NEET-PG 2015 Practice Questions

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.

Q: Which of the following is a derivative of paramesonephric duct in males ?

Prostatic utricle. ***Prostatic utricle*** - The **prostatic utricle** is a blind-ending pouch located in the prostatic urethra. - It represents a **rudimentary derivative of the paramesonephric (Müllerian) duct** in males, which normally regresses due to the presence of Müllerian-inhibiting substance (MIS). *Trigone of bladder* - The trigone of the bladder is derived from the caudal ends of the **mesonephric ducts** (Wolffian ducts), not the paramesonephric ducts. - It forms through the incorporation of these ducts into the posterior wall of the bladder. *Paraphoron* - The **paraphoron** is a vestigial structure found in females, representing remnants of the caudal parts of the **epoophoron tubules**. - These are derived from the **mesonephric tubules**, not the paramesonephric ducts, and are not found in males. *Gartner's duct* - **Gartner's duct** is a remnant of the **mesonephric (Wolffian) duct** in females, typically running along the lateral wall of the vagina or uterus. - It is not found in males and is derived from a different embryonic structure than the paramesonephric duct.

Q: Which of the following statements about the limbus fossa ovalis is false?

Derived from septum primum. ***Derived from septum primum*** - The **limbus fossa ovalis** (or annulus ovalis) is a structure in the right atrium that forms the prominent rim of the **fossa ovalis**. - It is derived from the inferior border of the **septum secundum**, not the septum primum, which primarily forms the floor of the fossa ovalis. *Forms the rim around fossa ovalis* - The **limbus fossa ovalis** is indeed the thickened, crescent-shaped border of tissue that surrounds the **fossa ovalis** in the interatrial septum. - This anatomical arrangement is a remnant of the **foramen ovale** from fetal circulation [1]. *In right atrium* - The **fossa ovalis** and its surrounding limbus are located on the septal wall of the **right atrium** [1]. - This position is crucial for its role as a key landmark in interatrial septum anatomy. *Also called Annulus ovalis* - The term **annulus ovalis** is a widely accepted synonym for the **limbus fossa ovalis**. - Both terms describe the same anatomical structure, the fibrous rim surrounding the fossa ovalis.

Q: Prolactin secreting gland develops from -

Rathke's pouch. ***Rathke's pouch*** - The **anterior pituitary gland**, which secretes prolactin [2], develops embryologically from **Rathke's pouch**. - Rathke's pouch is an **ectodermal evagination** from the roof of the primitive oral cavity (stomodeum). *Infundibulum* - The **infundibulum** is also known as the pituitary stalk, connecting the hypothalamus to the posterior pituitary [1]. - It is derived from **neuroectoderm** and forms part of the posterior pituitary, not the prolactin-secreting anterior pituitary [1]. *Tuber cinereum* - The **tuber cinereum** is a part of the **hypothalamus**. - It is involved in regulating several bodily functions but does not directly give rise to the prolactin-secreting gland. *3rd ventricle* - The **3rd ventricle** is one of the four ventricles of the brain, filled with **cerebrospinal fluid**. - It is a part of the central nervous system and is not involved in the embryological development of the pituitary gland.

Q: Which Brodmann's area is primarily associated with motor speech?

Area 44. Area 44 - **Brodmann Area 44** is primarily known as **Broca's area**, which is critical for **motor speech production** and language processing [1]. - Damage to this area typically results in **Broca's aphasia**, characterized by non-fluent speech and difficulty forming complete sentences [1]. Area 1, 2, 3 - These Brodmann areas constitute the **primary somatosensory cortex**, responsible for processing **tactile and proprioceptive information** from the body. - They are involved in sensory perception, not directly with motor speech production. Area 4, 6 - **Brodmann Area 4** is the **primary motor cortex**, involved in executing voluntary movements [2]. **Brodmann Area 6** is the **premotor and supplementary motor cortex**, involved in planning and coordinating movements [2]. - While these areas are crucial for motor control, they are not specifically associated as the primary center for motor speech in the same way Broca's area is. Area 40 - **Brodmann Area 40**, also known as the **supramarginal gyrus**, is part of the **parietal lobe** and is involved in phonological processing, language perception, and spatial cognition. - While it plays a role in language, it is not the primary area for motor speech production.

Q: Broca's area is primarily involved in which of the following functions?

Speech production. ***Speech production*** - **Broca's area** is a region in the frontal lobe of the dominant hemisphere, typically the left, that is crucial for the formation of coherent and grammatically correct speech. - Damage to this area leads to **Broca's aphasia**, characterized by **non-fluent speech**, difficulty retrieving words, and impaired syntax. *Language comprehension* - **Wernicke's area**, located in the temporal lobe, is primarily responsible for **language comprehension**. - Patients with **Wernicke's aphasia** can produce fluent speech but have difficulty understanding spoken and written language. *Language repetition* - The **arcuate fasciculus**, a bundle of nerve fibers connecting Broca's and Wernicke's areas, is essential for **language repetition**. - Lesions in this pathway result in **conduction aphasia**, where comprehension and fluency are relatively preserved, but repetition is severely impaired. *Reading ability* - Reading ability involves a complex network of brain regions, including the **angular gyrus** and **visual cortex**, in addition to language areas. - While Broca's area contributes to the motor planning aspects of reading aloud, it is not its primary function.

Q: Maximum density of muscle spindle is found in?

Lumbricals. ***Lumbricals*** - **Lumbricals** are small, intricate muscles in the hand, responsible for fine motor control and precise movements like grasping and manipulating objects. - The high density of **muscle spindles** in lumbricals allows for extremely accurate feedback on muscle length and tension, crucial for **proprioception** and delicate tasks. *Calf muscle* - **Calf muscles** (gastrocnemius and soleus) are large muscles primarily involved in powerful movements like walking and running. - While they do contain muscle spindles for proprioception, their density is lower compared to muscles involved in fine motor control. *Quadriceps muscle* - The **quadriceps femoris** is a large muscle group in the thigh responsible for knee extension and powerful leg movements. - They contain muscle spindles to monitor muscle stretch, but not with the extreme density seen in muscles with fine motor functions. *Triceps* - The **triceps brachii** is a large muscle on the back of the upper arm, primarily responsible for elbow extension. - It has a moderate density of muscle spindles, sufficient for coordinating arm movements but not as high as muscles designed for precision.

Q: During the sympathetic fight-or-flight response, what is the primary cardiovascular effect of epinephrine and norepinephrine on skeletal muscle vasculature?

Increased blood flow to muscles. ***Increased blood flow to muscles*** - **Epinephrine** and **norepinephrine** cause **vasodilation** in skeletal muscle arterioles, shunting blood toward tissues critical for immediate physical action. - This response ensures that muscles have adequate **oxygen** and **nutrients** to support intense activity, enabling a quick escape or confrontation. *Increased blood flow to the skin* - During fight-or-flight, the body prioritizes essential organs, causing **vasoconstriction** in the skin to redirect blood flow away from non-essential areas. - This redirection helps to conserve blood and reduce potential blood loss from surface injuries. *Bronchoconstriction* - **Epinephrine** and **norepinephrine** actually cause **bronchodilation**, leading to the relaxation of airway smooth muscles. - This effect increases the diameter of the airways, allowing more air to enter and exit the lungs, thereby enhancing **oxygen intake** and carbon dioxide expulsion. *Decreased heart rate* - The primary effect of **epinephrine** and **norepinephrine** is to **increase heart rate** and myocardial contractility. - This cardiac acceleration enhances **cardiac output**, ensuring rapid and efficient delivery of oxygenated blood throughout the body to meet the demands of stress.

Question 1

What structures are derived from the neural crest?

Accepted Answer

All of the options

Answer

Melanocytes

Answer

Dental papillae

Answer

Adrenal medulla

Question 2

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 3

What is the remnant of the umbilical artery?

Accepted Answer

Medial umbilical ligament

Answer

Ligamentum arteriosum

Answer

Ligament teres

Answer

Ligamentum venosum

Question 4

Which of the following is a derivative of paramesonephric duct in males ?

Accepted Answer

Prostatic utricle

Answer

Trigone of bladder

Answer

Paraphoron

Answer

Gartner's duct

Question 5

Which of the following statements about the limbus fossa ovalis is false?

Accepted Answer

Derived from septum primum

Answer

Also called Annulus ovalis

Answer

In right atrium

Answer

Forms the rim around fossa ovalis

Question 6

Prolactin secreting gland develops from -

Accepted Answer

Rathke's pouch

Answer

Infundibulum

Answer

Tuber cinereum

Answer

3rd ventricle

Question 7

Which Brodmann's area is primarily associated with motor speech?

Accepted Answer

Area 44

Answer

Area 1, 2, 3

Answer

Area 4, 6

Answer

Area 40

Question 8

Broca's area is primarily involved in which of the following functions?

Accepted Answer

Speech production

Answer

Language comprehension

Answer

Language repetition

Answer

Reading ability

Question 9

Maximum density of muscle spindle is found in?

Accepted Answer

Lumbricals

Answer

Calf muscle

Answer

Triceps

Answer

Quadriceps muscle

Question 10

During the sympathetic fight-or-flight response, what is the primary cardiovascular effect of epinephrine and norepinephrine on skeletal muscle vasculature?

Accepted Answer

Increased blood flow to muscles

Answer

Increased blood flow to the skin

Answer

Bronchoconstriction

Answer

Decreased heart rate

NEET-PG 2015

Anatomy

Physiology