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,

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 framework

2. Attachment of muscles

3. Protects vital organs• Cranium: Brain • Thoracic: Heart &

lungs

4. 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 dominant

2. Adolescent to Mid adult (40-50): Balance

3. 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 risk

1. Low intake of dietary calcium and Vit D

2. Lack of physical exercise

3. 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)