51. A differential cell count of a blood smear from a patient with a parasitic infection is likely to reveal an increase in the circulating numbers of which of the following cell types?
(A) Basophils (B) Eosinophils (C) Erythrocytes (D) Lymphocytes (E) Monocytes (F) Neutrophils (G) Platelets
Correct Answer: (B) Eosinophils
An increase in eosinophils, known as eosinophilia, is a classic sign of a parasitic infection (e.g., helminths) and allergic reactions. Eosinophils combat parasites by releasing cytotoxic granules.
52. Which of the following cell types is most likely to be absent in a differential cell count of a blood smear from a normal patient?
(A) Basophils (B) Eosinophils (C) Erythrocytes (D) Lymphocytes (E) Monocytes (F) Neutrophils (G) Platelets
Correct Answer: (A) Basophils
Basophils are the least numerous type of circulating leukocyte, typically accounting for less than 1% of the white blood cell population. Due to their low concentration, they are the most likely to be missed (or not counted) in a standard small-sample differential count.
53. Which of the following cell types is capable of returning to the circulation after leaving the blood to enter the connective tissue?
(A) Basophils (B) Eosinophils (C) Erythrocytes (D) Lymphocytes (E) Monocytes (F) Neutrophils (G) Platelets
Correct Answer: (D) Lymphocytes
Unlike most other leukocytes, lymphocytes (specifically B and T cells) are designed to recirculate. They leave the blood to survey tissues and secondary lymphoid organs and can then re-enter the bloodstream via the lymphatic system.
54. Which of the following cell types normally is the most numerous of the circulating leukocytes?
(A) Basophils (8) Eosinophils (C) Erythrocytes (D) Lymphocytes (E) Monocytes (F) Neutrophils (G) Platelets
Correct Answer: (F) Neutrophils
Neutrophils are the most abundant type of white blood cell (leukocyte) in the peripheral blood, typically constituting 50-70% of the total leukocyte count in a healthy adult.
55. Which of the following cells is an agranulocyte that becomes phagocytic after it enters the connective tissues?
(A) Basophil (B) Eosinophil (C) Erythrocyte (D) Lymphocyte (E) Monocyte (F) Neutrophil (G) Platelet
Correct Answer: (E) Monocyte
A monocyte is a circulating agranulocyte. When it leaves the bloodstream and enters the connective tissue, it differentiates into a macrophage, which is a highly active, long-lived phagocytic cell.
56. Which of the following cell types has cytoplasmic granules that contain heparin and histamine?
(A) Basophils (B) Eosinophils (C) Erythrocytes (D) Lymphocytes (E) Monocytes (F) Neutrophils (G) Platelets
Correct Answer: (A) Basophils
Basophils contain large, dark-staining cytoplasmic granules that release various vasoactive mediators upon activation, including histamine (a vasodilator) and heparin (an anticoagulant).
57. Which of the following substances is present in higher concentrations in plasma than in serum?
(A) Albumin (B) Fibrinogen (C) Glucose (D) lnununoglobulin (F) Major basic protein (F) Serotonin (G) Thrombosthenin
Correct Answer: (B) Fibrinogen
Plasma contains all coagulation factors, including fibrinogen. Serum is the fluid remaining after blood has clotted, meaning fibrinogen has been consumed and removed to form the fibrin clot.
58. Which of the following terms refers to the percentage of packed erythrocytes per unit volume of blood?
(C) Hemoglobin (D) Hematocrit (E) Hematopoiesis (F) Hematoma (G) Hemolysis
Correct Answer: (D) Hematocrit
Hematocrit is the formal term for the ratio of the volume of packed red blood cells (erythrocytes) to the total blood volume, expressed as a percentage.
59. Which of the following is the predominant form of hemoglobin present in etythrocytes at birth?
(A) Carboxyhemoglobin (B) HbA (C) HbA$_{2}$ (D) HbB (E) HbF (F) HbS
Correct Answer: (E) HbF
Hemoglobin F (HbF), or fetal hemoglobin, is the predominant form of hemoglobin at birth. It has a higher affinity for oxygen than adult hemoglobin (HbA), which aids in fetal oxygen uptake.
60. Which of the following cell types is likely to account for most of this increase?
(A) Basophils (B) B lymphocytes (C) Eosinophils (D) Monocytes (E) Neutrophils (F) Null cells
Correct Answer: (E) Neutrophils
Assuming this question refers to a typical acute bacterial infection (the most common cause of high leukocyte counts tested), the increase in white blood cells (leukocytosis) is predominantly due to an increase in circulating neutrophils (neutrophilia).
61. Which of the following epidermal layers contains enucleate squamous keratinocytes and is the most superficial layer?
(A) Stratum basale (B) Stratum corneum (C) Stratum granulosum (9) Stratum lucidum (F) Stratum spinosum
Correct Answer: (B) Stratum corneum
The stratum corneum is the most superficial layer, consisting of flattened, dead, keratin-filled cells (squames) that have lost their nuclei (enucleate).
62. Which of the following epidermal layers is most likely to contain both desmosomes and hemidesmosomes?
(A) Stratum basale (B) Stratum corneum (C) Stratum granulosum (0) Stratum lucidum (F) Stratum spinosum
Correct Answer: (A) Stratum basale
The cells of the stratum basale use hemidesmosomes to anchor themselves to the basement membrane and desmosomes to anchor to adjacent cells.
63. Keratohyaline granules are particularly abundant and mitotic activity is rare in which of the following epidermal layers?
(A) Stratum basale (B) Stratum corneum (C) Stratum granulosum (D) Stratum lucidum (E) Stratum spinosum
Correct Answer: (C) Stratum granulosum
The stratum granulosum is defined by the abundant presence of keratohyaline granules (which contain proteins necessary for keratin aggregation). Mitotic activity is restricted to the stratum basale and lower spinosum.
64. Which of the following epidermal layers is the most superficial layer in which keratinocyte mitosis occurs continuously and in which cells are attached to their neighbors during interphase by abundant desmosoines?
(A) Stratum basale (B) Stratum corneum (C) Stratum granulosum (9) Stratum lucidum (El Stratum spinosum
Correct Answer: (A) Stratum basale
The stratum basale is the deepest layer, where continuous keratinocyte mitosis (cell renewal) occurs. The basal cells are attached by desmosomes.
65. Which of the following is (are) often absent in thick skin but typically present in thin skin?
(A) Arrector pili muscles (B) Meissner’s corpuscles (C) Stratum basale (D)) Stratum corneum (E) Stratum lucidum (F) Stratum spinosum (G) Sweat glands
Correct Answer: (A) Arrector pili muscles
Thick skin (palms/soles) lacks hair follicles and, consequently, also lacks the associated arrector pili muscles (and sebaceous glands). Thin skin covers the rest of the body and contains them.
66. Which of the following is typical of the reticular dermis but not of the papillary dermis?
(A) Capillaries that nourish the epidermis (B) Dense irregular connective tissue (C) Loose (areolar) connective tissue (D) Meissner’s corpuscles (E) Sweat gland ducts (F) Type-I collagen (G) Arteriovenous anastomoses
Correct Answer: (B) Dense irregular connective tissue
The reticular dermis is the deeper, thicker layer composed of large, haphazardly arranged bundles of dense irregular connective tissue, primarily Type I collagen. The papillary dermis is loose connective tissue.
67. Which of the following is characteristic of sweat glands but not of sebaceous glands?
(A) Adenomeres are typically acinar in shape (B) Adenomeres contain clear cells and dark cells (C) Adenomeres have a “foamy” appearance (D) Ducts empty mainly into hair follicles (E) Mode of secretion is holocrine (F) Rate of secretion is controlled by circulating androgens (G) Secretory product is oily to waxy in nature
Correct Answer: (B) Adenomeres contain clear cells and dark cells
The secretory portion (adenomere) of an eccrine sweat gland is a coiled tubule containing clear cells (secreting water/electrolytes) and dark cells (secreting mucin). Sebaceous glands are acinar and utilize holocrine secretion.
68. Albinism can result from an inherited defect in the gene encoding which of the following enzymes?
(A) Catalase (B) Collagenase (C) Lysyl oxidase (D) Na+/K+ ATPase (E) Papain (F) Prolyl hydroxylase (G) Tyrosinase
Correct Answer: (G) Tyrosinase
The most common form of albinism is caused by a defect in tyrosinase, the enzyme that catalyzes the initial step in the synthesis of melanin (pigment) from tyrosine.
69. The border between which of the following is a significant site of arteriovenous anastomoses in the skin?
(A) Dermis and epidermis (B) Epidermis and basal lamina (C) Papillary dermis and reticular dermis (D) Stratum basale and stratum spinosum (E) Stratum spinosum and stratum granulosum
Correct Answer: (C) Papillary dermis and reticular dermis
The subpapillary plexus, where many arteriovenous anastomoses (shunts) are found for thermoregulation, is located at the border between the superficial papillary dermis and the deeper reticular dermis.
70. Which of the following best describes the composition of a renal lobule?
(A) Renal pyramid and associated cortex (B) Medullary ray and all nephrons that empty into it (C) Renal pyramid and all aephrons that empty into it (U) Interlobular artery and all nephrons it supplies (E) Renal corpuscle and all associated renal tubules
Correct Answer: (B) Medullary ray and all nephrons that empty into it
A renal lobule is centered around a medullary ray (straight tubules and collecting ducts) and includes all the cortical tissue (nephrons and renal corpuscles) whose collecting ducts drain into that ray.
71. Blood in the arcuate arteries subsequently flows into which of the following vascular channels?
(A) Afferent arteriole(s) (B) Efferent arterioles (C) Glomerular capillaries (D) Interlobar arteries (E) Interlobular arteries (F) Peritubular capillaries (C) Stehlate veins
Correct Answer: (E) Interlobular arteries
The arcuate arteries run along the cortico-medullary border and give rise to the interlobular arteries (cortical radial arteries), which extend into the cortex and branch into the afferent arterioles.
72. Collections of cortical tissue between the medullary pyramids are called:
(A) Interlobular cortex (B) Juxtamedullary nephrons (C) Medullary rays (I)) Renal columns of Bertin (E) Renal lobes
Correct Answer: (D) Renal columns of Bertin
The renal columns of Bertin are extensions of the renal cortex that project downward between the renal pyramids (medulla).
73. Which of the following vessels are typically seen at the border between the renal cortex and medulla?
(A) Arcuate arteries and veins (B) lnterlobar arteries and veins (C) lnterlobular arteries and veins (1)) Stellate veins (E) Vasa recta
Correct Answer: (A) Arcuate arteries and veins
The arcuate arteries and veins form an arching network located precisely at the junction of the renal cortex and medulla.
74. Which of the following cell types comprises the visceral layer of Bowman’s capsule?
(A) Endothelial cell (B) Juxtaglomerular cell (C) Mesangial cell (0) Podocyte (E) Polkissen (extra mesangial cell)
Correct Answer: (D) Podocyte
The visceral layer of Bowman’s capsule is made up of specialized epithelial cells called podocytes, whose foot processes wrap around the glomerular capillaries to regulate filtration.
75. Which of the following types of epithelium lines the urinary bladder?
(A) Pseudostratifled columnar (B) Simple columnar (C) Simple cuboidal (0) Sim squamous (E) Stratified cuboidal (F) Stratified squamous (G) Transitional
Correct Answer: (G) Transitional
The urinary bladder is lined by transitional epithelium (urothelium), a stratified epithelium uniquely adapted to stretch and recoil as the bladder fills and empties.