Histology Test 1 Questions

1. In preparing tissue for routine light microscopic study, which procedure immediately precedes clearing the specimen with an organic solvent? a. Dehydration b. Fixation c. Staining d. Clearing e. Embedding

A

1. Which component of bone impedes the distribution of nutrients and oxygen to osteocytes? a. ECM b. Canaliculi c. Periosteum d. Cell processes e. Haversian canals

A

1. Which of the following connective tissue components is located in the ECM but not in the ground substance? a. Collagen bundles b. Fibronectin c. GAGs d. Hyaluronan e. Proteoglycans

A

10. A 42-year-old woman of Mediterranean descent presents with multiple oral blisters and a few cutaneous blisters on her back and buttocks. The superficial bullae are fragile, some have unroofed to form ulcerated lesions, and there is a positive Nikolsky sign. Blood tests reveal antibodies to a subfamily of cadherins and immunohistochemical staining of a biopsy from the oral mucosa shows distribution of the antigen throughout the epithelium. In what structures is the defect that is causing this patient's condition? a. Desmosomes b. Tight junctions c. Hemidesmosomes d. Gap junctions e. Reticular lamina

A

10. A healthy 32-year-old man lifts weights regularly as part of his workout. In one of his biceps muscle fibers at rest, the length of the I band is 1.0 μm and the A band is 1.5 μm. Contraction of that muscle fiber results in a 10% shortening of the length of the sarcomere. What is the length of the A band after the shortening produced by muscle contraction? a. 1.50 μm b. 1.35 μm c. 1.00 μm d. 1.90 μm e. 0.45 μm

A

3. An individual genetically unable to synthesize normal occludin is likely to have epithelia with defective regulation in which of the following? a. Material crossing the epithelium between the cells (paracellular movement) b. Communication between the cells c. Attachment to the basement membrane d. Strong attachment to neighboring cells e. Movement of membrane proteins in the apical domains of cells

A

5. 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 rib(s) and sternum d. Chondrocytes of the injured cartilage e. Stem cells circulating with blood

A

6. Resolution in electron microscopy greatly exceeds that of light microscopy due to which of the following? a. The wavelength of the electrons in the microscope beam is shorter than that of a beam of light. b. The lenses of an electron microscope are of greatly improved quality. c. For electron microscopy the tissue specimen does not require staining. d. The electron microscope allows much greater magnification of a projected image than a light microscope provides. e. An electron microscope can be much more finely controlled than a light microscope.

A

9. An 11-month-old girl is referred to a pediatric gastroenterology clinic due to a history of generalized weakness, slow growth, and refractory diarrhea. For the past month she has been hospitalized regularly to receive parenteral nutrition. Examination of the epithelium lining her small intestine confirms that the failure to absorb nutrients is most likely due to a significant decrease in which of the following? a. Microvilli b. Gap junctions c. Cilia d. Cell layers e. Basement membrane thickness

A

1. Functions of the basement membrane include which of the following? a. Contractility b. Molecular filtering c. Active ion transport d. Excitability e. Modification of secreted proteins

B

2. What cells numerous in loose connective tissue are filled with secretory granules and stain with metachromasia? a. Macrophages b. Mast cells c. Fibrocytes d. Active fibroblasts e. Leukocytes

B

2. With the transmission electron microscope skeletal muscle fibers can be seen to contain structures called triads. What do the two lateral components of a triad represent? a. Attachment sites for thick myofilaments b. Sites for calcium sequestration and release c. Sites for impulse conduction into the fiber d. Sites for ATP production e. Sites for synthesis of proteins to be secreted outside the cell

B

3. In a light microscope used for histology, resolution and magnification of cells are largely dependent on which component? a. Condenser b. Objective lens c. Eyepieces or ocular lenses d. Specimen slide e. The control for illumination intensity

B

3. What is the first step of collagen production that occurs after the protein undergoes exocytosis? a. Cross-linking of collagen fibrils with a short-linking collagen b. Removal of the terminal nonhelical domains by peptidases c. Hydroxylation of lysine and proline d. Assembly of subunits to form a larger structure e. Disulfide bond formation

B

4. In smooth muscle calcium released by the smooth ER initiates contraction by binding to what protein? a. Actin b. Calmodulin c. Desmin d. Myosin light chain kinase e. Tropomyosin

B

4. Which area in cartilage is relatively collagen-poor and proteoglycan-rich? a. Fibrocartilage b. Territorial matrix c. Epiphyseal plate d. Interterritorial matrix e. Perichondrium

B

5. Which of the following cellular features is used in naming types of epithelia? a. Shape of cells in the basal layer b. Number of cell layers c. Presence of a basal lamina d. Size of the nuclei e. Nature of the cell junctions that are present

B

6. 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

B

7. Microscopic autoradiography uses radioactivity and can be employed to study what features in a tissue section? a. The types of enzymes found in various cell locations b. Cellular sites where various macromolecules are synthesized c. The sequences of mRNA made in the cells d. The dimensions of structures within the cells e. The locations of genes transcribed for specific mRNA

B

7. The major lubricant for diarthrotic joints is synthesized by cells located in which joint structure? a. Nucleus pulposus b. Synovial membrane c. Articular cartilage d. Annulus fibrosus e. Fibrous capsule

B

8. With a 5-year history of chronic respiratory infections, a 23-year-old, non-smoking man is referred to an otolaryngologist. A bronchial biopsy indicates altered structures in the epithelial cells. Which of the following, if altered to reduce function, is most likely involved in this patient's condition? a. Hemidesmosomes b. Cilia c. Basolateral cell membrane folds d. Microvilli e. Tight junctions

B

9. 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 (inflammation). 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 c. Type III d. Type IV e. Type VII

B

9. A 36-year-old man is referred by his family physician to the pulmonary 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 compounds 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

B

9. A 42-year-old woman, who has been a type I diabetic for 30 years, falls when she trips over the vacuum cleaner hose. She tried to break her fall by placing her hand out to save herself and in the process her wrist was forced backward, breaking her radius near the wrist. Which of the following is produced in the first step in healing this bone injury? a. Osteoid b. Hematoma c. Bony callus d. Fibrocartilage e. Compact bone

B

9. A 5-year-old boy sustains a small tear in his gastrocnemius muscle when he is involved in a bicycle accident. Regeneration of the muscle will occur through which of the following mechanisms? a. Dedifferentiation of muscle cells into myoblasts b. Differentiation of muscle satellite cells c. Fusion of damaged myofibers to form new myotubes d. Hyperplasia of existing muscle fibers e. Differentiation of fibroblasts to form myoblasts

B

10. 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 irritable, 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 afebrile, 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

C

10. A 46-year-old woman presents with pain in the left leg that worsens on weight bearing. An x-ray shows demineralization, and a bone biopsy decalcified with EDTA shows reduction in bone quantity. The patient had undergone menopause at age 45 without estrogen replacement. She reports long-standing diarrhea. In addition, laboratory tests show low levels of vitamin D, calcium, and phosphorus, and elevated alkaline phosphatase. A second bone biopsy was taken but not decalcified, which showed extensive deposition of uncalcified osteoid on all the bone surfaces. On the basis of these data, the best diagnosis would be which of the following? a. Osteoporosis b. Scurvy c. Osteomalacia d. Rickets e. Hypoparathyroidism

C

10. 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 patient's 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 tissue, 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.

C

2. Using immunohistochemistry a population of cells is shown to be positive for the protein connexin. From this we can infer that the cells are connected by what type of junction? a. Tight (occluding) junctions b. Zonula adherens c. Gap junctions d. Hemidesmosomes e. Desmosomes (macula adherens)

C

2. 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 diploë in cranial bones

C

2. Which of the following staining procedures relies on the cationic and anionic properties of the material to be stained? a. Enzyme histochemistry b. PAS reaction c. H&E staining d. Immunohistochemistry e. Metal impregnation techniques

C

3. 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

C

3. Which characteristic is unique to cardiac muscle? a. Contain centrally located nuclei b. Striated c. Often branched d. Multinucleated e. Lack T-tubules

C

5. Which feature typifies T-tubules? a. Evaginations of the sarcoplasmic reticulum b. Sequester calcium during muscle relaxation, releasing it during contraction c. Carry depolarization to the muscle fiber interior d. Overlie the A-I junction in cardiac muscle cells e. Rich supply of acetylcholine receptors

C

6. 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.

C

6. The release of lipid droplets from cells is which type of secretion? a. Merocrine b. Serous c. Apocrine d. Mucous e. Holocrine

C

6. Which characteristic is unique to smooth muscle? a. T-tubules lie across Z lines b. Each thick filament is surrounded by six thin filaments c. Thin filaments attach to dense bodies d. Cells are multinucleated e. Cells have centrally located nuclei

C

7. Exocrine glands in which the acini all produce a secretion of heavily glycosylated, hydrophilic proteins are an example of which type of gland? a. Serous gland b. Mixed gland c. Mucous gland d. Tubuloacinar gland e. Simple gland

C

7. 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

C

8. 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 a most likely target of such drugs? a. Cadherins b. Adhesins c. Integrins d. Glycolipids of the cell membrane e. Fibrillin

C

8. To identify and localize a specific protein within cells or the ECM, one would best use what approach? a. Autoradiography b. Enzyme histochemistry c. Immunohistochemistry d. TEM e. Polarizing microscopy

C

1. The basal lamina of a muscle fiber is part of which structure? a. Perimysium b. Epimysium c. Fascia d. Endomysium e. Sarcoplasmic reticulum

D

4. What is an important part of the role played by macrophages during maintenance and renewal of strong extracellular fibers in connective tissue? a. Storage for a major energy source needed for ECM maintenance b. Production of specific collagen subunits c. A sentinel function against invaders entering the ECM d. Secretion of MMPs e. Presentation of antigens important for assembly of collagen bundles

D

4. 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

D

5. Sulfated GAGs are important constituents of what extracellular structures? a. Hyaluronan b. Elastic fibers c. Type I collagen d. Proteoglycans e. Multiadhesive glycoproteins

D

6. Which "zone" of endochondral ossification in the growing femur of an adolescent is the farthest from that bone's secondary ossification center? a. Zone of hypertrophy b. Zone of reserve cartilage c. Zone of calcified cartilage d. Zone of ossification e. Zone of proliferation

D

8. A 66-year-old man who lives alone has a severe myocardial infarction and dies during the night. The medical examiner's office is called the following morning and describes the man's body as being in rigor mortis. This state of rigor mortis is due to which one of the following? a. Inhibition of Ca2+ leakage from the extracellular fluid and sarcoplasmic reticulum b. Enhanced retrieval of Ca2+ by the sarcoplasmic reticulum c. Failure to disengage tropomyosin and troponin from the myosin active sites d. Absence of ATP preventing detachment of the myosin heads from actin e. Increased lactic acid production

D

8. Osteoarthritis is characterized by the progressive erosion of articular 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

D

9. In situ hybridization is a histologic technique used to visualize what type of macromolecule? a. Proteins b. Carbohydrates c. Certain enzymes d. Nucleic acids e. Lipids

D

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.

D

1. 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

E

10. Hospital laboratories frequently use unfixed, frozen tissue specimens sectioned with a cryostat for rapid staining, microscopic examination, and diagnosis of pathologic conditions. Besides saving much time by avoiding fixation and procedures required for paraffin embedding, frozen sections retain and allow study of what macromolecules normally lost in the paraffin procedure? a. Carbohydrates b. Small mRNA c. Basic proteins d. Acidic proteins e. Lipids

E

3. 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 II

E

4. An intermediate filament protein found in cytoplasm of most epithelial cells is which of the following? a. Actin b. Vimentin c. Laminin d. Myosin e. Keratin

E

4. Cellular storage deposits of glycogen, a free polysaccharide, could best be detected histologically using what procedure? a. Autoradiography b. Electron microscopy c. Enzyme histochemistry d. H&E staining e. PAS reaction

E

5. Adding heavy metal compounds to the fixative and ultrathin sectioning of the embedded tissue with a glass knife are techniques used for which histologic procedure? a. Scanning electron microscopy b. Fluorescent microscopy c. Enzyme histochemistry d. Confocal microscopy e. TEM

E

5. In the diaphysis of a typical long bone which of the following structures is in closest proximity to the trabeculae of cancellous bone? a. Interstitial lamellae b. Osteons c. Sharpey fibers d. Outer circumferential lamellae e. Inner circumferential lamellae

E

7. Dense regular connective tissue typically involves which of the following 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

E

7. In one type of muscle, numerous gap junctions, desmosomes, and adherens junctions are specifically localized in which structures? a. Myofilaments b. Dense bodies c. Sarcomeres d. Neuromuscular spindles e. Intercalated discs

E

8. A 25-year-old man presents with persistent joint pain and a history of recurrent fractures of each humerus. His hematocrit and complete blood count (CBC) are normal, but blood calcium levels are high. Hormone levels are all within normal ranges except PTH that exceeds normal by threefold. Which if the following could be prescribed to offset the effects of the elevated PTH? a. Vitamin D b. Vitamin C c. Recombinant RANK ligand d. Somatotrophin (growth hormone) e. Calcitonin

E