formation of blood and lymphatic supply, which vessels supply blood to the diaphyseal surface of each epiphyseal cartilage, where bone is replacing cartilage?

Epiphyseal vessels (correct)Metaphyseal vessels Periosteal vessels All of the listed responses are correct. I DON'T KNOW YET

Bone mass reduction occurs initially between the ages of ________.

30-40

Which of the following is the correct description of the congenital disorder of the skeleton called achondroplasia?

Due to unusually slow growth of the epiphyseal cartilages in a child, affected adults have short, stocky limbs and abnormal proportions. Most cases result from spontaneous mutation.

Concerning the hormonal regulation of bone growth, which of the following statements is not true?

Growth hormone and thyroxine both stimulate bone growth and maintain proper epiphyseal cartilage activity until puberty. (correct)In children and pregnant women, calcitonin inhibits osteoblasts, and decreases the rate of calcium loss in the urine. Parathyroid hormone stimulates osteoclast and osteoblast activity, increases the rate of calcium absorption from the small intestine, and decreases calcium loss in the urine. The sex hormones, estrogen and testosterone, cause osteoblasts to produce bone faster than the rate of epiphyseal cartilage expansion; eventually, the epiphyseal cartilages narrow and ossify. It is not true that in children and pregnant women, calcitonin inhibits osteoblasts, and decreases the rate of calcium loss in the urine. The thyroid glands of children and pregnant women secrete the hormone calcitonin, which inhibits osteoclasts and increases the rate of calcium loss in the urine. Calcitonin is of uncertain significance in the healthy nonpregnant adult. The parathyroid glands release parathyroid hormone, which stimulates osteoclast and osteoblast activity, increases the rate of calcium absorption along the small intestine, and reduces the rate of calcium loss in the urine. At puberty, bone growth accelerates dramatically. The sex hormones, estrogen and testosterone, stimulate osteoblasts to produce bone faster than the rate of epiphyseal cartilage expansion. Over time, the epiphyseal cartilages narrow and eventually ossify, or "close." Growth hormone, produced by the pituitary gland, and thyroxine, from the thyroid gland, stimulate bone growth. In proper balance, these hormones maintain normal activity at the epiphyseal cartilages until roughly the time of puberty.

Which of the following describes a connection between the skeletal system and the endocrine system?

Growth hormone from the pituitary gland promotes bone growth.

Which of the following is the correct description of the congenital disorder of the skeleton called achondroplasia?

It is caused by inadequate production of growth hormone before puberty, resulting in a person having normal proportions, but very short stature. THE CORRECT ANSWER (correct)Due to unusually slow growth of the epiphyseal cartilages in a child, affected adults have short, stocky limbs and abnormal proportions. Most cases result from spontaneous mutation. It is caused by hypersecretion of growth hormone before puberty, resulting in a person having excessive growth. An abnormal gene causes excessive cartilage formation at the epiphyseal cartilages; this results in the person having extremely long and slender limbs. Another characteristic of this disorder is arterial wall weakness. I DON'T KNOW YET Achondroplasia results from abnormal epiphyseal activity. The child's epiphyseal cartilages grow unusually slowly, and the adult has short, stocky limbs and abnormal proportions. Most cases are the result of spontaneous mutations. Inadequate production of growth hormone before puberty produces pituitary dwarfism. People with this condition are very short, but unlike achondroplastic dwarfs, their proportions are normal. Excessive growth resulting in gigantism occurs if there is hypersecretion of growth hormone before puberty. Marfan's syndrome is linked to defective connective tissue structure. Extremely long and slender limbs result from excessive cartilage formation at the epiphyseal cartilages. An abnormality of a gene on chromosome 15 that affects the protein fibrillin is responsible. The skeletal effects are striking, but associated arterial wall weaknesses are more dangerous.

Which of the following statements about intramembranous ossification is FALSE?

It normally occurs in the deeper layers of the dermis. Intramembranous ossification is also known as dermal ossification. (correct) It begins when mesenchymal cells differentiate into osteoclasts within embryonic or fibrous connective tissue. Examples of intramembranous ossification include the frontal and parietal bones, the mandible, and the clavicle.

Which of the following congenital disorders of the skeleton involves excessive cartilage formation at the epiphyseal cartilages, resulting in extremely long and slender limbs?

Marfan's syndrome

What would be the effect if an adolescent boy entered puberty at age 16 instead of age 11?

Osteoblasts would not increase their rate of bone deposition to exceed the cartilage production until age 16.

Which cell population of mature bone directs both the release of calcium from bone to blood and the deposition of calcium salts in the surrounding matrix?

Osteocytes

________ are struts or plates within spongy bone which assist in withstanding stresses in a specific direction.

Trabeculae

Which vitamins are essential for normal bone growth and remodeling?

Vitamins A and C

When a bone is broken, a blood clot develops. The name for this clot is __________.

a fracture hematoma

After the perichondrium is converted to a periosteum, the inner osteogenic layer produces a thin layer of compact bone around the shaft of the cartilage known as __________.

bone collar

A shallow depression on the surface of a bone is called a ________.

fossa

A small, flat articular surface is a ________.

facet

Which bone has a trochanter?

femur

An elongated cleft is a(n) ________.

fissure

The scapula is an example of what type of bone?

flat

Which of the following is most likely to have a nerve pass through it?

foramen

Which of the following terms refers to a rounded passageway for blood vessels or nerves?

foramen

Which of the following bones would you classify as a sesamoid (seed-shaped) bone?

patella (kneecap)

An extension of a bone that is set at an angle to the rest of the bone is usually called a ________.

ramus

Treating a compound fracture differs from other fractures most significantly due to ________.

risk of infection