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Question 1
Correct
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During the fetal stage, the mesonephric tubules gives rise to the?
Your Answer: Wolffian duct
Explanation:The development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the pronephros, mesonephros, and metanephros. The development of the pronephric duct proceeds in a cranial-to-caudal direction. As it elongates caudally, the pronephric duct induces nearby intermediate mesoderm in the thoracolumbar area to become epithelial tubules called mesonephric tubules. Each mesonephric tubule receives a blood supply from a branch of the aorta, ending in a capillary tuft analogous to the glomerulus of the definitive nephron. The mesonephric tubule forms a capsule around the capillary tuft, allowing for filtration of blood. This filtrate flows through the mesonephric tubule and is drained into the continuation of the pronephric duct, now called the mesonephric duct or Wolffian duct. The nephrotomes of the pronephros degenerate while the mesonephric duct extends towards the most caudal end of the embryo, ultimately attaching to the cloaca.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 2
Incorrect
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What is the most likely condition a new born infant is likely to suffer from, if he/she was born with incomplete fusion of the embryonic endocardial cushions?
Your Answer: Patent ductus arteriosus
Correct Answer: An atrioventricular septal defect
Explanation:The endocardial cushions in the heart are the mesenchymal tissue that make up the part of the atrioventricular valves, atrial septum and ventricular septum. An incomplete fusion of these mesenchymal cells can cause an atrioventricular septal defect. The terms endocardial cushion defect, atrioventricular septal defect and common atrioventricular canal defect can be used interchangeably with one another.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 3
Correct
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What are some of the derivatives of the second pharyngeal arch?
Your Answer: Stylohyoid muscle
Explanation:Also known as the hyoid arch, it forms the side and front of the neck. From its cartilage develops the styloid process, stylohyoid ligament and lesser cornu of the hyoid bone. The muscular derivatives include the muscles of facial expression, stapedius, stylohyoid and the posterior belly of the digastric. All these are innervated by cranial nerve VII but migrate into the area of the mandibular arch.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 4
Incorrect
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Which organs amongst these are the derivatives of the endoderm?
Your Answer:
Correct Answer: Epithelial part of the tympanic cavity
Explanation:Endoderm derivatives include the epithelium of the following: gastrointestinal tract and its glands, glandular cells of the liver and pancreases, urachus and urinary bladder, pharynx, trachea and alveoli, part of the tonsils, thyroid and parathyroid, tympanic cavity and thymus and part of the anterior pituitary gland.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 5
Incorrect
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What are the derivatives of the first brachial arch?
Your Answer:
Correct Answer: Gives rise to the sphenomandibular ligament
Explanation:The first brachial arch (mandibular) gives rise to the mandibular and maxillary processes. Muscles and bones of this process originate within the arch’s mesoderm. The first arch cartilage (Meckel’s) ossifies to form the incus and malleus of the middle ear. Its perichondrium gives rise to he sphenomandibular ligament and through intermembraneous ossification after the mandible forms, the rest of the cartilage disappears. Muscles of the first arch include: mylohyoid, tensor tympany and palati, temporalis, masseter and lateral pterygoids and the anterior belly of the epigastric. This first arch is supplied by the trigeminal nerve.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 6
Incorrect
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Which of the following organs is an ectoderm derivative?
Your Answer:
Correct Answer: Adrenal medulla
Explanation:Ectoderm derivatives include the adrenal medulla, posterior pituitary, the epidermis of the skin, nails, hair, sweat glands, mammary glands, sebaceous glands, the central nervous system, the peripheral nervous system, the retina and lens of eye, the pupillary muscle of the iris, melanocytes, Schwann cells and odontoblasts.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 7
Incorrect
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Which one of the following is a derivative of the midgut?
Your Answer:
Correct Answer: Caecum
Explanation:The primary intestinal loop is formed from the midgut which gives rise to the distal half of the duodenum, the jejunum, ascending colon, proximal two thirds of the transverse colon and the ileum.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 8
Incorrect
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In the adult heart, the sinus venosus gives rise to the:
Your Answer:
Correct Answer: Coronary sinus
Explanation:The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. It exists distinctly only in the embryonic heart (where it is found between the two venae cavae); however, the sinus venosus persists in the adult. In the adult, it is incorporated into the wall of the right atrium to form a smooth part called the sinus venarum, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis. The sinus venosus also forms the SA node and the coronary sinus.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 9
Incorrect
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Which of the following statements is true regarding the umbilical cord?
Your Answer:
Correct Answer: Is filled with jelly of Wharton
Explanation:The umbilical cord that connects the fetus to the placenta is about 50cm long. This tissue consists of the body stalk and vitelline duct. The former containing the allantoic diverticulum and the umbilical vessels. The latter contains the connection linking the digestive tube and the yolk sac. This cord is wrapped by stratum of ectoderm and gelatinous tissue or jelly of Wharton. The right umbilical vein plus the vitelline vessels and ducts disappear and this at birth the cord has three vessels which are the umbilical vein and two umbilical arteries.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 10
Incorrect
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During uterogrowth, the second pharyngeal arch gives rise to which structures?
Your Answer:
Correct Answer: Stylohyoid muscle
Explanation:The second pharyngeal arch or hyoid arch, is the second of six pharyngeal arches that develops in fetal life during the fourth week of development and assists in forming the side and front of the neck. Derivatives:
Skeletal – From the cartilage of the second arch arises:
Stapes,
Temporal styloid process,
Stylohyoid ligament, and
Lesser cornu of the hyoid bone.
Muscles:
Muscles of face
Occipitofrontalis muscle
Platysma
Stylohyoid muscle
Posterior belly of Digastric
Stapedius muscle
Auricular muscles
Nerve supply: Facial nerve
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This question is part of the following fields:
- Anatomy
- Embryology
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