Chapter 6- Bones and bone tissue

Ligaments

What connects bone to bone?

Tendons

Muscle are attached to bones via ____?

Calcium and phosphate

What is stored in bone and bone tissue in the skeletal system?

Blood cell production

Bone marrow that gives rise to blood cells and platelets is what function in the skeletal system?

Chondroblasts

What forms the matrix in bone?

Chondrocytes

What is surrounded by matrix and are within the lacunae?

Matrix

What consist of collagen fibers for strength, and proteoglycans for resiliency?

Perichondrium

A double layered connective tissue sheath that covers cartilage of developing bone except at articulations.

Articular cartilage

What covers bones at joints and has no perichondrium

Appositional

Type of growth where new chondrocytes and new matrix at the periphery.

Interstitial

Type of growth where chondrocytes within the tissue divide and add more matrix between the cells

Organic and inorganic material

What does the bone matrix consist of?

Collagen and proteoglycans

What is consisted in the organic matrix of the bone?

hydroxyapatite

What is consisted of the inorganic material in the bone matrix?

Bone becomes bendable

What happens if minerals are removed from the bone matrix?

Bone becomes brittle

What happens if collagen is removed from the bone matrix?

Osteoblasts

The formation of bone through ossification or osteogenesis, collage is produced by osteoblasts and precursors of hydroxyapatite stored in vesicles.

Ossification

Formation of bone by osteoblasts

Osteocytes

Mature bone cells surrounded by matrix but can make small amounts of matrix to maintain it.

Lacunae

Spaces occupied by osteocyte cell body

Canaliculi

Canals occupied by osteocyte cell processes, unique to bone.

Osteoclasts

Resorption of bone, derived by monocytes, multinucleated, ruffled border where cell membrane borders bone and resorption is taking place.

Mesenchymal cells

What becomes chondroblasts or osteoblasts, in embryonic tissue and bone marrow.

Woven bone

Collagen fibers randomly oriented, first type of bone formed by osteoblasts during ossification, during fetal development, growth, and fracture repair.

Remodeling

Osteoclasts remove old bone and osteoblasts add new

Lamellar bone

Mature bone in sheets called lamellae, fibers are oriented in one direction in each layer, but in different directions in different layers for strength.

Trabeculae

Interconnecting rods or plates of bone, like scaffolding, spaces are filled with marrow and oriented along stress lines.

Compact bone

Solid, outer layer surrounding each bone; has more matrix and is denser than spongy bone.

How is bone organized?

Blood vessels enter the bone and the lamellae are oriented around the blood vessels

Osteon, Haversian system

The functional unit of compact bone is an _____ or _____ system.

Osteon, haversian canal

Composed of concentric rings of matrix around a central canal, giving the appearance of bulls-eye, osteocytes are sandwiched between rings of the matrix and connected by canaliculi.

Central or haversian canals

Parallel to the long axis in bone.

Lamellae

Concentric, circumferential, interstitial in compact bone.

Perforating or Volkmann’s canal

Contain blood vessels that run from the periosteum or medullary cavity to the osteocytes in their lacunae. Deliver blood to central canals. Nutrients and wastes travel to and from osteocytes

Osteons

Consist of central canal filled with blood vessels, concentric lamellae of the bone surround the central canal, lacunae and canaliculi contain osteocytes and fluid.

Circumferential lamellae

What is located on the periphery of a bone in compact bone

Interstitial lamellae

What is located between osteons in compact bone?

Diaphysis

Shaft; primarily compact bone surrounding the medullary cavity

Medullary cavity

red marrow for blood cell formation in kids, In adult, red marrow is replaced by yellow in limb bones

Epiphysis

End of the bone; primarily spongy bone covered with compact bone. Within joints, covered with hyaline cartilage called articular cartilage.

Epiphyseal plate

Growth plate, hyaline cartilage present until growth stops

Epiphyseal line

Epiphyseal plate is ossified as bone stop growing in length

Periosteum

Connective tissue membrane covering the outer surface of a bone.

Irregular collagenous

Outer portion of the periosteum contains _______ connective tissue containing blood vessels and nerves.

Osteoclasts, osteochondral

The inner portion of the periosteum is a single layer of bone cells including ______ and _____ progenitor cells.

Tendons, ligaments

Fibers of ____ and _____ becomes continuous with fibers of periosteum.

Perforating fibers

Some tendon/ligament fibers penetrate through the periosteum and into the bone. Strengthen attachment of tendon to bone

Endosteum

Single cellular layer of connective tissue that lines all internal spaces including cavities in spongy bone and medullary cavity

Flat bones

No diaphysis, epiphyses, sandwich of spongy between compact bone

Short and irregular bones

Compact bone that surrounds spongy bone center; similar to structure of epiphyses of long bones

Sinuses

Air filled spaces line by mucous membranes located in some flat and irregular bones.

Intramembranous ossification

What type of ossification take place in embryonic connective tissue membrane?

Endochondral ossification

What type of ossification take place in cartilage?

Intramembranous and endochondral

Which type of ossification produce woven bone and then is remodeled

Connective tissue formed in embryonic and mesenchyme CT

Where does intramembranous ossification take place?

Skull bones, mandible, diaphysis of clavicles

What does intramembranous ossification form?

5th week of embryonic development

When does intramembranous ossification occur?

Centers of ossification

Where does the ossification begin in intramembranous ossification

Fontanels

what are the large membrane covered spaces between skull bones in in intramembranous ossification?

Bones of the skull, part of the mandible epiphyses of clavicles and most remaining bones of skeletal system.

What forms during endochondral ossification

8th week of development

When does endochondral ossification occur?

Cartilage model formation

Embryonic mesenchymal cells aggregate in region of future bone formation.

Cartilage model formation

Process where cells differentiate into osteochondral progenitor cells that become chondroblasts that produce a hyaline cartilage model have the approximate shape of the future bone

Bone

______ growth in length occurs at the epiphyseal plate, organized into five zones.

Articular cartilage

Does not ossify and persist through life

Zone of resting cartilage

What zone is slowly dividing chondrocytes

Zone of proliferation

What zone consist of new cartilage produced on the epiphyseal side of the plate as the chondrocyte divide and form stacks of cells

Zone of hypertrophy

What zone consist of chondrocytes mature and enlarge, cells near the epiphysis are younger, cells near diaphysis are older and undergoing hypertrophy?

Zone of calcification

What zone consist of the matrix being calcified and chondrocytes die, blood vessels enter from diaphysis carrying osteoblasts from endosteum?

Ossified bone

What is cartilage of the diaphyseal side of the plate being replaced by bone called?

Does not

Thickness of epiphyseal plate _____ increase.

Articular cartilage

Epiphyses increase in size due to the growth at the ____ ______?

Calcified, ossified

In deepest part, nearer bone tissue, cartilage is _____ and ______ to new bone.

Does not

Articular cartilage persist throughout life and _____ become ossified.

Nutrition

What consist of lack of calcium, protein and other nutrients during growth and development can cause bones to be small

Vitamin D

Necessary for absorption of calcium from intestines

Rickets

Lack of vitamin D during childhood

Osteomalacia

Lack of vitamin D during adulthood leading to softening of bones

Vitamin C

Necessary for collagen synthesis by osteoblasts

Scurvy

Deficiency of vitamin C

Vitamin C

Lack of this vitamin may also causes wounds not to heal or teeth to fall out.

Growth Hormones

From anterior pituitary, stimulates interstitial cartilage growth and appositional bone growth

Thyroid Hormone

Required for growth of all tissues

Reproductive hormones

Such as estrogen and testosterone, cause growth at puberty but also the closure of the epiphyseal plate and the cessation of growth

Bone remodeling

Involved in bone growth, changes in bone shape, adjustments in bone due to stress, bone repair, and Ca2+ion regulation

Basic multicellular units

Temporary groups of osteoclasts and osteoblasts that remodel bones, Remove old bone matrix and replace it with new bone matrix caused by….

Remodeling, formation of additional bone, alter trabecular to align with stress

What increased stress causes bone to increase in strength.

Hematoma formation

Localized mass of blood released from blood vessels but confined within an organ or space. Clot formation. Bone tissue dies because disruption of blood flow

Callus formation

mass of bone tissue that forms at a fracture site and connects the broken ends of the bone.

Internal bone repair

Blood vessels grow into clot in hematoma, fibroblasts produce collagen and granulation tissue, cartilage is within the collagen, osteoblasts invade and new bone is formed

External bone repair

Collar around opposing ends, bone/cartilage collar stabilizes two pieces

Callus ossification

Callus replaced by woven, spongy bone.

Bone remodeling

Replacement of spongy bone and damaged material by compact bone, sculpting of site by osteoclasts.

Calcium

Bone is a major storage site for _____

Osteoblasts, osteoclasts

Calcium enters bone when________ create new bone; calcium leaves bone when _______ break down bone (reabsorption).

Roles of calcium

Stimulation of skeletal muscle contraction, Stimulation and regulation of cardiac muscle contraction, Exocytosis of cellular molecules including those involved in neural signaling

Parathyroid hormone, calcitriol, calcitonin

What hormones control blood calcium levels?

Parathyroid hormone

Reduction in blood calcium is stimulus for release of _____?

Effects of the parathyroid hormone

Activates osteoclasts, increases number of osteoclasts, and prevents inhibition of osteoclast formation, calcium released into blood –increasing blood calcium.

Reabsorption

parathyroid hormone stimulates _______ of calcium from urine in the kidney tubules.