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Question 1
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 2
Incorrect
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Commonest cause of precocious puberty is:
Your Answer: Abnormal skull development
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 3
Incorrect
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Branches V2 and V3 of the Trigeminal nerve develop from which pharyngeal arch?
Your Answer: 6th
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 4
Incorrect
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Which one of the following statements is related to testicular feminization syndrome?
Your Answer: There's usually very low testosterone levels
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 5
Incorrect
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From which germ layer does the myenteric plexus of the GI tract developed:
Your Answer:
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
Incorrect
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Question 7
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 8
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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Question 9
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 10
Incorrect
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Which one of the following statements is true regarding androgen insensitivity syndrome?
Your Answer:
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 11
Incorrect
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Which one of the following statements regarding Turner's syndrome is true?
Your Answer:
Correct 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 12
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 13
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 14
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 15
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 16
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 17
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 18
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 19
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 20
Incorrect
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Question 21
Incorrect
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Question 22
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 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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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 25
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 26
Incorrect
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Regarding fertilization & implantation:
Your Answer:
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 27
Incorrect
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Turner's syndrome is characterised by :
Your Answer:
Correct 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 28
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 29
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 30
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 31
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 32
Incorrect
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Question 33
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 34
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 35
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 36
Incorrect
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From which germ cell layer does the GI tract initially develop?
Your Answer:
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 37
Incorrect
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Regarding implantation, how many days after fertilisation does it typically occur?
Your Answer:
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 38
Incorrect
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Which of the following hormones is secreted by the corpus luteum in a non pregnant state?
Your Answer:
Correct 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 39
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 40
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:
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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SESSION STATS - PERFORMANCE PER SPECIALTY
