Histology Flashcards
7 cards from real NBME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Histology flashcards as text
Type II pneumocytes in the alveoli are cuboidal cells with lamellar bodies. Their primary function is to produce which substance?
Answer: Surfactant to reduce alveolar surface tension
Type II pneumocytes synthesize and secrete pulmonary surfactant (dipalmitoylphosphatidylcholine) from lamellar bodies, preventing alveolar collapse.
Parietal cells of the gastric fundus are characterized by an extensive tubulovesicular system and mitochondria. They secrete which substance?
Answer: Hydrochloric acid and intrinsic factor
Parietal (oxyntic) cells secrete HCl via H+/K+ ATPase and intrinsic factor necessary for vitamin B12 absorption in the ileum.
Brunner's glands, which secrete alkaline mucus to neutralize gastric acid, are located exclusively in the submucosa of which segment of the GI tract?
Answer: Duodenum
Brunner's glands are a histological hallmark of the duodenum, where their alkaline secretions protect the mucosa from chyme entering from the stomach.
Podocytes in the renal glomerulus wrap foot processes (pedicels) around glomerular capillaries. The filtration slits between foot processes are bridged by which protein?
Answer: Nephrin
Nephrin is the key structural protein of the slit diaphragm between podocyte pedicels, and mutations in nephrin cause congenital nephrotic syndrome.
In the adrenal cortex, the zona glomerulosa produces mineralocorticoids (aldosterone), while the zona fasciculata produces glucocorticoids. The zona reticularis primarily secretes which hormones?
Answer: Androgens (DHEA and androstenedione)
The zona reticularis, the innermost cortical layer, produces weak androgens (DHEA, androstenedione) that are converted to sex steroids peripherally.
Sertoli cells in the seminiferous tubules form the blood-testis barrier and provide which critical function for developing spermatids?
Answer: Mechanical support and phagocytosis of residual bodies during spermatogenesis
Sertoli cells physically support germ cells, secrete androgen-binding protein and inhibin, and phagocytose excess cytoplasm shed during spermiogenesis.
Parafollicular C cells of the thyroid gland, which arise from neural crest cells, produce which hormone in response to elevated serum calcium?
Answer: Calcitonin
C cells secrete calcitonin when serum calcium rises, inhibiting osteoclast activity and promoting renal calcium excretion to lower blood calcium.