Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Histology Exam 2
VWU Histology course
| Question | Answer |
|---|---|
| Types of Bone | Shapes: Long, short, flat and irregular Developmental: intramembranous and endochondral Density of steons: spongy and compact Histology: primaryy and secondary |
| Basic functions | Primary component of adult skeleton, provides support for fleshy structures and attachment for skeletal muscles, forms levers that make body movements possible, protects vital organs/harbors bone marrow, and a reservoir for calcium, phosphate & other ions |
| Bone components | Calcified intercellular matrix with three major cell types: osteocytes, osteoblasts, and osteoclasts |
| Osteocytes | mature bone cells (occurs in lacunae between lamellae- layers of matrix) osteoblasts surrounded by their secretions |
| Osteoblasts | synthesize organic components of the matrix type I collagen fibers, proteoglycans and several glycoproteins, including osteonectin deposition of inorganic components is also dependent upon osteoblast activity |
| Osteoclasts | multi-nucleated giant cells that are invovled in reabsorption and remodeling of bony tissues in areas of bone reabsorption they form etched depressions or crypts known as Howship lacunae |
| Linings of Bones | all bones are lined w/ connective tissues on their internal (endosteum) and external surfaces (periosteum) these layers are rich in osteoprogenitor cells (used to repair bone) |
| osteoprogenitor cell transformation | osteoprogenitor --> osteoblast --> osteocyte |
| Bone Histology | bone is hard, rich in calcium phosphate so it cannot be sectioned w/out special preparations (decalcification) physiology of osseous tissue is difficult to study in living conditions |
| Osteoblasts | during matrix synthesis they have a cuboidal or columnar shape activity is stimulated by Parathyroid hormone ultrastructure is similar to other synthetic cells, when active osteoblacts produce osteoid (layer of uncalcified bone) |
| Osteoblasts | calcium salt crystal deposition occurs subsequent to osteoid production osteoblasts release osteoclci, which binds to calcium ions, and alkaline phosphatase, which raises the local concentration of phosphate ions |
| Osteoid | similar to mature bone expect for the fact that it doesn't have calcium ions |
| How to osteocytes occur | when osteoblasts are surrounded by their secretions |
| What osteoblasts develop when they become osteocytes | ong cytoplasmic extenstions that are surrounded by calcifying matrix (known as canaliculi) |
| Osteocytes have little what and more of what compared to osteoblasts | RER and Golgi apparatus and more condensed nuclear chromatin |
| Bone diseases | osteomalacia osteitis fibrosa cystica osteopetrosis osteoporosis |
| osteomalacia | mineralization of bone is impaired |
| osteitis fibrosa cystica | increased osteoclast activity resulting in the removal of bone matrix and fibrous degeneration |
| osteoetrosis | osteoclasts lacking ruffled borders and bone reabsorption is defective "marble bones" |
| osteoporosis | when bone reabsorption exceeds the rate of bone formation |
| What happens in active osteoclasts | the surface facing the boney matrix has ruffled border and they secrete collagenase and other enzymes and pump ions to catalyze the dissolution of hydroxyapatite crystals |
| What kind of receptors do osteoclasts have | receptors for thyroid hormones (but not parathyroid) |
| Bone Matrix | 50% inorganic material by dry weigh hydroxyapatite is very abundant, but bicarbonate, citrate, magnesium, potassium, and sodium is also present organic molecules include: Type I collagen and ground substance (proteoglycan, osteonectin and osteocalcin |
| What do the inorganic components in bone matrix do | give bone its strength to resistance to compression removal of calcium salts causes bone to bend |
| what do the organic components in bone matrix do | provide bone with its shape removal of collagen causes brittle bones |
| rickets | lack of calcium in the diet |
| Periosteum | vascularized tissues covering the surfaces of bone, rich in bone forming cells |
| Sharpey's fibers | bundles of fibers that penetrate the boney matrix |
| Osteoprogenitor cells | innermost layer of the periosteum, rich in mesenchymal stem cells this is important to bone growth and repair |
| Endosteum | composed of single thin layers of connective tissue contaiing osteoprogenitor cells and osteoblast lines marrow cavities |
| What are periosteum and endosteum's primary function | to provide nutrition to osseous tissue and bone repair or growth |
| Two major bone types | Compact bone and Cancellous bone |
| Compact bone | osseous tissue w/out cavities |
| Cancellous bone (spongy) | osseous tissues w/ numerous interconnecting cavities |
| Epiphysis (bulbous ends) | composed of spongy bone covered in thin layer of compact bone Long bone structure |
| Diaphysis (cylindrical shaft) | compact bone w/ thin lining of spongy bone on inner surface facing bone marrow cavity Long bone structure |
| Flat Bones | Two layers of compact bones ( tabula externa and tabula interna) Layers are separated by thicker layer of spongy bone (diploe) Two types, microscopically, Immature (primary) bone and Mature (secondary) bone |
| Immature (Primary) Bone Tissue | First to appear in embryonic development Features random diposition of collagen fibers (woven bone) Replaced by mature bone, except in tures of the skull, tooth sockets and insertions of some tendons Has lower mineral content than mature bone |
| Mature (secondary or lamellar) Bone | Found in adults Organized, parallel lamellae, form concentric circles around a vascular canal Each complex is known as Osteon or Haversian System |
| Cement Layer | rich in collagen; boundaries of each osteon |
| What are the two mechanisms for osteogenesis | Intramembrane ossification and Endochondral ossification |
| Intramembranous Ossification | Begins w/ ossification center where mesenchymal cells differentiate into osetoblasts osteoblasts produce osteoid, some become encapsulated and are known as osteocytes islands of osteoids fuse to form larger plates which give the bone a spongy appearance |
| Endochondral Ossification | Ossification begins w/ a central piece of Hyaline cartilage forms long and short bones of the body different zones of cartilage growth and development become apparent |
| Endochondral Ossification | Diaphysis is the Primary (immature) ossification center; secondary ossification centers occur at the epiphyses cavities w/in each become bone marrow cavities |
| Where does cartilage remain in the secondary ossification centers | in the articular cartilage facing the joint and at the epiphyseal plate |
| Epiphyseal plate (growth plate) | responsible for elongation of the developing bone |
| Bone remodeling | turnover rate of bone changes w/ age in children the rate is 200x faster than in adults this process is aggected by hormones |
| What are the hormones that affect bone remodeling | parathyroid, calcitonin, growth hormones, and sex hormones |
| Metabolic role of Bone | Skeleton is the body's reservoir for 99% of calcium In cancellous bone is where the principal mechanism for raising blood calcium levels occur |
| Pituitary Dwarfism | lack of growth hormone (somatotropin) causes lack of growth at epiphyseal plates produces small long bones of the skeleton that are normal width |
| Gigantism | excessive secretion of GH causes excessive growth at epiphyseal plate, producing longer than normal bones that have the same width |
| Acromegaly | increase in growth hormone in adults causing the thickening of long bones |
| How can sex hormones affect the growth of bones | by affecting the closure of epiphyses |
| Osteosarcoma (bone tumor) | skeleton is frequently the site of metastases form other tumors like breast, prostate, colon, lung and thyroid |
| Joints | regions where bones are capped and surrounded by connective tissues based on movement permitted joints may be diarthroses or synarthroses |
| Synotoses | bones united by bone tissue sutures in skull |
| synchondroses | bones united by hyaline cartilage ribs to sternum |
| syndesmoses | bones united by fibrocartilage or ligament of dense connective tissue |
| types of synathroses | synostoses, synchondroses, and syndesmoses |
Created by:
heavenelizabeth
Popular Histology sets