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Skeletal system part 1: bone . Honors Anatomy & Physiology. Bone . a combination of CT, epithelial & nervous tissues 18% of weight of human body Skeletal System includes bones & cartilage Part 1: Bone Part 2: Axial Skeleton Part 3: Appendicular Skeleton Part 4: Joints . FUNCTIONS. - PowerPoint PPT Presentation
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SKELETAL SYSTEM
PART 1: BONE Honors Anatomy & Physiology
a combination of CT, epithelial & nervous tissues
18% of weight of human body Skeletal System includes bones &
cartilage Part 1: Bone Part 2: Axial Skeleton Part 3: Appendicular Skeleton Part 4: Joints
BONE
FUNCTIONS1. SUPPORT skeleton
serves as structural framework by supporting soft tissues & providing attachments for tendons of muscle
2. PROTECTION Protects most
important soft tissue organs from injury
FUNCTIONS3. MOVEMENT Skeletal muscles
attach to bones, when the muscle contract the bones move
4. MINERAL HOMEOSTASIS
Bone stores calcium, phosphorus which both help make bone strong
If body needs these minerals bone releases them
FUNCTIONS5. BLOOD CELL
PRODUCTION red bone marrow
produces RBCs, WBCs, & platelets
6. TRIGLYCERIDE STORAGE
yellow bone marrow stores triglycerides (chemical energy reserve)
PARTS OF A LONG BONE1. Diaphysis:
shaft or body; the long cylindrical portion of the bone
2. Epiphysis:distal & proximal ends of bone
PARTS OF A LONG BONE3. Metaphysis: region
between diaphysis & epiphysis
in growing bone includes metaphyseal plate (hyaline cart. that allows bone to lengthen
4. Articular Cartilage:
layer of hyaline cartilage covering part of epiphysis where bone forms a joint with articulating bone
METAPHYSIS
ARTICULAR CARTILAGE
STRUCTURE OF LONG BONES
5. PERIOSTEUM tough , dense,
irregular CT surrounds bone wherever it is not covered by hyaline cartilage
helps in repair of fractures
Attachment pt for ligaments
6. MEDULLARY CAVITY
aka Marrow Cavity
space w/in diaphysis that contains yellow bone marrow in adults
PERIOSTEUM
MEDULLARY CAVITY
STRUCTURE OF LONG BONES
7. ENDOSTEUM thin
membrane that lines marrow cavity
contains 1 layer of bone-forming cells and CT
HISTOLOGY OF BONE bone consists of widely separated
cells surrounded by large amts extracellular matrix
*bone is hard due to crystallized inorganic mineral salts
*bone is flexible due to collagen
1. OSTEOGENIC CELLS Stem cells from mesenchyme
(origin of all CT) only bone cells to divide
TYPES OF BONE CELLS
2. OSTEOBLASTS bone-building cells synthesize & secrete collagen
fibers initiate calcification
TYPES OF BONE CELLS
3. OSTEOCYTES mature bone cells main cells in bone maintain exchange of nutrients &
wastes with blood
TYPES OF BONE CELLS
4. OSTEOCLASTS huge cells that form by merging
of many (50)monocytes in endosteum ruffled border faces bone surface:
releases lysosomal enzymes & acids that digest underlying bone (bone resorption): part of normal maintenance, growth, development, & repair of bone
TYPES OF BONE CELLS
OSTEOCLASTS
TYPES OF BONE (2)1. Compact bone
few open spaces outer bone layer of all bones
2. Spongy bone inside bones
strongest form of bone beneath periosteum of all bone functions:
protection & support resists stresses produced by weight
& movement
COMPACT BONE
OSTEON:aka Haversian Systemsrepeating units thru out compact boneeach one has central canal with concentrically arranged lamellae (rings), lacunae (filled with 1 osteocyte)
aligned in same direction along lines of stress
space between osteon filled with interstial lamellae
PARTS OF COMPACT BONE
COMPACT BONE
absence of osteons made of lamellae arranged in
irregular columns called trabeculae
makes up most of inside of short, flat, or irregular bones & epiphysis of long bones
lighter than compact bone Function:
support & protect red bone marrow
SPONGY BONE
SPONGY BONE
BONE GROWTH1. longer: @ epiphyseal plate1. wider: called appositional growth periosteal osteoblasts on outer
surface of bone osteoclast remove compact bone
inner border
BONE GROWTH: LONGER
BONE GROWTH: WIDER
Most bones are formed b/4 birth but each one continually renews itself for rest of life
~5% of bone being remodeled @ any given time
bone remodeling is the ongoing replacement of old bone tissue by new bone tissue1. Bone Resorption2. Bone Deposition
BONE REMODELING
removal of minerals & collagen fibers from bone by osteoclasts
results in destruction of bone extracellular matrix
BONE RESORPTION
addition minerals & collagen fibers to bone by osteoblasts
BONE DEPOSITION
1. Minerals Ca, P, F, Mg, Fe, Mn
2. Vitamins C needed to make collagen fibers & for
osteoblast osteocyte E & B12 needed for protein synthesis
3. Hormones IGF’s in childhood (insulin-like growth
factors) estrogens & androgens important in
puberty
FACTORS AFFECTING BONE GROWTH & REMODELING
Fracture: any break in a bone Fractures named by:
severityshape or position of fracture line
person who 1st described it
FRACTURE & REPAIR OF BONE
TYPES OF FRACTURES OF BONE
TYPES OF BONE FRACTURES
TYPES OF BONE FRACTURES
TYPES OF BONE FRACTURES
FRACTURE REPAIR
Bone is body’s main reservoir for calcium (stores 99% of total body Ca)
Normal blood level Ca 9 -11 mg/100mL
Calcium important for:Muscle contractionNerve impulsesBlood clottingMany enzymes require Ca as cofactor)
CALCIUM HOMEOSTASIS
2 hormones control Ca in/out bone:
1. Calcitonin Decreases blood Ca levels by
putting more Ca into bone2. Parathyroid Hormone (PTH)
Increases blood Ca levels by taking Ca out of bone (increasing osteoclast resorption)
CONTROL OF CALCIUM
1. Osteoporosis condition of porous bones
(resorption > deposition) causes: deficient Ca in diet USA: > 1 million fractures
(hip, wrist, vertebrae) & afflicts 30 million Americans
decreased stature, hunched back, bone pain
HOMEOSTATIC IMBALANCES IN BONE