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Question 1
Correct
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All of the following complications can be found in a pregnant patient with a bicornuate uterus, except?
Your Answer: Polyhydramnios
Explanation:Women with a bicornuate uterus are at increased risk of recurrent abortions, premature birth, fetal malpositioning, placenta previa and retained products of placenta leading to post partum haemorrhage.
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This question is part of the following fields:
- Embryology
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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
Incorrect
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Ootidogenesis refers to which process during Oogenesis?
Your Answer: 2nd Meiotic Division
Correct 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 4
Correct
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How many days after fertilisation does the blastocyst form?
Your Answer: 5 days
Explanation:Shortly after the Morula enters into the uterus, approximately on the 4th day after fertilization a fluid filled cystic cavity appears in the morula and transforms the morula into a blastocyst.
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This question is part of the following fields:
- Embryology
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Question 5
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 6
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 7
Incorrect
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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: Progesterone and Oestrogen
Correct Answer: PGE2
Explanation:Functional closure of the ductus arteriosus is neonates is completed within the first few days after birth. It normally occurs by the 12th postnatal week. It has been suggested that persistent patency of DA results from a failure of the TGF-B induction after birth. Due to increased arterial pO2, constriction of the DA occurs. In addition to this on inflation the bradykinin system is activated with cause the smooth muscles in the DA to constrict. A decrease in the E2 prostaglandin is also an important factor as raised levels have been indicated in keeping the patency of the DA.
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This question is part of the following fields:
- Embryology
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Question 8
Correct
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From which germ cell layer does the GI tract initially develop?
Your Answer: Endoderm
Explanation:The GI tract forms from the endoderm. The endoderm grows laterally and then ventrally finally folding on its self to form the gut tube.
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This question is part of the following fields:
- Embryology
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Question 9
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: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 10
Incorrect
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At birth, approximately how many oocytes are present in the ovaries?
Your Answer: 100,000
Correct Answer: 1 million
Explanation:Female infants are thought to be born with the total number of gametes they will posses in their lifetime. About 1 million healthy oocytes are present at birth. However, only about 300,000 of these oocytes survive to puberty, a number which continues to decline until all the oocytes are depleted triggering menopause.
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This question is part of the following fields:
- Embryology
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Question 11
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 12
Correct
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Androgen insensitivity syndrome is characterised by which one of the following karyotypes?
Your Answer: 46XY
Explanation:Genetically, patients suffering from androgen insensitivity syndrome are 46XY. They are males but insensitive to male hormones i.e. androgens.
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This question is part of the following fields:
- Embryology
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Question 13
Correct
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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: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 15
Correct
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How many days after fertilisation does the blastocyst hatch from the zone pellucida?
Your Answer: 5-Jul
Explanation:Shortly after the morula enters the uterus, around the 4th day after fertilization, a clear cystic cavity starts forming inside the morula. The fluid passes through the zona pellucida from the uterine cavity and hence forms the blastocyst.
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This question is part of the following fields:
- Embryology
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Question 16
Correct
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Question 17
Correct
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All of the following statements are true regarding Turner's syndrome except?
Your Answer: The streak ovaries should be removed surgically due to 25% tendency to be malignant
Explanation:Girls with Turner’s syndrome (45,X) are not at risk for malignancy. Patients with feminizing testicular syndrome with XY chromosome composition and patients with mixed gonadal dysgenesis are at risk for malignancy, and bilateral gonadectomy is performed.
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This question is part of the following fields:
- Embryology
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Question 18
Correct
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Which one of the following statements regarding Turner's syndrome is true?
Your Answer: Usually presents with primary amenorrhea
Explanation:Turner syndrome patients present with primary amenorrhea, have non functional or streak ovaries and cant conceive. They are 45X genetically.
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This question is part of the following fields:
- Embryology
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Question 19
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 20
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 21
Correct
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What is the life span of the corpus luteum in days?
Your Answer: 14-16
Explanation:After the release of the oocyte, the theca and the granulosa cells form the corpus luteum which undergoes extensive vascularization for continued steroidogenesis. Progesterone is secreted by the luteal cells and is synthesized from cholesterol. The luteal phase lasts for 14 days and if implantation does not occurs the corpus luteum starts to degenerate. As B-HCG produced by the implanted embryo maintains it and without it luteolysis occurs.
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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 one of the following statements is related to testicular feminization syndrome?
Your 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 23
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, decreased bradykinin & decreased Prostaglandin E2
Correct Answer: Increased arterial pO2, increased bradykinin & decreased Prostaglandin E2
Explanation:Functional closure of the ductus arteriosus is neonates is completed within the first few days after birth. It normally occurs by the 12th postnatal week. It has been suggested that persistent patency of DA results from a failure of the TGF-B induction after birth. Due to increased arterial pO2, constriction of the DA occurs. In addition to this on inflation the bradykinin system is activated with cause the smooth muscles in the DA to constrict. A decrease in the E2 prostaglandin is also an important factor as raised levels have been indicated in keeping the patency of the DA.
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This question is part of the following fields:
- Embryology
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Question 24
Correct
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Question 25
Incorrect
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A Bicornuate uterus is due to which of the following?
Your Answer: PKD-1 gene mutations
Correct Answer: Abnormal fusion and reabsorption of the paramesonephric ducts
Explanation:A Bicornuate uterus (heart shaped) is the result of abnormal fusion and reabsorption of the paramesonephric ducts during embryogenesis. Mullerian agenesis typically results in failure to form a uterus. Mullerian duct fusion abnormalities can cause a bicornuate malformation. PKD-1 gene abnormalities are associated with PCOS. Crossed fused ectopia result in Horseshoe kidney.
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This question is part of the following fields:
- Embryology
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Question 26
Incorrect
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Regarding implantation, how many days after fertilisation does it typically occur?
Your Answer: 5
Correct Answer: 8
Explanation:Fertilization usually occurs in the fallopian tubes after ovulation. The zygote moves through the fallopian tube and implants in the endometrium about 7-9 days after fertilisation, or 6-12 days after ovulation.
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This question is part of the following fields:
- Embryology
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Question 27
Incorrect
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Which one of the following changes are in the correct sequence regarding female puberty?
Your Answer: Thelarche, menarche, maximal growth velocity
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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Question 28
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 29
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 30
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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