Term
|
Definition
| In bone the extracellular matrix is calcified |
|
|
Term
| Cartilage is invested with ______? |
|
Definition
|
|
Term
|
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
|
Definition
red: blood forming, present in early age
yellow: fatty tissue, present in older age |
|
|
Term
|
Definition
Diaphyses: shaft of bone
Epiphyses: the "ends" of the bone |
|
|
Term
|
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
|
|
Term
| The concentric rings of bone are called... |
|
Definition
|
|
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
|
Definition
| The rate of bone breakdown is greater than the rate of bone deposition. |
|
|
Term
| Estrogen has an ______ affect on osteoclast activity. |
|
Definition
|
|
Term
|
Definition
| a genetically determined defect in cartilage that disrupts the normal growth of the skeleton. |
|
|
Term
| Bones are derived from... |
|
Definition
|
|
Term
| The rudiments of the skeleton are present of ___ weeks of gestation |
|
Definition
|
|
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
|
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
|
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
|
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
|
Definition
| the epiphyses at the end of bone--contribute to growth in length of bone |
|
|
Term
|
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
|
|
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
|
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
|
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
|
Definition
| an exaggerated thoracic curvature; "widow's hump" |
|
|
Term
|
Definition
| Adult form of rickets; bones are softened, deformed, and more susceptible to fractures |
|
|
Term
|
Definition
| defective mineralization of bone in children; usually caused by insufficiency of sunlight or Vitamin D |
|
|
