Ch. 6 Flashcards
The skeletal system
What are the functions of the bone?
She May Probably have Lice Support Mineral and lipid storage Protection Hematopoiesis Leverage
What are the two parts of the skeleton?
Axial : thoracic cage, vertebral column, and skull
Appendicular: shoulder and hip girdles and limps
What are the shapes bones can be classified in?
Lets Start Fires, I'm Smoking Witches Long Bones Short Bones Flat Bones Irregular Bones Sesamoid Bones Wormian/Sutural Bones
What are the two major components of bones?
Inorganic and Organic components
Inorganic components of bones:
Minerals
Provide crush resistance
Ca++ and PO4-3 combine to form hydroxyapatite crystals
nucleation
the formation of a crystal
Organic components of bones:
proteins that provide flexibility and resistance to twisting forces
Ground substance composed of Glycosaminoglycans (GAG) proteins which include hyaluronic acid and chondrotitin sulfate
What is the function of red bone marrow?
Hematopoiesis
What is the function of yellow bone marrow?
stores lipids and fats
What is a nutrient foramen?
hole that allows the passage of blood vessels
Epiphysis line
- only spot where bones grow in length.
- hyaline is replaced with bone until it is fused as we grow
Osteogenesis
ossification (the process of bone tissue formation) starts in the womb
What are the two types of ossification?
endochondral ossification and intramembranous ossification
endochondral ossification
bone develops from a template of hyaline cartilate. Used to form long bones
intramembranous ossification
bone develops directly from a template of fibrous connected tissue. Used to form flat bones.
What are the two ways growth in cartilage can occur?
appositional growth - growth from the outside
interstitial grown - growth from between the cells
What are the reasons for bone remodeling?
adjustment of strength
change in shape
replacement of brittle osteoid
osteoclasts cause bone resorption by:
acidification
secretion of acid proteases
acidification
acts primarily on the mineral components of bone
breaks hydroxyapatite crystals back into ionized calcium and phosphate
osteoblasts
Help Ca++ and PO4-3 to be deposited at this location by:
- removing the “effects” from the osteoclast
- producing alkaline phosphatase
- inhibiting the inhibitors of calcium phosphate precipitation
- secreting collagen fibers and GAG proteins
Which hormones increase osteoblast activity?
- growth hormone
- thyroid hormones
- estrogen
- 24, 25 (OH)2 vitamin D
- calcitonin
Which hormones increase osteoclast activity?
cytokines
parathormone
1, 25 (OH)2 vitamin D
Bones will be remodeled when put under _______ _____
compressive stress
Wolff’s Law
a bone remodels in response to the demands placed on it
Piezoelectric effect
when a crystal (or solid material) is compressed, an electric charge is generated
What plays a larger role in Piezoelectric effect?
collagen (collagenous fibers) while hydroxyapatite crystals play a smaller role
Osteoblasts will continue to build bone until what 2 conditions are met?
until it can withstand the compressive stress or the compressive stress is removed
What are examples of diseases of the bone?
Osteopenia
Osteoporosis
Osteomalacia
osteopenia
bone gets softer and weaker
osteoporosis
Bone loss. Bone is less able to withstand compressive stress
Who is more likely to get osteoporosis and why?
Women because:
- mostly use estrogen for bone remodeling. After menopause, there is less estrogen
- women have less bone to begin with
- child birth means less calcium for mom
osteomalacia
adult rickets, softening of the bone
- due to deficiency in vitamin D or Ca++
- can’t make enough crystals
