NEET-PG 2015 - Anatomy Practice Questions

Q: Oxyntic cells are present in -

Body. ***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.

Q: Which is the first bone to start ossifying?

Clavicle. ***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.

Q: The incudomalleolar joint is a?

Saddle joint. ***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.

Q: Fossa ovalis is a remnant of -

Septum primum. ***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.

Q: Nephron is derived from ?

Metanephros. ***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.

Q: Fibrous stroma of liver is derived from -

Mesoderm from the septum transversum. ***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.

Q: What structures are derived from the neural crest?

All of the options. ***All of the options*** - The **neural crest** is a multipotent, migratory cell population that contributes to the formation of many diverse tissues and organs during vertebrate development. - Neural crest cells give rise to a wide array of derivatives, including components of the nervous system, pigment cells, skeletal and connective tissues of the head and face, and endocrine glands [1]. *Melanocytes* - **Melanocytes**, the pigment-producing cells found in the skin, hair, eyes, and other tissues, are derived from the **neural crest** [2]. - These cells migrate extensively during development from the neural crest to their final destinations throughout the body. - Neural crest-derived melanocytes produce melanin, which provides pigmentation and protection against UV radiation [2]. *Dental papillae* - The **dental papilla** is crucial for tooth development and is formed from **ectomesenchymal cells** that are derived from the cranial neural crest. - These cells differentiate into the odontoblasts that produce dentin and also contribute to the pulp of the tooth. *Adrenal medulla* - The cells of the **adrenal medulla**, which produce catecholamines like epinephrine and norepinephrine, are specialized **postganglionic sympathetic neurons** derived from the neural crest. - They develop from neuroectodermal cells that migrate to the developing adrenal gland.

Q: Heart tube is formed in a gelatinous matrix rich in:

Hyaluronic acid secreted by the myocardium. ***Hyaluronic acid secreted by the myocardium*** - The developing **heart tube** forms within a gelatinous extracellular matrix that is rich in **hyaluronic acid**. - This **hyaluronic acid** is secreted by the **myocardium** (the developing heart muscle), which plays a crucial role in the initial formation and remodeling of the heart. *Hyaluronic acid secreted by the endocardium* - While the endocardium is an important layer of the heart, it is the **myocardium** that primarily secretes the **hyaluronic acid** critical for heart tube formation during early development. - The **endocardium** forms the inner lining and primarily acts in blood-tissue interaction and valvular development later on. *Chondroitin sulfate secreted by the endocardium* - **Chondroitin sulfate** is a component of the extracellular matrix, but it is not the primary proteoglycan responsible for the initial formation environment of the heart tube. - Furthermore, its secretion is not predominantly from the **endocardium** in this context. *Chondroitin sulfate secreted by the myocardium* - Although the myocardium is responsible for secreting extracellular matrix components, **chondroitin sulfate** is not the predominant or critical molecule responsible for the initial gelatinous matrix allowing heart tube formation. - **Hyaluronic acid** plays this key role in early cardiogenesis.

Q: What is the remnant of the umbilical artery?

Medial umbilical ligament. ***Medial umbilical ligament*** - The **umbilical arteries** (paired structures) carry deoxygenated blood from the fetus to the placenta during development [2]. - After birth, these arteries obliterate and persist as the **medial umbilical ligaments** (two in number, one on each side), extending from the internal iliac arteries to the umbilicus along the anterior abdominal wall. - The proximal portions of the umbilical arteries remain patent as the **superior vesical arteries**, which supply the bladder. *Ligamentum arteriosum* - This is the remnant of the **ductus arteriosus**, which shunted blood from the pulmonary artery to the aorta, bypassing the fetal lungs [2]. - It connects the arch of the aorta to the pulmonary artery. *Ligament teres* - Also known as the **round ligament of the liver**, this is the remnant of the **fetal umbilical vein** (a single midline structure) [1]. - The umbilical vein carried oxygenated blood from the placenta to the fetus [1], [2]. *Ligamentum venosum* - This is the fibrous remnant of the **ductus venosus**, a shunt in fetal circulation that bypassed the liver by connecting the umbilical vein to the inferior vena cava [1]. - It is located deep within the liver, forming a fissure.

Question 1

Oxyntic cells are present in -

Accepted Answer

Body

Answer

Pylorus

Answer

Cardia

Answer

None of the options

Question 2

Which is the first bone to start ossifying?

Accepted Answer

Clavicle

Answer

Femur

Answer

Tibia

Answer

Mandible

Question 3

The incudomalleolar joint is a?

Accepted Answer

Saddle joint

Answer

Pivot joint

Answer

Ellipsoid joint

Answer

Hinge joint

Question 4

Hilton's law primarily relates to which of the following?

Accepted Answer

Nerve supply of joints, muscles moving them, and overlying skin

Answer

Nerve innervation only

Answer

Blood supply to joints

Answer

None of the above

Question 5

Fossa ovalis is a remnant of -

Accepted Answer

Septum primum

Answer

Septum secundum

Answer

Septum spurium

Answer

AV cushion

Question 6

Nephron is derived from ?

Accepted Answer

Metanephros

Answer

Ureteric bud

Answer

Mesonephric duct

Answer

Mesonephros

Question 7

Fibrous stroma of liver is derived from -

Accepted Answer

Mesoderm from the septum transversum

Answer

Endoderm from the foregut

Answer

Endoderm from the midgut

Answer

Endoderm from the hindgut

Question 8

What structures are derived from the neural crest?

Accepted Answer

All of the options

Answer

Melanocytes

Answer

Dental papillae

Answer

Adrenal medulla

Question 9

Heart tube is formed in a gelatinous matrix rich in:

Accepted Answer

Hyaluronic acid secreted by the myocardium

Answer

Hyaluronic acid secreted by the endocardium

Answer

Chondroitin sulfate secreted by the endocardium

Answer

Chondroitin sulfate secreted by the myocardium

Question 10

What is the remnant of the umbilical artery?

Accepted Answer

Medial umbilical ligament

Answer

Ligamentum arteriosum

Answer

Ligament teres

Answer

Ligamentum venosum

NEET-PG 2015 — Anatomy