Chapter 6 - Bone Tissue

Describe how mechanical stress impacts bone remodeling.

Increasing stress activates osteoblast activity and the formation of new matrix.

In compact bone, what are the remnants of old osteons found between complete osteons called?

Interstitial lamellae

PTH is a hormone released by parathyroid glands in response to which of the following?

Low blood calcium levels

Which of the following describes the zone of calcification in an epiphyseal plate?

Minerals are deposited between the columns of lacunae.

What do osteoblasts produce?

Osteoblasts produce (deposit) bone matrix.

A low blood calcium level stimulates the release of which hormone?

Parathyroid hormone

Which of the following describes the lacunae of osseous tissue?

Spaces between lamellae that contain osteocytes

True or false: Compact bone comprises most of the diaphysis of a long bone.

True

True or false: If bone matrix loses calcium, it becomes overly flexible; if it loses collagen, it becomes too brittle.

True

Select all that apply. Passageways or canals that extend from the periosteum to the medullary canal are called ______. (Select all that apply.)

Volkmann canals perforating canals

______ bone is the first type of bone to form during ossification.

Woven

In what zone of the metaphysis are chondrocytes multiplying and aligning into longitudinal columns in flattened lacunae?

Zone of cell proliferation

Osteoblasts are activated when ______.

blood calcium levels are high

During endochondral ossification, as cartilage at the primary ossification center breaks down, a ______ forms around the cartilage model in order to provide support.

bone collar

What is an osteoclast?

A bone-destroying cell that plays an important role in bone remodeling

What are osteoblasts?

Bone-forming cells that produce and package matrix collagen and proteoglycans

What are perforating canals?

Canals that extend from the periosteum to the medullary cavity

________ produce and maintain the cartilaginous matrix. Osteoblasts are bone forming cells.

Chondrocytes

Describe the zone of cell hypertrophy.

Chondrocytes in this zone are no longer dividing, but are enlarging; there is a thinning of lacunae walls

During endochondral ossification, where does the primary ossification center form?

Diaphysis

Calcitriol _____ blood calcium levels.

increases

Growth at the epiphyseal plate involves _______ cartilage growth followed by ______ bone growth on the surface of the cartilage.

interstitial, appositional

Mechanical stress applied to bone increases _____ activity in bone tissue.

osteoblast

Immature bone cells that produce the organic bone matrix are called ______.

osteoblasts

Stem cells in developing bone that give rise to osteoblasts are called ______ progenitor cells.

osteochondral

Which cells become osteoblasts during intramembranous ossification?

osteochondral progenitor cells

The structure of compact bone that consists of a central canal and all the concentric lamellae that surround it is called a Haversian system or a(n) _________________ .

osteon

PTH is secreted by the ______ and regulates blood calcium levels.

parathyroid gland

During endochondral ossification, the perichondrium becomes the ______.

periosteum

The epiphyses are sites of ______.

secondary ossification centers.

Bone tissue comprised of trabeculae is called ______ bone.

spongy

The type of bone that is composed of small columns of bone loosely arranged in a grid-work pattern is known as ____ bone.

spongy

Spongy bone consists of _______.

trabeculae, whereas compact bone consists of osteons.

During endochondral bone formation, the most likely location for a secondary ossification center is the ______.

epiphysis

Which osseous tissue is found at the surface of all bones?

Compact

What is intramembranous ossification?

Formation of bone within a connective tissue membrane

What is the central or Haversian canal?

The passageway in the center of the osteon which contains blood vessels

What would happen to a bone if it were to lose its collagen component?

The bone would be very brittle.

The majority of calcium needed to maintain homeostasis is stored in the ______.

bones

The zone of the epiphyseal plate that is composed of enlarged chondrocytes and calcified cartilage matrix is known as the zone of ______.

calcification

The zone within the epiphyseal plate that contains enlarged chondrocytes and calcified cartilage matrix describes the zone of ______.

calcification

An increased blood calcium level stimulates the release of:

calcitonin

The hormone ______ is released by the thyroid gland when blood calcium levels are elevated. Its effect is to inhibit osteoclast activity.

calcitonin

Bones are the primary storage location for ______.

calcium

Parathyroid hormone (PTH) is the principle hormone in regulating blood levels of ______.

calcium

The channel extending through the center of an osteon is called a ______ canal.

central

An osteon can best be described as a(n) ______.

central canal and all the concentric lamellae that surround it

At the surface of compact bone, layers of bone tissue are found encircling the entire diaphysis. These layers are called ______ lamellae. While the lamellae that surround the central canals of osteons are called ______.

circumferential, concentric

The type of bone that appears solid and forms the outer layers of each bone is ______.

compact bone

Bone tissue comprised of osteons (Haversian systems) is called ______ bone.

compact, dense, or cortical

An osteon consists of circular layers of bone matrix surrounding a central canal. These circular layers of bone matrix are called _____.

concentric lamellae

The bull's eye appearance of the osteon is created by layers of ______ that surround the central canal.

concentric lamellae

The layers of bony matrix arranged around the central canal of an osteon are called ______ lamellae, while the outer surfaces of compact bone are formed by ______ lamellae.

concentric, circumferential

The hollow space in which an osteocyte resides is called a(n) __________.

lacuna or lacunae

Appositional bone growth occurs ______.

on the surface cartilage

The zone of the epiphyseal plate that is nearest the epiphysis and contains randomly arranged chondrocytes is the zone of ______.

resting cartilage

The zone of the epiphyseal plate that is closest to the epiphysis is the zone of ______ and the zone closest to the diaphysis is the zone of ______.

resting cartilage, calcification

Calcitriol is derived from _____.

vitamin D

Bone with randomly oriented collagen fibers formed during fetal development is called bone.

woven

Many bones of the skull form by which type of ossification?

Intramembranous

Click and drag on elements in order Place the zones of the epiphyseal plate in order beginning with the zone nearest the epiphysis.

1. Zone of resting cartilage 2. Zone of proliferation 3. Zone of hypertrophy 4. Zone of calcification

Where is the primary ossification center during endochondral ossification in a long bone?

Diaphysis

Define calcitonin.

Hormone that functions to decrease blood calcium levels

During intramembranous ossification, bone matrix is deposited by which type of cells?

Osteoblasts

Select all that apply Identify the cells that osteochondral progenitor cells can become.

Osteoblasts and Chondroblasts

Which bone cells are responsible for bone reabsorption?

Osteoclasts

What are mature bone cells found within lacunae of compact bone called?

Osteocytes

_________ are mature bone cells found within lacunae of compact bone

Osteocytes

What are osteocytes?

Osteocytes are former osteoblasts that have become trapped in the matrix they deposited.

Describe the zone of resting cartilage.

The zone with randomly arranged chondrocytes nearest the epiphysis

What are interstitial lamellae?

They are remnants of concentric lamellae that were partially removed during bone remodeling.

Osteoclasts become active when ______.

blood calcium levels are low

When blood calcium levels rise above normal, bone cells called ______ are activated to create more bone matrix.

osteoblasts

The bone cells responsible for the breakdown of bone tissue are called ______.

osteoclasts

When blood calcium falls, the type of bone cells called _______ break down bone matrix and release calcium into the blood.

osteoclasts

When blood calcium falls, the type of bone cells called _________ break down bone matrix and release calcium into the blood.

osteoclasts

The removal of bone matrix is the function of the bone cells called _____________.

osteoclasts or osteoid