Anatomy Ch. 6 Quiz
Frank does not begin puberty until he's 16. What effect would you predict this will have on his stature?
Frank will probably be shorter than if he had started puberty earlier.
What major effects of parathyroid hormone oppose those of calcitonin?
Parathyroid hormone stimulates osteoclast activity, increases the rate of intestinal absorption, and decreases to the rate of excretion of calcium ions
What are the functional relationships between the skeleton, on the one hand, and the digestive and urinary systems, on the other?
The digestive and urinary systems play important roles in providing the calcium and phosphate minerals needed for bone growth. In return, the skeleton provides protection and acts as a reserve of calcium, phosphate, and other minerals that can compensate for changes in the dietary supplies of these ions.
Sally falls and breaks her right leg, the doctor says the proximal end of the tibia where the epiphysis meats the diaphysis is fractured. Later on, she learns her right leg is 2cm shorter than her left. Why?
The fracture might have damaged the epiphyseal cartilage in the right leg. Even though the bone healed properly, the damaged leg did not produce as much cartilage as the undamaged.
In physical anthropology, cultural conclusions can be drawn from a thorough examination of the skeletons of ancient peoples. What sorts of clues might bones provide as to the lifestyles of those individuals?
The matrix of bone will absorb traces of minerals from the diet. These minerals can be identified hundreds of years later. A diet rich in calcium and vitamin B will produce denser bones than a diet lacking these. Cultural practices such as binding of appendages, or wrapping of infant heads will manifest in misshapen bones. Heavy muscular activity will result in larger bone markings, indicating an athletic lifestyle.
Why are stresses or impacts to the side of the shaft in a long bone more dangerous than stress applied to the long axis of the shaft?
The osteons are parallel to the long axis of the shaft, which does not bend when forces are applied to either end. Stresses or impacts to the side of the shaft can lead to a fracture.
What hormonal factors are necessary for normal bone growth and maintenance?
calcitriol, growth hormone, thyroxine, estrogens in females, androgens in males, calcitonin, and parathyroid hormone
What nutritional factors are essential for normal bone growth and maintenance?
calcium salts, phosphate salts, vitamins A, C, and D3
Two-thirds of the weight of bone is accounted for by
crystals of calcium phosphate
The presence of an epiphyseal line indicates
growth bone diameter is just beginning
List the organic and inorganic components of bone matrix.
organic: collagen inorganic: hydroxyapatite
What are the five primary functions of the skeletal system?
support, storage of minerals and lipids, blood cell production, protection, leverage
Which 3 organs or tissues interact to assist in the regulation of calcium ion concentration in body fluids?
the bones, intestinal tract, and kidneys
Dislocations involving synovial joints are usually prevented by all of the following, except
the presence of bursae
How might bone markings be useful in identifying the remains of a criminal who has been shot and killed?
Bone markings give clues as to the size, age, sex, and general appearance of an individual.
If spongy bone has no osteons, how do nutrients reach the osteocytes?
By diffusing along the canaliculi that open onto the surface of the trabeculae
The vitamins essential for normal adult bone maintenance and repair are
C and D
What is the primary difference between endochondral ossification and intramembranous ossification?
In intramembranous ossification, bone develops from mesenchyme or fibrous connective tissue. In endochondral ossification, bone develops from a cartilage model.
why do extended periods of inactivity cause degenerative changes in the skeleton?
It leads to the removal of calcium salts. Up to 1/3 of the bone mass can be lost, causing bones to become thin and brittle.
Why would a physician concerned about the growth patterns of a young child request an X-ray of the hand?
There are many long bones in the hand, each of which has an epiphyseal cartilage. Measuring the width of these plates will provide clues to the hormonal control of growth in the child
Why does a second fracture in the same bone tend to occur at a site different from that of the first fracture?
When a bone fracture is repaired, the bone tends to be stronger and thicker than normal at the fracture site.
Which of the conditions would you possibly observe in a child who is suffering from rickets?
bowed legs
The hormones that coordinate the storage, absorption, and excretion of calcium ions are
calcitonin and parathyroid hormone
What are the primary parts of a typical long bone?
diaphysis (shaft), epiphysis, epiphyseal cartilages/line, articulate cartilage, medullary canal, periosteum, endosteum
The process of bone growth at the epiphyseal cartilage is similar to
endochondral ossification
List four distinctive cell populations of osseous tissue.
osteocytes, osteoblasts, osteoclasts, osteoprogenitor cells
The basic functional unit of compact bone is the Haversian system or
osteon
The non-pathological loss of bone that occurs with aging is called
osteopenia
The membrane found wrapping the bones, except at the joint cavity, is the
periosteum
Blood cell formation occurs in the bones of the skeleton in areas of
red bone marrow
The primary reason that osteoporosis accelerates after menopause in women is
reduced levels of circulating estrogens