MEC Entrance: Human Biology & Diseases
100 High-Yield MCQs for CEE
1. Digestive System & Nutrition
1. The Sphincter of Oddi guards the opening of:
Answer: B
It controls the flow of digestive juices (bile and pancreatic juice) into the duodenum.
It controls the flow of digestive juices (bile and pancreatic juice) into the duodenum.
2. Which vitamin is essential for the maturation of RBCs?
Answer: C
Vitamin B12 (Cyanocobalamin) and Folic acid are crucial for RBC maturation. Deficiency leads to Megaloblastic anemia.
Vitamin B12 (Cyanocobalamin) and Folic acid are crucial for RBC maturation. Deficiency leads to Megaloblastic anemia.
3. Brunner's glands are found in:
Answer: A
Brunner's glands secrete alkaline mucus to protect the duodenum from acidic chyme.
Brunner's glands secrete alkaline mucus to protect the duodenum from acidic chyme.
4. The hardest constituent of the tooth is:
Answer: D
Enamel is the hardest substance in the human body, secreted by Ameloblasts (Ectodermal).
Enamel is the hardest substance in the human body, secreted by Ameloblasts (Ectodermal).
5. Steatorrhea is due to the deficiency of:
Answer: B
Deficiency of pancreatic lipase prevents fat digestion, leading to fat excretion in stools (Steatorrhea).
Deficiency of pancreatic lipase prevents fat digestion, leading to fat excretion in stools (Steatorrhea).
6. Rennin acts on:
Answer: C
Rennin (Chymosin) curdles milk casein in infants' stomachs. Ideally absent or negligible in adults.
Rennin (Chymosin) curdles milk casein in infants' stomachs. Ideally absent or negligible in adults.
7. Kuffer cells are characteristic of:
Answer: A
Kupffer cells are specialized macrophages located in the liver sinusoids.
Kupffer cells are specialized macrophages located in the liver sinusoids.
8. Maximum absorption of water occurs in:
Answer: D
While most nutrients are absorbed in the small intestine, significant water reabsorption for feces formation happens in the colon.
While most nutrients are absorbed in the small intestine, significant water reabsorption for feces formation happens in the colon.
9. Deficiency of Nicotinic acid causes:
Answer: B
Pellagra (4 D's: Dermatitis, Diarrhea, Dementia, Death) is caused by Niacin (B3) deficiency.
Pellagra (4 D's: Dermatitis, Diarrhea, Dementia, Death) is caused by Niacin (B3) deficiency.
10. Dental formula of a human child (deciduous dentition) is:
Answer: C
Premolars are absent in milk teeth. Formula: I 2/2, C 1/1, PM 0/0, M 2/2.
Premolars are absent in milk teeth. Formula: I 2/2, C 1/1, PM 0/0, M 2/2.
2. Respiratory System
11. The amount of air inspired or expired during normal breathing is:
Answer: B
Tidal Volume (TV) is approx 500 ml in a normal adult.
Tidal Volume (TV) is approx 500 ml in a normal adult.
12. Dissociation curve of haemoglobin is:
Answer: C
Oxygen-Hb dissociation curve is S-shaped (Sigmoid). Myoglobin curve is Hyperbolic.
Oxygen-Hb dissociation curve is S-shaped (Sigmoid). Myoglobin curve is Hyperbolic.
13. Chloride shift is essential for the transport of:
Answer: A
Also called Hamburger's phenomenon. It maintains ionic balance between RBC and plasma during CO2 transport as bicarbonates.
Also called Hamburger's phenomenon. It maintains ionic balance between RBC and plasma during CO2 transport as bicarbonates.
14. Adam's Apple corresponds to:
Answer: D
The laryngeal prominence of the thyroid cartilage is commonly called Adam's apple.
The laryngeal prominence of the thyroid cartilage is commonly called Adam's apple.
15. Pneumotaxic center is located in:
Answer: B
It regulates the switch-off point of inspiration. Respiratory rhythm center is in the Medulla.
It regulates the switch-off point of inspiration. Respiratory rhythm center is in the Medulla.
16. Hering-Breuer reflex is related to:
Answer: C
Stretch receptors in bronchioles trigger this reflex to stop inspiration and prevent lung rupture.
Stretch receptors in bronchioles trigger this reflex to stop inspiration and prevent lung rupture.
17. Emphysema is characterized by:
Answer: A
Common in smokers, alveolar walls are damaged, reducing surface area for exchange.
Common in smokers, alveolar walls are damaged, reducing surface area for exchange.
3. Circulatory System
18. Papillary muscles are located in:
Answer: C
They anchor the Chordae tendineae to the AV valves in the ventricles.
They anchor the Chordae tendineae to the AV valves in the ventricles.
19. Dub sound of heart is produced during:
Answer: B
'Lub' is 1st sound (AV closure); 'Dub' is 2nd sound (Semilunar closure at start of diastole).
'Lub' is 1st sound (AV closure); 'Dub' is 2nd sound (Semilunar closure at start of diastole).
20. Bundle of His is a network of:
Answer: D
It is specialized cardiac musculature (modified myocardium), not nerve tissue, distributing impulses to ventricles.
It is specialized cardiac musculature (modified myocardium), not nerve tissue, distributing impulses to ventricles.
21. Erythroblastosis fetalis occurs when:
Answer: A
Rh incompatibility: Mother Rh- sensitized by Rh+ fetus (inherited from Rh+ father).
Rh incompatibility: Mother Rh- sensitized by Rh+ fetus (inherited from Rh+ father).
22. Carotid labyrinth contains:
Answer: C
Monitors blood pressure (Baro) and chemical composition/pH (Chemo) of blood going to the brain.
Monitors blood pressure (Baro) and chemical composition/pH (Chemo) of blood going to the brain.
23. Which WBC is most abundant?
Answer: B
Neutrophils (60-65%), Lymphocytes (20-25%), Monocytes (6-8%), Eosinophils (2-3%), Basophils (0.5-1%).
Neutrophils (60-65%), Lymphocytes (20-25%), Monocytes (6-8%), Eosinophils (2-3%), Basophils (0.5-1%).
24. Vitamin K is required for:
Answer: A
Vitamin K is essential for liver synthesis of clotting factors II (Prothrombin), VII, IX, and X.
Vitamin K is essential for liver synthesis of clotting factors II (Prothrombin), VII, IX, and X.
25. Blood group AB is universal recipient because:
Answer: D
Blood group AB has both Antigens A and B on RBCs but no antibodies in plasma, preventing agglutination with donor blood.
Blood group AB has both Antigens A and B on RBCs but no antibodies in plasma, preventing agglutination with donor blood.
4. Excretory System
26. Loop of Henle is meant for absorption of:
Answer: B
Especially the descending limb is permeable to water, concentrating the urine.
Especially the descending limb is permeable to water, concentrating the urine.
27. Podocytes are found in:
Answer: C
They are epithelial cells of the visceral layer of Bowman's capsule, forming filtration slits.
They are epithelial cells of the visceral layer of Bowman's capsule, forming filtration slits.
28. Which is the threshold substance?
Answer: A
High threshold substances (Glucose, Amino acids) are completely reabsorbed up to a threshold level.
High threshold substances (Glucose, Amino acids) are completely reabsorbed up to a threshold level.
29. Presence of RBC in urine is called:
Answer: D
Pyuria = Pus; Glycosuria = Sugar; Ketonuria = Ketone bodies; Haematuria = Blood/RBC.
Pyuria = Pus; Glycosuria = Sugar; Ketonuria = Ketone bodies; Haematuria = Blood/RBC.
30. Renin is secreted by:
Answer: B
JG cells secrete Renin in response to low BP, initiating the RAAS pathway.
JG cells secrete Renin in response to low BP, initiating the RAAS pathway.
31. Ornithine cycle performs:
Answer: C
Also called Urea cycle, it converts toxic ammonia into urea in the liver.
Also called Urea cycle, it converts toxic ammonia into urea in the liver.
5. Nervous System & Senses
32. Number of cranial nerves in humans is:
Answer: C
12 pairs in amniotes (Reptiles, Birds, Mammals). 10 pairs in Anamniotes (Fish, Amphibians).
12 pairs in amniotes (Reptiles, Birds, Mammals). 10 pairs in Anamniotes (Fish, Amphibians).
33. Which is the longest cranial nerve?
Answer: A
Vagus (X) is the longest/most widely distributed. Trigeminal (V) is the largest. Trochlear (IV) is the smallest/thinnest.
Vagus (X) is the longest/most widely distributed. Trigeminal (V) is the largest. Trochlear (IV) is the smallest/thinnest.
34. Centre for body temperature regulation (Thermostat) is:
Answer: B
Hypothalamus regulates temperature, hunger, thirst, and emotions.
Hypothalamus regulates temperature, hunger, thirst, and emotions.
35. Nissl's granules are found in:
Answer: D
Found in Cyton (cell body) and Dendrites, absent in Axon. They are RER + Ribosomes (protein synthesis).
Found in Cyton (cell body) and Dendrites, absent in Axon. They are RER + Ribosomes (protein synthesis).
36. Organ of Corti is located on:
Answer: C
The hearing apparatus (Organ of Corti) rests on the Basilar membrane in the Scala media.
The hearing apparatus (Organ of Corti) rests on the Basilar membrane in the Scala media.
37. Blind spot in the eye is the place where:
Answer: B
Optic disc (Blind spot) is the exit point of the optic nerve, lacking photoreceptors.
Optic disc (Blind spot) is the exit point of the optic nerve, lacking photoreceptors.
38. Saltatory conduction occurs in:
Answer: A
Impulse jumps from node to node (Nodes of Ranvier), increasing speed of conduction.
Impulse jumps from node to node (Nodes of Ranvier), increasing speed of conduction.
6. Endocrine System
39. Which gland is called the 'Master Gland'?
Answer: B
Pituitary controls many other endocrine glands. (Note: Hypothalamus is the 'Master of Master Gland').
Pituitary controls many other endocrine glands. (Note: Hypothalamus is the 'Master of Master Gland').
40. Tetany is caused by:
Answer: C
Deficiency of PTH leads to low blood calcium (Hypocalcemia), causing muscle spasms (Tetany).
Deficiency of PTH leads to low blood calcium (Hypocalcemia), causing muscle spasms (Tetany).
41. 3F hormone (Fight, Flight, Fright) is secreted by:
Answer: D
Adrenaline (Epinephrine) from Adrenal Medulla.
Adrenaline (Epinephrine) from Adrenal Medulla.
42. Diabetes insipidus is due to deficiency of:
Answer: A
ADH (Vasopressin) deficiency causes water loss (polyuria). Insulin deficiency causes Diabetes mellitus.
ADH (Vasopressin) deficiency causes water loss (polyuria). Insulin deficiency causes Diabetes mellitus.
43. Grave's disease is associated with:
Answer: B
Autoimmune hyperthyroidism characterized by exophthalmos (protruding eyes).
Autoimmune hyperthyroidism characterized by exophthalmos (protruding eyes).
44. Which is a heterocrine gland?
Answer: C
Pancreas has both Exocrine (enzymes) and Endocrine (Islets of Langerhans) parts.
Pancreas has both Exocrine (enzymes) and Endocrine (Islets of Langerhans) parts.
7. Reproductive System & Embryology
45. Leydig cells secrete:
Answer: B
Interstitial cells of Leydig in testes secrete Androgens (Testosterone) under the influence of LH (ICSH).
Interstitial cells of Leydig in testes secrete Androgens (Testosterone) under the influence of LH (ICSH).
46. Fertilization normally occurs in:
Answer: C
Specifically in the Ampulla of the Fallopian tube.
Specifically in the Ampulla of the Fallopian tube.
47. Sertoli cells are found in:
Answer: D
They provide nutrition to developing sperms (Nurse cells) and form the blood-testis barrier.
They provide nutrition to developing sperms (Nurse cells) and form the blood-testis barrier.
48. The corpus luteum secretes mainly:
Answer: A
Essential for maintaining the endometrium for pregnancy.
Essential for maintaining the endometrium for pregnancy.
49. Implantation occurs at which stage?
Answer: B
The Blastocyst implants in the uterine wall about 7 days after fertilization.
The Blastocyst implants in the uterine wall about 7 days after fertilization.
50. Acrosome of sperm is derived from:
Answer: C
It contains lytic enzymes (Hyaluronidase) to penetrate the egg.
It contains lytic enzymes (Hyaluronidase) to penetrate the egg.
8. Skeletal System
51. Total number of bones in human face is:
Answer: A
Cranium has 8 bones, Face has 14 bones. Total skull = 22 (excluding ear ossicles and hyoid).
Cranium has 8 bones, Face has 14 bones. Total skull = 22 (excluding ear ossicles and hyoid).
52. Glenoid cavity articulates:
Answer: D
It forms the shoulder joint (Ball and socket). Acetabulum is in the pelvic girdle.
It forms the shoulder joint (Ball and socket). Acetabulum is in the pelvic girdle.
53. Floating ribs in humans are:
Answer: B
They are not connected to the sternum anteriorly. 1-7 True, 8-10 Vertebrochondral (False).
They are not connected to the sternum anteriorly. 1-7 True, 8-10 Vertebrochondral (False).
54. Which is the sesamoid bone?
Answer: C
Both Patella (knee cap) and Pisiform (wrist) are sesamoid bones (developed within tendons). Patella is the largest.
Both Patella (knee cap) and Pisiform (wrist) are sesamoid bones (developed within tendons). Patella is the largest.
9. Human Diseases & Immunity
55. Widal test is used for the diagnosis of:
Answer: B
Detects antibodies against Salmonella typhi O and H antigens.
Detects antibodies against Salmonella typhi O and H antigens.
56. Vector for Kala-azar (Leishmaniasis) is:
Answer: A
Phlebotomus argentipes (Sandfly). Pathogen is Leishmania donovani.
Phlebotomus argentipes (Sandfly). Pathogen is Leishmania donovani.
57. Interferons are:
Answer: D
Proteins secreted by virus-infected cells to protect neighbors from viral infection.
Proteins secreted by virus-infected cells to protect neighbors from viral infection.
58. Causative agent of Syphilis is:
Answer: C
A spirochete bacterium. Gonorrhea is caused by Neisseria.
A spirochete bacterium. Gonorrhea is caused by Neisseria.
59. Elephantiasis (Filariasis) is transmitted by:
Answer: A
Culex fatigans is the vector for Wuchereria bancrofti.
Culex fatigans is the vector for Wuchereria bancrofti.
60. Antibodies are chemically:
Answer: B
Immunoglobulins (Ig) are glycoproteins produced by B-lymphocytes (Plasma cells).
Immunoglobulins (Ig) are glycoproteins produced by B-lymphocytes (Plasma cells).
61. BCG vaccine protects against:
Answer: C
Bacille Calmette-Guerin.
Bacille Calmette-Guerin.
62. AIDS virus attacks:
Answer: A
HIV binds to CD4 receptors on Helper T-cells (CD4+ cells), destroying immunity.
HIV binds to CD4 receptors on Helper T-cells (CD4+ cells), destroying immunity.
63. Which cancer is associated with EBV (Epstein-Barr Virus)?
Answer: D
Common in African children. EBV also causes Infectious Mononucleosis.
Common in African children. EBV also causes Infectious Mononucleosis.
64. Mantoux test is for:
Answer: B
Tuberculin skin test. Schick test is for Diphtheria.
Tuberculin skin test. Schick test is for Diphtheria.
65. Entamoeba histolytica causes:
Answer: C
Infective stage: Tetranucleate cyst. Stool contains Charcot-Leyden crystals.
Infective stage: Tetranucleate cyst. Stool contains Charcot-Leyden crystals.
10. Mixed High-Yield Questions
66. Haversian canal is found in:
Answer: A
Haversian system (Osteon) is the characteristic feature of mammalian compact bone.
Haversian system (Osteon) is the characteristic feature of mammalian compact bone.
67. Connective tissue sheath covering the muscle fascicle is:
Answer: B
Epimysium covers entire muscle; Perimysium covers fascicle (bundle); Endomysium covers single fiber.
Epimysium covers entire muscle; Perimysium covers fascicle (bundle); Endomysium covers single fiber.
68. Payer's patches produce:
Answer: D
Found in Ileum (intestinal tonsils), responsible for immunity (GALT).
Found in Ileum (intestinal tonsils), responsible for immunity (GALT).
69. The functional unit of contractile system in striated muscle is:
Answer: C
Distance between two Z-lines.
Distance between two Z-lines.
70. Which is the longest cell in the human body?
Answer: A
Nerve cells (Neurons) can be up to a meter long.
Nerve cells (Neurons) can be up to a meter long.
71. Phagocytosis was discovered by:
Answer: B
Elie Metchnikoff described the cellular immunity (phagocytosis).
Elie Metchnikoff described the cellular immunity (phagocytosis).
72. Down's syndrome is due to:
Answer: C
Trisomy 21 (Mongolism). Trisomy 18 is Edwards. XXY is Klinefelter.
Trisomy 21 (Mongolism). Trisomy 18 is Edwards. XXY is Klinefelter.
73. Alpha cells of Islets of Langerhans secrete:
Answer: D
Alpha: Glucagon. Beta: Insulin. Delta: Somatostatin.
Alpha: Glucagon. Beta: Insulin. Delta: Somatostatin.
74. The most important cartilage in the embryonic skeleton is:
Answer: A
Most of the embryonic skeleton is Hyaline cartilage, replaced by bone (Endochondral ossification).
Most of the embryonic skeleton is Hyaline cartilage, replaced by bone (Endochondral ossification).
75. Which valve is the 'Mitral Valve'?
Answer: B
Left Atrioventricular valve (Bicuspid) resembles a Bishop's miter.
Left Atrioventricular valve (Bicuspid) resembles a Bishop's miter.
76. Histamine is secreted by:
Answer: A
Involved in inflammatory reactions and allergies.
Involved in inflammatory reactions and allergies.
77. The joint between Atlas and Axis is:
Answer: C
Allows rotation of the head (No movement).
Allows rotation of the head (No movement).
78. Sphygmomanometer measures:
Answer: D
Normal BP is 120/80 mmHg.
Normal BP is 120/80 mmHg.
79. Which immunoglobulin can cross the placenta?
Answer: B
IgG is the smallest and most abundant, providing passive immunity to the fetus. IgA is in colostrum.
IgG is the smallest and most abundant, providing passive immunity to the fetus. IgA is in colostrum.
80. Normal pH of human blood is:
Answer: C
Slightly alkaline (7.35 - 7.45).
Slightly alkaline (7.35 - 7.45).
81. Ptyalin is an enzyme present in:
Answer: A
Salivary amylase (Ptyalin) digests starch into maltose.
Salivary amylase (Ptyalin) digests starch into maltose.
82. Largest lymphatic organ in the body is:
Answer: B
Spleen acts as a blood filter and reservoir.
Spleen acts as a blood filter and reservoir.
83. Eustachian tube connects Middle ear with:
Answer: C
Specifically the Nasopharynx, to equalize pressure across the tympanic membrane.
Specifically the Nasopharynx, to equalize pressure across the tympanic membrane.
84. Vitamin C is also known as:
Answer: D
Essential for collagen synthesis and scurvy prevention.
Essential for collagen synthesis and scurvy prevention.
85. The smallest bone in the human body is:
Answer: A
Stapes (Stirrup) in the middle ear. Longest is Femur.
Stapes (Stirrup) in the middle ear. Longest is Femur.
86. Excretory unit of kidney is:
Answer: B
Approx 1 million nephrons per kidney.
Approx 1 million nephrons per kidney.
87. Part of brain involved in balancing and posture:
Answer: C
Arbor vitae is found here. Alcohol affects this part first (loss of balance).
Arbor vitae is found here. Alcohol affects this part first (loss of balance).
88. Test tube baby implies:
Answer: D
IVF (In Vitro Fertilization) followed by ET (Embryo Transfer).
IVF (In Vitro Fertilization) followed by ET (Embryo Transfer).
89. Yellow colour of urine is due to:
Answer: A
Urochrome is a breakdown product of hemoglobin.
Urochrome is a breakdown product of hemoglobin.
90. Total number of muscles in human body is approx:
Answer: B
639 skeletal muscles. Gluteus maximus is largest; Stapedius is smallest.
639 skeletal muscles. Gluteus maximus is largest; Stapedius is smallest.
91. Gout is due to accumulation of:
Answer: C
Deposition of sodium urate crystals in joints causes arthritis.
Deposition of sodium urate crystals in joints causes arthritis.
92. Nerve impulse is initiated by influx of:
Answer: D
Depolarization is caused by rapid influx of Sodium ions. Repolarization by efflux of Potassium.
Depolarization is caused by rapid influx of Sodium ions. Repolarization by efflux of Potassium.
93. Deficiency of Iodine leads to:
Answer: A
Enlargement of thyroid gland.
Enlargement of thyroid gland.
94. Oxygen is transported in blood mainly as:
Answer: B
97% as OxyHb; 3% dissolved in plasma.
97% as OxyHb; 3% dissolved in plasma.
95. Vital capacity of lung is:
Answer: C
Max air breathed out after max inspiration. Also TLC - Residual Volume.
Max air breathed out after max inspiration. Also TLC - Residual Volume.
96. Which is not a part of the hind brain?
Answer: D
Thalamus is part of Forebrain (Diencephalon).
Thalamus is part of Forebrain (Diencephalon).
97. Which blood vessel carries least urea?
Answer: A
Blood leaving the kidney (Renal vein) has been filtered. Hepatic vein has max urea.
Blood leaving the kidney (Renal vein) has been filtered. Hepatic vein has max urea.
98. Father of Genetics is:
Answer: B
Gregor Johann Mendel working on Pisum sativum.
Gregor Johann Mendel working on Pisum sativum.
99. Number of autosomes in human sperm is:
Answer: C
Sperm has 23 chromosomes: 22 autosomes + 1 sex chromosome (X or Y).
Sperm has 23 chromosomes: 22 autosomes + 1 sex chromosome (X or Y).
100. Sarcoma is cancer of:
Answer: D
Cancer of connective tissue (Bone, Muscle, Cartilage). Epithelial cancer is Carcinoma.
Cancer of connective tissue (Bone, Muscle, Cartilage). Epithelial cancer is Carcinoma.
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