Chapter 5 homework/extra credit
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
2, 4, 1, 3
Place the events in the proper sequence in which they occur during endochondral ossification
Bone collar forms around shaft, Primary ossification center forms, Medullary cavity develops in shaft, Secondary ossification centers form, Elongation continues at epiphyseal plate, Epiphyseal plate closes to form line.
Which anatomical structures of the skeleton are complex, dynamic organs that contain osseous tissue, other connective tissue, smooth muscle, and neural tissue?
Bones
Which of the following accounts for almost two-thirds the weight of bone?
Calcium phosphate
Which of the following is found at the ends of bones?
Epiphysis
In endochondral ossification, a hyaline cartilage model is converted into bone tissue by the activity of osteoblasts. Which of the following bones is formed in this manner?
humerus
Which of the following is NOT a function of the skeletal system? -leverage for body movements -production of red and white blood cells -production of melanin -protection of the brain and spinal cord
production of melanin
Intramembranous ossification initially produces spongy bone tissue, which is composed of struts known as __________________. Channels between these struts allow the passage of blood vessels.
spicules
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 function of the skeletal system changes the magnitude and direction of the forces generated by skeletal muscles?
Leverage
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?
Metaphyseal vessels
When a bone is broken, a blood clot develops. The name for this clot is __________.
a fracture hematoma
Which bone structure isolates and protects the bone from surrounding tissues, provides a route and a place of attachment for circulatory and nervous supply, actively participates in bone growth and repair, and attaches the bone to the connective tissue network of the deep fascia?
Periosteum
Which of the following is found within each epiphysis?
secondary ossification center
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
Which of the following is a function of the skeletal system? -All of the listed responses are correct. -Protection -Leverage -Support
All of the listed responses are correct.
Which type of lamellae fill in the spaces between the osteons in compact bone?
Interstitial lamellae
Which of the following is true of the periosteum?
It contains Sharpey's fibers, which are perforating collagen fibers that help bond tendons to bones.
Which vessels form as blood vessels invade the cartilage model at the start of endochondral ossification?
Nutrient artery and vein
Which cells in bone are considered "bone-forming" because they secrete the organic components of the bone matrix?
Osteoblasts
Which vitamins are essential for normal bone growth and remodeling?
Vitamins A and C
Which bone has a trochanter?
femur
Place the events in the proper sequence in which they occur during intramembranous ossification.
osteoblasts form and produce osteoid, bone tissues expands to form spicules, vessels are trapped by growing spicules, continuous plate of spongy bone to forms
Put the steps in endochondral ossification in order from beginning to end of the process. 1. 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. 2. 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. 3. Capillaries and osteoblasts migrate into the epiphysis, creating secondary ossification centers. 4. 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. 5. 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. 6. 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.
2, 4, 1, 6, 3, 5
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.
4, 5, 2, 6, 3, 1
Elsie is 75 years old and has been diagnosed with osteoporosis. Which of the following things could she do to help improve or maintain her bone strength? -She should do regular weight-bearing exercises. -She should take medications that slow the reabsorption of bone matrix. -She should be sure to consume enough calcium in her diet. -All of the listed options would be helpful.
All of the listed options would be helpful.
Concerning the hormonal regulation of bone growth, which of the following statements is not true? -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. -Growth hormone and thyroxine both stimulate bone growth and maintain proper epiphyseal cartilage activity until puberty.
In children and pregnant women, calcitonin inhibits osteoblasts, and decreases the rate of calcium loss in the urine.
Which of the following statements about intramembranous ossification is FALSE? -It begins when mesenchymal cells differentiate into osteoclasts within embryonic or fibrous connective tissue. -Intramembranous ossification is also known as dermal ossification. -It normally occurs in the deeper layers of the dermis. -Examples of intramembranous ossification include the frontal and parietal bones, the mandible, and the clavicle.
It begins when mesenchymal cells differentiate into osteoclasts within embryonic or fibrous connective tissue.
Which of the following statements about the periosteum is FALSE? -It is an incomplete layer, with the thickness of one cell and with bone matrix occasionally exposed. -It consists of an inner cellular layer containing osteoprogenitor cells. -It is continuous with the joint capsule that encloses the joint. -It actively participates in bone growth and repair.
It is an incomplete layer, with the thickness of one cell and with bone matrix occasionally exposed.
______________ produce the osteoid that makes up the organic portion of bone matrix. When they become trapped within gaps in this matrix, they are known as osteocytes.
Osteoblasts
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
Which of the following statements about the skeletal system is FALSE? -Red blood cells, white blood cells, and platelets are produced in the yellow marrow, which fills the internal cavities of many bones. -Calcium is the most abundant mineral in the human body; 98 percent of the calcium in the body is deposited in the bones of the skeleton. -Many bones of the skeleton can change the magnitude and direction of the forces generated by skeletal muscles. -Individual bones or groups of bones provide a framework for the attachment of soft tissues and organs.
Red blood cells, white blood cells, and platelets are produced in the yellow marrow, which fills the internal cavities of many bones.
Which of the following accurately states a difference between compact bone and spongy bone?
Spongy bone is arranged into trabeculae.
Which of the following statements regarding factors that regulate bone growth is FALSE? -The active form of vitamin C, calcitriol, must be obtained from the diet. -Vitamins A and C are essential for normal bone growth and remodeling. -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. -Hormones regulate the pattern of growth by changing the rates of osteoblast and osteoclast activity.
The active form of vitamin C, calcitriol, must be obtained from the diet.
In a gross anatomy class, students are examining two cadavers. One is from a 35-year-old man who practiced bodybuilding before suffering a fatal heart attack. The other is from a 75-year-old woman who had severe osteoporosis. Which of the following statements comparing their skeletons is FALSE? -The bones of the female contain a greater amount of calcium than the bones of the male. -The diameter of the shaft of the femur is greater in the male than in the female. -The bones of the male have thicker attachment points for muscles than the female. -The bones of the female are thinner and much more porous.
The bones of the female contain a greater amount of calcium than the bones of the male.
If Heather breaks her leg and wears a cast for two months, what changes will you expect to observe in her leg when the cast is removed?
The healed bone will have lost bone mass because it will not have been stressed.
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
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
A foramen is a _____.
hole or opening
The formation of dermal bones begins when aggregated mesenchymal cells differentiate and begin producing osteoid. These aggregations where bone formation gets started are known as _____________.
ossification centers
Which of the following is NOT a vital component of bone matrix? -calcium -phosphates -potassium -collagen
potassium
Which of the following would lead to epiphyseal closure?
slower cartilage formation and faster osteoblast activity
A sharp or pointed process is a _____.
spine
Which of the following is correctly matched? -sulcus: a chamber within a bone -trochlea: a grooved process that is shaped like a pulley -meatus: a low ridge -facet: a shallow depression
trochlea: a grooved process that is shaped like a pulley
