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127 Cards in this Set
- Front
- Back
What are the two components of ECM?
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- ground substance
- fibers |
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What are the components in the ground substances of ECM?
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1) GAGs: long, unbranched polymer of disaccharides
- hyaluronic acid - chondroitin sulfate: hyaline cartilage, elastic cartilage, bones. - dermatan sulfate:bind type I collagen - keratin sulfate: bone, cartilage, cornea - heparan sulfate (intracellular): bind FGF 2) proteoglycans: GAGs + core protein - aggrecan: keratan sulfate, chondroitin sulfate - perlecan: helaran sulfate 3) glycoproteins: - fibronectin: bind type I, III, IV collagen, RGD sequence - laminin: bind type IV collagen, heparan sulfate, integrins, entactin - entactin: link laminin with type IV collagen - chondronectin: bind type II collagen (in cartilage) - osteopontin: cell adhesion to ECM (include osteoclasts) - ocsteonectin - thrombospondin |
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What is a major function of GAGs in ECM?
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Resist compression:
sulfated GAGs carry - charge -> attract + charge (Na) -> hydration -> resist compression |
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What types of GAGs are there?
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1) hyaluronic acid
2) chondroitin sulfate 3) dermatan sulfate: bind to type I collagen 4) keratin sulfate 4) heparan sulfate |
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Where do you find hyaluronic acid, a type of GAG?
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widely distributed:
- loose connective tissue - skin - unbilical cord - synovial fluid - cartilage |
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Where do you find chondroitin sulfate, a type of GAG?
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- hyaline cartilage
- elastic cartilage - bone |
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Where do you find dermatan sulfate, a type of GAG?
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- dermis
- tendons - ligaments - heart valves - organ capsules - sclera - fibrocartilage - arteries (adventitia) - nerves (epineurium) |
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Where do you find keratan sulfate, a type of GAG?
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- bone
- cartilage - cornea |
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Where do you find heparan sulfate, a type of GAG?
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- fibroblast and epithelial cell surface
- basal and external lamina |
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Which of the following GAGs binds type I collagen fibrils?
- hyaluronic acid - chondroitin sulfate - dermatan sulfate - keratan sulfate - heparan sulfate |
dermatan sulfate
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Which of the following GAGs is intracelluar?
- hyaluronic acid - chondroitin sulfate - dermatan sulfate - keratan sulfate - heparan sulfate |
heparan sulfate
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What is it called when a GAGs are attached to a core protein?
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proteoglycan
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Which of the following GAGs provide mechanical support?
- hyaluronic acid - chondroitin sulfate - dermatan sulfate - keratan sulfate - heparan sulfate |
- chondroitin sulfate
- keratan sulfate |
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Which of the following GAGs resist compressive force?
- hyaluronic acid - chondroitin sulfate - dermatan sulfate - keratan sulfate - heparan sulfate |
- hyaluronic acid
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Name two types of proteoglycans.
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- aggrecan: core protein + keratan sulfate and chondroitin sulfate
- perlecan: core protein + heparan sulfate |
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What is the function of aggrecan, a type of proteoglycan?
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- Binding sites for growth factors (i.e. FGF) and other signaling molecules.
- selective permeability to ECM in certain locations. |
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Where do you find glycoprotein fibronectin and what is its specific function at each location?
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1) in matrix: forms fibrils in ECM, cell adhesion (actin cytoskeleton) to ECM by binding to fibronectin receptor on cell surface.
2) on cell surface: transiently adhere cells to ECM 3) in plasma: blood clotting, would healing, phagocytosis |
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What family of receptor does fibronectin receptor belong to?
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integrin family of receptors
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How does fibronectin bind to fibronectin receptors?
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via RGD sequence (arg-gly-asp)
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What does fibronectin bind to?
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- fibronectin receptors (RGD sequence)
- collagen: type I, III, IV - heparan sulfate - hyaluronic acid |
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Which of the folllowing type of glycoprotein binds to type I, III, IV collagen?
- fibronectin - laminin - entactin - chondronectin - osteopontin - osteonectin - thrombospondin |
- fibronectin
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Which of the folllowing type of glycoprotein binds to type II collagen?
- fibronectin - laminin - entactin - chondronectin - osteopontin - osteonectin - thrombospondin |
- chondronectin
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Which of the folllowing type of glycoprotein binds to type IV collagen?
- fibronectin - laminin - entactin - chondronectin - osteopontin - osteonectin - thrombospondin |
- laminin (IV)
- fibronectin (I, III, IV) |
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Which of the folllowing type of glycoprotein binds to laminin and type IV collagen?
- fibronectin - laminin - entactin - chondronectin - osteopontin - osteonectin - thrombospondin |
- entactin
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Which of the folllowing type of glycoprotein promote cell adhesion to ECM including osteoclasts in bones?
- fibronectin - laminin - entactin - chondronectin - osteopontin - osteonectin - thrombospondin |
- osteopontin
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Which of the folllowing type of glycoprotein links material to type I collagen and influences calcification by inhibiting crystal growth?
- fibronectin - laminin - entactin - chondronectin - osteopontin - osteonectin - thrombospondin |
- osteonectin
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What does lamine, a type of glycoprotein, bind?
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- cell surface integrin
- heparan sulfate - type IV collagen - entactin |
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What is the most abundant structural protein of the ECM?
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collagen
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Where do you find type II collagen fibrils?
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- hyaline cartilage
- elastic cartilage - vitreous body - nucleus pulposus |
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Chondrocytes make what type of collagen?
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Type II
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What is the function of type I collagen?
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resist tension
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What is the function of type II collagen?
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- resist intemittent pressure
- provide clear path for light in the eye (vitreous body) |
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What is the function of type III collagen?
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structural maintenance in expansible organs
- dermis - muscularis of arteries - intestines - uterus |
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What types of collagens form fibrils?
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Type I, II, III, V, VII, XI
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Which type of collagen forms sheetlike network?
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Type IV:
- support and filtration in basal(external) lamina. |
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Which type of collagen link type IV collagen of basal lamina to underlying connective tissue at epidermal-dermal junction?
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Type VII: anchoring fibril
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What types of collagen are linkers (FACIT) collagen?
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- type IX: bind to type II collagen, in hyaline cartilage.
- type XII: bind to type I collagen, in skin. |
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Which type of collagen is a marker for epiphyseal growth palte cartilage?
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Type X
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Where do the following events of collagen synthesis happen?be specific.
- preprocollagen synthesis - hydroxylation - glycosylation - procollagen formation |
intracellular: ER
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What is the function of procollagen peptidase and where is it located?
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- cleave procollagen and convert to tropocollagen
- on E surface of fibroblast |
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What amino acids do you find in tropocollagen?
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- glycine: every third AA
- hydroxyproline: precedes gly - proline: follow gly - hydroxylysine: unique to collagen |
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What stage of collagen synthesis is this?
triple helix axial polarity 280nm long, 1.5nm in diameter |
tropocollagen
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Where do the following events of collagen synthesis happen?be specific.
- addition of carbohydrates to procollagen |
golgi
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Where do the following events of collagen synthesis happen?be specific.
- cleavage of procollagen by procollagen peptidase |
E-surface of fibroblast
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Where do the following events of collagen synthesis happen?
- crosslinking of tropocollagen by lysyl oxidase |
ECM
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Where are the genes encoding alpha chains of collagen located?
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chromosomes 7 and 17
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Describe the banding pattern of type I,II,and III collagen.
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transverse banding periodicity of 67nm: dark-light-dark pattern
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Tensile strength of collagen is provided by ____.
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crosslinking of tropocollagen by lysyl oxidase.
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Lysyl oxidase crosslinks which two fibers?
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- collagen
- elastin |
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Give two types of elastic fibers.
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- elastin
- fibrillin |
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What amino acids do you find in elastin?
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- glycine
- proline - desmosine, isodesmosine |
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What is the function of fibrillin?
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- main component of the peripheral microfibrils that are part of elastic fibers.
- organize elastin into fibers |
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Name three dense regular connective tissue.
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- tendons
- ligaments - aponeurosis |
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What type of connective tissue is this?
- attaches bone to bone |
ligaments
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What type of connective tissue is this?
- attaches a muscle to the periosteum of a bone |
tendon
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What type of connective tissue is this?
- extends from a skeletal muscle as a broad, flat layer. |
aponneurosis
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Where are Golgi tendon organs located?
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at the junction of a tendon and a muscle
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What is the function of tendon organs?
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- initiate tendon reflexes
- protect tendons and associate muscles from damage due to excessive tension. - monitor muscle contraction |
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T/F: Tendon organs had a thin capsule of connective tissue that encloses a few tendon fascicles.
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T.
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How does tendon organs protect tendons and associate muscles from excessive tension?
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- feedback inhibition: increase tension -> increase frequency of inhibitory impulses -> inhibition of muscle contraction
- excite motor neurons that innervate antagonistic muscles |
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What is this phenomenon?
droping of the heavy weight that you thought you can lift. |
Tendon reflex
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T/F: Cartilage is a special type of fibrous connective tissue.
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T.
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T/F: Cartilage is vascular.
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F.
Cartilage is avascular (except in the perichondrion): - no blood vessels - no nerves |
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What type of tissue is perichondrion?
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dense irregular connective tissue
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How does cartilage receive nutrients since it is avascular?
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diffusion
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Name the three types of cartilage.
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1) hyaline cartilage
2) elastic cartilage 3) fibrocartilage |
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Which type of cartilage is this?
- contains a resilent gel - most abundant in the body - weakest of the three |
hyaline cartilage
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Where do you find hyaline cartilage in adults?
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- articular ends of long bones
- walls of larger respiratory passages: nose, larynx, trachea, bronchi. - ventral ends of ribs |
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Where do you find hyaline cartilage in fetuses?
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- temporary skeleton, later replaced with bone
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What does hyaline cartilage matrix contain?
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- aggrecan proteoglycan: chondroitin sulfate, keratan sulfate
- chondronectin (glycoprotein) - type II collagen: not visible since it only forms fibrils - territorial matrix - interterritorial matrix |
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What are the two places you don't see perichondrion around cartilages?
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- articular surface in joints
- epiphyseal plate |
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How many layers are there in perichondrion and what does each layer contain?
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1)outer fibrous layer:
- type I collagen - fibroblasts - blood vessels 2)inner chondrogenic layer: - chondroblasts |
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What is the function of perichondrion?
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- provide blood supply for the avascular cartilaginous tissue.
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What type of cells are located superfically and deeper in hyaline cartilage?
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- superficial: ovoid chondrocytes
- deeper: spherical chondrocytes, may form cell nests |
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What do chondrocytes do?
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- manufacture cartilage matrix through nutrients and wastes materials pass to and from cells.
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T/F: Cartilages are metabolically inactive.
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T.
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What growth mechanism(s) do cartilages utilize?
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- interstitial: during childhood and adolescence
- appositional: starts later, continues throughout life |
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Which type of cartilage growth mechanism is this?
- division of preexisting chrondrocytes - during childhood and adolescents |
interstital
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Which type of cartilage growth mechanism is this?
- deeper cells of chondrogenic layer of perichondrion divide and differentiate into chondrocytes - continues throughout life |
appositional
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What type of cartilage is this?
- yellowish perichondrion which contains network of elastic fibers |
elastic cartilage
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Where do you find elastic cartilage?
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- pinna of ears
- eustachian tube - epiglottis |
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What type of cartilage is this?
- lacks identifiable perichondrion - alternating rows of chondrocytes (fibroblast-derived) and type I collagen - strongest of the three |
fibrocartilage
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Where do you find fibrocartilage in the body?
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- intervertebral disks
- articular disks - pubic symphysis - insertions of some tendons and ligaments. |
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T/F: Bone is a dynamic tissue that constantly undergoes changes in shapes.
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T.
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Applied pressure results in ___, whereas applied tension results in ____.
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Applied pressure results in bone resorption, whereas applied tension results in bone formation.
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What are the two components of bone matrix?
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1) mineral (inorganic) portion:
- hydroxyappetite (calcium phosphate) - citrate ions - bicarbonate ions 2) organic portion: osteoid - proteoglycans: chondroitin sulfate, keratan sulfate - gylcoproteins: osteonectin, osteocalcin, osteopontin |
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How is periosteum attached to bone?
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Sharpey's fibers: type I collagen.
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Which of the following cells is located in the bone matrix whereas others are located in the surface of bone matrix?
- osteoprogenitor cells - osteoblasts - osteocytes - osteoclasts |
- osteocytes
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Name the two types of bones.
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1) spongy(cancellous, trabecullar) bone:
- interconnected trabecullae 2) compact (cortical) bone: - no trabeculae or marrow cavities |
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Which classification of bone is this?
- 1st compact bone produced during fetal development and bone repair - many osteocytes - large, irregularly arranged collagen bundles - low mineral content |
- primary (immature, woven) bone
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Which classification of bone is this?
- compact bone of adult - calcified matrix arranged in regular concentric layers (lamellae) - osteon (Haversian system) |
- secondary (mature, lamelar) bone
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What growth mechanism(s) does bone utilize?
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appositional only!
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Why do bones only do appositional growth?
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- osteocytes are end cells: not able to divide
- nonexpandable lacuna: calcified matrix |
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What are the two types of osteogenesis?
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- intramembranous ossification
- endochondrial ossification |
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Explain intramembranous ossification.
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Occurs in embryo:
- mesencyme -> condense to sheets of highly vascular connective tissue -> form primary ossification center (* direct conversion from mesenchyme to primary ossification center) |
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What bones in our body are formed by intramembranous ossification?
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flat bones of the skull
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Explain endochondrial ossification.
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In embryo:
- mesenchyme -> form hyaline cartilage model of ossification at the diaphysis -> matrix calcification -> death of hypertrophied chondrocytes -> form periosteal bone collar -> invasion of periosteal bud (nutrient artery and osteoprogenitor cells)-> primary center of ossification (diaphysis) -> form marrow cavity After birth: - secondary ossification centered at the epiphysis at each end of the bone |
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How do bones grow in length?
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- interstitial growth of cartilage at epiphyseal plate
- bone resorption by oseoclasts in the zone of ossification. |
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Name the zones in epiphyseal plate.
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1) zone of reserve (resting cartilage): inactive chondrocytes
2) zone of proliferation: - hGH-> IGF -> chondrocytes divide. - Ihh -> PTH-RP -> chondrocyte proliferation, inhibit hypertrophy - Ihh -> regulate formation of bone collar 3) zone of hypertrophy: maturing cartilage - ALPase - VEGF -> invasion of blood vessels -> break through horizontal walls - type X collagen: marker of differentiation 4) zone of calcification: - dead chondrocytes - calcified matrix 5) zone of ossification: - progenitor cells become osteoblasts(produce osteoid), osteoclasts (bone resorption, remove calcified matrix) |
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How is the balance between proliferating and hypertrophic chondrocytes achieved?
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Feedback loop between Ihh and PTH-RP:
- Ihh secreted by chondrocytes in proliferating zone: regulate bone collar formation - Ihh stimulate PTH-RP which stimulate chondrocyte proliferation and inhibit hypertrophy. |
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When does fetal hematopoiesis start?
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5th month.
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What molecules do hypertrophied chondrocytes secrete?
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- ALPase: increase Ca2+ and PO4 levels.
- VEGF: induce blood vessel invasion - type X collagen: marker for differentiation |
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How do bone grow in diameter?
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Appostional growth
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All synovial joints are classified as ____.
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diarthrosis
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Synovial cavity is enclosed by ____ except at the area of articular cartilage.
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articular capsule
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Describe the layers of articular capsule.
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1) outer fibrous capsule:
- dense irregular connective tissue that attaches to periosteum of bones - prevent bone dislocation, resist strains 2) inner synovial membrane: - areolar connective tissue with elastic fibers - Type A cells: macrophages (remove debris) - Type B cells: resemble fibroblasts (secrete synovial fluid), well developed RER. |
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Which type of cell in synovial membrane is this?
- well developed RER - secrete synovial fluid |
Type B cells: resemble fibroblasts
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Which type of cell in synovial membrane is this?
- small amount of RER - remove debris from joint spaces |
Type A cells: macrophages
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What is the function of synovial fluid?
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- reduce friction
- supply nutrients to chondrocytes - remove wastes - has phagocytes to remove microbes and debris |
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What is the appearnce and content of synovial fluid?
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- appearance: viscous, clear, pale, yellow fluid
- contents: hyaluronic acid interstitial fluid filtered from plasma phagocytic cells |
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What is the benefit of warming up before exercise?
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It stimulates the production and secretion of synovial fluid.
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How does articular cartilage act as absorber of intermittent mechanical pressure?
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- hydrophilic proteoglycans contain lots of water
- reciprocal electrostatic repulsion of - charged GAG creat spaces for water |
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How is type II collagen arranged in articular cartilages?
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as gothic arches: distribute forces generated by pressure in the tissue.
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Which of the following types of synovial joints does not do angular movements?
- plannar - hinge - pivot - condyloid - saddle - ball and socket |
plannar:
- intercarpal - sternocostal - vertbrocostal |
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Structural classification of joints is based on what two facts?
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1) presence/absence of a synovial cavity
2) type of connective tissue that binds bones together - fibrous joints: sutures, syndemosis, gomphosis - cartilagenous joints: synchondrosis, symphysis - synovial joints |
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What are some functional classification of joints?
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- synarthrosis: immovable
- amphiarthrosis: slightly movable - diarthrosis: freely movable |
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Name some fibrous joints.
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- sutures
- syndemosis: distal tibiofibular joint - gomphosis |
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Name some cartilaginous joints.
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- syncondrosis: connecting material is hyaline cartilage (epiphyseal plate)
- symphysis: bones connected by flat disc of fibrocartilage (pubic symphysis, intervertebral disc) |
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What type of joint is this?
sutures |
fibrous joint or synarthrosis
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What type of joint is this?
syndemosis |
fibrous joints
syndemosis: greater distance between articulating bones and more fibrous connective tissue. |
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What type of joint is this?
distal tibiofibular joint |
syndemosis
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What type of joint is this?
gomphosis |
fibrous joint
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What type of joint is this?
synchondrosis |
cartilaginous joint
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What type of joint is this?
symphysis |
cartilaginous joints
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What type of joint is this?
epiphyseal plate |
synchondrosis
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What type of joint is this?
pubic symphysis |
symphysis
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What type of joint is this?
intervertebral disc |
symphysis
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