Anatomy
5 questionsPubic symphysis is which type of joint?
Collecting part of kidney develops from ?
At which level do the somites initially form?
The cardiac jelly formed around the heart tube during early development contributes to the formation of:
Sinus venosus receives blood from all EXCEPT:
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 61: Pubic symphysis is which type of joint?
- A. Gomphosis
- B. Fibrous joint
- C. Primary cartilaginous
- D. Secondary cartilaginous (Correct Answer)
Explanation: ***Secondary cartilaginous*** - The **pubic symphysis** is a classic example of a **secondary cartilaginous joint**, also known as a **symphysis**. - These joints are characterized by a plate of **fibrocartilage** sandwiched between two layers of hyaline cartilage, uniting two bones and allowing for limited movement. *Gomphosis* - A **gomphosis** is a type of **fibrous joint** where a peg-like process fits into a socket, primarily found in the attachment of teeth to their sockets in the jaw. - It is distinct from the cartilaginous structure of the pubic symphysis. *Fibrous joint* - While fibrous joints are characterized by fibrous connective tissue connecting bones, this category is too broad, and doesn't specify the unique cartilaginous nature of the pubic symphysis. - Examples include sutures in the skull, syndesmoses, and gomphoses, none of which fit the structure of the pubic symphysis. *Primary cartilaginous* - A **primary cartilaginous joint**, or **synchondrosis**, involves bones united by **hyaline cartilage**, like the epiphyseal plates of growing bones. - These joints are typically temporary and eventually ossify, or they allow for very restricted movement, unlike the fibrocartilage and slight movement of the pubic symphysis.
Question 62: Collecting part of kidney develops from ?
- A. Mesonephros
- B. Metanephros
- C. Ureteric bud (Correct Answer)
- D. Pronephros
Explanation: ***Ureteric bud*** - The **ureteric bud** (also known as the metanephric diverticulum) is an outgrowth of the **mesonephric duct** that develops into the collecting system of the kidney. - It gives rise to the **ureter**, **renal pelvis**, major and minor calyces, and all collecting ducts. *Pronephros* - **Pronephros** is the earliest, most rudimentary, and transient excretory structure that appears in human embryos. - It is non-functional in humans and **degenerates completely** by the fourth week of gestation. *Mesonephros* - The **mesonephros** develops after the pronephros and functions as a temporary kidney during the early fetal period (weeks 4-8). - Its tubules primarily contribute to the **male reproductive system** (e.g., epididymis, ductus deferens) and **degenerate** in females. *Metanephros* - The **metanephros** is the definitive kidney in mammals and gives rise to the **nephrons** (glomeruli, Bowman's capsule, proximal and distal convoluted tubules, loop of Henle). - While it's crucial for kidney development, the **collecting part** specifically originates from the ureteric bud, which interacts with the metanephric mesenchyme.
Question 63: At which level do the somites initially form?
- A. Lumbar level
- B. Sacral level
- C. Cervical level (Correct Answer)
- D. Thoracic level
Explanation: Cervical level - Somites, which are segmented blocks of paraxial mesoderm, initially appear in the **occipital/cranial cervical region** of the developing embryo around day 20 of development. - The first somite pair forms at the **occipital level**, and subsequent somites develop in a **cranio-caudal sequence**. - Development proceeds both cranially (forming occipital somites) and caudally (forming cervical, thoracic, lumbar, and sacral somites) from this initial formation. - By the end of the 5th week, approximately **42-44 somite pairs** are present. *Thoracic level* - Thoracic somites form subsequent to the initial occipital/cervical somites, as the segmentation process extends caudally. - The formation of somites is a sequential process along the **cranio-caudal axis**. *Lumbar level* - Lumbar somites develop later in the embryological timeline, after the cervical and thoracic regions have undergone somite formation. - The **caudal regions** receive somites progressively as development continues. *Sacral level* - Sacral somites are among the last to form, representing the caudal extent of somite development. - Their formation follows the cranio-caudal progression of somite appearance.
Question 64: The cardiac jelly formed around the heart tube during early development contributes to the formation of:
- A. Pericardium
- B. Mesocardium
- C. Myocardium
- D. Endocardium (Correct Answer)
Explanation: Endocardium (Endocardial Cushions/Valves/Septa) - The **cardiac jelly** is an acellular, gelatinous matrix rich in **hyaluronic acid** that lies between the endocardium and the primordial myocardium during early heart development. - It undergoes **endothelial-to-mesenchymal transformation (EMT)** to form the **endocardial cushions** [1]. - These cushions are critical for forming: - **Atrioventricular (AV) valves** (mitral and tricuspid) [1] - **Semilunar valves** (aortic and pulmonary) [1] - **Cardiac septa** (portions of atrial, ventricular, and AV septa) [1] - While cardiac jelly doesn't form the endocardial lining itself (which is already present as endothelium), it forms the endocardial cushions that are essential endocardial derivatives. *Pericardium* - The **pericardium** develops from the **pleuropericardial folds** and **somatic and splanchnic mesoderm**, forming the fibrous and serous outer coverings of the heart. - It is completely distinct from cardiac jelly, which is an intra-cardiac structure. *Mesocardium* - The **dorsal mesocardium** is a transient mesentery that temporarily connects the developing heart tube to the dorsal wall of the pericardial cavity. - It rapidly degenerates by **day 22-23** to form the **transverse pericardial sinus**. - It does not contribute to cardiac jelly or any heart wall structures. *Myocardium* - The **myocardium** differentiates directly from the **splanchnic mesoderm** surrounding the endocardial tube. - It forms the muscular contractile layer of the heart wall. - Cardiac jelly lies between the endocardium and myocardium but does not form myocardial tissue.
Question 65: Sinus venosus receives blood from all EXCEPT:
- A. Vitelline vein
- B. Umbilical vein
- C. Common cardinal vein
- D. Subcardinal vein (Correct Answer)
Explanation: Sinus venosus receives blood from all EXCEPT: ***Subcardinal vein*** - The **subcardinal vein** is primarily involved in draining the developing **kidneys** and gonads during embryonic development. - While it contributes to the formation of the **inferior vena cava**, it does not directly empty into the sinus venosus. - The subcardinal veins are part of a different venous drainage system that develops independently from the sinus venosus tributaries. *Vitelline vein* - The **vitelline veins** drain blood from the **yolk sac**, which is the primary site of early hematopoiesis. - These veins directly empty into the **sinus venosus** in the early embryo. - They eventually give rise to the **hepatic portal system** and hepatic sinusoids. *Umbilical vein* - The **umbilical vein** carries **oxygenated and nutrient-rich blood** from the placenta to the fetus [1]. - In the early embryo, the umbilical veins drain directly into the **sinus venosus**. - Later in development, the left umbilical vein bypasses the liver via the **ductus venosus** to enter the inferior vena cava [1], [2]. *Common cardinal vein* - The **common cardinal veins** collect blood from the entire embryo, draining both the anterior (from the cephalic region) and posterior (from the trunk and lower limbs) parts. - These veins represent the main drainage system of the developing embryo and directly empty into the sinus venosus. - They are the primary tributaries of the sinus venosus during early cardiac development.
Community Medicine
1 questionsWhat is the Chandler's Index for Hookworm that indicates a significant health problem?
NEET-PG 2013 - Community Medicine NEET-PG Practice Questions and MCQs
Question 61: What is the Chandler's Index for Hookworm that indicates a significant health problem?
- A. > 200
- B. > 100
- C. > 300
- D. > 50 (Correct Answer)
Explanation: ***> 50*** - A Chandler's Index of **> 50** indicates a significant public health problem due to **hookworm infection**. - **Chandler's Index** is calculated as the **average egg count per person in a community** (total hookworm eggs counted ÷ number of persons examined), used to assess the population-level burden of hookworm infection. - A value **> 50** suggests that the community has a significant hookworm problem requiring public health intervention. *> 300* - This value is significantly higher than the threshold for a significant public health problem and would indicate an **extremely severe burden of infection**. - While this represents a very high Chandler's Index, it's not the standard cut-off for defining a "significant" health problem (which is the lower threshold of >50). *> 200* - A Chandler's Index of **> 200** would denote a very high intensity of hookworm infection in the community. - However, this is not the standard threshold used to define when hookworm becomes a "significant" public health issue - the threshold is lower at >50. *> 100* - A Chandler's Index of **> 100** represents a substantial level of hookworm infection within a population. - However, the widely recognized cutoff for a "significant health problem" is **> 50**, indicating public health concern even at this moderate level of community infection burden.
Dental
1 questionsWhat is the first permanent tooth to erupt?
NEET-PG 2013 - Dental NEET-PG Practice Questions and MCQs
Question 61: What is the first permanent tooth to erupt?
- A. First premolar
- B. Second premolar
- C. First molar (Correct Answer)
- D. Second molar
Explanation: ***First molar*** - The **first molars** are typically the first permanent teeth to erupt, usually around **6 years of age**. - They erupt distal to the primary second molars and are not preceded by primary teeth, making them crucial for establishing the **occlusion**. *First premolar* - **First premolars** typically erupt later, between **10 and 11 years of age**, replacing the primary first molars. - Their eruption is part of the **exchange of primary teeth** for permanent successors. *Second premolar* - The **second premolars** erupt even later, usually between **11 and 12 years of age**, replacing the primary second molars. - They are also involved in the **replacement of primary teeth**, not the initial permanent eruption. *Second molar* - **Second molars** erupt much later than the first molars, typically between **11 and 13 years of age**, distal to the first molars. - They are part of the **later stages of permanent dentition development**.
Internal Medicine
1 questionsMigraine is due to
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 61: Migraine is due to
- A. Cortical spreading depression (Correct Answer)
- B. Dilatation of cranial blood vessels
- C. Constriction of cranial blood vessels
- D. Inflammation of the meninges
Explanation: ***Cortical spreading depression*** - The current understanding is that **cortical spreading depression (CSD)** is the initiating event in migraine with aura, characterized by a wave of neuronal and glial depolarization that spreads across the cerebral cortex, leading to a temporary shutdown of neuronal activity [1]. - CSD is thought to activate the **trigeminal nerve**, subsequently causing the release of inflammatory neuropeptides and contributing to the pain phase [1]. *Dilatation of cranial blood vessels* - While **vasodilation of intracranial and extracranial blood vessels** does occur during the headache phase of migraine, it is now considered a *consequence* of the initial neurological events rather than the primary cause [1]. - This vasodilation contributes to the throbbing sensation of migraine pain but does not explain the aura or the initiation of the attack. *Constriction of cranial blood vessels* - **Vasoconstriction** was previously thought to be the cause of the migraine aura, but this theory has largely been disproven. - While some temporary constriction may precede CSD, it is not the primary mechanism behind the migraine attack. *Inflammation of the meninges* - While **neurogenic inflammation** of the meninges, involving the release of inflammatory mediators like **calcitonin gene-related peptide (CGRP)**, does play a role in sensitizing the trigeminal system and contributing to migraine pain, it is a downstream effect. - It is not the initial trigger for a migraine attack but rather part of the pain pathway activated by events like CSD.
Physiology
1 questionsThe temperature centre is?
NEET-PG 2013 - Physiology NEET-PG Practice Questions and MCQs
Question 61: The temperature centre is?
- A. Supraoptic nucleus of hypothalamus
- B. Paraventricular nucleus of hypothalamus
- C. Preoptic nucleus of hypothalamus (Correct Answer)
- D. Suprachiasmatic nucleus of hypothalamus
Explanation: **Preoptic nucleus of hypothalamus** - The **preoptic nucleus** within the **hypothalamus** serves as the primary **thermoregulatory center** in the brain. - It contains both **heat-sensitive** and **cold-sensitive neurons** that monitor core body temperature and initiate appropriate responses to maintain homeostasis. *Supraoptic nucleus of hypothalamus* - The **supraoptic nucleus** is primarily involved in the production of **antidiuretic hormone (ADH)**, which regulates water balance. - It plays a crucial role in **fluid and electrolyte balance**, not temperature regulation. *Paraventricular nucleus of hypothalamus* - The **paraventricular nucleus** is multifunctional, producing **oxytocin** and **vasopressin** (ADH), and is involved in stress response and feeding. - While it has broad regulatory roles, it is not the primary center for **temperature control**. *Suprachiasmatic nucleus of hypothalamus* - The **suprachiasmatic nucleus (SCN)** is the body's main **circadian clock**, regulating daily rhythms like the sleep-wake cycle. - Its primary function is to synchronize biological activities with the **24-hour light-dark cycle**, not directly control body temperature.
Psychiatry
1 questionsMuttering delirium is seen with: NEET 13
NEET-PG 2013 - Psychiatry NEET-PG Practice Questions and MCQs
Question 61: Muttering delirium is seen with: NEET 13
- A. Datura (Correct Answer)
- B. Castor oil plant
- C. Cocaine (stimulant)
- D. Monkshood (Aconitum)
Explanation: ***Datura*** - **Datura poisoning** is characterized by an **anticholinergic toxidrome**, which includes central nervous system effects like **muttering delirium, hallucinations**, and disorientation. - The patient exhibits features like **dilated pupils, dry mouth, flushed skin**, and **tachycardia** due to the blockage of muscarinic acetylcholine receptors. *Castor oil plant* - The **castor oil plant** contains **ricin**, a potent toxin that causes **gastrointestinal symptoms** (nausea, vomiting, abdominal pain, bloody diarrhea) and eventually multi-organ failure. - It does not typically cause the central nervous system effects like **muttering delirium** seen with Datura poisoning. *Cocaine (stimulant)* - **Cocaine** is a central nervous system stimulant that causes **euphoria, agitation, paranoia, dilated pupils**, and **tachycardia**. - While it can cause psychosis, the specific **muttering delirium** is not its hallmark presentation; instead, it is associated with a hyperadrenergic state. *Monkshood (Aconitum)* - **Monkshood** contains **aconitine**, a neurotoxin that primarily affects cardiac and neurological function, causing **paresthesias, muscle weakness, bradycardia**, and potentially fatal arrhythmias. - It does not typically cause the **muttering delirium** with features of an anticholinergic syndrome.