CH 6

(c) hyaline, elastic, and fibrous,

(11) The three major types of cartilage in the body are (a) collagen, reticular,and elastic, (b) areolar, adipose, and reticular, (c) hyaline, elastic, and fibrous, (d) tendons, reticular, and elastic.

Osteocyte Osteoblasts Osteoclasts Osteogenic cells

(12) List the four distinctive cell populations of osseous tissue.

Endochondral - bone replaces a cartilage model Intramembranous - bone replaces mesenchyme or fibrous connective tissue

(14) What is the primary difference between endochondral ossification and intramembranous ossification?

Organic = collagen Inorganic = hydroxyapatite crystals

(15) List the organic and inorganic components of bone matrix.

A) calcium , phosphate , vitamins A, C, D3

(16) What nutritional factors are essential for normal bone growth and maintenance?

Bones Intestinal tract Kidneys

(17) Which three organs or tissues interact to assist in the regulation of calcium ion concentration in body fluids?

-Parathyroid hormone stimulates osteoclast activity, -increases the rate of intestinal absorption of calcium ions, -decreases the rate of excretion of calcium ions by the kidneys. -These effects increase blood calcium levels.

(18) What major effects of parathyroid hormone oppose those of calcitonin?

The osteons are aligned 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.

(20) 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?

it leads to the removal of calcium salts from bones. They become thin and brittle

(21) Why do extended periods of inactivity cause degenerative changes in the skeleton?

The digestive and urinary (kidneys) provide calcium and phosphate minerals needed for bone growth. 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.

(22) What are the functional relationships between the skeleton, on the one hand, and the digestive and urinary systems, on the other?

There are many long bones in the hand, each of which has an epiphyseal cartilage (plate). Measuring the width of these plates will provide clues to the hormonal control of growth in the child.

(23) Why would a physician concerned about the growth patterns of a young child request an x-ray of the hand?

(b) endochondral ossification

(25) The process of bone growth at the epiphyseal cartilage is similar to (a) intramembranous ossification (b) endochondral ossification (c) the process of osteopenia (d) the process of healing a fracture (e) the process of calcification.

D) Bowed Legs

(28) Which of the following conditions would you possibly observe in a child who is suffering from rickets? (a) abnormally short limbs, (b) abnormally long limbs (c) oversized facial bones (d) bowed legs (e) weak, brittle bones

(b) Cartilage is avascular, so nutrients and other molecules must diffuse to the site of injury

(28) Why does damaged cartilage heal slowly? (a) Chondrocytes cannot be replaced if killed, and other cell types must take their place, (b) Cartilage is avascular, so nutrients and other molecules must diffuse to the site of injury, (c) Damaged cartilage becomes calcified, thus blocking the movement of materials required for healing, (d) Chondrocytes divide more slowly than other cell types, delaying the healing process, (e) Damaged collagen cannot be quickly replaced, thereby slowing the healing process.

(a) Frank will probably be taller than if he had started puberty earlier

(29) Frank does not begin puberty until he is 16. What effect would you predict this will have on his stature? (a) Frank will probably be taller than if he had started puberty earlier (b) Frank will probably be shorter than if he had started puberty earlier (c) Frank will probably be a dwarf (d) Frank will have bones that are heavier than normal, (e) The late onset of puberty will have no effect on Frank's stature

(a) periosteum,

(3) The membrane found wrapping the bones, except within the joint cavity, is the (a) periosteum, (b) endosteum, (c) perforating fibers (d) a, b, and c are correct.

(c) osteon

(4) The basic functional unit of compact bone is the Haversian system or (a) osteocyte (b) osteoclast (c) osteon (d) osseous matrix (e) osseous lamellae.

(b) C and D3,

(5) The vitamins essential for normal adult bone maintenance and repair are (a) A and E (b) C and D3, (c) B and E, (d) B complex and K.

(b) calcitonin and parathyroid hormone

(6)The hormones that coordinate the storage, absorption, and excretion of calcium ions are (a) growth hormone and thyroxine (b) calcitonin and parathyroid hormone (c) calcitriol and cholecalciferol (d) estrogens and androgens.

(a) epiphyseal growth has ended

(8) The presence of an epiphyseal line indicates (a) epiphyseal growth has ended (b) epiphyseal growth is just beginning (c) growth of bone diameter is just beginning (d) the bone is fractured at the location (e) no particular event.

(a) reduced levels of circulating estrogens

(9) The primary reason that osteoporosis accelerates after menopause in women is (a) reduced levels of circulating estrogens (b) reduced levels of vitamin C (c) diminished osteoclast activity (d) increased osteoblast activity.

support, storage of minerals and lipids, blood cell production protection leverage.

Name the five primary functions of the skeletal system.

crystals of calcium phosphate,

Two-thirds of the weight of bone is accounted for by (a) crystals of calcium phosphate, (b) collagen fibers (c) osteocytes (d) calcium carbonate.

calcitriol, growth hormone, thyroxine, estrogen/androgen calcitonin, and parathyroid hormone (PTH)

What hormonal factors are necessary for normal bone growth and maintenance?

The presence of lamellae is indicative of spongy bone, which is located in an epiphysis.

pg 187. A sample of bone has lamellae, which are not arranged in osteons. Is the sample most likely taken from the epiphysis or diaphysis?

estrogens play an important role in moving calcium into bones. After menopause, the level of these hormones decreases dramatically. (this happens every month) In men, the level of sex hormones (androgens) does not decrease until much later in life.

pg 202. Why is osteoporosis more common in older women than in older men?

the bone would be weaker and less flexible

pg. 184 How would the compressive strength of a bone be affected if the ratio of collagen to hydroxyapatite increased?

it would be weaker

pg. 184 If the activity of osteoclasts exceeds the activity of osteoblasts in a bone, how will the mass of the bone be affected?

4. mature bone cells - osteocytes, bone-building cells- osteoblasts, bone-resorbing cells. - osteoclasts

pg. 184 Mature bone cells are known as _____, bone-building cells are called _____, and _____ are bone-resorbing cells.

Compact bone: -have osteons (Haversian systems) -makes up diaphysis (shaft) -It protect, support, and resist stress. Spongy Bone: - has trabeculae -short, flat irregular bones found at epiphyses -stores marrow and provide support

pg. 187 Compare the structures and functions of compact bone and spongy bone.

fibrous connective tissue

pg. 192 During intramembranous ossification, which type of tissue is replaced by bone?

the perichondrium

pg. 192 In endochondral ossification, what is the original source of osteoblasts?

If the epiphyseal cartilage is still present, growth is still occurring. If it is not, the bone has reached full height.

pg. 192 How could x-rays of the femur be used to determine whether a person has reached full height?

will result in excessive bone growth, making the person taller.

pg. 195 A 7-year-old child has a pituitary gland tumor involving the cells that secrete growth hormone (GH), resulting in increased levels of GH. How will this condition affect the child's growth?

the epiphyseal cartilages grow enough until growth spurt catches on to it later on

pg. 195 A child who enters puberty several years later than the average age is generally taller than average as an adult. Why?

Weight lifter causes more stress to their bones than joggers

pg. 195 Why would you expect the arm bones of a weight lifter to be thicker and heavier than those of a jogger?

Parathyroid hormone (PTH) influences osteoclast activity, PTH serves to increase blood calcium levels by causing its release from bone, calcitonin decreases blood calcium levels by causing calcium to remain in bone. When calcium level is high then calcitonin slows down osteoclast

pg. 197 Identify the hormones involved in stimulating and inhibiting the release of calcium ions from bone matrix.

18. Their bones are poorly mineralized = they are flexible

pg. 197 Why does a child who has rickets have difficulty walking?

20. By inhibiting osteoclast activity and increasing the rate of calcium excretion by the kidneys.

pg. 197 How does calcitonin help lower the calcium ion concentration of blood?

an increase in the level of calcium ions in the blood.

pg. 197 What effect would increased PTH secretion have on blood calcium levels?

inadequate ossification and is common during the aging process. Decreased osteoblast and increase osteoclast

pg. 202 Define osteopenia.