CHAPTER 6: THE SKELETAL SYSTEM - Warner Pacific College

CHAPTER 6: THE SKELETAL SYSTEM

Copyright © 2010 Pearson Education, Inc.

SKELETAL CARTILAGE


Figure 6.1 The bones and cartilages of the human skeleton.

Cartilage in external ear

Cartilage in Intervertebral disc

Cartilages in nose Articular Cartilage of a joint

Epiglottis Thyroid cartilage Cricoid cartilage

Larynx Trachea Lung

Costal cartilage

Respiratory tube cartilages in neck and thorax Pubic symphysis Meniscus (padlike cartilage in knee joint) Articular cartilage of a joint

Bones of skeleton Axial skeleton Appendicular skeleton

Cartilages Hyaline cartilages Elastic cartilages

Fibrocartilages Copyright © 2010 Pearson Education, Inc.

GROWTH OF CARTILAGE


Intervertebral discs are made of which type of cartilage? 1) Elastic cartilage 2) Fibrocartilage 3) Hyaline cartilage


BONE CLASSIFICATION


AXIAL VS. APPENDICULAR


Figure 6.1 The bones and cartilages of the human skeleton.

Cartilage in external ear

Cartilage in Intervertebral disc

Cartilages in nose Articular Cartilage of a joint

Epiglottis Thyroid cartilage Cricoid cartilage

Larynx Trachea Lung

Costal cartilage

Respiratory tube cartilages in neck and thorax Pubic symphysis Meniscus (padlike cartilage in knee joint) Articular cartilage of a joint

Bones of skeleton Axial skeleton Appendicular skeleton

Cartilages Hyaline cartilages Elastic cartilages

Fibrocartilages Copyright © 2010 Pearson Education, Inc.

Figure 6.2 Classification of bones on the basis of shape.

(a) Long bone (humerus)

(b) Irregular bone (vertebra), right lateral view Copyright © 2010 Pearson Education, Inc.

(c) Flat bone (sternum)

(d) Short bone (talus)

FUNCTIONS OF BONES


True or false: Every bone has the same primary functions. 1) True 2) False


BONE STRUCTURE GROSS STRUCTURE


Figure 6.3 The structure of a long bone (humerus of arm).

Articular cartilage

Proximal epiphysis

Compact bone Spongy bone Epiphyseal line Periosteum Compact bone Medullary cavity (lined by endosteum)

Diaphysis

Endosteum

(b) Yellow bone marrow Compact bone Periosteum Perforating (Sharpey’s) fibers Nutrient arteries

Distal epiphysis (a) Copyright © 2010 Pearson Education, Inc.

(c)

Figure 6.5 Flat bones consist of a layer of spongy bone sandwiched between two thin layers of compact bone.

Spongy bone (diploë) Compact bone

Trabeculae


The connective tissue surrounding a bone is called the… 1) 2) 3) 4)

Diaphysis Endosteum Epiphysium Periosteum


True or false: Trabeculae are found in compact bone. 1) True 2) False


BONE STRUCTURE MICROSCOPIC ANATOMY


Figure 6.4 Comparison of different types of bone cells.

(a) Osteogenic cell

(b) Osteoblast

(c) Osteocyte

(d) Osteoclast

Stem cell

Matrix-synthesizing cell responsible for bone growth

Mature bone cell that maintains the bone matrix

Bone-resorbing cell


Figure 6.6 A single osteon.

Structures in the central canal

Artery with capillaries Vein Nerve fiber Lamellae Collagen fibers run in different directions

Twisting force Copyright © 2010 Pearson Education, Inc.

Figure 6.7 Microscopic anatomy of compact bone. Spongy bone

Compact bone

Central (Haversian) canal

Perforating (Volkmann’s) canal Endosteum lining bony canals and covering trabeculae

Osteon (Haversian system) Circumferential lamellae

(a) Perforating (Sharpey’s) fibers Lamellae

Nerve Vein Artery Canaliculi Osteocyte in a lacuna (b) Copyright © 2010 Pearson Education, Inc.

Periosteal blood vessel Periosteum

Lamellae Central canal Lacunae

Lacuna (with osteocyte) (c)

Interstitial lamellae

The cells which build new bone are: 1) 2) 3) 4)

Osteoblasts Osteogenic cells Osteoclasts Osteocytes


Osteocytes receive their nutrition from fluid in the ________, which are connected to the larger ___________. 1) Canaliculi / central canal 2) Lamellae / lacunae 3) Osteoblasts / lacunae


BONE STRUCTURE CHEMICAL COMPOSITION OF BONE


Hydroxyapatite is part of the _______ component of bone. 1) Cellular 2) Organic 3) Inorganic


OSTEOGENESIS INTRAMEMBRANOUS OSSIFICATION


Figure 6.8 Intramembranous ossification. Mesenchymal cell Collagen fiber Ossification center

Osteoid

Osteoblast Osteoid Osteocyte Newly calcified bone matrix

Osteoblast 1 Ossification centers appear in the fibrous connective tissue membrane. • Selected centrally located mesenchymal cells cluster and differentiate into osteoblasts, forming an ossification center.

Mesenchyme condensing to form the periosteum Trabeculae of woven bone Blood vessel

2 Bone matrix (osteoid) is secreted within the fibrous membrane and calcifies. • Osteoblasts begin to secrete osteoid, which is calcified within a few days. • Trapped osteoblasts become osteocytes.

Fibrous periosteum Osteoblast Plate of compact bone Diploë (spongy bone) cavities contain red marrow

4 Lamellar bone replaces woven bone, just deep to 3 Woven bone and periosteum form. the periosteum. Red marrow appears. • Accumulating osteoid is laid down between embryonic blood vessels in a random manner. The result is a network • Trabeculae just deep to the periosteum thicken, and are later replaced with mature lamellar bone, forming compact bone (instead of lamellae) of trabeculae called woven bone. • Vascularized mesenchyme condenses on the external face plates. • Spongy bone (diploë), consisting of distinct trabeculae, perof the woven bone and becomes the periosteum. sists internally and its vascular tissue becomes red marrow. Copyright © 2010 Pearson Education, Inc.

OSTEOGENESIS ENDOCHONDRIAL OSSIFICATION


Figure 6.9 Endochondral ossification in a long bone. Month 3

Week 9

Birth

Childhood to adolescence Articular cartilage

Secondary ossification center Epiphyseal blood vessel

Area of deteriorating cartilage matrix Hyaline cartilage

1 Bone collar

Epiphyseal plate cartilage

Spongy bone formation

Bone collar Primary ossification center

Medullary cavity

Blood vessel of periosteal bud

2 Cartilage in the

3 The periosteal

center of the forms around hyaline cartilage diaphysis calcifies and then develops model. cavities.

bud invades the internal cavities and spongy bone begins to form.


Spongy bone

4 The diaphysis elongates

and a medullary cavity forms as ossification continues. Secondary ossification centers appear in the epiphyses in preparation for stage 5.

5 The epiphyses

ossify. When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages.

The starting point for endochondrial ossification is called the… 1) 2) 3) 4)

Medullary cavity Periosteal bud Primary ossification center Bone collar


POSTNATAL BONE GROWTH AND REMODELING


Figure 6.10 Growth in length of a long bone occurs at the epiphyseal plate.

Resting zone

1 Proliferation zone

Cartilage cells undergo mitosis. 2 Hypertrophic zone

Older cartilage cells enlarge. Calcified cartilage spicule Osteoblast depositing bone matrix Osseous tissue (bone) covering cartilage spicules Copyright © 2010 Pearson Education, Inc.

Calcification zone Matrix becomes calcified; cartilage cells die; matrix begins deteriorating. 3

Ossification zone New bone formation is occurring. 4

Figure 6.11 Long bone growth and remodeling during youth.

Bone growth

Cartilage grows here.

Bone remodeling

Articular cartilage

Epiphyseal plate

Cartilage is replaced by bone here. Cartilage grows here. Cartilage is replaced by bone here.


Bone is resorbed here. Bone is added by appositional growth here. Bone is resorbed here.

Growth of bone length is due largely to increasing numbers of cells in the _______ zone… 1) 2) 3) 4)

calcification hypertrophic ossification proliferation


CONTROL OF BONE REMODELING


Figure 6.12 Parathyroid hormone (PTH) control of blood calcium levels.

Calcium homeostasis of blood: 9–11 mg/100 ml BALANCE BALANCE

Stimulus

Falling blood Ca2+ levels

Thyroid gland Osteoclasts degrade bone matrix and release Ca2+ into blood. Copyright © 2010 Pearson Education, Inc.

Parathyroid glands PTH

Parathyroid glands release parathyroid hormone (PTH).

Figure 6.13 Bone anatomy and bending stress.

Load here (body weight)

Head of femur

Tension here

Compression here Point of no stress


Which of the following does NOT control bone growth or remodeling?

1) 2) 3) 4) 5)

Growth hormone Mechanical force Parathyroid hormone Thyroid hormone Calcitonin


FRACTURES


Table 6.2 Common Types of Fractures (1 of 3)






The type of fracture which commonly occurs in porous bones subjected to a fall is a… 1) 2) 3) 4) 5) 6)

Comminuted fracture Compression fracture Spiral fracture Epiphyseal fracture Depression fracture Greenstick fracture


BONE REPAIR


Figure 6.15 Stages in the healing of a bone fracture.

Hematoma

Internal callus (fibrous tissue and cartilage)

1 A hematoma forms.


External callus

New blood vessels

Bony callus of spongy bone Healed fracture

Spongy bone trabecula

2 Fibrocartilaginous callus forms.

3 Bony callus forms.

4 Bone remodeling occurs.

True or false: if a bone breaks, it bleeds.

1) True 2) False


HOMEOSTATIC IMBALANCES


Figure 6.16 The contrasting architecture of normal versus osteporotic bone.


The disease which causes children to have soft, malformed bones due to vitamin D or calcium deficiency is… 1) Rickets 2) Osteomalacia 3) Osteporosis 4) Paget’s Disease


FETAL SKELETAL DEVELOPMENT


Figure 6.17 Fetal primary ossification centers at 12 weeks.

Parietal bone Occipital bone

Mandible

Frontal bone of skull

Clavicle Scapula Radius Ulna

Ribs

Humerus

Vertebra Ilium Tibia Femur


CHAPTER 6: THE SKELETAL SYSTEM - Warner Pacific College

Recommend Documents