Anatomy MCQ 0056

The most distal portion of the maxillary alveolar bone is the

a. Tuberosity

b. Retromolar area

c. Palatine raphe

d. Palatine fovea

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The Correct option is A

Anatomy MCQ 0054

Blood from the internal carotid artery reaches the posterior cerebral artery by the

a. Anterior cerebral artery

b. Anterior communicating artery

c. Posterior communicating artery

d. Posterior superior cerebellar artery

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The Correct option is C

Explanation with High Yield Facts:

The internal carotid artery is joined to the posterior cerebral artery via the posterior communicating artery, which is part of the circle of Willis.

Anatomy MCQ 0055

The infraorbital nerve is a branch of the

a. Optic nerve

b. Oculomotor nerve

c. Ophthalmic nerve

d. Maxillary nerve

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The Correct option is D

Explanation with High Yield Facts:

It is a branch of the maxillary (CN V2) nerve. The maxillary nerve branches from the trigeminal ganglion and exits the skull through the foramen rotundum. When it reaches the pterygopalatine ganglion, it terminates as the infraorbital and zygomatic nerves.

Anatomy MCQ 0051

Deoxygenated blood from the transverse sinus drains into the _

a. Inferior sagittal sinus

b. Confluence of sinuses

c. Sigmoid sinus

d. Straight sinus

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The Correct option is C

Explanation with High Yield Facts:

Deoxygenated blood from the transverse sinus drains to the sigmoid sinus, which empties into the internal jugular veins. The transverse sinuses receive blood from the confluence of sinuses, which is located in the posterior cranium.

Anatomy MCQ 0052

The vestigial cleft of Rathke's pouch in the hypophysis is located between the .

a. Anterior and posterior lobes

b. Anterior lobe and hypothalamus

c. Posterior lobe and hypothalamus

d. Median eminence and the optic chiasm

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The Correct option is A

Explanation with High Yield Facts:

The vestigial cleft of Rathke's pouch is located between the anterior and posterior lobesspecifically, between the pars intermedia and anterior lobe. It consists of cyst-like spaces (Rathke's cysts) and represents the vestigial lumen of Rathke's pouch.

Anatomy MCQ 0053

Involution of the thymus would occur following which year in a healthy individual?

a. 0 years (at birth).

b. 12th year.

c. 20th year.

d. 60thyear.

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The Correct option is B

Explanation with High Yield Facts:

The thymus is active at birth and increases in size until puberty (around age 12), after which it gradually atrophies and is replaced by fatty tissue.

Histology MCQ 0009

The muscle that is found in the walls of the heart is characterized by '

a. A peripherally placed nucleus

b. Multiple nuclei

c. Intercalated discs

d. Fibers with spindle-shaped cells

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The Correct option is C

Explanation with High Yield Facts:

Intercalated discs are only found in cardiac muscle. Multiple, peripherally positioned nuclei are found in the fibers of skeletal muscle. Smooth muscle cells are spindle-shaped.

Anatomy MCQ 0050

All of the following are found in the posterior triangle of the neck except one. Which one is the exception?

a. External jugular vein.

b. Subclavian vein.

c. Hypoglossal nerve.

d. Phrenic nerve.

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The Correct option is C

Explanation with High Yield Facts:

The hypoglossal (CN XII) nerve is not found in the posterior triangle;. it is, however, present in the submandibular triangle. Contents of the posterior triangle include the external jugular and subclavian vein and their tributaries, the subclavian artery and its branches, branches of the cervical plexus, CN XI, nerves to the upper limb and muscles of the triangle floor, the phrenic nerve, and the brachial plexus.

Anatomy MCQ 0049

The auriculotemporal nerve encircles which of the following vessels?

a. Maxillary artery.

b. Superficial temporal artery.

c. Deep auricular artery.

d. Middle meningeal artery.

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The Correct option is D

Explanation with High Yield Facts:

After branching from the mandibular nerve (CN V), the auriculotemporal nerve travels posteriorly and encircles the middle meningeal artery, remaining posterior and medial to the condyle. It then continues up towards the TMJ, external ear, and temporal region, passing through the parotid gland and traveling with the superficial temporal artery and vein.

Anatomy MCQ 0048

Which of the following muscles adducts the vocal cords?

a. Lateral cricoarytenoid.

b. Posterior cricoarytenoid.

c. Cricothyroid.

d. Vocalis.

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The Correct option is A

Explanation with High Yield Facts:

Lateral cricoarytenoid. The oblique and transverse arytenoids and thyroartenoid also adduct the vocal folds. The posterior cricoarytenoids abducts the vocal cords. The cricothyroid muscle raises the cricoid cartilage and tenses the vocal cords.

Histology MCQ 0008

Which of the following strata of oral epithelium is engaged in mitosis?

a. Basale.

b. Granulosum.

c. Corneum.

d. Spinosum.

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The Correct option is A

Explanation with High Yield Facts:

The site of cell division (mitosis) occurs in the stratum basale (basal layer, stratum germinativum) of oral epithelium.

Anatomy MCQ 0046

The superior and inferior ophthalmic veins drain into the

a. Internal jugular vein

b. Pterygoid plexus

c. Frontal vein

d. Facial vein

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The Correct option is D

Explanation with High Yield Facts:

The superior and inferior ophthalmic veins drain into the facial vein and cavernous sinus.

Anatomy MCQ 0047

The masseter originates from the

a. Condyle of the mandible

b. Infratemporal crest of the sphenoid bone

c. Inferior border of the zygomatic arch

d. Pyramidal process of the palatine bone

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The Correct option is C

Explanation with High Yield Facts:

The masseter originates from the inferior border of the zygomatic arch; specifically, its superficial head and deep head originate from the anterior two thirds or posterior one third of the inferior border, respectively. Its superficial head inserts into the lateral surface of the angle of the mandible; its deep head inserts into the ramus and body of the mandible.

Anatomy MCQ 0044

The lateral pterygoid muscle attaches to which of the following?

a. Lateral surface of the lateral pterygoid plate.

b. Medial surface of the lateral pterygoid plate.

c. Lateral surface of the medial pterygoid plate.

d. Medial surface of the medial pterygoid plate.

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The Correct option is A

Explanation with High Yield Facts:

The inferior head of the lateral pterygoid muscle attaches to the lateral surface of the lateral pterygoid plate of sphenoid bone. Its superior head attaches to the infratemporal crest of the greater wing of sphenoid bone. The deep fibers of the medial pterygoid muscle attach to the medial surface of the lateral pterygoid plate.

Anatomy MCQ 0045

Which of the following muscles is responsible for the formation of the posterior tonsillar pillar?

a. Stylopharyngeus.

b. Tensor veli palatine.

c. Palatoglossus.

d. Palatopharyngeus.

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The Correct option is D

Explanation with High Yield Facts:

The palatopharyngeus forms the posterior tonsillar pillar. It also functions to close off the nasopharynx and larynx during swallowing. The anterior tonsillar pillar is formed by the palatoglossus.

Embryology MCQ 0024

The greater omentum is derived from which of the following embryonic structures?

a. Dorsal mesoduodenum

b. Dorsal mesogastrium

c. Pericardioperitoneal canal

d. Pleuropericardial membranes

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The Correct option is B

Explanation with High Yield Facts:

Both the omental bursa and the greater omentum are derived from the dorsal mesogastrium, which is the mesentery of the stomach region.

The dorsal mesoduodenum (choice A) is the mesentery of the developing duodenum, which later disappears so that the duodenum and pancreas come to lie retroperitoneally.

The pericardioperitoneal canal (choice C) embryologically connects the thoracic and peritoneal canals.

The pleuropericardial membranes (choice D) become the pericardium and contribute to the diaphragm.

Anatomy MCQ 0043

Thoracic duct is also called

a. Hensen’s duct

b. Bernard’s duct

c. Pecquet duct

d. Hoffman’s duct

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The Correct option is D

Explanation with High Yield Facts:

• Hensen’s duct: ductus reuniens, a small canal leading from the saccule to the cochlear duct; called also canalis reuniens, Hensen's canal or duct, and Reichert's canal.
• Bernard’s duct: ductus pancreaticus accessorius, accessory pancreatic duct: a small inconstant duct draining a part of the head of the pancreas into the minor duodenal papilla; called also minor pancreatic duct, and duct of Santorini or Bernard.
• Pecquet duct: The major efferent lymph duct into which lymph from most of the peripheral lymph nodes drains. Recirculating lymphocytes that have left the circulation in the lymph node return to the blood through the thoracic duct.
• Hoffman’s duct: (Pancreatic duct). The excretory duct of the pancreas that extends through the gland from tail to head, where it empties into the duodenum at the greater duodenal papilla. Synonyms: ductus pancreaticus, Hoffmann's duct, Wirsung's canal, Wirsung's duct.

Embryology MCQ 0023

From which of the following fetal vessels do the umbilical arteries arise?

a. Aorta

b. Carotid arteries

c. Ductus arteriosus

d. Iliac arteries

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The Correct option is D

Explanation with High Yield Facts:

The paired umbilical arteries arise from the iliac arteries. They supply unoxygenated fetal blood to the placenta. The single umbilical vein takes the newly oxygenated fetal blood from the placenta to the liver and then to the inferior vena cava via the ductus venosus.

Anatomy MCQ 0042

Which of these statements about the common bile duct is false?

a. Lies in the free edge of the lesser omentum

b. Lies anterior to the portal vein

c. Lies to the right of the hepatic artery

d. Lies anterior to the first part of the duodenum

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The Correct option is D

Explanation with High Yield Facts:

The common bile duct lies in the free edge of the lesser omentum, anterior to the portal vein and to the right of the hepatic artery. It passes posterior to the first part of the duodenum before opening into the second part.

Embryology MCQ 0020

The smooth part of the right atrium derives from which of the following embryonic structures?

a. Bulbus cordis

b. Primitive atrium

c. Primitive ventricle

d. Sinus venosus

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The Correct option is D

Explanation with High Yield Facts:

The smooth part of the right atrium (the sinus venarum) is derived from the sinus venosus. The coronary sinus and the oblique vein of the left atrium also derive from the sinus venosus. The bulbus cordis (choice A) gives rise to the smooth part of the right ventricle (conus arteriosus) and the smooth part of the left ventricle (aortic vestibule). The primitive atrium (choice B) gives rise to the trabeculated part of the right and left atria.The primitive ventricle (choice C) gives rise to the trabeculated part of the right and left ventricles.

Embryology MCQ 0021

Which of the following characteristics is similar for spermatogenesis and oogenesis?

a. Age at which meiosis begins

b. Amount of cytoplasm retained

c. DNA replication during meiosis

d. Length of prophase I

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The Correct option is C

Explanation with High Yield Facts:

The actual process of manipulation of DNA and chromosomes during meiosis is very similar in spermatogenesis and oogenesis. However, the processes also differ in many other respects: In oogenesis, the process of meiosis begins before birth, and arrests between birth and puberty in prophase I. In contrast, spermatogenesis does not begin until puberty (see choice A). The egg retains a large volume of cytoplasm (choice B), while nearly all the cytoplasm is stripped during formation of a sperm. As noted above, in oogenesis, meiosis is arrested in prophase I, which is consequently very prolonged in the female. In spermatogenesis, meiosis is completed in a much shorter time (choice D).

NOTE: Both the egg and the sperm have mitochondria, but those of the sperm are left outside when the sperm nucleus enters the egg, and consequently do not contribute to the mitochondrial genome of the fetus. Instead, the mitochondria are transmitted from the egg to the fetus. Traits coded for by mitochondrial DNA are therefore inherited in a matrilineal fashion.

Embryology MCQ 0018

At which of the following ages does fetal movement first occur?

a. 1 month

b. 2 months

c. 4 months

d. 6 months

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The Correct option is B

Explanation with High Yield Facts:

Neuromuscular development is sufficient to allow fetal movement in the eighth week of life. Other features of week 8 include the first appearance of a thin skin, a head as large as the rest of the body, forward-looking eyes, appearance of digits on the hands and feet, appearance of testes and ovaries (but not distinguishable external genitalia), and a crown-rump length of approximately 30 mm. By the end of the eighth week, nearly all adult structures have at least begun to develop, and the fetus "looks like a baby".

Embryology MCQ 0019

A patient, who appears to be female, is found to be 46, XY. The patient's vagina is very shallow, ending in a blind pouch, and there are palpable masses in the labia. The diagnosis of testicular feminization syndrome is made. Which of the following was most likely present during the early fetal life of this individual?

a. A streak ovary

b. A uterus

c. Depressed levels of testosterone

d. MIF (Mullerian inhibitory factor)

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The Correct option is D

Explanation with High Yield Facts:

Testicular feminization is a disorder of the androgen receptor. Phenotypically, the patient appears female, but has a blindly ending vagina and lacks a uterus or other female internal reproductive organs. The patient has an XY genotype. Since the gene for testes determining factor (TDF) is on the Y chromosome, TDF will cause the indifferent gonad to develop into a testis containing Sertoli cells. Sertoli cells at this stage will secrete MIF, a substance that suppresses the paramesonephric ducts, preventing the formation of female internal reproductive organs. This patient would not have a streak ovary, a finding in Turner's syndrome that is associated with a 45, XO genotype. In fact, the patient would have testes, since the genetic complement contained a Y chromosome. The testes in individuals with testicular feminization syndrome are often undescended and are usually removed surgically. This patient would not possess a uterus. Both of these structures are derived from the paramesonephric duct, which is suppressed by MIF. Depressed levels of testosterone would not occur in this patient. In fact, individuals with testicular feminization syndrome have normal or even slightly elevated levels of testosterone. The development of female external genitalia is the result of defective androgen receptors, not depressed levels of testosterone.

Embryology MCQ 0016

Which of the pharyngeal pouches develops into the palatine tonsil?

a. First

b. Second

c. Third

d. Fourth

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The Correct option is B

Explanation with High Yield Facts:

The epithelial lining of the second pharyngeal pouch buds into the mesenchyme to form the palatine tonsil. Part of the pouch remains in the adult as the tonsillar fossa.

The first pharyngeal pouch (choice A) develops into the middle ear cavity and eustachian tube.

The third pharyngeal pouch (choice C) develops into the thymus and the inferior parathyroid glands.

The fourth pharyngeal pouch (choice D) gives rise to the superior parathyroid glands. Recall that abnormal development of the 3rd and 4th pouches leads to DiGeorge syndrome and results in hypocalcemia as well as abnormal cellular immunity and consequent susceptibility to viral and fungal illnesses.

The fifth pharyngeal pouch gives rise to the C cells of the thyroid gland. These cells secrete calcitonin–a hormone that lowers serum calcium.

Embryology MCQ 0017

During anatomy lab, a medical student notes a fibrous band that runs on the visceral surface of the liver. It is attached on one end to the inferior vena cava and on the other end to the left branch of the portal vein. In the embryo, this structure corresponds to the

a. Ductus venosus

b. Ligamentum teres

c. Ligamentum venosum

d. Umbilical arteries

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The Correct option is A

Explanation with High Yield Facts:

This question could have tricked you if you didn't catch the key words, "in the embryo." If you read the question too quickly and thought you were going to be asked to identify the structure described, you probably chose choice C (ligamentum venosum), since that is indeed the structure in question.

However, in the embryo, this fibrous band is actually the ductus venosus. The ductus venosus is an embryonic vessel that allows blood to bypass the fetal liver; this prevents the depletion of oxygen and nutrient-rich blood in the hepatic sinusoids. The embryonic umbilical vein (choice E) actually becomes the fibrous ligamentum teres (choice B). The ligamentum teres is located in the free margin of the falciform ligament. The embryonic umbilical arteries (choice D) become the medial umbilical ligaments.

Embryology MCQ 0015

A 12-month-old child is diagnosed with an atrial septal defect. What is the most common cause of such a congenital heart malformation?

a. Failure of formation of the septum primum

b. Failure of formation of the septum secundum

c. Incomplete adhesion between the septum primum and septum secundum

d. Malformation of the membranous interventricular septum

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The Correct option is C

Explanation with High Yield Facts:

The most common form of atrial septal defect is located near the foramen ovale (not to be confused with a patent foramen ovale, which is of little or no hemodynamic significance). They result from incomplete adhesion between the septum primum and the septum secundum during development. Atrial septal defects less commonly result from failures of formation of the septum primum (choice A) and septum secundum (choice B). Malformations of the interventricular septum (choices D) cause ventricular septal defects rather than atrial septal defects.

Embryology MCQ 0014

A newborn male child is noted to have hypospadiasis. A complete evaluation determines that the child has no other genitourinary anomalies. Nonetheless, hypospadiasis repair will be performed to prevent which of the following possible sequelae?

a. Bladder exstrophy

b. Hydrocele

c. Phimosis

d. Urinary tract infection

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The Correct option is D

Explanation with High Yield Facts:

Hypospadiasis, which is congenital displacement of the urethral opening onto the ventral surface (underside) of the penis, is due to malformation of the urethral groove and canal. Hypospadiasis frequently accompanies other genitourinary anomalies, especially cryptorchidism. Isolated hypospadiasis is repaired because the abnormal opening is often constricted, leading to urinary retention and ascending urinary tract infections. Another important consequence of hypospadiasis is sterility, which occurs if the opening is too close to the base of the penis to permit normal ejaculation. Although hypospadiasis can occur in isolation, it is strongly associated with other urogenital anomalies.

Bladder exstrophy (choice A) is a completely unrelated congenital malformation in which the abdominal wall and anterior bladder wall form incompletely, and the bladder mucosa is exposed to the environment.

Hydrocele (choice B) is a serous accumulation in the tunica vaginalis, often producing a readily apparent scrotal mass. Hydrocele usually arises without any obvious cause.

Phimosis (choice C) is the condition in which the foreskin cannot be retracted over the head of the penis. It is usually either a congenital malformation or a consequence of scarring.

Embryology MCQ 0013

A 25-year-old female presents to her obstetrician after taking a home pregnancy test with a positive result. She states that twins run in her family and would like an ultrasound to determine if she has a twin pregnancy. Radiographic studies confirm that the embryo has split at the blastocyst stage. Splitting of the embryo at the blastocyst stage results in which of the following?

a. Conjoined twins

b. Dizygotic twins

c. Fraternal twins

d. Monozygotic twins

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The Correct option is D

Explanation with High Yield Facts:

Monozygotic twins, or identical twins, develop from a single fertilized egg that subsequently splits during either the blastomere or blastocyst stage. It is more common in the blastocyst stage at the end of the first week. This results in two inner cell masses in the same blastocyst cavity. They usually develop a common placenta and chorionic cavities but separate amniotic cavities. Splitting in the second week usually results in shared amniotic cavities as well. Conjoined twins (choice A), or Siamese twins, result from incomplete splitting of the embryo. Dizygotic twins (choice B) and fraternal twins (choice C) are the same, and are the most common type of twins. They share the same genetic relatedness as do siblings of separate pregnancies. This type of twinning occurs because of simultaneous double ovulation followed by fertilization by two sperm. They each develop their own placenta and membranes.

Anatomy MCQ 0041

Which of these statements about the pancreas gland is false?

a. Lies anterior to the left kidney

b. Derives part of its blood supply from the splenic artery only

c. Has parts in both the supracolic and infracolic compartments

d. Is pierced by the middle colic artery

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The Correct option is D

Explanation with High Yield Facts:

The tail of the pancreas crosses the left kidney as it passes to the hilum of the spleen. The blood supply is from the splenic, superior and inferior pancreaticoduodenal arteries. The gland is pierced by the superior mesenteric artery. The middle colic arises from the lower border.

Anatomy MCQ 0040

Which of the following stimuli induce visceral pain?

a. Distension

b. Pressure

c. Cauterisation

d. Cutting

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The Correct option is A

Explanation with High Yield Facts:

Viscera are insensitive to: - cutting - crushing - burning

However visceral pain is caused by Excessive distension. Spasmodic contraction of smooth muscles Ischemia

The pain felt in the region of the viscus is called true visceral pain.

Referred pain: Pain arising in viscera may also be felt in the skin or other somatic tissues, supplied by somatic nerves arising from the same spinal segment. If the inflammation spreads from a diseased viscus to the parietal peritoneum it causes local somatic pain overlying body wall. In acute appendicitis pain is at first felt in the peri umbilical region (T10) and then is localised to Mcburney’s point.

Embryology MCQ 0012

What is the length of the Human spermatozoa (Sperm)?

a. 50 micrometers

b. 100 micrometers

c. 200 micrometers

d. 500 micrometers

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The Correct option is A

Explanation with High Yield Facts:

The measurements of different parts of spermatozoon:-

• Head - 4.0 μm
• Neck - 0.3 μm
• Middle piece - 7 μm
• Principal piece - 40 μm
• End piece - 5-7μm
• Approximately 58.3μm

As it is released from the wall of the seminiferous tubule into the lumen, the spermatozoon is non-motile but structurally mature. Its expanded head contains little cytoplasm and is connected by a short constricted neck to the tail.

The tail is a complex flagellum and is divided into middle, principal and end pieces. The head contains the elongated flattened nucleus with condensed, deeply staining chromatin and the acrosomal cap anteriorly, which contains acid phosphatase, hyaluronidase, neuraminidase and proteases necessary for fertilisation. In the centre of the neck, is a well formed centriole, corresponding to the proximal centriole of the spermatid from which it differentiated. The axonemal complex is derived from the distal centriole.

A small amount of cytoplasm exists in the neck covered by plasma membrane continuous with that of the head & tail.

The middle piece - a long cylinder - consists of an axial bundle of microtubules, the axoneme, outside which is a cylinder of nine dense outer fibres, surrounded by a helical mitochondrial sheath.

The annulus is an electron - dense body at the caudal end of the middle piece. The principal piece - motile part of cell - The axoneme and the surrounding dense fibres are continuous from the neck region through the whole length of the tail except for its terminal 5- 7μm, in which the axoneme alone persists. The end piece has a typical structure of a flagellum, with a simple nine plus two arrangement of microtubules.