Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
75 Cards in this Set
- Front
- Back
|
In fibrous CT are found what type(s) of:
cell types collagens glycosaminoglycans (GAGS) adhesive glycoproteins |
cells: fibroblasts, hepatocytes, myoblasts
collagens: Type I (forms bundles) GAGS: Hyaluronic acid, Chondroitin Sulfate, Haparan Sulfate Adhesive GPs: Fibronectin (FN) |
|
|
In cartilage, vitreous body, is found what...
cell type(s) collagens GAGS Adhesive glycoproteins |
Cells: chondrocytes
Collagens: Type II (forms fibers) GAGS: Hyalonuric Acid, Chondroitin Sulfate, Keratan Sulfate Adhesive GPs: Chondronectin |
|
|
In basement membrane is found what
Cell types Collagens GAGS Adhesive GPs |
Cells: Epithelial and Endothelial cells
Collagens: Type IV GAGS: Chondroitin Sulfate, Heparan Sulfate, Dermatan Sulfate Adhesive GPs: Laminin |
|
|
What does Type III collagen form and where is it found?
|
Reticular fibers
smooth mm, marrow, lung vessels, lymph organs |
|
|
What is the main difference between types of ECM and how do you distinguish using LM?
|
Identity proportion of
Cells - indicated by dark staining of nuclei GAGS - white space, corresponding to ground substance (unstained) Collagen - pink, eosinophilic fibers OUTSIDE of cells |
|
|
2 features of Collagen PRIMARY STRUCTURE
|
(1) Every 3rd residue = Gly
(2) high Pro and Lys content, some of which are hydroxylated to form point of attachment of sugars (--> glycoprotein) |
|
|
Describe SECONDARY STRUCTURE of collagen
|
Entirely helical, but NOT alpha-helical
|
|
|
Describe TERTIARY STRUCTURE of collagen
|
There is no tertiary structure
|
|
|
QUATERNARY STRUCTURE of collagen
|
Triple helix
- can fit closely together b/c every third residue is Gly which offers little steric hindrance |
|
|
How are collagen fibrils stabilized?
|
Repetetive H bonds
COVALENT cross-linking btw collagen molecules |
|
|
3 collagen defects/diseases
|
Osteogenesis imprefecta (Gly988 --> Cys988, disrupts triple helix; brittle bones & skeletal deformities)
Ehlors-Danlas Syndrome (congenital, defective post-translational steps of fiber formation; hypermobility of joints) Scurvy (Vit. C deficiency) |
|
|
Describe the pathway from Vit C deficiency to SCURVY
|
Ascorbate = required co-factor of prolyl hydroxylase and lysyl hydrolase.
Decrease in functional hydroxylating enzymes --> decrease in stabilizing H bonds between fibrils Problems occur most where collagen turnover is high |
|
|
Of what 3 PROTEINS are ELASTIC FIBERS composed?
|
ELASTIN
FIBRILLIN MAGP (microfibril-associated glycoprotein) |
|
|
Describe COMPOSITION of ELASTIN
|
collagen-like protein
Gly and Pro rich 2 unusual amino acids: desmosine and isodemosine, which are easily cross-linked, providing great elasticity |
|
|
Describe arrangement of 3 proteins in elastin
(p. 196 CP) |
Elastin in two parallel sheets
MAGP sandwhiched in between elastin Fibrillin runs from inner surface of one elastin molecule, across MAGP, to outer surface of next elastin over on opposite side |
|
|
2 common properties of GAGS
|
Polysaccharides consisting of repeating disaccharide units
negatively charged b/c of COO- and SO4- groups |
|
|
In what form do most GAGS exist?
|
PROTEOGLYCAN
|
|
|
3 DOMIAINS of GAG Proteoglycans
|
CS region (closest to COOH terminal)
-100 C4S chains cov. attached to core protein KS region (middle) - ~60 KS chains cov. attached to core protein HA BINDING region - devoid of GAGs in proteoglycan molecule, but used to bind non-covalently to HA in forming proteoglycan AGGREGATE |
|
|
PROTEOGLYCAN AGGREGATE
|
aka: aggrecan of cartilage
links individual proteoglycan molecules through HA binding region to HA backbone to form aggregate |
|
|
Physical properties of proteoglycans
|
(1) high density negative charges
(2) adjacent GAGs and proteoglycans REPEL each other (3) proteoglycans occupy largest possible space, encompassing large volume of water (4) can regulate fluid balance through REVERSIBLE COMPRESSIBLITY |
|
|
REVERSIBLE COMPRESSIBILITY
|
mechanism for fluid exchange - important to avascular tissue for obtaining nutrients
when pressure applied, structures deform by squeezing out water; when pressure removed, repulsion drives structure to expand and water reenters |
|
|
What ion do SO4(-2) and COO(-) groups bind, and why?
|
Ca2+
to provide physical shield for preventing growth of calcium crystals (calcification, Ca3(PO4)2) |
|
|
FUNCTION of ADHESIVE GLYCOPROTEINS
|
link ECM components to the cell
|
|
|
QUATERNARY STRUCTURE of FIBRONECTIN
|
2 polypeptides linked by S-S bonds
|
|
|
5 binding domains on each FN polypeptide
|
(1) Fibrin-binding
(2) Collagen-binding (3) Cell-binding (4) - Heparan-binding (5) Fibrin-binding |
|
|
Which which 2 domains does FN bind ECM
|
Collagen binding domain
Heparan binding domain |
|
|
Describe FN cell binding domain
|
sequence motif RGD (Arg, Gly, Asp) binds INTEGRINS (transmembrane receptors)
|
|
|
Finish the (general) pathway:
Binding of ligands (e.g.: heparin) to FN on outside of cell --> This is an example of what type of cell-cell signaling and why? |
--> signals to inside of cell
--> alters actin cytoskeleton --> modulates response of cell to other signals JUXTACRINE - mechanical linkage, followed by biochemical signal |
|
|
Examples of chemical signals whose effect on cells is modulated by the binding of ligands to the integrin receptors on those cells
|
heparan-dependent GF
fibroblast GF (thus demonstrating the importance of ANCHORAGE) |
|
|
Define BASAL LAMINA
|
interface btw sheet of epithelial cells anchored to underlying CT
synthesized by epithelial cells |
|
|
Define LAMINA RETICULARIS
|
CT underlying basal lamina
synthesized by CT cells |
|
|
Define BASEMENT MEMBRANE
|
LM designation corresponding to basal lamina + lamina reticularis
|
|
|
Define EXTERNAL LAMINA
|
structure corresponding to basal lamina for
(1) smooth and skeletal mm. (2) adipose tissue (3) Schwann cells |
|
|
3 FUNCTIONS of all types of basal lamina
|
(1) attachment
(2) barrier (e.g.: in kidney) (3) restricts/regulates epithelial migration |
|
|
Following for Basal Lamina:
Collagen Proteoglycans Adhesive GPs |
Collagen: mostly Type IV
Proteoglycans: percalan (heparan sulfate proteoglycan) Adhesive GPS: laminin and entactin |
|
|
For Lamina reticularis,
Collagen Adhesive GP |
Collagen: TYpe III
Adhesive GP: FN |
|
|
Type of cartilage found in...
EPIPHYSEAL PLATES |
HYALINE CARTILAGE
|
|
|
Type of cartilage found in...
COSTAL CARTILAGES |
HYALINE CARTILAGE
|
|
|
Type of cartilage found in...
NASAL CAVITY |
HYALINE CARTILAGE
|
|
|
Type of cartilage found in...
LARYNX |
HYALINE CARTILAGE
|
|
|
Type of cartilage found in...
TRACHEA |
HYALINE CARTILAGE
|
|
|
Type of cartilage found in...
PINNA OF EXTERNAL EAR |
ELASTIC CARTILAGE
|
|
|
Type of cartilage found in...
EXTERNAL ACOUSTIC MEATUS |
ELASTIC CARTILAGE
|
|
|
Type of cartilage found in...
AUDITORY TUBE |
ELASTIC CARTILAGE
|
|
|
Type of cartilage found in...
EPIGLOTTIS |
ELASTIC CARTILAGE
|
|
|
Type of cartilage found in...
INTERVERTEBRAL DISKS |
FIBROCARTILAGE
|
|
|
Type of cartilage found in ...
SYMPHYSIS PUBIS |
FIBROCARTILAGE
|
|
|
Type of cartilage found in ...
ARTICULAR DISKS |
FIBROCARTILAGE
|
|
|
Type of cartilage found in ...
MENISCUS |
FIBROCARTILAGE
|
|
|
Type of cartilage found in ...
INSERTION OF TENDONS |
FIBROCARTILAGE
|
|
|
What cellular activity is indicated by cytoplasmic basophilia?
|
PROTEIN SYNTHESIS
(e.g: in chondrocytes active in matrix production) |
|
|
The cartilage in the epiphyseal growth plate remains functional as long as...
|
...the bone grows in length
|
|
|
IN what 4 locations of the adult body is hyaline cartilage present?
|
trachea, bronchi, larynx, nose
|
|
|
In what 3 locations of the adult body is elastic cartilage present?
|
external acoustic meatus, auditory tube, epiglottis
|
|
|
What types of cartilage are surrounded by perichondrium?
|
Non-articular hyaline cartilage
Elastic cartilage |
|
|
PERICHONDRIUM
|
dense CT composed of cells indistinguishable from fibroblasts.
Analogous to capsule surrounding organ. Source of new cartilage cells |
|
|
Fibrocartilage is a combination of... (2 things)
|
(1) dense regular CT
(2) hyaline cartilage |
|
|
Describe the distribution of chondrocytes in fibrocartilage
|
chondrocytes dispersed
singularly and in rows in isogenous pairs/groups LESS matrix associated with them than in hyaline cartilage |
|
|
What requirement is indicated of tissue possessing fibrocartilage?
|
resistance to compression and shearing forces
|
|
|
First step of chondrogenesis
|
aggregation of chondroprogenitor MESENCHYMAL CELLS
|
|
|
Which transcription factor differentiates chondroprogenitor mesenchymal cells into CHONDROBLASTS?
|
SOX-9
|
|
|
At what stage are chondroblasts considered chondrocytes?
|
When they are completely surrounded by matrix
|
|
|
APPOSITIONAL GROWTH
|
process that forms new cartilage at the surface of existing cartilage
|
|
|
INTERSTITIAL GROWTH
|
process that forms new cartlage within an existing cartilage mass
|
|
|
New cartilage cells produced during APPOSITIONAL GROWTH derive from...
|
surrounding perichondrium
|
|
|
New cartilage ceels produced during INTERSTITIAL GROWTH derive from...
|
division of chondrocytes within their lacunae
|
|
|
OSTEOPROGENITOR CELLS
|
derived from mesenchymal cells
give rise to osteoblasts |
|
|
OSTEOBLASTS
|
secrete ECM of bone
|
|
|
OSTEOCYTE
|
osteoblast fully surrounded by secreted matrix
|
|
|
OXTEOCLASTS
|
bone-resorbing cells (phagocytotic)
multinucleate |
|
|
OSTEOCLASTS are derived from...
|
fusion of HEMOPOIETIC PROGENITOR CELLS and MONOCYTE LINEAGES
|
|
|
Osteoblasts can derive from which cells in mature bone?
|
PERIOSTEAL CELLS
|
|
|
SHARPEY'S FIBERS
|
strong, collagenous fibers connecting bone to ligaments and tendons
run at angle to fibers of bone CT |
|
|
What regions does ENDOSTEUM line?
|
area of compact bone facing marrow cavity
trabeculae of spongy bone within marrow cavity |
|
|
Through what structures do blood vessels run in bone?
|
Haversian and Volksmann's Canals
|
