Electron microscopy in histology — MCQs

A scientist is studying the anatomy and function of bone growth. He is able to create a cell line of osteocytes with a mutation that prevents the osteocytes from exchanging nutrients and waste products within neighboring lamellae. This mutation most likely affected which of the following cell structures?

A 42-year-old man presents to his primary care provider complaining of foamy urine for the last 2 weeks. He has also begun to notice swelling in his hands and feet, and he says that his shoes have not been fitting normally. On exam, the patient has a temperature of 98.8°F (37.1°C), blood pressure is 132/84 mmHg, pulse is 64/min, and respirations are 12/min. The patient has 2+ pitting edema bilaterally up to his shins. A 24-hour urine study is found to contain 9.0 g of protein. The patient is referred to a specialist and undergoes a renal biopsy. On light microscopy, the glomeruli demonstrate basement membrane thickening. On electron microscopy, subepithelial deposits are seen. Which of the following is a characteristic of this patient’s disease?

An investigator is studying the interaction between epithelial cells and calcium ion concentration. When the calcium ion concentration available to a sample of epithelial tissue is decreased, an increased gap between adjacent epithelial cells is seen on electron microscopy. This observed decrease in cell adhesion is most likely due to an effect on which of the following proteins?

A 45-year-old man presents to the office with complaints of facial puffiness and mild swelling in his lower back. He denies chest pain, blood in the urine, or fever. He was recently diagnosed with colon cancer. The vital signs include a blood pressure of 122/78 mm Hg, a pulse of 76/min, a temperature of 36.9°C (98.4°F), and a respiratory rate of 10/min. On physical examination, there is mild facial puffiness that is pitting in nature and presacral edema. His other systemic findings are within normal limits. Urinalysis shows: pH 6.2 Color light yellow RBC none WBC 3–4/HPF Protein 4+ Cast oval fat bodies Glucose absent Crystal none Ketone absent Nitrite absent 24 hours urine protein excretion 4.8 g A renal biopsy is ordered and diffuse capillary and basement membrane thickening is noted. Which of the following findings is expected to be present if an electron microscopy of the biopsy sample is performed?

An investigator is studying the effects of zinc deprivation on cancer cell proliferation. It is hypothesized that because zinc is known to be a component of transcription factor motifs, zinc deprivation will result in slower tumor growth. To test this hypothesis, tumor cells are cultured on media containing low and high concentrations of zinc. During the experiment, a labeled oligonucleotide probe is used to identify the presence of a known transcription factor. The investigator most likely used which of the following laboratory techniques?

A 4-year-old male is accompanied by his mother to the pediatrician. His mother reports that over the past two weeks, the child has had intermittent low grade fevers and has been more lethargic than usual. The child’s past medical history is notable for myelomeningocele complicated by lower extremity weakness as well as bowel and bladder dysfunction. He has been hospitalized multiple times at an outside facility for recurrent urinary tract infections. The child is in the 15th percentile for both height and weight. His temperature is 100.7°F (38.2°C), blood pressure is 115/70 mmHg, pulse is 115/min, and respirations are 20/min. Physical examination is notable for costovertebral angle tenderness that is worse on the right. Which of the following would most likely be found on biopsy of this patient’s kidney?

An investigator is conducting a study to document the histological changes in the respiratory tree of a chronic smoker. He obtains multiple biopsy samples from the respiratory system of a previously healthy 28-year-old man. Histopathological examination of one sample shows simple cuboidal cells with a surrounding layer of smooth muscle. Chondrocytes and goblet cells are absent. This specimen was most likely obtained from which of the following parts of the respiratory system?

A 38-year-old man comes to the physician because of a 6-month history of chest discomfort and progressive dyspnea. He cannot do daily chores without feeling out of breath. He was diagnosed in childhood with a milder X-linked dystrophinopathy that has caused progressive proximal muscle weakness and gait abnormalities over the years. Physical examination shows a waddling gait and weak patellar reflexes. Cardiovascular examination shows a holosystolic murmur, displaced point of maximal impulse, and bilateral pitting edema of the ankles. Laboratory studies show elevated levels of brain natriuretic peptide. Which of the following is the most likely underlying cause of this patient's muscle weakness?

An investigator is examining tissue samples from various muscle tissue throughout the body. She notices that biopsies collected from a specific site have a high concentration of sarcoplasmic reticulum, mitochondria, and myoglobin; they also stain poorly for ATPase. Additionally, the cell surface membranes of the myocytes in the specimen lack voltage-gated calcium channels. These myocytes are found in the greatest concentration at which of the following sites?

A 24-year-old male with cystic fibrosis is brought to the emergency room by his mother after he had difficulty breathing. He previously received a lung transplant 6 months ago and was able to recover quickly from the operation. He is compliant with all of his medications and had been doing well with no major complaints until 2 weeks ago when he began to experience shortness of breath. Exam reveals a decreased FEV1/FVC ratio and biopsy reveals lymphocytic infiltration. Which of the following components is present in the airway zone characteristically affected by the most likely cause of this patient's symptoms?