Oxyntic cells are present in -
Which is the first bone to start ossifying?
The incudomalleolar joint is a?
Hilton's law primarily relates to which of the following?
Fossa ovalis is a remnant of -
Nephron is derived from ?
Fibrous stroma of liver is derived from -
What muscle is attached to the superior nuchal line?
Which of the following structures is not related to the third part of the duodenum?
Which nerve is preserved in dissecting the superficial and deep lobes of the parotid gland?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 91: Oxyntic cells are present in -
- A. Pylorus
- B. Cardia
- C. Body (Correct Answer)
- D. None of the options
Explanation: ***Body*** - **Oxyntic cells**, also known as **parietal cells**, are predominantly located in the **fundus and body** of the stomach [1], [2]. - These cells are responsible for secreting **hydrochloric acid (HCl)** and **intrinsic factor**, which are crucial for digestion and vitamin B12 absorption [1]. - The gastric glands in the body contain the highest concentration of parietal cells [2]. *Pylorus* - The pylorus is the distal part of the stomach that connects to the duodenum. - It primarily contains **G cells**, which secrete **gastrin**, a hormone that stimulates HCl secretion from parietal cells [3]. - Pyloric glands contain mainly mucus-secreting cells, with few or no parietal cells [2]. *Cardia* - The cardia is the region near the gastroesophageal junction (entrance of the stomach). - This area primarily contains **cardiac glands** with mucus-secreting cells that protect the esophageal lining from gastric acid reflux. - Parietal cells are sparse or absent in the cardia [2]. *None of the options* - This option is incorrect because the **body of the stomach** is the correct location for oxyntic cells.
Question 92: Which is the first bone to start ossifying?
- A. Femur
- B. Clavicle (Correct Answer)
- C. Tibia
- D. Mandible
Explanation: ***Clavicle*** - The **clavicle** is the **first bone to begin ossification** in the human body, starting around the **5th-6th week of gestation**. - It ossifies via **intramembranous ossification**, making it unique among long bones [1]. - This early ossification is a key landmark in fetal skeletal development and is consistently taught across medical curricula. *Mandible* - The **mandible** begins ossification around the **6th week of gestation**, shortly after the clavicle [1]. - While it is one of the earliest bones to ossify, it is **not the first**. - It also undergoes intramembranous ossification [1]. *Femur* - The **femur**, a long bone, begins ossification around the **7th-8th week of gestation** [1]. - It ossifies via **endochondral ossification**, which typically occurs later than intramembranous ossification [1]. *Tibia* - The **tibia** also begins ossification around the **7th-8th week of gestation**. - Like the femur, it follows the endochondral ossification pathway.
Question 93: The incudomalleolar joint is a?
- A. Saddle joint (Correct Answer)
- B. Pivot joint
- C. Ellipsoid joint
- D. Hinge joint
Explanation: ***Saddle joint*** - The **incudomalleolar joint** is classified as a **saddle joint** (also called a **sellar joint**), which is a type of synovial joint. - It has reciprocally concave-convex articular surfaces that fit together like a rider on a saddle. - This joint allows **slight gliding movements** between the head of the malleus and the body of the incus during sound transmission. - Standard anatomy texts including **Gray's Anatomy** classify this as a saddle joint based on its structural characteristics. *Pivot joint* - A **pivot joint** allows rotation around a single axis, such as the **atlantoaxial joint** (atlas rotating around the dens of axis) or the **proximal radioulnar joint**. - While the ossicular chain as a whole undergoes rotatory movement during sound transmission, the **incudomalleolar joint itself** is not classified as a pivot joint anatomically. *Ellipsoid joint* - An **ellipsoid joint** (condyloid joint) allows movement in two planes (flexion/extension and abduction/adduction) but restricts rotation. - Examples include the **radiocarpal joint** and **metacarpophalangeal joints** of the fingers. - The incudomalleolar joint has a different articular surface configuration. *Hinge joint* - A **hinge joint** permits movement primarily in one plane (flexion and extension), like a door hinge. - Examples include the **elbow joint**, **knee joint**, and **interphalangeal joints**. - This does not match the structural or functional characteristics of the incudomalleolar joint.
Question 94: Hilton's law primarily relates to which of the following?
- A. Nerve innervation only
- B. Nerve supply of joints, muscles moving them, and overlying skin (Correct Answer)
- C. Blood supply to joints
- D. None of the above
Explanation: ***Nerve supply of joints, muscles moving them, and overlying skin*** - **Hilton's law** states that the nerve supplying a joint also supplies the muscles that move the joint and the skin overlying the insertions of those muscles - This anatomical principle is clinically significant as it explains **referred pain patterns** from joints to surrounding structures - The law demonstrates the **functional integration** between joint innervation, muscle control, and cutaneous sensation *Nerve innervation only* - While Hilton's law involves nerve innervation, this option is too vague and incomplete - The law specifically describes the **relationship between three components**: joint nerves, muscle nerves, and cutaneous nerves - Simply stating "nerve innervation only" misses the **clinical significance** of the anatomical pattern *Blood supply to joints* - This refers to the vascular supply of joints (articular arteries), which is important for joint nutrition - However, **Hilton's law** specifically addresses **nerve supply patterns**, not vascular anatomy - Blood supply to joints follows different anatomical principles *None of the above* - This is incorrect because Hilton's law clearly relates to the integrated nerve supply pattern described in the correct option - The law is a fundamental principle in anatomy explaining the **functional relationship** between joint, muscle, and skin innervation
Question 95: Fossa ovalis is a remnant of -
- A. Septum primum (Correct Answer)
- B. Septum secundum
- C. Septum spurium
- D. AV cushion
Explanation: ***Septum primum*** - The **fossa ovalis** is a depression in the right atrium that represents the sealed-off foramen ovale [2]. - It is formed from the **septum primum**, which becomes the floor of the fossa ovalis. *Septum secundum* - The **septum secundum** forms the limbus or rim of the fossa ovalis, not the fossa itself. - This structure develops later than the septum primum and partially covers the foramen ovale during fetal development [2]. *Septum spurium* - The **septum spurium** is an embryonic ridge in the right atrium that typically regresses during development and does not contribute to the fossa ovalis. - It is a transient structure formed by the confluence of the right and left venous valves. *AV cushion* - The **atrioventricular (AV) cushions** contribute to the formation of the AV valves and the atrial and ventricular septa, but not directly to the fossa ovalis [1]. - They are crucial for separating the atria from the ventricles and forming the mitral and tricuspid valves.
Question 96: Nephron is derived from ?
- A. Ureteric bud
- B. Mesonephric duct
- C. Metanephros (Correct Answer)
- D. Mesonephros
Explanation: ***Metanephros*** - The **metanephric mesenchyme**, also known as the **metanephros**, gives rise to the excretory units of the kidney, which are the nephrons. - This mesenchymal tissue differentiates to form the **glomerulus**, Bowman's capsule, proximal and distal convoluted tubules, and the loop of Henle. *Ureteric bud* - The **ureteric bud** originates from the mesonephric duct and forms the collecting system of the kidney, including the ureter, renal pelvis, calyces, and collecting ducts. - It induces the differentiation of the metanephric mesenchyme but does not directly form the nephron itself. *Mesonephric duct* - The **mesonephric duct** (Wolffian duct) is a primitive embryonic structure that gives rise to the ureteric bud and parts of the male reproductive system. - It does not directly form any part of the nephron. *Mesonephros* - The **mesonephros** is a transient embryonic kidney that functions briefly during fetal development. - It degenerates and does not contribute to the formation of the definitive nephrons in the mature kidney.
Question 97: Fibrous stroma of liver is derived from -
- A. Endoderm from the foregut
- B. Endoderm from the midgut
- C. Endoderm from the hindgut
- D. Mesoderm from the septum transversum (Correct Answer)
Explanation: ***Mesoderm from the septum transversum*** - The **fibrous stroma of the liver**, which provides its structural framework, develops from the **mesoderm** of the **septum transversum** [1]. - The septum transversum is a thick mass of mesoderm that contributes to the formation of the **diaphragm** and the connective tissue elements of the liver [1]. *Endoderm from the foregut* - While the **parenchymal cells (hepatocytes)** of the liver are derived from the **endoderm of the foregut**, this tissue forms the functional units, not the fibrous supporting stroma. - The endoderm forms the glandular tissue, while the mesoderm forms the connective tissue [1]. *Endoderm from the midgut* - The midgut endoderm gives rise to structures like the **small intestine**, cecum, appendix, ascending colon, and part of the transverse colon, but not the liver's stroma [2]. - Its primary role is in forming the epithelial lining of these digestive organs. *Endoderm from the hindgut* - The hindgut endoderm develops into the distal third of the transverse colon, descending colon, sigmoid colon, rectum, and superior part of the anal canal, - It plays no role in the development of the liver's fibrous stroma.
Question 98: What muscle is attached to the superior nuchal line?
- A. Trapezius muscle (Correct Answer)
- B. Scalenus anterior
- C. Coracobrachialis muscle
- D. Biceps Brachii muscle
Explanation: ***Trapezius muscle*** - The **trapezius muscle** is a large, triangular muscle of the back that extends from the **occipital bone** (including the superior nuchal line) to the lower thoracic vertebrae. - Its **superior fibers** originate from the **medial one-third of the superior nuchal line** and the external occipital protuberance. *Scalenus anterior* - The **scalenus anterior** muscle originates from the **transverse processes of cervical vertebrae**, specifically C3-C6. - It inserts onto the **first rib** and is involved in neck flexion and elevation of the first rib during forced inspiration. *Coracobrachialis muscle* - The **coracobrachialis muscle** originates from the **coracoid process of the scapula**. - It inserts into the **medial surface of the humerus** and is involved in shoulder flexion and adduction. *Biceps Brachii muscle* - The **biceps brachii muscle** has two heads: the short head originates from the **coracoid process**, and the long head originates from the **supraglenoid tubercle of the scapula**. - It inserts onto the **radial tuberosity** and is primarily responsible for elbow flexion and forearm supination.
Question 99: Which of the following structures is not related to the third part of the duodenum?
- A. Superior mesenteric vessels
- B. Right ureter
- C. Head of pancreas
- D. Quadrate lobe of liver (Correct Answer)
Explanation: ***Quadrate lobe of liver*** - The **quadrate lobe of the liver** is located on the visceral surface of the liver, bounded by the gallbladder fossa, ligamentum teres, and porta hepatis. [1] - It is anatomically related to the **first part of the duodenum** and the pylorus, but has **no direct relationship** with the retroperitoneal **third part of the duodenum**, which lies at the L3 vertebral level. [2] - The third part of the duodenum is too inferior and posterior to have any relationship with the quadrate lobe. *Superior mesenteric vessels* - The **superior mesenteric artery** and **vein** cross **anteriorly** to the **third part of the duodenum** as it runs horizontally from right to left. - The duodenum passes between the aorta posteriorly and the superior mesenteric vessels anteriorly, creating a potential site for compression (**superior mesenteric artery syndrome**). *Right ureter* - The **right ureter** is a **posterior relation** of the **third part of the duodenum**, as both structures are retroperitoneal. [2] - The ureter descends on the psoas major muscle, passing behind the third part of the duodenum during its course toward the pelvis. *Head of pancreas* - The **head of pancreas**, specifically the **uncinate process**, lies **superior and posterior** to the **third part of the duodenum**. - The uncinate process hooks around posteriorly to the superior mesenteric vessels and has an intimate relationship with the third part of the duodenum.
Question 100: Which nerve is preserved in dissecting the superficial and deep lobes of the parotid gland?
- A. Glossopharyngeal
- B. Hypoglossal
- C. Lingual
- D. Facial (Correct Answer)
Explanation: ***Correct: Facial*** - The **facial nerve (CN VII)** passes directly through the parotid gland, dividing it into superficial and deep lobes. Dissection of these lobes requires careful identification and preservation of the facial nerve and its branches to avoid paralysis. - Injury to the facial nerve during parotidectomy can lead to various degrees of **facial paralysis**, affecting muscle movements like smiling, eye closure, and forehead wrinkling. *Incorrect: Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** supplies the carotid sinus and stylopharyngeus muscle and provides secretomotor innervation to the parotid gland via the otic ganglion. - It does not traverse the parotid gland itself, so it is not directly at risk during the dissection of the superficial and deep lobes. *Incorrect: Hypoglossal* - The **hypoglossal nerve (CN XII)** primarily controls the intrinsic and extrinsic muscles of the tongue, responsible for tongue movement. - It is located inferior to the parotid gland and is not in the field of dissection for separating the parotid lobes. *Incorrect: Lingual* - The **lingual nerve**, a branch of the mandibular nerve (CN V3), provides sensation to the **anterior two-thirds of the tongue** and carries parasympathetic fibers for submandibular and sublingual glands. - While it is in the general vicinity of the orofacial region, it does not pass through the parotid gland and is therefore not directly at risk during the dissection of the parotid lobe.