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Question 1
Incorrect
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Question 2
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 3
Correct
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Which of the following statements is FALSE regarding Turner's syndrome?
Your Answer: Buccal smear is chromatin positive
Explanation:Turner syndrome patients have high FSH levels and low oestrogen levels. They have a short stature and buccal smear is chromatin negative.
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This question is part of the following fields:
- Embryology
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Question 4
Incorrect
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Which structure is the primary mechanism for shunting blood away from the fetal pulmonary circulation?
Your Answer: Umbilical Arteries
Correct Answer: Foramen Ovale
Explanation:Blood enters the right atrium of the fetal heart and most passes through the foramen ovale into the left atrium. From there it is pumped through the aorta. The foramen ovale is the major structure for bypassing the fetal pulmonary circulation. Some of the blood in the right atrium does enters the right ventricle and then into the pulmonary artery however most of this passes through the ductus arteriosus into the aorta thus bypassing the fetal pulmonary circulation.
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This question is part of the following fields:
- Embryology
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Question 5
Incorrect
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From which germ layer does the myenteric plexus of the GI tract developed:
Your Answer: Neural tube of Ectoderm
Correct Answer: Neural crest of Ectoderm
Explanation:During the 5th week, the neural crest cells migrate along each side of the spinal cord where they form ganglions located dorsolateral to the aorta. Some of these cells migrate ventrally and form neurons in the preaortic ganglia as the celiac and mesenteric ganglia.
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This question is part of the following fields:
- Embryology
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Question 6
Correct
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When does Oocytogenesis complete?
Your 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 7
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 8
Incorrect
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Branches V2 and V3 of the Trigeminal nerve develop from which pharyngeal arch?
Your Answer: 3rd
Correct 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 9
Incorrect
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Which one of the following features is associated with Turner's syndrome?
Your Answer: Normal height
Correct Answer: Primary amenorrhea
Explanation:Turner syndrome patients present with primary amenorrhea. These ladies have non functional or streak ovaries and they cant conceive. Their genetic traits is 45X. They have a shielded chest, webbed neck and low height. These patients suffer from primary amenorrhea.
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This question is part of the following fields:
- Embryology
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Question 10
Incorrect
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Ootidogenesis refers to which process during Oogenesis?
Your Answer: Growth and maturation
Correct 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 11
Incorrect
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Regarding fertilization & implantation:
Your Answer: The trophoblast invades the endometrium & differentiate into an outer cytotrophoblast & an inner cyncytiotrophoblast
Correct 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 12
Incorrect
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How many days after fertilisation does the morula form?
Your Answer: 6
Correct Answer: 4
Explanation:When there are about 12-32 blastomeres, the developing human is referred to as morula. It enters the uterine cavity around the 4th day after fertilization.
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This question is part of the following fields:
- Embryology
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Question 13
Incorrect
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Regarding the closure of the ductus arteriosus (DA) after birth which of the following most accurately describes the mechanisms leading to closure of the DA?
Your Answer: Increased arterial pO2, increased bradykinin & increased Prostaglandin E2
Correct Answer: Increased arterial pO2, increased bradykinin & decreased Prostaglandin E2
Explanation:Normal closure of the ductus arteriosus (DA) is brought about by a number of mechanisms. Upon delivery the new born babies first breath inflates the lungs and this causes a rise in pO2. Oxygen is known to cause constriction of the DA in vivo and in vitro. In addition the decreased vascular resistance means the pressure within the lumen of the DA drops aiding closure. In addition on inflation of the lungs, the lungs produce bradykinin which stimulates smooth muscle constriction of the ductus. The most important factor is thought to be the drop in Prostaglandin E2. Prostaglandin E2 maintains patency of the Ductus in the unborn child but after birth is metabolised in the lungs and its levels fall rapidly within 3 hours of birth.
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This question is part of the following fields:
- Embryology
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Question 14
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 15
Incorrect
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Normal physiological gut herniation occurs at how many weeks gestation?
Your Answer: 1 week
Correct 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 16
Incorrect
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All of the following statements are true about Androgen insensitivity syndrome except:
Your Answer: No uterus
Correct 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 17
Incorrect
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Question 18
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 19
Incorrect
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In fetal circulation:
Your Answer: Oxygenated blood goes along the umbilical arteries
Correct 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 20
Incorrect
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Which one of the following changes are in the correct sequence regarding female puberty?
Your Answer:
Correct 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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SESSION STATS - PERFORMANCE PER SPECIALTY
