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Question 1
Incorrect
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Which one of the following statements is true regarding androgen insensitivity syndrome?
Your Answer: Usually have secondary amenorrhea
Correct 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 2
Incorrect
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From which germ cell layer does the GI tract initially develop?
Your Answer: Paraxial Mesoderm
Correct 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 3
Incorrect
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All of the following may result from a bicornuate uterus except:
Your Answer: Abnormal fetal lie
Correct 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 4
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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Question 5
Incorrect
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Regarding implantation, how many days after fertilisation does it typically occur?
Your Answer: 3
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 6
Incorrect
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Regarding feto-maternal blood circulation, which of the following statements is false?
Your Answer:
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 7
Incorrect
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Which structure is the primary mechanism for shunting blood away from the fetal pulmonary circulation?
Your Answer:
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 8
Incorrect
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The external carotid artery develops from which pharyngeal arch?
Your Answer:
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 9
Incorrect
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Question 10
Incorrect
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In the non-pregnant state which of the following hormones is secreted by the corpus luteum?
Your Answer:
Correct Answer: Progesterone
Explanation:The Corpus Luteum is a temporary endocrine structure that secretes two steroid hormones: 1. Progesterone (17a Hydroxyprogesterone) and 2. Oestradiol. The corpus luteum also secretes Inhibin A. In the menstrual cycle if fertilisation doesn’t occur the corpus luteum stops secreting progesterone and degenerates into a corpus albicans. If fertilisation occurs hCG signals the corpus to continue progesterone production and it is then termed the corpus luteum graviditatis
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This question is part of the following fields:
- Embryology
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Question 11
Incorrect
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In a non-ovulating follicle, follicular growth is followed by:
Your Answer:
Correct Answer: Atresia
Explanation:During the ovulatory cycle, only one follicle will ovulate. The remaining non-ovulating follicles undergo disintegration. This process is known as atresia.
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This question is part of the following fields:
- Embryology
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Question 12
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:
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 13
Incorrect
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Branches V2 and V3 of the trigeminal nerve develop from which pharyngeal arch?
Your Answer:
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 14
Incorrect
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All of the following are features of Turner's syndrome except:
Your Answer:
Correct 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 15
Incorrect
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Normal physiological gut herniation occurs at how many weeks gestation?
Your Answer:
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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Which of the following statements is FALSE regarding Turner's syndrome?
Your Answer:
Correct 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 17
Incorrect
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How many days after fertilisation does the blastocyst form?
Your Answer:
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 18
Incorrect
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Ootidogenesis refers to which process during Oogenesis?
Your Answer:
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 19
Incorrect
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Which one of the following statements is related to testicular feminization syndrome?
Your Answer:
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 20
Incorrect
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Ootidogenesis refers to which process during Oogenesis?
Your Answer:
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 21
Incorrect
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Question 22
Incorrect
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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:
Correct 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 23
Incorrect
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The second meiotic division of the oocyte is normally completed:
Your Answer:
Correct 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 24
Incorrect
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How many days after fertilisation does the blastocyst hatch from the zone pellucida?
Your Answer:
Correct 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 25
Incorrect
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Which one of the following statements best suits Androgen insensitivity syndrome?
Your Answer:
Correct 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 26
Incorrect
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Commonest cause of precocious puberty is:
Your Answer:
Correct 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 27
Incorrect
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Which one of the following features is associated with Turner's syndrome?
Your Answer:
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 28
Incorrect
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Question 29
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:
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 30
Incorrect
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Levels of which of the following hormones are increased in ovarian dysgenesis?
Your Answer:
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 31
Incorrect
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Branches V2 and V3 of the Trigeminal nerve develop from which pharyngeal arch?
Your Answer:
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 32
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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Question 33
Incorrect
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All of the following statements are true regarding Turner's syndrome except?
Your Answer:
Correct 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 34
Incorrect
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How many days after fertilisation does the morula form?
Your Answer:
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 35
Incorrect
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Question 36
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:
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 37
Incorrect
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Androgen insensitivity syndrome is characterised by which one of the following karyotypes?
Your Answer:
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 38
Incorrect
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When does Oocytogenesis complete?
Your Answer:
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 39
Incorrect
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At birth, approximately how many oocytes are present in the ovaries?
Your Answer:
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 40
Incorrect
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All of the following features are associated with congenital uterine malformations except:
Your Answer:
Correct Answer: Pregnancy induced hypertension
Explanation:Congenital uterine abnormalities are associated with an increased risk of spontaneous abortions, preterm delivery of the foetus, fetal growth retardation and malpresentation.
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This question is part of the following fields:
- Embryology
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Question 41
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:
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 42
Incorrect
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In fetal circulation:
Your Answer:
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 43
Incorrect
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Question 44
Incorrect
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The best confirmatory test for Turner's syndrome is done by:
Your Answer:
Correct 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 45
Incorrect
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Which one of the following statements is true regarding the development of external genitalia?
Your Answer:
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 46
Incorrect
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What is the life span of the corpus luteum in days?
Your Answer:
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 47
Incorrect
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All of the following statements are true about Androgen insensitivity syndrome except:
Your Answer:
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 48
Incorrect
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From which germ cell layer does the GI tract initially develop?
Your Answer:
Correct 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 49
Incorrect
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Which pharyngeal arch is closest to the head of the embryo?
Your Answer:
Correct 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 50
Incorrect
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All of the following complications can be found in a pregnant patient with a bicornuate uterus, except?
Your Answer:
Correct 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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SESSION STATS - PERFORMANCE PER SPECIALTY
