Ch. 6 Practice and checkpoint questions

Two thirds of the weight of bone is accounted for by A) crystals of calcium phosphate B) collagen fibers C) osteocytes D) calcium carbonate

A) crystals of calcium phosphate

What nutritional and hormonal factors are essential for normal bone growth and maintenance?

A) calcium salts, phosphate salts, and vitamins A, C and D B) calcitriol, growth hormone, thyroximine, estrogens (in females) or androgens (in males), calcitonin, and parathyroid hormone (PTH)

What are the six broad categories for classifying a bone according to shape?

1. Long bones, 2. Short bones, 3. Flat bones, 4. Irregular bones, 5. Sutiral bones, 6. Sesamoid bones

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 event

A) epiphyseal growth has ended

The membrane found wrapping the bones, except at the joint cavity, is the A) periosteum B) endosteum C) perforating fibers

A) periosteum

The vitamins essential for normal adult bone maintenance and repair are A) A and E B) C and D C) B and E D) B complex and K

B) C and D

The hormones that coordinate the storage, absorption and excretion of calcium ions are A) growth hormone and thyoxine B) calcitonin and parathyroid hormone C) D)

B) calcitonin and parathyroid hormone

Blood cell formation occurs in A) yellow bone marrow B) red bone marrow c) the matrix of bone tissue d) the ground substance of bones

B) red bone marrow

The basic functional unit of compact bone is the Haversian system or A) osteocyte B) osteoclast C) osteon D) osseous matrix

C) osteon

What are the primary parts of a typical long bone?

Diaphysis (shaft), epiphysis, epiphyseal cartilage/line, articular cartilage, medullary canal, periosteum, endosteum

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

Fibrous connective tissue is replaced when osteoblasts differentiate within a mesenchymal (fibrous connective tissue).

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

Hydroxyapatite make the bone hard, by adding more collagen the bone would become flexible allowing for twisting and bending of the bone. However the more collagen the less compression the bone can handle.

What is the primary difference between endochondral ossification and intramembranous ossification?

In intramembranous ossification, the bone replaces mesenchyme or fibrous connective tissue. In endochondral ossification, bone replaces a cartilage model.

List the organic and inorganic components of bone matrix

Organic = collagen Inorganic = hydroxyapatite crystals

List the four distinctive cell populations of osseous tissue

Osteocytes, osteoblasts, osteoclasts, osteoprogenitor cells

Why is osteoporosis more common in older women than in older men?

Sex hormones are important in maintaining normal rates of bone deposition. After menopause, the condition accelerates due to a decline in circulating estrogens. Men continue to produce androgens until late in life.

What are the five primary functions of the skeletal system?

Support, storage of minerals and lipids, blood cell production, protection and leverage

What is a bone marking?

Surface features of the bone which indicate sites where blood vessels or nerves lie alongside or penetrate the bone.

If the activity of osteoclast exceeds the activity of osteoblast in a bone, how will the mass of the bone be affected?

The bone would become less dense, bones would weaken.

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

The cells of the inner layer of the perichondrium in this region then differentiate into osteoblasts and begin producing a thin layer of bone around the shaft of the cartilage.

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

The sample would be found in the epiphysis because in the spongy bone, lamellae are not arranged in osteons.

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

a) The basic functional unit of mature compact bone is the osteon, or Haversian system. In an osteon, the osteocytes are arranged in concentric layers around a central canal, or Haversian canal which contains a capillary & a venule. Unlike spongy bone compact bones thrive at stress points. compact is solid, strong, and resistant to bending b) Spongy bone, lamellae are not arranged in osteons. The matrix in spongy bone forms a meshwork of supporting bundles of fibers called trabeculae which have NO capillaries or venules in the matrix of the spongy bone. Spongy bone receives its nutrients by diffusion along canaliculated that open onto the surface of trabeculae, red bone marrow is found between the trabeculae of spongy bone and blood vessels within this tissue deliver nutrients to the trabeculae and remove wastes generated by the osteocytes. Spongy bone provides strength and its bony plates are most highly developed in the regions of the epiphyses that are subjected to forces of compression. Both compact and spongy tissues are usually present in every bone. Compact bone in the diaphysis of a long bone forms a rigid tube with a hollow chamber called the "medullary cavity." The cavity is continuous with the spaces of the spongy bones.

Mature bone cells are known as____, bone building cells are called____, and_____ are bone-resorbing cells.

osteocytes osteoblasts osteoclasts

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

the bones, the intestinal tract, and the kidneys