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Exam 1---4
Hamster
48
Anatomy
Undergraduate 4
10/01/2010

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Cards

Term
Cartilage vs bone
Definition
In bone the extracellular matrix is calcified
Term
Cartilage is invested with ______?
Definition
Perichondrium
Term
Perichondrium
Definition
highly vascularized, it is innervated, wraps all cartilage except articular cartilage of joint surfaces; cells in perichondrium produce "new" cartilage: chondroblasts
Term
Do blood vessels run through cartilage?
Definition
No, blood vessels are located at its surface (its perichondrium)
Term
Bone and cartilage similarities
Definition
extracellular matrix is rigid, chrondrocytes and osteocytes are found in lacunae, cartilage is invested in perichondrium; bone is invested in periosteum
Term
Bone and cartilage--differences
Definition
- Extracellular matrix of Bone is calcified, cartilage is not
-cartilage is unified throughout whereas bone is not uniform
- diffusion cannot be used to supply osteocytes with nutrients b/c of the calcified extracellular matrix
Term
Gen structure of all bones
Definition
hollow; dense outer shell called compact bone; outer shell composes a network of spongy bone (trabecular bone); the "hollow" portion is the marrow cavity (in the shaft)
Term
red vs yellow marrow
Definition
red: blood forming, present in early age
yellow: fatty tissue, present in older age
Term
Diaphyses and Epiphyses
Definition
Diaphyses: shaft of bone
Epiphyses: the "ends" of the bone
Term
Periosteum
Definition
A dense connective tissue sheet that invests bone in the same way that perichondrium invests cartilage
Term
The ends/articular surfaces of bones are covered with _____?
Definition
Articular cartilage--usually made of hyaline cartilage; Articular cartilage is not covered with perichondrium
Term
Lone bones will have an _______ at the ends.
Definition
epiphyseal or growth plate
Term
epiphyseal (growth) plate
Definition
The site where growth in length of bone occurs.
Term
Bone is a highly __________ tissue
Definition
vascularized; blood vessels enter through small holes called nutrient foramina
Term
Bones have "big canal" and "little canal"
Definition
1) Big canal: Haversian canal
2) little canal: canaliculus containing filopodium (=extension of the bone cell into the canaliculi to reach nutrient source)
Term
Blood vessels usually travel _____ to the long axis of the bone.
Definition
Parallel
Term
The concentric rings of bone are called...
Definition
lamellae
Term
In higher altitudes you need more red or yellow marrow?
Definition
Red b/c you need more RBC's
Term
Three main types of bone cells
Definition
1) osteoblasts--bone-forming cells
2) osteocytes: "maintain the status quo"
3) osteoclasts: break down or reabsorb bone
Term
osteoporosis
Definition
The rate of bone breakdown is greater than the rate of bone deposition.
Term
Estrogen has an ______ affect on osteoclast activity.
Definition
inhibatory
Term
Achondroplasia
Definition
a genetically determined defect in cartilage that disrupts the normal growth of the skeleton.
Term
Bones are derived from...
Definition
mesoderm
Term
The rudiments of the skeleton are present of ___ weeks of gestation
Definition
Eight
Term
2 ways in which the skeleton develops/grows
Definition
1) Intramembranous ossification
2) Endochondral ossification
Term
Intramembranous ossification
Definition
Bone develops on a pre-exising membrane; examples: bones of the calvaria (skull cap) and clavicle
Term
Endochondral ossification
Definition
Bone replaces a pre-existing cartilage model; example: all long bones
Term
At about 8 weeks of gestation the developing brain is covered by a _____
Definition
tough connective tissue membrane
Term
Ossification centers
Definition
In specific regions of the membrane covering the brain, cells differentiate into osteoblasts. These cells begin to lay down bone on the membrane.
Term
Fontanelles
Definition
Areas of membrane that still exist at birth between the developing flat bones of the skull; allow the skull to grow rapidly in sych, close at about 2 years of age
Term
Microcephaly
Definition
The condition that results from premature closure of the fontanelles
Term
Endochondral ossification
Definition
bone replaces pre-existing cartilage model (usually hyaline cartilage); lone bones the best example of this; TH thought to be a major player in this process
Term
Process of endochondral ossification
Definition
1) long bones start as hyaline cartilage model
2) Primary ossification centers appear at 8 weeks--process starts in the middle
3)cells in the middle of the cartilage start breaking the cartilage down and osteoblasts start laying down bone to replace
4)throughout gestation, the cartilage component grows in length
5)At birth: shaft (diaphyses) is bone and ends (epiphyses) are still cartilage
6) Second ossification centers appear after birth, first at one end of bone and then at the other
7) growth plate: where the bones grow in length, the cartilage interposed between the ossification centers
8) closure of epiphyseal plates will result in end growth in length
Term
Growth epiphyses
Definition
the epiphyses at the end of bone--contribute to growth in length of bone
Term
Traction epiphyses
Definition
other epiphyses or sites of growth, not at the ends of bones; sites for muscle attachment.
Term
Cell types involved in bone remodeling
Definition
osteoblasts and osteoclasts
Term
Role of PTH (parathyroid hormone)
Definition
secreted in response to drop in blood calcium levels; stimulates osteoblasts
Term
Role of estrogen and testosterone in bone development
Definition
stimulate osteoblasts
Term
Role of GH (growth hormone)
Definition
Promotes:
-intestinal absorption of calcium
-the proliferation of cartilage at epiphyses plates
- elongation of bones
Term
4 major steps in bone repair
Definition
1) hematoma formation
2) fibrocartilaginous callus formation
3) hard callus of spongy bone
4) "bone remodeling"
Term
Hematoma formation
Definition
the hematoma is converted to granulation tissue by invasion of cells and blood vessels
Term
Fibrocartilaginous callus formation
Definition
deposition of collagen and fibrocartilage: granulation tissue converted to soft callus
Term
hard callus of spongy bone
Definition
osteoblasts deposit a temporary bony collar around fracture to unite broken pieces while ossification occurs
Term
"bone remodeling"--osteoclast and osteoblast activity
Definition
Osteoclasts: remove small bone fragments
Osteoblasts: deposit spongy bone then convert it to compact bone
Term
Osteoporosis
Definition
when bones become so porous that they eventually may crumble from the weight of the person; when the rate of bone breakdown or reabsorption is greater than the rate of bone deposition; may lead to compression fractures of vertebral bodies
Term
Kyphosis
Definition
an exaggerated thoracic curvature; "widow's hump"
Term
Osteomalacia
Definition
Adult form of rickets; bones are softened, deformed, and more susceptible to fractures
Term
Rickets
Definition
defective mineralization of bone in children; usually caused by insufficiency of sunlight or Vitamin D
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