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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 - PowerPoint PPT Presentation
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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
Functions of Skeleton1. Supporting framework2. Attachment of
muscles3. Protects vital organs
• Cranium: Brain • Thoracic: Heart &
lungs4. Reservoir of minerals
• Calcium & Phosphorus
5. Red bone marrow• Formation of RBC
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
Macroscopic structure of Long Bone
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 cont’
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)
Formation of Bone Using your book as a reference, How does the
skeleton seem to develop? Ossification starts at 12 wks.
Epiphyseal disk (line = adult) 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
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:1. Infancy to Adolescent: Osteoblastic
activity dominant2. Adolescent to Mid adult (40-50):
Balance3. Post middle age: Osteoclastic activity
dominant leading to certain diseases
Microscopic Bone structure
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
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 osteocytesosteoblasts
: build boneosteoclasts
: remove bone
“Bone destroyers” Osteoclasts (microscopic)
Multi-nucleated cells
Release “digestive” enzymes to reshape or remodel bone
Nutrition Corner! www.waltonfeed.com/self/health/vit-min/calcium.html
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?
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?
Osteoporosis
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
Common Sites of Osteoporotic fractures
Spinal column (vertebrae) Distal Radius / Ulna Hip fractures (actually is
neck of femur NOT actual hip)
WHY DO YOU THINK?
Osteoporosis cont’
Factors which INCREASE risk1. Low intake of dietary calcium and Vit D2. Lack of physical exercise3. Menopause:
ovaries produce less estrogens…ceases decreases bone absorption of Calcium… Decreasing secondary sex
characteristics
Prevention methods
How can someone, especially woman, prevent this?
1. Calcium supplements: 1000mg – 1500mg per day. Ex: 8oz glass milk = 275 mg
2. Regular physical exercise program. WHY?
3. 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)