Bone for test 3

Synthesized by the combined action of the skin, kidneys, and liver, _________ promotes bone resorption but is also necessary for bone deposition.

calcitriol

Which hormone(s) is(are) represented by A?

calcitriol

It is common to find __________ in compact bone, but they are not seen in spongy bone.

central canals

A fracture in which the bone is broken into three or more pieces is called a __________ fracture.

comminuted

The cortex of the long bone's diaphysis is made of _________.

compact bone

Osseous tissue is a(an) ____________ tissue.

connective

The thin layer of slightly denser spongy bone that separates an adult's epiphysis from the diaphysis is called the __________.

epiphyseal line

The spaces found within the concentric lamellae are called __________, and they contain __________.

lacunae; osteocytes

Which of the following is not a function of parathyroid hormone (PTH)?

lower blood calcium

Wolff's law of bone explains the effect of __________.

mechanical stress on bone remodeling

Hypocalcemia can cause __________.

muscle spasms

Bone-forming cells are called __________.

osteoblasts

New bone is deposited by cells known as __________.

osteoblasts

When ____________ become enclosed in lacunae, they become cells called _____________.

osteoblasts and osteocytes

Which one of the following bone cells would have the greatest number of lysosomes?

osteoclasts

Blood Ca2+ deficiency stimulates __________ secretion, which leads to __________.

parathyroid hormone; increased osteoclast activity

Red bone marrow does not contain __________.

yellow bone marrow

The plasma membrane of __________ have a ruffled border with many deep infoldings, whereas __________ have long, thin, fingerlike cytoplasmic processes.

osteoclasts; osteocytes

The most common bone disease is __________.

osteoporosis

Arteriosclerosis is one example of ectopic ossification, which means __________.

abnormal calcification of a tissue

Phosphate is necessary for all of the following except __________.

amino acids

If a thyroid tumor secreted an excessive amount of calcitonin, we would expect ___________.

an elevated level of osteoblast activity

Mature bones are remodeled throughout life via a process known as __________.

appositional growth

Hypersecretion of which hormone(s) would result in hypocalcemia?

B

Which cell is responsible for bone deposition?

B (osteoblast)

Calcium plays an essential role in all of the following except __________

DNA synthesis

Which cell is responsible for bone resorption?

E (osteoclast)

Which cell is stimulated by the hormones calcitriol and PTH?

E (osteoclast)

Red bone marrow is important in the production of new bone cells

False

Osteogenic cells are bone stem cells that differentiate into osteoblasts and osteoclasts.

False (give rise to osteoblasts)

Intramembranous ossification is common in children, whereas endochondral ossification is typical in young adults.

False (ossification: process of laying down new bone intramembranous: bone forming in a membrane; replacement of embryonic connective tissue; produces flat bones endochondral: formation of bone within cartilage; early fetal development; takes place in long bones)

Concentric lamellae within an osteon are connected by lacunae.

False ( connected by canaliculi)

Osteomalacia results in bone brittleness.

False Osteomalacia -softening of the bones

Which hormone(s) is(are) represented by B?

calcitonin

Which of the following exemplifies a positive feedback process happening in bone mineral deposition?

The first few crystals that form attract more calcium and phosphate.

Hypercalcemia causes depression of the nervous system.

True

Hypercalcemia is rare, but hypocalcemia can result from a wide variety of conditions.

True

Most blood cells are produced in the red marrow of bones.

True

Osteoid tissue is similar to bone except for a lack of minerals.

True

Osteoporosis often leads to an exaggerated thoracic spinal curvature, which is called kyphosis.

True

Parathyroid hormone (PTH) binds to receptors on osteoblasts.

True

The hematopoietic tissue in a bone is otherwise known as myeloid tissue.

True

The expanded ends of a long bone are called the __________.

epiphyses

Osteoporosis is most common in elderly women because of the lack of ___________, which would otherwise inhibit ____________.

estrogen; osteoclast activity

Which of the following is an inorganic component of the bone matrix?

hydroxyapatite

The hardness of bone comes from __________, whereas __________ provide(s) some degree of flexibility.

hydroxyapatite and other minerals; proteins

Which of the following does not put women at risk for hypocalcemia?

removal of the thyroid gland

The process of dissolving bone and returning its minerals to the bloodstream is known as _________.

resorption

The result of blood calcium and phosphate levels being too low for normal deposition is a softness of the bones called __________ in children and __________ in adults.

rickets, osteomalacia

Spicules and trabeculae are found in __________.

spongy bone