Copyright John Wiley Sons, Inc. All rights reserved. Chapters 6 Bone Tissue Lecture slides...

Copyright © John Wiley & Sons, Inc. All rights reserved.

Chapters 6Bone Tissue

Lecture slides prepared by Curtis DeFriez, Weber State University


Bone Growth and Remodeling A balance must exist between the actions of

__________ and ___________. If too much new tissue is formed, the bones

become abnormally thick and heavy (___________).

Excessive loss of ___________ weakens the bones, as occurs in osteoporosis.

They may also become too “soft”, as seen in the bone diseases ___________ and ___________.


Bone Growth and RemodelingInteractions Animation

Bone Remodeling

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Bone Growth and RemodelingNormal bone metabolism depends on

several factors: ___________ are an essential component.

Large amounts of ___________ and ___________ and smaller amounts of magnesium, fluoride, and manganese are required for bone growth and remodeling.


Bone Growth and Remodeling Vitamins are also necessary for normal bone

metabolism: Vitamin ___ stimulates activity of osteoblasts. Vitamin ___ is needed for synthesis of collagen. Vitamin ___ is essential to healthy bones because

it promotes the absorption of calcium from foods in the gastrointestinal tract into the blood.

Vitamins ___ and ____ are needed for synthesis of bone proteins.


Bone Growth and Remodeling Hormones are key contributors to normal bone

metabolism. During childhood, the hormones most important to

bone growth are ___________ hormone (___) and growth factors called _____ (produced by the liver). Both stimulate ___________, promote ___________ at the epiphyseal plate, and enhance __________synthesis.

___________ hormones and ___________ also promote bone growth by stimulating osteoblasts and protein synthesis.


Bone Growth and Remodeling Hormones continued… The sex hormones (___________ and ___________)

cause a dramatic effect on bone growth, such as the sudden “growth spurt” that occurs during the teenage years.• The sex hormones also promote widening of

the pelvis in the female skeleton.• They are also responsible for closing the

epiphyseal plates at the end of ___________.


Bone Growth and Remodeling Hormones continued… ___________ hormone (___) and ___________ are

critical for balancing the levels of ___________ and ___________ between blood and bone.• Maintaining a normal serum Ca2+ level

takes precedence over mineralizing bone (usually both can be done) – can you suggest an explanation why this is true?


Calcium Homeostasis Day to day control of calcium regulation mainly

involves: ______ stimulates osteoclastic activity and ______ serum

calcium level. ___________ (thyrocalcitonin), and to a lesser extent _____

and the sex hormones, stimulate osteoblastic activity and ______ serum calcium level.

Vitamin ___ is needed for absorption of the Ca2+ and PO4–

ions from the small intestine, and reabsorption of those same ions in the kidneys.

The role of regulating serum Ca2+ levels and mineralizing bone is under hormonal control, and is carefully balanced.


Calcium Homeostasi

s


Exercise and Bone Tissue Under mechanical stress, bone tissue becomes

__________ through deposition of mineral salts and production of collagen fibers by osteoblasts. Unstressed bones, on the other hand, become ___________. Astronauts in space suffer rapid loss of bone

_________. The main mechanical stresses on bone are those that

result from the pull of skeletal muscles and the pull of gravity (weight-bearing activities).


Aging and Bone Tissue A decrease in bone mass occurs as the level

of sex hormones diminishes during __________ age (especially in women after menopause).

Bone ___________ by osteoclasts outpaces bone deposition by osteo_______.

Since female bones are generally smaller and less massive than males to begin with, old age has a greater adverse effect in females.


Aging and Bone Tissue There are two principal effects of aging on bone

tissue: ___________mass• The loss of calcium from bones is one of the

symptoms in osteoporosis. ___________• Collagen fibers give bone its tensile strength, and

protein synthesis ___________ with age.• The loss of tensile strength causes the bones to

become very brittle and susceptible to ___________.


Aging and Bone Tissue ___________ is a condition where bone resorption

outpaces bone deposition. Often due to depletion of calcium from the

body or inadequateintake

Copyright John Wiley Sons, Inc. All rights reserved. Chapters 6 Bone Tissue Lecture slides...

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