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Question 1
Correct
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Question 2
Correct
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Which structure is the primary mechanism for shunting blood away from the fetal pulmonary circulation?
Your Answer: Foramen Ovale
Explanation:Oxygenation of fetal blood occurs in the placenta before it returns in the umbilical vein which joins the left branch of the portal vein. It bypasses the capillaries of the liver by going through the ductus venosus, which is obliterated after birth and becomes the ligamentum venosum. The oxygenated blood enters the inferior vena cava and is transported to the right atrium and
then through the patent foramen ovale to the left atrium and on to the left ventricle. From the left ventricle, the blood flows into the aorta and through the fetal vascular network. Blood returning from the head of the foetus passes through the superior vena cava to the right atrium and straight on to the right ventricle and pulmonary artery. However, it does not enter the pulmonary
circulation, being short-circuited by the ductus arteriosus to the aorta. Aortic blood is carried via the umbilical arteries back to the placenta for reoxygenation. At birth, the three short circuits, the ductus venosus, foramen ovale and ductus arteriosus, close. -
This question is part of the following fields:
- Embryology
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Question 3
Correct
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Question 4
Correct
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All of the following statements are true about Androgen insensitivity syndrome except:
Your Answer: The chromosomal sex is 46XX
Explanation:Patients suffering from androgen insensitivity syndrome have 46XY chromosomes. Due to insensitivity to androgens, they have female characteristics e.g. scant pubic or body hairs, enlarged mammary glands, and a small penis.
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This question is part of the following fields:
- Embryology
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Question 5
Correct
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Ootidogenesis refers to which process during Oogenesis?
Your Answer: 1st and 2nd Meiotic Divisions
Explanation:Oogonium become Primary Oocyte via Growth/Maturation. This process is called oocytogenesis Primary Oocyte undergoes 2 meiotic divisions to become Ootids. This process is called Ootidogenesis Ootids differentiate into Ovum
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This question is part of the following fields:
- Embryology
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Question 6
Correct
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Normal physiological gut herniation occurs at how many weeks gestation?
Your Answer: 8 weeks
Explanation:At about 8-12 weeks gestation, normal physiological herniation of the fetal bowel occurs. The midgut protrudes into the base of the umbilicus, and undergoes a 90-degree anticlockwise rotation. When the abdominal cavity enlarges enough to fit the developing midgut, the intestines undergo another 180-degree rotation before returning to the abdominal cavity.
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This question is part of the following fields:
- Embryology
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Question 7
Correct
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Branches V2 and V3 of the trigeminal nerve develop from which pharyngeal arch?
Your Answer: 1st
Explanation:Trigeminal nerve has three divisions, the first is the ophthalmic division that does not originate from any of the pharyngeal arches, the second and third divisions, namely, the maxillary and the mandibular region develop from the first pharyngeal arch.
Pharyngeal Arches:
1st = Trigeminal V2 & V3 (CN V)
2nd = Facial (CN VII)
3rd = Glossopharyngeal (CN IX)
4th and 6th = Vagus (CN X) -
This question is part of the following fields:
- Embryology
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Question 8
Incorrect
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Regarding feto-maternal blood circulation, which of the following statements is false?
Your Answer: Oxygenated blood returns to the foetus via a single umbilical vein
Correct Answer: At term the placenta receives 70% of uterine blood flow
Explanation:The placenta is important for regulating feto-maternal blood circulation, ensuring that the two circulatory systems do not come into direct contact. The placenta receives 70-80% of the uterine blood flow into the decidual spiral arteries where nutrient, waste and gaseous exchange with fetal blood takes place via the villous core fetal vessels. Deoxygenated blood arrives at the placenta via two uterine arteries while oxygenated, nutrient-rich blood is circulated back to the foetus via a single umbilical vein. The pressure in the umbilical vein is about 20 mmHg.
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This question is part of the following fields:
- Embryology
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Question 9
Correct
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The second meiotic division of the oocyte is normally completed:
Your Answer: After the sperm penetrates the secondary oocyte
Explanation:Upon penetration, if all is normally occurring, the process of egg-activation occurs, and the oocyte is said to have become activated. This is thought to be induced by a specific protein phospholipase c zeta. It undergoes its secondary meiotic division, and the two haploid nuclei (paternal and maternal) fuse to form a zygote.
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This question is part of the following fields:
- Embryology
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Question 10
Correct
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Turner's syndrome is characterised by :
Your Answer: Streak ovaries
Explanation:Turner syndrome, a condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure of the ovaries to develop and heart defects. Streak ovaries are a form of ovarian dysgenesis and are associated with Turner syndrome. Occasionally they may be functional and secondary sexual characteristics may develop.
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This question is part of the following fields:
- Embryology
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Question 11
Correct
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All of the following may result from a bicornuate uterus except:
Your Answer: Congenital anomalies of the baby
Explanation:Literature review shows that bicornuate uterus is associated with increase risk of spontaneous abortion in about 36% of patients. There is also an increased risk of preterm birth, malpresentation and fetal growth retardation.
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This question is part of the following fields:
- Embryology
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Question 12
Correct
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Which one of the following statements is true regarding the development of external genitalia?
Your Answer: The genital fold forms the scrotum in males
Explanation:Genital folds lead to the formation of the scrotum in males while in females they form the posterior labial commissure. Genital tubercles form the labia majora whereas the tubercle itself becomes the mons pubis. The labia minora is formed by the urogenital folds.
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This question is part of the following fields:
- Embryology
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Question 13
Correct
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Several mechanisms have been proposed as to what causes closure of the Ductus Arteriosus (DA) at Parturition. Which of the following is the most important in maintaining the patency of the DA during pregnancy?
Your Answer: PGE2
Explanation:Prostaglandin E1 and E2 help maintain the patency of the DA during pregnancy. PGE2 is by far the most potent and important. It is produced in large quantities by the placenta and the DA itself.
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This question is part of the following fields:
- Embryology
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Question 14
Incorrect
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Which one of the following statements is related to testicular feminization syndrome?
Your Answer: Kalman's syndrome is a recognized cause
Correct Answer: There are usually normal testes
Explanation:Androgen insensitivity (testicular feminization) syndrome is a rare inherited form of male pseudo hermaphroditism that occurs in phenotypically normal women with adequate breast development, normal external genitalia, a vagina of variable depth, absent uterus, and sparse or absent pubic hair and axillary hair. Testosterone levels are normal or elevated.
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This question is part of the following fields:
- Embryology
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Question 15
Correct
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Which one of the following statements best suits Androgen insensitivity syndrome?
Your Answer: Gonadectomy must be performed after puberty because of the increased risk of malignancy
Explanation:Androgen insensitivity syndrome patients have 46XY chromosomes. They are males by genotype but appear as female because of insensitivity to male hormones. It is advisable to perform gonadectomy in these patients after puberty because these patients are at increased risk of developing malignancy.
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This question is part of the following fields:
- Embryology
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Question 16
Correct
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Regarding fertilization & implantation:
Your Answer: The sperm head penetrates through the corona radiata & zona pellucida while the tail remains outside
Explanation:During fertilization, a sperm must first fuse with the plasma membrane and then penetrate the female egg cell to fertilize it. Fusing to the egg cell usually causes little problem, whereas penetrating through the egg’s hard shell or extracellular matrix can be more difficult. Therefore, sperm cells go through a process known as the acrosome reaction, which is the reaction that occurs in the acrosome of the sperm as it approaches the egg. The acrosome is a cap-like structure over the anterior half of the sperm’s head. Upon penetration, if all is normally occurring, the process of egg-activation occurs, and the oocyte is said to have become activated. This is thought to be induced by a specific protein phospholipase c zeta. It undergoes its secondary meiotic division, and the two haploid nuclei (paternal and maternal) fuse to form a zygote. To prevent polyspermy and minimize the possibility of producing a triploid zygote, several changes to the egg’s cell membranes render them impenetrable shortly after the first sperm enters the egg.
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This question is part of the following fields:
- Embryology
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Question 17
Correct
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Which of the following hormones is secreted by the corpus luteum in a non pregnant state?
Your Answer: Progesterone
Explanation:The corpus luteum is formed from the granulosa cells of the mature follicle. The structure functions as a transient endocrine organ which secretes mainly progesterone with additional secretion of oestradiol and inhibin, which serve to suppress FSH levels. In the event of no pregnancy, the corpus luteum stops producing progesterone and degenerates into the corpus albicans.
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This question is part of the following fields:
- Embryology
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Question 18
Correct
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Ootidogenesis refers to which process during Oogenesis?
Your Answer: 1st and 2nd Meiotic Divisions
Explanation:During the early fetal life, oogonia proliferate by mitosis. They enlarge to form primary oocyte before birth. No primary oocyte is form after birth. The primary oocyte is dormant is the ovarian follicles until puberty. As the follicle matures, the primary oocyte completes its first meiotic division and gives rise to secondary oocyte. During ovulation the secondary oocytes starts the second meiotic division but is only completed if a sperm penetrates it. This 1st and 2nd meiotic division is known as ootidogenesis.
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This question is part of the following fields:
- Embryology
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Question 19
Correct
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Which one of the following statements is true regarding androgen insensitivity syndrome?
Your Answer: They have no uterus
Explanation:Androgen insensitivity syndrome means that patients are phenotypically males but they are resistant or insensitive to male androgen hormones. They do not have a uterus. Due to insensitivity to androgens these patients often have female traits but their genetic makeup is of male, 46XY.
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This question is part of the following fields:
- Embryology
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Question 20
Incorrect
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The external carotid artery develops from which pharyngeal arch?
Your Answer: 3rd
Correct Answer: 1st
Explanation:The maxillary arteries and the external carotid arteries develop from the first pharyngeal arch. The stapedial arteries arise from the second, the common carotid artery and the internal carotid arteries from the third and the arch of the aorta and the right subclavian artery from the forth arch.
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This question is part of the following fields:
- Embryology
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Question 21
Incorrect
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When does Oocytogenesis complete?
Your Answer: Puberty
Correct Answer: Birth
Explanation:During the early fetal life, oogonia proliferate by mitosis. They enlarge to form primary oocyte before birth. No primary oocyte is form after birth. The primary oocyte is dormant is the ovarian follicles until puberty. As the follicle matures, the primary oocyte completes its first meiotic division and gives rise to secondary oocyte. During ovulation the secondary oocytes starts the second meiotic division but is only completed if a sperm penetrates it. This 1st and 2nd meiotic division is known as ootidogenesis.
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This question is part of the following fields:
- Embryology
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Question 22
Correct
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Which pharyngeal arch is closest to the head of the embryo?
Your Answer: 1st
Explanation:The arches are numbered according to their proximity to the head i.e. the 1st is the closest to the head end of the embryo and the 6th closest to the tail end as shown by the diagram below the table
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This question is part of the following fields:
- Embryology
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Question 23
Correct
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Branches V2 and V3 of the Trigeminal nerve develop from which pharyngeal arch?
Your Answer: 1st
Explanation:1st Arch = Trigeminal V2 & V3 (CN V) 2nd Arch = Facial (CN VII) 3rd Arch = Glossopharyngeal (CN IX) 4th and 6th Arches = Vagus (CN X)
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This question is part of the following fields:
- Embryology
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Question 24
Correct
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Which one of the following changes are in the correct sequence regarding female puberty?
Your Answer: Thelarche, maximal growth velocity, menarche
Explanation:Thelarche means appearance of the breast tissue under the influence of oestrogen from the ovaries. It heralds the onset of puberty among girls. It is followed by an increase in growth velocity followed by menarche which is the time of first menstrual bleeding.
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This question is part of the following fields:
- Embryology
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Question 25
Correct
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From which germ cell layer does the GI tract initially develop?
Your Answer: Endoderm
Explanation:GI Tract initially forms via gastrulation from the endoderm of the trilaminar embryo around week 3. It extends from the buccopharyngeal membrane to the cloacal membrane. Later in development there are contributions from all three germ cell layers.
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This question is part of the following fields:
- Embryology
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Question 26
Correct
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The best confirmatory test for Turner's syndrome is done by:
Your Answer: Chromosomal analysis (Karyotyping)
Explanation:Standard karyotyping is the best confirmatory test for the diagnosis of Turner syndrome among patients who have some doubtful clinical presentations. It is done on peripheral blood mononuclear cells.
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This question is part of the following fields:
- Embryology
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Question 27
Incorrect
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A 15 year old girl is being investigated for primary amenorrhoea. She has normal FSH,LH and E2 levels on hormone profiling and normal secondary sexual characteristics. An ultrasound shows no uterus. What is the likely diagnosis?
Your Answer: Testicular Feminisation Syndrome
Correct Answer: Rokitansky-Kuster-Hauser syndrome
Explanation:Mullerian agenesis occurs in 1 in 5000 to 1 in 40000 girls. The Mullerian system does not develop which results in an absent uterus and upper vagina. This condition is also known as Rokitansky-Kuster-Hauser syndrome, The ovarian function is normal and so the most common presentation is amenorrhea in the presence of an otherwise normal pubertal development.
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This question is part of the following fields:
- Embryology
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Question 28
Correct
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In fetal circulation:
Your Answer: Most of the blood entering the right atrium flows into the left atrium
Explanation:Circulation in the foetus: 1. Deoxygenated fetal blood is conducted to the placenta via the two umbilical arteries. The umbilical arteries arise from the internal iliac arteries.
2. Gas exchange occurs in placenta.
3. Oxygenated blood from the placenta passes through the single umbilical vein and enters the inferior vena cava (IVC).
4. About 50% of the blood in the IVC passes through the liver and the rest bypasses the liver via the ductus venosus. The IVC also drains blood returning from the lower trunk and extremities.
5. On reaching the heart, blood is effectively divided into two streams by the edge of the interatrial septum (crista dividens) (1) a larger stream is shunted to the left atrium through the foramen ovale (lying between IVC and left atrium) (2) the other stream passes into right atrium where it is joined by blood from SVC which is blood returning from the myocardium and upper parts of body. This stream therefore has a lower partial pressure of oxygen.
6. Because of the large pulmonary vascular resistance and the presence of the ductus arteriosus most of the right ventricular output passes into the aorta at a point distal to the origin of the arteries to the head and upper extremities. The diameter of the ductus arteriosus is similar to the descending aorta. The patency of the ductus arteriosus is maintained by the low oxygen tension and the vasodilating effects of prostaglandin E2;
7. Blood flowing through the foramen ovale and into left atrium passes into the left ventricle where it is ejected into the ascending aorta. This relatively oxygen rich blood passes predominantly to the head and upper extremities. -
This question is part of the following fields:
- Embryology
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Question 29
Incorrect
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Question 30
Correct
SESSION STATS - PERFORMANCE PER SPECIALTY
