Concept 49.5: Animal skeletons function in support, protection, and movement
The Skeletal System Bone as a Living Tissue. Functions of Bones 1. Support 1. Support 2. Protection...
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Transcript of The Skeletal System Bone as a Living Tissue. Functions of Bones 1. Support 1. Support 2. Protection...
The Skeletal The Skeletal SystemSystem
Bone as a Living TissueBone as a Living Tissue
Functions of BonesFunctions of Bones
1. Support1. Support 2. Protection2. Protection 3. Movement3. Movement 4. Storage 4. Storage
(Minerals, medullary cavity stores (Minerals, medullary cavity stores marrow)marrow)
5. Blood cell formation5. Blood cell formation Hematopoiesis Hematopoiesis
Bone CompositionBone Composition
Cortical bone – dense outer layer; Cortical bone – dense outer layer; looks smooth & solidlooks smooth & solid
Trabecular (Spongy) bone – inner Trabecular (Spongy) bone – inner framework of small needle-like/flat framework of small needle-like/flat pieces of bone (trabeculae) that have pieces of bone (trabeculae) that have spaces in betweenspaces in between Spaces between filled with red or Spaces between filled with red or
yellow bone marrowyellow bone marrow
Spongy Spongy BoneBone
Shape Categories of BonesShape Categories of Bones
1. 1. Long bonesLong bones All limb bones (except kneecap, wrist, & All limb bones (except kneecap, wrist, &
ankle bones) are long bonesankle bones) are long bones
Long Bone StructureLong Bone Structure
1. Diaphysis – shaft of bone; cortical bone and 1. Diaphysis – shaft of bone; cortical bone and medullary cavity with yellow bone marrow medullary cavity with yellow bone marrow (fat)(fat)
2. Epiphyses – bone ends; covered in layer of 2. Epiphyses – bone ends; covered in layer of articular cartilage, red bone marrowarticular cartilage, red bone marrow
3. Membranes – 3. Membranes – a. periosteum – double-layered a. periosteum – double-layered
membrane that covers external surface membrane that covers external surface of bone of bone
b. endosteum – lines medullary cavityb. endosteum – lines medullary cavity
Shape Categories of BonesShape Categories of Bones
2. 2. Short bonesShort bones – cube shaped – cube shaped Wrist and ankle bonesWrist and ankle bones
3. 3. Flat bones Flat bones – thin, somewhat – thin, somewhat
curvedcurved Ribs, scapulaRibs, scapula
Shape Categories of BonesShape Categories of Bones
4. 4. Irregular bonesIrregular bones – have – have complicated shape that does not fit complicated shape that does not fit in other 3 categoriesin other 3 categories Vertebrae, hip bones are irregular Vertebrae, hip bones are irregular
Short BoneShort Bone
Composition of BoneComposition of Bone
Osteocyte= mature bone cellOsteocyte= mature bone cell
Osteon (aka Haversian system) – column Osteon (aka Haversian system) – column parallel to long axis of boneparallel to long axis of bone Haversian canal – run length of bone; osteocytes Haversian canal – run length of bone; osteocytes
here here
Lamella – hollow tubes of bone matrix; make Lamella – hollow tubes of bone matrix; make up osteons; like rings on tree trunkup osteons; like rings on tree trunk
Microscopic Anatomy of Microscopic Anatomy of Compact BoneCompact Bone
Lacunae – small cavities in bonesLacunae – small cavities in bones
Volkmann’s canal – perforating canal; Volkmann’s canal – perforating canal; runs sideways, connects blood/nerve runs sideways, connects blood/nerve to central canalsto central canals
Canaliculi – small sideways canals Canaliculi – small sideways canals connecting lacunae and central canal; tie connecting lacunae and central canal; tie all osteocytes in an osteonall osteocytes in an osteon
OsteonOsteon
Bone Growth & Bone Growth & DevelopmentDevelopment
Bone deposition, build bone – osteoblasts
Remove/remodel – osteoclast
Epiphyseal plate = growth plate
Ossification – Bone Ossification – Bone DevelopmentDevelopment
Aka osteogenesisAka osteogenesis
1. Formation of bony skeleton1. Formation of bony skeleton 2. Bone growth2. Bone growth
length length width (with stress)width (with stress)
Hypertrophy vs. atrophyHypertrophy vs. atrophy 3. Remodeling3. Remodeling
OssificationOssification
Factors Affecting Bone Factors Affecting Bone Development, Growth & Development, Growth &
RepairRepair Deficiency of Vitamins:
Vitamin A - slows bone development, Vita C – fragile bones, Vita D – rickets
Insufficient or Excessive GH: dwarfism or Gigantism
Sex Hormones – promote bone formation; stimulate ossification of epiphyseal plates
Physical Stress – stimulates bone growth
Axial SkeletonAxial Skeleton