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 Skeleton 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 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: Infancy to Adolescent: Osteoblastic activity dominant Adolescent to Mid adult (40-50): Balance 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 osteocytes osteoblasts: build bone osteoclasts: remove bone

                                                         

“Bone destroyers” Osteoclasts (microscopic) Multi-nucleated cells Release “digestive” enzymes to reshape or remodel bone

Homeostasis Alert!! 0-18yrs: OB forming bone, little OC activity 18yrs.-40yrs. Remodeling phase: Equal OB deposition of bone & OC resorption of bone. 40yrs (approx): more OC activity to release the calcium phosphate from “storage”

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?

Compare the X-rays Pediatric X-Ray Adult X-Ray

Use vs. Disuse 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 risk Low intake of dietary calcium 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. 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)

Homework www.waltonfeed.com/self/health/vit-min/calcium.html Please read the following link to the article regarding nutritional health of the skeletal system. What nutrients are important to good bone health? Please create a chart including: nutrient, why, and example in the diet.