basin lang Flashcards
(50 cards)
Which of the following connective tissue components is located in the ECM but not in the ground substance?
Collagen bundles
Fibronectin
GAGs
Hyaluronan
Proteoglycans
collagen bundles
What cells numerous in loose connective tissue are filled with secretory granules and stain with metachromasia?
Macrophages
Mast cells
Fibrocytes
Active fibroblasts
Leukocytes
Mast cells
What is the first step of collagen production that occurs after the protein undergoes exocytosis?
-Cross-linking of collagen fibrils with a short-linking collagen
-Removal of the terminal nonhelical domains by peptidases
-Hydroxylation of lysine and proline
-Assembly of subunits to form a larger structure
-Disulfide bond formation
Removal of the terminal nonhelical domains by peptidases
- What is an important part of the role played by macrophages dur-
ing maintenance and renewal of strong extracellular fibers in con-
nective tissue?
-Storage for a major energy source needed for ECM maintenance
-Production of specific collagen subunits
-A sentinel function against invaders entering the ECM
-Secretion of MMPs
-Presentation of antigens important for assembly of collagen
bundles
Secretion of MMPS
Sulfated GAGs are important constituents of what extracellular
structures?
-Hyaluronan
- Elastic fibers
-Type I collagen
- Proteoglycans
- Multiadhesive glycoproteins
proteoglycans
Which of the following contains binding sites for integrins and is an
important part of the ECM in both loose connective tissue and dense
irregular connective tissue?
a. Aggrecan
b. Fibronectin
c. Perlecan
d. Fibrillin
e. Most types of collagen
Fibronectin
Dense regular connective tissue typically involves which of the fol-
lowing features?
a. Contains mostly synthetically active fibroblasts
b. Contains much ground substance
c. Contains a similar cell population as areolar connective tissue
d. Predominant tissue type in the stroma of most organs
e. Predominantly located in tendons and ligaments
Predominantly located in tendons and ligaments
Research scientists at a small biotech firm are investigating new
methods of controlling the growth and metastasis of malignant
cells in patients diagnosed with breast cancer. They have developed
a novel peptide-based drug, potentially deliverable therapeutically,
that disrupts the tumor cells’ ability to adhere to the ECM, which
in turn triggers apoptosis. Which of the following is the most likely
target of such drugs?
a. Cadherins
b. Adhesins
c. Integrins
d. Glycolipids of the cell membrane
e. Fibrillin
integrins
A 36-year-old man is referred by his family physician to the pulmo-
nary clinic. He complains of shortness of breath following physical
activity and decreased capacity for exercise. He says that strenuous
exercise including yard work is impossible without sitting down and
resting every few minutes. After taking several deep breaths during
the physical examination, he begins to wheeze. He is not a smoker
and works in an office not exposed to dust, fumes, or other irritants.
He appears slightly jaundiced. Serum alpha-1-antitrypsin (AAT)
concentration analysis is below normal and is followed up with AAT
phenotype and DNA testing that indicates one copy of S and one of
Z mutations with 40% abnormal AAT production. Urinalysis shows
elevated levels of desmosine and isodesmosine. These excreted com-
pounds normally contribute to efficient lung function by which of
the following mechanisms?
a. Posttranslational modification of fibrillin
b. Cross-linking elastin
c. Activating elastase
d. Activating AAT
e. Binding type IV collagen to elastin
Cross-linking elastin
A 33-year-old homeless woman has been living in an abandoned
building and eating dried meat and bread from the dumpster behind
a delicatessen. She smokes cigarettes “bummed” from others. She
presents at a free clinic with bleeding under the skin, particularly
around hair follicles, and bruises on her arms and legs. She is irrita-
ble, clinically depressed, and fatigued with general muscle weakness.
Her gums are bleeding, swollen, purple, and spongy, with several
loose teeth. She has an infected toe, which may be broken. She is afe-
brile, a glucose finger-stick is normal, and the urine dipstick shows
no sugar, protein, or ketones. You suspect a vitamin deficiency. What
might be the underlying mechanism for this patient’s symptoms?
a. Decreased degradation of collagen
b. Stimulation of prolyl hydroxylase
c. Formation of unstable collagen helices
d. Excessive callus formation in healing fractures
e. Organ fibrosis
Formation of unstable collagen helices
The molecular basis for the shock absorbing properties of cartilage involves which of the following?
a. Electrostatic interaction of proteoglycans with type IV collagen
b. Ability of glycosaminoglycans to bind anions
c. Noncovalent binding of glycosaminoglycans to protein cores
d. Sialic acid residues in the glycoproteins
e. Hydration of glycosaminoglycans
Hydration of glycosaminoglycans
What distinguishes cartilage from most other connective tissues?
a. Its extracellular matrix is rich in collagen.
b. Its predominant cell type is a mesenchymal derivative.
C.Its predominant cell type secretes both fibers and proteoglycans.
d. It lacks blood vessels.
e. It functions in mechanical support.
It lacks blood vessels.
Which feature is typical of elastic cartilage?
a. Primary skeletal tissue in the fetus
b. No identifiable perichondrium
c. Found in intervertebral discs
d. Most widely distributed cartilage type in the body
e. Collagen is mainly type
Collagen is mainly type
Which area in cartilage is relatively collagen-poor and proteoglycan-rich?
a. Fibrocartilage
b. Territorial matrix
c. Epiphyseal plate
d. Interterritorial matrix
e. perichondrium
Territorial matrix
What is the source of the mesenchymal progenitor cells activated for the repair of hyaline cartilage of accident-damaged costal cartilages?
a. Perichondrium
b. Adjacent loose connective tissue
c. Bone of the adjacent ribs) and sternum
d. Chondrocytes of the injured cartilage
e. Stem cells circulating with blood
Perichondrium
How does articular cartilage differ from most other hyaline cartilage?
a. It undergoes mainly appositional growth.
b. It contains isogenous groups of chondrocytes.
c. It lacks a perichondrium.
d. Its matrix contains aggrecan.
e. It is derived from embryonic mesenchyme.
It lacks a perichondrium.
Which step occurs first in chondrogenesis?
a. Appositional growth
b. Conversion of chondroblasts to chondrocytes
c. Formation of mesenchymal condensations
d. Interstitial growth
e. Secretion of collagen-rich and proteoglycan-rich matrix
Formation of mesenchymal condensations
Osteoarthritis is characterized by the progressive erosion of articu-lar cartilage. The matrix metalloproteinases involved in this erosion primarily act on which matrix component?
a. Aggrecan
b. Link proteins
c. Network-forming collagen
d. Fibril-forming collagen
e. Chondronectin
Fibril-forming collagen
A 28-year-old woman visits the family medicine clinic complaining of loss of the sense of smell, nosebleeds, problems with swallowing, and hoarseness. She admits to “casual, social use” of cocaine on a regular basis since her sophomore year of college. A complete examination of her nose with a speculum and otoscope shows severe rhinitis (inflam-mation). There is also perforation and collapse of the nasal cartilage resulting in a “saddle nose” deformity. Erosions in the enamel of her front teeth are noted. The breakdown of the nasal cartilage releases collagen fibers primarily of which type?
a. Type I
b. Type II с. Type III
d. Type IV
e. Type VII
Type II
A 66-year-old man who suffered from severe osteoarthritis is referred to an orthopedic surgeon for replacement of his right knee.
He had been actively involved in both high school and intercollegiate football and had continued running until about the age of 45 as a form of relaxation and exercise. With the patients permission, the removed joint is used by investigators performing a proteomic analysis of different joint tissues. The meniscus was found to contain almost exclusively type I collagen and aggrecan was undetectable.
What is the most likely explanation for this result?
a. The meniscus normally consists of dense regular connective tis-sue, which contains primarily type I collagen.
b. The meniscus normally consists of fibrocartilage, which contains only type I collagen.
c. The meniscus had undergone repeated rounds of repair due to wear-and-tear during which its hyaline cartilage component was replaced by dense connective tissue.
d. Osteoarthritic injury in the knee resulted in the chondrocytes of the meniscus switching from expression of genes for type II collagen to type I collagen.
e. Elastic cartilage is normally replaced by fibrocartilage during aging and this process can be accelerated by exercise.
The meniscus had undergone repeated rounds of repair due to wear-and-tear during which its hyaline cartilage component was replaced by dense connective tissue.
Which component of bone impedes the distribution of nutrients and oxygen to osteocytes?
a. ECM
b. Canaliculi Periosteum
d.Cell processes
e. Haversian canals
Haversian Canals
Which if the following most accurately describes compact bone?
a. Predominant bone type in the epiphyses of adult long bones
b. Also known as cancellous bone
c. Characterized by the presence of osteons
d. Lines the medullary (marrow) cavity
e. Forms the diploe in cranial bones
Characterized by the presence of osteons
In healthy bone, canaliculi are likely to contain which one of the following?
a. Capillaries
b. Nerve axons
c Osteocytic processes
d. Osteoid
e. Osteoclasts in resorption lacunae
Osteocytic processes
Which of the following most accurately describes the endosteum?
a. Composed of two layers: osteogenic and fibrous
b. Continuous with the joint capsule
c. Attached to the bone surface by collagen bundles called Sharpey
fibers
d. Lines the medullary cavity
e. Contains mature osteocytes
Lines the medullary cavity
