D236 Pathophysiology - Set 2 - Part 2

Correct Answer: Diapedesis

Diapedesis or extravasation allows white blood cells to squeeze through vessel walls reaching tissue infection sites.
Option a is incorrect because chemotaxis is directed movement toward chemical signals, not the vessel exit process itself.
Option c is incorrect because opsonization marks pathogens for destruction but doesn't describe white cell vessel emigration.
Option d is incorrect because degranulation releases cell contents but doesn't describe the transmigration through vessel walls.

Correct Answer: Loss of function

Loss of function mutations in tumor suppressors remove growth inhibition, allowing uncontrolled proliferation leading to cancer.
Option a is incorrect because gain of function in tumor suppressors would increase growth inhibition, not cause disease.
Option c is incorrect because silent mutations don't change protein function, so wouldn't cause disease in tumor suppressors.
Option d is incorrect because neutral mutations by definition don't affect function enough to cause disease phenotypes.

Correct Answer: Macrosomia development

Maternal hyperglycemia causes fetal hyperinsulinemia leading to excessive growth or macrosomia, complicating delivery and newborn health.
Option a is incorrect because growth restriction typically results from placental insufficiency or other factors, not maternal hyperglycemia.
Option c is incorrect because neural tube defects relate to folate deficiency and early development, not gestational diabetes.
Option d is incorrect because while diabetes increases some risks, macrosomia is the primary fetal complication from hyperglycemia.

Correct Answer: Histamine

Histamine from mast cells causes vasodilation and increased permeability, producing classic inflammatory signs of redness and swelling.
Option a is incorrect because interferon helps fight viral infections through immune activation, not vascular changes described.
Option c is incorrect because insulin regulates glucose metabolism, not inflammatory vascular responses causing redness and swelling.
Option d is incorrect because thyroxine regulates metabolism and growth, not acute inflammatory vascular changes described here.

Correct Answer: Transfer RNA molecules

Transfer RNA molecules have anticodons matching messenger RNA codons, ensuring correct amino acid sequence during translation.
Option a is incorrect because DNA remains in nucleus providing the template, not directly participating in translation.
Option c is incorrect because ribosomal proteins provide structural support but don't match codons with amino acids.
Option d is incorrect because RNA polymerase synthesizes RNA from DNA but doesn't participate in protein translation.

Correct Answer: Carrier heterozygote

Mothers of hemophiliac sons are typically carriers with one normal and one affected X chromosome allele.
Option a is incorrect because homozygous affected females are extremely rare and would show bleeding symptoms themselves.
Option c is incorrect because normal homozygotes couldn't pass hemophilia alleles to produce affected sons as described.
Option d is incorrect because affected heterozygote terminology doesn't apply to X-linked recessive conditions in females.

Correct Answer: Progressive deterioration

Mechanical stress causes progressive cartilage deterioration in osteoarthritis, leading to bone-on-bone contact causing pain and stiffness.
Option a is incorrect because bacterial infection causes septic arthritis with acute symptoms, not the chronic deterioration described.
Option b is incorrect because crystal deposition causes gout or pseudogout, not the mechanical cartilage wear of osteoarthritis.
Option d is incorrect because immune attack characterizes rheumatoid arthritis, not the mechanical deterioration in osteoarthritis.

Correct Answer: Ammonia buffer

The ammonia buffer system in kidneys converts ammonia to ammonium, trapping hydrogen ions for urinary excretion.
Option a is incorrect because bicarbonate buffering occurs throughout body fluids, not specifically the renal ammonia system described.
Option b is incorrect because phosphate buffers work in urine but ammonia system handles more acid during chronic acidosis.
Option d is incorrect because protein buffers work immediately in blood, not the specific renal excretion system described.

Correct Answer: Androgen excess

Elevated androgens in PCOS prevent normal follicle maturation, causing multiple cyst formation and menstrual irregularities observed.
Option a is incorrect because cortisol excess causes Cushing syndrome with different symptoms than the ovarian cysts described.
Option c is incorrect because thyroid deficiency affects metabolism broadly but doesn't specifically cause ovarian cyst formation.
Option d is incorrect because growth hormone excess causes acromegaly, not the ovarian cyst pattern seen in PCOS.

Correct Answer: Distance from gene

Enhancers can function from thousands of base pairs away while promoters are adjacent to gene start sites.
Option b is incorrect because both enhancers and promoters bind regulatory proteins, not a distinguishing characteristic between them.
Option c is incorrect because neither directly produces RNA; they regulate transcription of genes that produce RNA.
Option d is incorrect because mutation frequency isn't a defining characteristic distinguishing enhancers from promoters functionally.

Correct Answer: Acid compensation

Kussmaul respirations represent respiratory compensation for metabolic acidosis, eliminating carbon dioxide to raise blood pH levels.
Option a is incorrect because oxygen levels are typically normal; the breathing pattern compensates for acidosis, not hypoxia.
Option b is incorrect because while anxiety may occur, Kussmaul breathing is physiological compensation, not psychological response.
Option d is incorrect because hyperglycemia doesn't directly cause this breathing pattern; the resulting acidosis drives respiratory compensation.

Correct Answer: Trinucleotide repeats

Trinucleotide repeat expansion causes anticipation, with increasing repeats in successive generations causing earlier onset and greater severity.
Option a is incorrect because environmental factors don't explain the consistent generational pattern of increasing severity described.
Option c is incorrect because random mutations wouldn't show the predictable progressive worsening pattern of genetic anticipation.
Option d is incorrect because while epigenetics affects expression, trinucleotide expansion specifically causes anticipation phenomena described.

Correct Answer: Osteoclast cells

Osteoclasts derive from hematopoietic monocyte lineage, functioning as multinucleated cells that resorb bone during remodeling processes.
Option a is incorrect because osteoblasts come from mesenchymal stem cells and build bone, not break it down.
Option c is incorrect because osteocytes are mature osteoblasts trapped in matrix, not from blood cell lineage.
Option d is incorrect because chondrocytes produce cartilage and derive from mesenchymal cells, not blood cell lineage.

Correct Answer: Eye infection development

Gonorrhea causes ophthalmia neonatorum in newborns exposed during delivery, potentially causing blindness without prophylactic treatment given.
Option a is incorrect because congenital heart defects result from developmental problems or infections during pregnancy, not delivery exposure.
Option c is incorrect because hearing loss from congenital infections typically involves different pathogens like cytomegalovirus, not gonorrhea.
Option d is incorrect because limb abnormalities result from early pregnancy exposures to teratogens, not delivery infection transmission.

Correct Answer: Fibroblast cells

Fibroblasts synthesize collagen and extracellular matrix proteins forming the structural scaffold for tissue repair and regeneration.
Option a is incorrect because neutrophils fight infection through phagocytosis but don't produce the collagen framework described.
Option c is incorrect because mast cells release inflammatory mediators but don't synthesize structural collagen for healing.
Option d is incorrect because platelets initiate clotting and release growth factors but don't produce collagen directly.

Correct Answer: Contact inhibition

Contact inhibition prevents normal cells from overgrowing, but cancer cells lose this control allowing unlimited growth.
Option b is incorrect because apoptosis is programmed cell death, not the growth limitation from cell-to-cell contact.
Option c is incorrect because DNA repair fixes mutations but isn't the contact-dependent growth control mechanism described.
Option d is incorrect because differentiation involves specialization, not the density-dependent growth inhibition lost in cancer.

Correct Answer: Calcitriol hormone

Kidneys produce calcitriol, the active vitamin D form essential for calcium absorption and bone health maintenance.
Option a is incorrect because insulin is produced by pancreatic beta cells for glucose regulation, not kidney hormone production.
Option c is incorrect because thyroxine comes from thyroid gland regulating metabolism, not kidney-produced bone hormone.
Option d is incorrect because cortisol is produced by adrenal glands for stress response, not kidney bone regulation.

Correct Answer: Incomplete penetrance

Incomplete penetrance means not everyone with a disease allele shows symptoms, explaining variable disease expression patterns.
Option b is incorrect because codominance involves both alleles expressing equally, not absence of symptoms despite dominant allele.
Option c is incorrect because anticipation involves worsening across generations, not incomplete expression within single generation.
Option d is incorrect because imprinting involves parent-specific expression, not the incomplete penetrance phenomenon described here.

Correct Answer: Woven bone

Woven bone forms rapidly but irregularly during initial healing, later replaced by organized lamellar bone structure.
Option a is incorrect because cortical bone is mature dense bone, not the initial irregular bone formed during healing.
Option b is incorrect because trabecular bone is spongy bone in specific locations, not initial fracture healing bone.
Option d is incorrect because compact bone is another term for cortical bone, not the initial healing bone type.

Correct Answer: Antidiuretic hormone

Antidiuretic hormone from posterior pituitary increases during dehydration, causing kidneys to retain water and concentrate urine.
Option a is incorrect because growth hormone promotes growth and metabolism, not water retention during dehydration states.
Option c is incorrect because luteinizing hormone regulates reproduction, not water balance during dehydration conditions described.
Option d is incorrect because prolactin stimulates milk production, not kidney water retention during dehydration response.