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APL2 and 3 Skeletal Anatomy. The evil that men do lives after them, the good is oft interred with their bones. —William Shakespeare (1564-1616) Julius Caesar, Act III, Scene 2. Supporting framework Attachment of muscles Protects vital organs Cranium: Brain Thoracic: Heart & lungs
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APL2 and 3 Skeletal Anatomy The evil that men do lives after them, the good is oft interred with their bones. —William Shakespeare (1564-1616) Julius Caesar, Act III, Scene 2
Supporting framework Attachment of muscles Protects vital organs Cranium: Brain Thoracic: Heart & lungs Reservoir of minerals Calcium & Phosphorus Red bone marrow Formation of RBC Functions of Skeleton
L3: add to your #4 #5 Functions of the skeleton • 4. cont. Storage Site of Inorganic Salts, such as CALCIUM. Calcium may be removed from bone to maintain a normal blood calcium level, which is essentially for BLOOD CLOTTING • 5. cont. Contains and Protects the Red Bone Marrow, Some White Blood Cells (Leukocytes) are also produced
Epiphysis: ends of a long bone. Contains mainly spongy bone Red Marrow fills it. Its fxn is to produce RBC Articular Cartilage: covers ends of long bone Hyaline cartilage Creates smooth surface Macroscopic structure of Long Bone
Endosteum: inner membrane lining MC MC contains yellow marrow (fat) Continuous with spongy bone Periosteum: tough outer “jacket” Composed of fibrous tissue Contains BV, Nerves, and Osteoblasts Initiates growth in DIAMETER Macroscopic Structure of Long bone
Epiphyseal Disk: area of bone where active growth occurs. AKA: growth plates Initiates growth in LENGTH When growing stops, disk is replaced by Epiphyseal line. Diaphysis: shaft of bone Outer wall contains mainly compact bone. Strong & resistant to bending Compact bone encloses Medullary canal. MC contains yellow marrow (Fat) Macroscopic structure cont’
Formation of Bone • Using your book as a reference, How does the skeleton seem to develop? Ossification starts at 12 wks.
Area of actively reproducing cartilage cells Contain osteblasts Will close approx 18yr. old Osteoblasts: “bone builders” Capable of producing collagen fibers (living=organic) May “cement” themselves in Lacunae (cavity) Osteocyte is mature osteoblast Epiphyseal disk (line = adult)
Femoral Epiphyseal disk: F=14-16 M=16-18 • Sacral / Hip: F=21-23 M=23-25
Bone Remodeling • Osseous tissue constantly being formed and resorbed (destroyed) • 3 stages: • Infancy to Adolescent: Osteoblastic activity dominant • Adolescent to Mid adult (40-50): Balance • Post middle age: Osteoclastic activity dominant leading to certain diseases
1. Haversian (osteonic) canal : contain blood vessels & nerves 2. Canaliculi: interconnecting channels. Allow osteocytes to communicate 3. Lamellae: thin sheets of bone matrix layered in circles around the canals 4. Lacunae: spaces that contain osteocytes Microscopic Bone structure
Haversian(osteonic) System=canal, lamellae, osteocytes and canaliculi Lamella: Concentric ring Haversion’s (osteonic) canal: runs through core Perforating canals: connect the Haversion canals Lacuna: contain osteocytes (mature bone cells) Types of osteocytes osteoblasts: build bone osteoclasts: remove bone
Multi-nucleated cells Release “digestive” enzymes to reshape or remodel bone “Bone destroyers” Osteoclasts (microscopic)
Calcium: mineral needed as primary make-up of inorganic salts of bones 99% in bone, 1% in blood Vitamin D: needed for Ca If a 20 year old woman consumes 400 mg of calcium a day (half of what is recommended), at age 55, she will have lost 1/3 of her calcium. RDA Requirements for Calcium 0.0-0.5 400 mg 0.5-1.0 600 mg 1-10 800 mg 11-24 1200 mg 25 + 800 mg Pregnant 1200mg Lactating 1200 mg What is the reasoning? Nutrition Corner! www.waltonfeed.com/self/health/vit-min/calcium.html
Use vs. Decreased use • Increased use (exercise): increases deposition of collagen and calcium(inorganic=non-living) salts • Bones get stronger • Decreased use: compact bone in diaphysis thins out & calcium removed from bone • Bones get weak and fragile
You create the Treatment protocol • Treatment concerns of 82 y.o. elderly woman (95 lbs.) • Concerns for a 47 y.o average sized woman • Pregnant 31 y.o woman • 313 lbs. 38 y.o. obese man. • 200lbs. 22 y.o man • How should they differ? Be similar?
Excessive loss of bone volume & mineral content. Trabeculae of spongy bone is lost/spaces develop Spontaneous fracture as result of weakened bone Aging reason for large % of fractures over age of 45 Osteoporosis
Spinal column (vertebrae) Distal Radius / Ulna Hip fractures (actually is neck of femur NOT actual hip) WHY DO YOU THINK? Common Sites of Osteoporotic fractures
Osteoporosis cont’ • Factors which INCREASE risk • Low intake of dietary calcium and Vit D • Lack of physical exercise • Menopause: • ovaries produce less estrogens…ceases • decreases bone absorption of Calcium… • Decreasing secondary sex characteristics
Prevention methods • How can someone, especially woman, prevent this? • Calcium supplements: 1000mg – 1500mg per day. Ex: 8oz glass milk = 275 mg • Regular physical exercise program. WHY? • What about Estrogen replacement therapy?
Homework • There are many different factors that can affect bone growth: Your homework is to research how one of these affects bone growth/what disorders can result. • 1. Vitamin A • 2. Vitamin C • 3. Vitamin D • 4. Pituitary growth hormone (too much, too little) • 5. Female sex hormone (estrogen) • 6. Male sex hormones (testosterone)