1.
The thyroid gland is connected to the tongue by a narrow tube, the thyroglossal duct. By 7 weeks, the thyroid gland has assumed its definitive shape and is usually located in its final site in the neck. By this time, the thyroglossal duct has normally degenerated and disappeared.
Correct Answer
A. True
Explanation
During embryonic development, the thyroid gland is connected to the tongue by a narrow tube called the thyroglossal duct. However, by 7 weeks, the thyroid gland has typically taken its final shape and is situated in its permanent location in the neck. At this stage, the thyroglossal duct has usually degenerated and disappeared. Therefore, the statement is true.
2.
The thyroid primordium consists of a solid mass of ectodermal cells.
Correct Answer
B. False
Explanation
The thyroid primordium does not consist of a solid mass of ectodermal cells. Instead, it is derived from endodermal cells that form a hollow structure known as the thyroid diverticulum. This diverticulum eventually gives rise to the thyroid gland. Therefore, the correct answer is false.
3.
Which of the following nerves are NOT innervated the anterior two thirds of the tongue?
Correct Answer
B. GlossopHaryngeal nerve
Explanation
The glossopharyngeal nerve is not innervated in the anterior two thirds of the tongue. This nerve is responsible for providing sensory information from the posterior one third of the tongue, as well as controlling some of the muscles involved in swallowing and salivation. The trigeminal nerve, on the other hand, innervates the anterior two thirds of the tongue, providing both sensory and motor functions. The hypoglossal nerve primarily controls the muscles of the tongue, including those involved in speech and swallowing.
4.
Which of the following nerves supplied all the muscles of the tongue, except for the palatoglossus muscle?
Correct Answer
C. Hypoglossal nerve
Explanation
The hypoglossal nerve is responsible for supplying all the muscles of the tongue, except for the palatoglossus muscle. This nerve controls the movement and coordination of the tongue muscles, allowing for actions such as swallowing, speaking, and chewing. The trigeminal nerve is responsible for sensory information from the face and motor functions like chewing, while the glossopharyngeal nerve is responsible for taste and swallowing sensations in the back of the throat.
5.
Which of the following salivary glands appear approximately two weeks later than the other glands?
Correct Answer
A. The sublingual glands
Explanation
The sublingual glands appear approximately two weeks later than the other salivary glands.
6.
The five facial primordia that appear as prominences around the stomodeum follow:
A frontonasal prominence
Paired maxillary prominences
Paired mandibular prominences
Correct Answer
A. True
Explanation
The statement is true because during embryonic development, the face forms from five prominences around the stomodeum (the future mouth). The frontonasal prominence gives rise to the forehead and the bridge of the nose. The paired maxillary prominences develop into the upper jaw and cheeks, while the paired mandibular prominences form the lower jaw and chin.
7.
As the medial nasal prominences merge, they form an intermaxillary segment. This segment gives rise to the:
The middle part (philtrum) of the upper lip.
Premaxillary part of the maxilla and its associated gingiva (gum)
Secondary palate
Correct Answer
B. False
Explanation
The correct answer is False. The intermaxillary segment gives rise to the premaxillary part of the maxilla and its associated gingiva (gum), not the middle part (philtrum) of the upper lip or the secondary palate.
8.
The ectoderm of the laryngotracheal tube gives rise to the epithelium of the lower respiratory organs and the tracheobronchial glands.
Correct Answer
B. False
Explanation
The ectoderm of the laryngotracheal tube does not give rise to the epithelium of the lower respiratory organs and the tracheobronchial glands. Instead, these structures are derived from the endoderm. Therefore, the statement is false.
9.
The lung buds grow into the coelomic cavity in the region:
Correct Answer
B. Pericardio-peritoneal canals
Explanation
The lung buds grow into the coelomic cavity in the region of the pericardio-peritoneal canals.
10.
The lung bud mesenchyme gives rise to the:
Correct Answer
C. Smooth muscles
Explanation
The lung bud mesenchyme gives rise to smooth muscles. Mesenchyme is the embryonic connective tissue from which various structures develop. In the case of the lungs, the lung bud mesenchyme differentiates into smooth muscle cells, which are important for the contraction and relaxation of the airway walls. Smooth muscles help regulate airflow and play a role in bronchoconstriction and bronchodilation.
11.
The adult lung alveoli number is reached by:
Correct Answer
E. Childhood 10 years of age
Explanation
The correct answer is childhood 10 years of age. This is because the development of lung alveoli continues throughout childhood and reaches its maximum number by the age of 10. The canalicular stage, terminal sac stage, and alveolar stage are all stages of lung development that occur during fetal development and early infancy. The newborn stage is the immediate period after birth. Therefore, the number of adult lung alveoli is not reached until childhood at the age of 10.
12.
The digestive system develops from the
Correct Answer
C. Endoderm
Explanation
The correct answer is endoderm. The digestive system develops from the endoderm, which is one of the three primary germ layers in the early embryo. The endoderm gives rise to the innermost layer of the digestive tract, including the lining of the stomach, intestines, and other associated organs like the liver and pancreas. The endoderm also plays a crucial role in the development of other systems, such as the respiratory system and certain glands.
13.
The oral membrane that breaks through to form the mouth is the
Correct Answer
A. Stomodeum
Explanation
The stomodeum is the correct answer because it is the oral membrane that breaks through to form the mouth. The stomodeum is an embryonic structure that develops during early development and eventually gives rise to the oral cavity. It is an important step in the formation of the mouth and plays a crucial role in the development of the digestive system. The proctodeum, on the other hand, is the embryonic structure that forms the terminal part of the digestive system, specifically the anus.
14.
The cloacal membrane that ruptures through to form the anus is the
Correct Answer
B. Proctodeum
Explanation
The cloacal membrane that ruptures through to form the anus is called the proctodeum. The proctodeum is an embryonic structure that develops during the formation of the digestive system. It is responsible for the development of the anal opening in the early stages of embryonic development. The stomodeum, on the other hand, is the embryonic structure that forms the oral cavity. Therefore, the correct answer in this case is proctodeum.
15.
The foregut of the endodermal tube produces evaginations or outpocketing that produce the
Correct Answer
A. Respiratory system-Trachea, Lungs
Explanation
The foregut of the endodermal tube produces evaginations or outpocketing that give rise to the respiratory system, specifically the trachea and lungs. This means that during development, the foregut undergoes a process where it forms these structures, which are essential for breathing and gas exchange in higher organisms. The trachea serves as the main airway that connects the lungs to the outside environment, while the lungs are responsible for oxygenating the blood and removing carbon dioxide. Therefore, the correct answer is the respiratory system, specifically the trachea and lungs.
16.
Which of the following is NOT produced by the outpocketing of the foregut of the endodermal tube
Correct Answer
C. Allantois
Explanation
The allantois is not produced by the outpocketing of the foregut of the endodermal tube. The foregut gives rise to several structures including the thyroid, liver, pancreas, trachea, and lungs. However, the allantois is derived from the hindgut and is involved in the development of the urinary bladder and umbilical cord in mammals.
17.
The hindgut of the endodermal tube produces evaginations or outpocketing that produce the
Correct Answer
B. Allantois
Explanation
The hindgut of the endodermal tube produces evaginations or outpocketing that produce the allantois. The allantois is an embryonic structure that plays a role in waste storage and gas exchange in many vertebrates. It is a sac-like structure that develops from the hindgut and extends into the connecting stalk of the embryo. In some animals, such as birds and reptiles, the allantois also functions as a respiratory organ, allowing for the exchange of gases between the embryo and the environment. Therefore, the allantois is the correct answer in this context.
18.
Place the events in the development of the Lower Respiratory Tract in order
A. gives rise to bronchioles and alveoli
B. bifurcates into two branches that grow laterally
C. pocket-like evagination from the midventral floor of the fore gut
D. grows downward and elongates
E. continues to branch dichotomously
Correct Answer
B. C D B E A
19.
The hepatic diverticulum produces all the following EXCEPT
Correct Answer
C. Pancreatic duct
Explanation
The hepatic diverticulum is an embryonic structure that gives rise to several organs in the digestive system. It eventually develops into the liver, gall bladder, proximal hepatic ducts, and bile duct. However, the pancreatic duct is not derived from the hepatic diverticulum. Instead, it originates from the foregut endoderm. Therefore, the correct answer is the pancreatic duct.
20.
The cloaca membrane forms from the
Correct Answer
A. Ectoderm and endoderm (no mesoderm)
Explanation
The cloaca membrane forms from the ectoderm and endoderm (no mesoderm) because the cloaca is a structure that develops during embryonic development and gives rise to the urogenital and digestive systems. The ectoderm is the outermost germ layer that gives rise to the skin and nervous system, while the endoderm is the innermost germ layer that gives rise to the lining of the digestive tract. The mesoderm, on the other hand, gives rise to the muscles, skeleton, and connective tissues. Therefore, in the formation of the cloaca membrane, only the ectoderm and endoderm are involved, with no contribution from the mesoderm.
21.
All these statements are true except for?
Ventral Mesentery, the thin, double-layered membrane gives rise to:
Correct Answer
C. The ventral border of the stomach grows faster than its dorsal border; this demarcates the developing greater curvature of the stomach
Explanation
The given statements are all true except for the statement that the ventral border of the stomach grows faster than its dorsal border, which demarcates the developing greater curvature of the stomach.
22.
The urogenital sinus gives rise to the
Correct Answer
E. B & c
Explanation
The urogenital sinus gives rise to the urinary bladder and urethra. The ureter, on the other hand, arises from the mesonephric duct. Therefore, the correct answer is b & c.
23.
The narrow portion of allantois between bladder region and urogenital sinus become
Correct Answer
A. Urethra
Explanation
The narrow portion of allantois between the bladder region and urogenital sinus develops into the urethra. The urethra is a tube that connects the bladder to the external opening of the body, allowing urine to be expelled. During development, the allantois initially extends from the hindgut and forms the bladder region. As the urogenital sinus develops, the narrow portion of the allantois between the bladder and urogenital sinus differentiates into the urethra, which serves as a passage for both urine and semen in males, and urine in females.
24.
All these statements are true except for?
Correct Answer
C. This septum divides the cranial portion of the foregut into a dorsal part, the laryngotracheal tube (primordium of larynx, trachea, bronchi, and lungs), and a ventral part (primordium of oropHarynx and esopHagus.
Explanation
The given statement is true. The tracheoesophageal septum divides the cranial portion of the foregut into a dorsal part, which is the laryngotracheal tube (primordium of larynx, trachea, bronchi, and lungs), and a ventral part (primordium of oropharynx and esophagus).
25.
All these statements about Terminal Sac Stage (26 Weeks to Birth) are true except for?
Correct Answer
D. By 26 weeks, the terminal sacs are lined mainly by squamous epithelial cells of endodermal origin—type II pneumocytes—across which gas exchange occurs.
Explanation
During the Terminal Sac Stage (26 Weeks to Birth), the terminal sacs are lined mainly by squamous epithelial cells of endodermal origin known as type II pneumocytes. These cells play a crucial role in gas exchange across the sacs. The other statements in the question are all true, including the development of more terminal sacs, the bulging of capillaries into these sacs, the establishment of the blood-air barrier for gas exchange, and the formation of surfactant to prevent the collapse of sacs during exhalation.
26.
All these statements are true except for?
Rotation of the stomach
Correct Answer
E. The rotation and growth of the stomach explain why the right vagus nerve supplies the anterior ventral wall of the adult stomach and the left vagus nerve innervates its posterior dorsal wall.
Explanation
The given explanation states that the rotation and growth of the stomach determine the innervation of its walls by the right and left vagus nerves. This means that the anterior ventral wall of the stomach is supplied by the right vagus nerve, while the posterior dorsal wall is innervated by the left vagus nerve. The other statements in the passage describe the process of rotation and growth of the stomach, but do not provide any information about the innervation. Therefore, the given explanation correctly identifies the statement that is not true based on the information provided.
27.
The foregut gives rise to the pharynx, lower respiratory system, esophagus, stomach, proximal part of the duodenum, liver, pancreas, and biliary apparatus.
Correct Answer
A. True
Explanation
The foregut is an embryonic structure that develops into various organs in the body, including the pharynx, lower respiratory system, esophagus, stomach, proximal part of the duodenum, liver, pancreas, and biliary apparatus. This means that these organs originate from the foregut during embryonic development. Therefore, the statement "The foregut gives rise to the pharynx, lower respiratory system, esophagus, stomach, proximal part of the duodenum, liver, pancreas, and biliary apparatus" is true.
28.
The midgut gives rise to the left one third to one half of the transverse colon, the descending and sigmoid colon, the rectum, and the superior part of the anal canal.
Correct Answer
B. False
Explanation
The midgut gives rise to the right two thirds of the transverse colon, the ascending colon, and the cecum, not the left one third to one half of the transverse colon, the descending and sigmoid colon, the rectum, and the superior part of the anal canal.
29.
Which of the following nerves innervate mainly the posterior one third of the tongue?
Correct Answer
C. GlossopHaryngeal nerve
Explanation
The glossopharyngeal nerve is responsible for innervating mainly the posterior one third of the tongue. This nerve carries sensory information from the taste buds located in this region of the tongue, as well as providing motor control to the muscles involved in swallowing and speech. The other options, such as the trigeminal nerve, facial nerve, and chorda tympani, are not primarily responsible for innervating the posterior one third of the tongue.
30.
Which of the following arteries supply the foregut derivatives?
Correct Answer
C. Celiac artery
Explanation
The celiac artery is the correct answer because it is responsible for supplying blood to the foregut derivatives. The foregut includes organs such as the stomach, liver, gallbladder, spleen, and the upper part of the small intestine. The celiac artery branches off from the abdominal aorta and provides oxygenated blood to these organs, ensuring their proper functioning. The superior and inferior mesenteric arteries, on the other hand, supply blood to the midgut and hindgut derivatives respectively, not the foregut.
31.
All these statements are true except for?
Correct Answer
D. At first, the sacs are separated from the oral cavity by the oropHaryngeal membrane. This membrane ruptures by the end of the sixth week, bringing the nasal and oral cavities into communication.
Explanation
The given answer is incorrect because it states that the oropharyngeal membrane ruptures by the end of the sixth week, bringing the nasal and oral cavities into communication. However, the correct statement is that the oropharyngeal membrane ruptures by the end of the fourth week, not the sixth week. This rupture allows for communication between the nasal and oral cavities.
32.
All these statements are true except for?
Correct Answer
A. The endodermal epithelium in the roof of each nasal cavity becomes specialized to form the olfactory epithelium.
33.
All of these statements are true except for?
Correct Answer
B. The lateral nasal prominences form the nasal septum, ethmoid bone, and cribriform plate.
Explanation
The correct answer is "The lateral nasal prominences form the nasal septum, ethmoid bone, and cribriform plate." This statement is incorrect because the lateral nasal prominences actually form the alae (sides) of the nose, not the nasal septum, ethmoid bone, and cribriform plate. The nasal septum is formed by the fusion of the medial nasal prominences, while the ethmoid bone and cribriform plate are part of the skull and not directly formed by the nasal prominences.
34.
Which of the following structures develop into the definitive kidney?
Correct Answer
C. MetanepHros
Explanation
The definitive kidney develops from the metanephros. The pronephros and mesonephros are temporary structures that form earlier in embryonic development and eventually degenerate. The metanephros is the final and functional kidney that develops later in embryogenesis and continues to function throughout life.
35.
Which of the following germ layers give rise to the pronephros, mesonephros and metanephros?
Correct Answer
B. Intermediate mesoderm
Explanation
The intermediate mesoderm gives rise to the pronephros, mesonephros, and metanephros. These structures are part of the developing urinary system in vertebrates. The pronephros is the first kidney-like structure to form, followed by the mesonephros and then the metanephros. The intermediate mesoderm is located between the paraxial mesoderm (which gives rise to skeletal muscles) and the lateral mesoderm (which gives rise to the circulatory system). This germ layer specifically differentiates into the urinary and reproductive systems during embryonic development.
36.
A portion of the urogenital ridge forms the nephrogenic cord, which gives rise to the urinary system.
Correct Answer
A. True
Explanation
The urogenital ridge is a structure that develops during embryonic development and gives rise to both the urinary and reproductive systems. Within the urogenital ridge, a portion called the nephrogenic cord specifically gives rise to the urinary system. Therefore, it is correct to say that a portion of the urogenital ridge forms the nephrogenic cord, which in turn gives rise to the urinary system.
37.
The lateral mesoderm forms a longitudinal elevation along the dorsal body wall called the urogenital ridge.
Correct Answer
B. False
38.
Which of the following gives rise to the parietal pleura?
Correct Answer
A. Somatic mesoderm
Explanation
The parietal pleura is derived from the somatic mesoderm. The somatic mesoderm is the layer of mesoderm that lines the body wall and gives rise to the connective tissue, muscles, and bones of the body. The parietal pleura specifically refers to the layer of mesothelial cells that lines the inner surface of the thoracic cavity. This layer is derived from the somatic mesoderm during embryonic development. Therefore, the correct answer is somatic mesoderm.
39.
The internal lining of the larynx originates from endoderm, but the cartilages and muscles originate from mesenchyme of the…………….
Correct Answer
D. 4th and 6th pHaryngeal arches
Explanation
The correct answer is 4th and 6th pharyngeal arches. The larynx develops from the endoderm, which forms the internal lining. However, the cartilages and muscles of the larynx originate from the mesenchyme of the 4th and 6th pharyngeal arches. These arches contribute to the development of various structures in the head and neck region during embryonic development.
40.
The tongue appears in embryos of approximately 4 weeks in the form of two lateral lingual swellings and one medial swelling. These three swellings originate from the………………
Correct Answer
A. 1st pHaryngeal arch
Explanation
The tongue develops from the first pharyngeal arch. This arch gives rise to several structures in the head and neck region, including the muscles of mastication, the maxilla, and the mandible. The two lateral lingual swellings and one medial swelling that form the tongue are derived from this arch.
41.
Which of the following structures is an adult derivative of the ureteric bud?
Correct Answer
E. All of them
Explanation
All of the structures listed (ureter, renal pelvis, major & minor calyx, and collecting duct) are derived from the ureteric bud. The ureteric bud is an outgrowth from the mesonephric duct that gives rise to the collecting system of the kidney, including the ureter, renal pelvis, major & minor calyx, and collecting duct. Therefore, all of these structures are adult derivatives of the ureteric bud.
42.
Which of the following structures is an adult derivative of the metanephric mesoderm?
Correct Answer
A. Connecting tubule
Explanation
The connecting tubule is the correct answer because it is an adult derivative of the metanephric mesoderm. The metanephric mesoderm is a structure that gives rise to the renal tubules, including the connecting tubule. The proximal and distal convoluted tubules, loop of Henle, renal capsule, and renal glomerulus are not derived from the metanephric mesoderm.
43.
Which of the following structures is an adult derivative of the metanephric vesicles?
Correct Answer
B. Proximal & distal convoluted tubule
Explanation
The proximal and distal convoluted tubules are the adult derivatives of the metanephric vesicles. This is because during kidney development, the metanephric vesicles give rise to the collecting duct system, which includes the proximal and distal convoluted tubules. These tubules play a crucial role in reabsorbing and secreting substances in the urine, helping to regulate water and electrolyte balance in the body.
44.
Which of the following structures is an adult derivative of the S-shaped renal tubule?
Correct Answer
E. All of them
Explanation
All of the structures mentioned (proximal and distal convoluted tubules, metanephric tubules, Loop of Henle, renal capsule, and renal glomerulus) are adult derivatives of the S-shaped renal tubule.
45.
What are the arrows pointing (grey square) in the figures A and B.
Correct Answer
A. TracheoesopHageal fold
Explanation
The arrows in figures A and B are pointing to the tracheoesophageal fold.
46.
What are the arrows pointing (blue square) in the figure C.
Correct Answer
C. EsopHagus
Explanation
The arrows in the figure C are pointing towards the esophagus. This is indicated by the label "Esophagus" in the given options. The esophagus is a muscular tube that connects the throat (pharynx) with the stomach. It is responsible for transporting food and liquids from the mouth to the stomach for digestion.
47.
What are the arrows pointing (green square) in the figure C.
Correct Answer
D. Trachea
Explanation
The arrows in the figure C are pointing towards the trachea.
48.
What are the arrows pointing (pink square) in the figure C.
Correct Answer
E. Lung buds
Explanation
The arrows in the figure C are pointing towards the lung buds.
49.
What are the arrows pointing (red square) in the figure D
Correct Answer
A. Epiglottis
Explanation
The arrows in the figure are pointing to the epiglottis. The epiglottis is a flap of cartilage located at the base of the tongue, just above the larynx. Its main function is to prevent food and liquid from entering the trachea during swallowing, by covering the opening of the larynx.
50.
What are the arrows pointing (grey square) in the figure D
Correct Answer
B. Laryngotracheal groove
Explanation
The arrows in the figure D are pointing towards the laryngotracheal groove.