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Question 1
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 2
Incorrect
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Which one of the following statements is true regarding the development of external genitalia?
Your Answer: The genital smoothing forms the labia majora
Correct 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 3
Incorrect
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Question 4
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 5
Incorrect
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Levels of which of the following hormones are increased in ovarian dysgenesis?
Your Answer: Progesterone
Correct Answer: Pituitary gonadotropins
Explanation:There is marked elevation of FSH and LH in ovarian dysgenesis, produced by the pituitary.
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This question is part of the following fields:
- Embryology
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Question 6
Incorrect
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What is the life span of the corpus luteum in days?
Your Answer: 20-22
Correct 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 7
Incorrect
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Question 8
Correct
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Commonest cause of precocious puberty is:
Your Answer: Idiopathic
Explanation:Precocious puberty can be defined as secondary sexual characteristics that occur before the age of 8 years in females and 9 years in males. In 80-90% of individuals it is idiopathic. Other causes include CNS anomalies and tumours, increased exposure to sex hormones/steroids, pituitary gonadotrophin secreting tumours and ovarian tumours etc.
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This question is part of the following fields:
- Embryology
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Question 9
Correct
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While evaluating a 33-year-old woman for infertility, you diagnose a bicornuate uterus. You explain that additional testing is necessary because of the woman's increased risk of congenital anomalies in which system?
Your Answer: Urinary
Explanation:Bicornuate uterus is associated with an increased chance of urinary tract anomalies. Urinary tract anomalies were present in about 23.6% of cases of bicornuate uterus patients.
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This question is part of the following fields:
- Embryology
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Question 10
Incorrect
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Question 11
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 12
Incorrect
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The external carotid artery develops from which pharyngeal arch?
Your Answer: 4th
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 13
Incorrect
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Androgen insensitivity syndrome is characterised by which one of the following karyotypes?
Your Answer: 47XXY
Correct 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 14
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 15
Correct
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All of the following are features of Turner's syndrome except:
Your Answer: The ovaries are usually well developed
Explanation:Turner syndrome patients have malfunctioning or streak ovaries due to which they can never conceive. It affects females, who will have a short stature, widely spaced nipples, webbed neck and karyotyping shows 45XO.
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This question is part of the following fields:
- Embryology
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Question 16
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 17
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 18
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 19
Correct
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At birth, approximately how many oocytes are present in the ovaries?
Your 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 20
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 21
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 22
Correct
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Question 23
Correct
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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: 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 24
Incorrect
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Ootidogenesis refers to which process during Oogenesis?
Your Answer: Differentiation
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 25
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: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 26
Incorrect
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How many days after fertilisation does the blastocyst form?
Your Answer: 4 days
Correct 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 27
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 28
Incorrect
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Regarding feto-maternal blood circulation, which of the following statements is false?
Your Answer: In the umbilical vein the pressure is approximately 20 mmHg
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 29
Correct
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Regarding implantation, how many days after fertilisation does it typically occur?
Your 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 30
Correct
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A Bicornuate uterus is due to which of the following?
Your 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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