chapter 6: the skeletal system
TRANSCRIPT
![Page 1: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/1.jpg)
Chapter 6: The Skeletal System
http://www.accessexcellence.org/RC/VL/xrays/
![Page 2: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/2.jpg)
FYE: Your Bones…
Bones aren’t just pieces of your skeleton They are a connective tissue impregnated with minerals! Bones aren’t dead!
They have cells, bloody supply & nerves (feelings!) Bones are strong!
Standing still the force on hip = 3x bodyweight (muscle pull) & a running man exerts a dead wt force of ~590 lbs!
![Page 3: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/3.jpg)
The Skeletal System
Parts of the skeletal system
Some Vocab…• BONE = Osseous Tissue• Osteology = Study of bones• Arthrology = Study of joints• Kinesiology = Study of movement
Bones Cartilage
Ligaments (connect bone to bone) Tendons (connect muscle to bone)
![Page 4: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/4.jpg)
Functions of the Skeletal System
Support For wt of entire body Framework for attachment
Leverage for muscle action Protection of internal organs
Storage Calcium & Phosphate Fat cells (in yellow marrow!)
Blood cell production = Hemopoiesis Red marrow makes cells Found in: pelvis, ribs, clavicle, vertebra, skull, ends of long bones
![Page 5: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/5.jpg)
Bone Shapes
Figure 6-1
Femur, Phalanges & metacarpals Tarsals
Sternum, scapula, ribs
Clavicle, patella
![Page 6: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/6.jpg)
The Structure of Bone
Figure 6-2
Features in a Long Bone Diaphysis (shaft)
Compact bone Marrow cavity
Epiphyses (ends) Spongy bone
Articular cartilage
Periosteum (covering)
Endosteum (lining)
![Page 7: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/7.jpg)
The Structure of Bone
Bone (Osseous Tissue) Specialized cells
2% of bone wt Calcium Phosphate crystals
67% of bone wt
Collagen fibers
Two types: Compact & Spongy
![Page 8: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/8.jpg)
Bone Tissue
Compact Bone Layers of compact cover all bone surfaces, except at joints
Found where stresses occur Osteon = basic functional unit of compact bone
Osteocytes surrounded by rings of matrix with a central canal
![Page 9: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/9.jpg)
Bone Tissue
Spongy Bone Network of bony rods (trabeculae) Found in center & in epiphysis Lighter to decrease wt of skeleton Spaces filled with marrow
![Page 10: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/10.jpg)
Microscopic Structure of Bone
Figure 6-3(a)
![Page 11: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/11.jpg)
Microscopic Structure of Bone
Figure 6-3(b)
![Page 12: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/12.jpg)
BONE CELLS
1. Osteocytes Mature bone cells in osteons & trabeculae
Most abundant cell Maintain normal structure by recycling Ca in matrix
2. Osteoblasts Cells that make new bone (osteogenesis)
3. Osteoclasts Bone eaters - secrete acid that dissolves matrix (osteolysis) to release stored minerals
Regulate Ca & Phosphate in blood
= Found in Endosteum & Periosteum
![Page 13: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/13.jpg)
Bone Formation and Growth
• Begins ~6wks after fertilization - embryo is ~12mm long
• Continues until 18-25 yrs
• Ossification = process of replacing connective tissue & cartilage with bone
![Page 14: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/14.jpg)
1. Intramembranous Ossification
• Stem cells in connective tissue (usually deep dermis) turn into osteoblasts & secrete matrix
• When matrix calcifies osteoblasts turn into osteocytes
• Ossification Center = where ossification 1st occurred, forms osteons of compact bone over time
• Flat bones of skull, lower jaw, clavicles form this way!
![Page 15: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/15.jpg)
1. Endochondral Ossification
• Cartilage model replaced by bone
• Most bones form this way - especially long bones
![Page 16: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/16.jpg)
Figure 6-52 of 6
Enlargingchondrocytes within
calcifying matrix
Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies.
Cartilagemodel
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 17: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/17.jpg)
Figure 6-53 of 6
Enlargingchondrocytes within
calcifying matrix
Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies.
Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone.
Cartilagemodel
Boneformation
Epiphysis
Diaphysis
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 18: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/18.jpg)
Figure 6-54 of 6
Enlargingchondrocytes within
calcifying matrix
Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies.
Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone.
Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center.
Cartilagemodel
Boneformation
Epiphysis
Diaphysis Marrowcavity
Primaryossificationcenter
Bloodvessel
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 19: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/19.jpg)
Figure 6-55 of 6
Enlargingchondrocytes within
calcifying matrix
Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies.
Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone.
Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center.
The bone of the shaft thickens, and the cartilage near each epiphysis is replaced by shafts of bone.
Cartilagemodel
Boneformation
Epiphysis
Diaphysis Marrowcavity
Primaryossificationcenter
Bloodvessel
Marrowcavity
Bloodvessel
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 20: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/20.jpg)
Enlargingchondrocytes within
calcifying matrix
Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies.
Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone.
Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center.
The bone of the shaft thickens, and the cartilage near each epiphysis is replaced by shafts of bone.
Blood vessels invade the epiphyses and osteo-blasts form secondary centers of ossification.
Cartilagemodel
Boneformation
Epiphysis
Diaphysis Marrowcavity
Primaryossificationcenter
Bloodvessel
Marrowcavity
Bloodvessel
Secondaryossificationcenter
Epiphysealcartilage
Articularcartilage
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
http://commons.bcit.ca/biology/ossification/files/ossification2.html
![Page 21: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/21.jpg)
Appositional Bone Growth
Figure 6-6
![Page 22: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/22.jpg)
Requirements For Normal Bone Growth
Hormones Growth Hormone Sex hormones, thyroid hormone, others
MineralsCalcium, phosphate
VitaminsVitamin D3
Vitamin CVitamin A
![Page 23: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/23.jpg)
Bone Remodeling/Homeostasis
• Remodeling - Continuous breakdown and reforming of bone tissue - 18% turned over/year
enables skeleton to adapt to new stresses
inactivity = degenerationFYE: Cast on leg for 6 wks - leg loses 1/3 bone mass!
FYE: your oldest bones are ~7 yrs!
needed for Ca regulation - bones store 2-4 lbs hormones control release into blood & storage
![Page 24: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/24.jpg)
Disorders in Bone Growth & Remodeling
• Osteoporosis = bone mass reduced, can happen at any age
inactivity low Ca age (males - lose 3%/decade starting in 30’s, females lose 8%)
![Page 25: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/25.jpg)
Disorders in Bone Growth & Remodeling
• Osteomalacia (Rickets) = Soft Bones from lack of Vit.D causes low Ca
![Page 26: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/26.jpg)
Disorders in Bone Growth & Remodeling
• Osteogenesis Imperfecta = Genetic disorder affecting collagen fiber formation (1 in 20,000)
![Page 27: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/27.jpg)
Disorders in Bone Growth & Remodeling
• Achondroplasia (Dwarfism) = Genetic disorder affecting cartilage formation mainly at epiphyses
![Page 28: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/28.jpg)
Disorders in Bone Growth & Remodeling
• Acromegaly (Giantism) = Excess growth hormone - most often after epiphyseal plates closed
![Page 29: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/29.jpg)
Disorders in Bone Growth & Remodeling
• Marfan’s Syndrome = Defective CT - excess cartilage at epiphyseal plates
![Page 30: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/30.jpg)
An Overview of the Skeleton
Figure 6-8(a)
![Page 31: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/31.jpg)
An Overview of the Skeleton
Figure 6-8(b)
![Page 32: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/32.jpg)
An Overview of the Skeleton
Figure 6-9
![Page 33: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/33.jpg)
The Axial Division: The Skull
Figure 6-10
![Page 34: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/34.jpg)
The Axial Division: The Skull
Figure 6-11(a)
![Page 35: Chapter 6: The Skeletal System](https://reader035.vdocument.in/reader035/viewer/2022062222/5697bfde1a28abf838cb2481/html5/thumbnails/35.jpg)
The Axial Division: The Skull
Figure 6-11(b)