For intramembranous ossification to take place, which of the following is necessary?
An ossification center forms in fibrous connective tissue
T/F In newborn infants, the medullary cavity and all areas of spongy bone contain yellow bone marrow.
Bones are covered and lined by a protective tissue called periosteum. The inner layer consists primarily of ______.
osteoblasts and osteoclasts.
Wolff's law is concerned with _____________.
the thickness and shape of a bone being dependent on stresses placed upon it.
Growth of bones is controlled by a symphony of hormones. Which hormone is important for bone growth during infancy and childhood?
The canal that runs through the cone of each osteon (the Haversion canal) is the site of ___.
blood vessels and nerve fibers.
The periosteum is secured to the underlying bone by dense connective tissue called _____.
Perforating (Sharpey's) fibers
In the epiphysial plate, cartilage grows ________.
By pushing the epiphysis away from the diaphysis.
T/F Short, irregular, and flat bones have large marrow cavities in order to keep the weight of bones light.
T/F Bone tissue in the skeleton of a human fetus is completely formed at six months gestation.
The universal loss of mass seen in the skeleton which begins at age 40 ______.
reflects incomplete osteon formation and mineralization.
T/F The periosteum is a tissue that serves only to protect the bone because it is not supplied with nerves or blood vessels.
A _____ exhibits chondrocytes housed in lacunae within the extracellular matrix. It contains large amounts of water, lacks nerve fibers, is avascular, and is surrounded by a fibrous perichondrium that resists expansion.
________ appear glassy; the fibers are collagenic. They provide support with flexibility and resilience and are the most abundant skeletal cartilages, accounting for the articular, costal, respiratory, and nasal cartilages.
________ cartilages contain abundant elastic fibers, in addition to collagen fibers, and are more flexible than hyaline cartilages. They support the outer ear and epiglottis.
________, which contain thick collagen fibers, are the most compressible cartilages and are resistant to stretch. They form intervertebral discs and knee joint cartilages.
T/F Cartilages grow from within (interstitial growth) and by addition of new cartilage tissue at the periphery (appositional growth).
Bones are classified as ______ on the basis of their shape and their proportional of compact or spongy bone.
Short, flat, or irregular
Name the functions of bones.
Bones give the body shape, protect and support body organs, provide levers for muscles to pull on, store calcium and other minerals, and are the site of blood cell production.
A ______ is composed of a diaphysis and epiphyses. The medullary cavity of the diaphysis contains yellow marrow; the epiphyses contain spongy bone.
T/F In adults, red marrow is found within the diploe of flat bones and occasionally within the epiphyses of long bones.
The structural unit of ______, consists of a central canal surrounded by concentric lamellae of bone matrix.
________ has slender trabecullae containing irregular lamellae which encloses red-marrow filled cavities.
What is bone composed of?
living cells (osteogenic cells, osteoblasts, osteocytes, and osteoclasts) and matrix.
The organic substances in bone matrix ______, while the inorganic components ______.
give the bone tensile strength, make bone hard
T/F Long bones increase in length by interstitial growth of the epiphyseal plate cartilage an its replacement by bone.
What is the most frequent cause of Osteomalacia and rickets (soft and deformed bones)?
inadequate vitamin D
________ is any condition in which bone breakdown outpaces bone formation, causing bones to become weak and porous.