Anatomy
6 questionsWhat is the nerve supply of the larynx above the level of the vocal cords?
Which muscle plays a role in winking?
All pass through jugular foramen except
Which of the following is NOT a content of the occipital triangle?
The roof of the olfactory region is formed by?
Which muscle is the deepest in the anterior neck region?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 341: What is the nerve supply of the larynx above the level of the vocal cords?
- A. Superior laryngeal (Correct Answer)
- B. Recurrent laryngeal
- C. Glossopharyngeal
- D. External laryngeal nerve
Explanation: ***Superior laryngeal*** - The **superior laryngeal nerve** branches into the internal and external laryngeal nerves. The **internal laryngeal nerve** (a branch of the superior laryngeal nerve) provides all sensory innervation to the larynx **above the vocal cords**. - It also carries **parasympathetic fibers** to the laryngeal glands in this region. *Recurrent laryngeal* - The **recurrent laryngeal nerve** provides sensory innervation to the larynx **below the vocal cords** [1]. - It also innervates all of the intrinsic muscles of the larynx except for the cricothyroid muscle [1]. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** primarily provides sensory innervation to the **posterior one-third of the tongue**, tonsils, pharynx, and middle ear. - It does not directly provide sensory innervation to the larynx. *External laryngeal nerve* - The **external laryngeal nerve**, a branch of the superior laryngeal nerve, is primarily **motor** and innervates the **cricothyroid muscle**. - It provides **no sensory innervation** to any part of the larynx.
Question 342: Which muscle plays a role in winking?
- A. Levator labii superioris
- B. Orbicularis oculi (Correct Answer)
- C. Levator palpebrae
- D. Corrugator supercilii
Explanation: ***Orbicularis oculi*** - This muscle is responsible for **closing the eyelid** and is essential for actions like blinking, squinting, and winking. - Its fibers encircle the eye and facilitate the **controlled closure** required for winking. *Levator labii superioris* - This muscle primarily functions to **elevate the upper lip**, playing a role in facial expressions such as sneering or smiling. - It has no direct involvement in the movement of the eyelids or the act of winking. *Corrugator supercilii* - This muscle is located in the eyebrow region and is responsible for **drawing the eyebrows medially and inferiorly**, creating vertical wrinkles between the eyebrows. - It is associated with expressions of frowning or concern, not eyelid closure. *Levator palpebrae* - This muscle is responsible for **opening the upper eyelid**, thus counteracting the action of the orbicularis oculi. - While essential for eye movement, it is not involved in the closing action required for winking.
Question 343: All pass through jugular foramen except
- A. Mandibular nerve (Correct Answer)
- B. Vagus nerve
- C. Internal jugular vein
- D. Glossopharyngeal nerve
Explanation: ***Mandibular nerve*** - The **mandibular nerve** (CN V3) exits the skull through the **foramen ovale**, not the jugular foramen. - It is a branch of the **trigeminal nerve** and is responsible for motor innervation to muscles of mastication and sensory innervation to the lower face and mouth. *Glossopharyngeal nerve* - The **glossopharyngeal nerve** (CN IX) is one of the three cranial nerves that exit through the **jugular foramen**. - It provides motor, sensory, and parasympathetic innervation including taste from posterior third of tongue and motor to stylopharyngeus muscle. *Vagus nerve* - The **vagus nerve** (CN X) is one of the major cranial nerves that exits the skull through the **jugular foramen**. - It provides extensive motor, sensory, and parasympathetic innervation to the head, neck, thorax, and abdomen. *Internal jugular vein* - The **internal jugular vein** is formed at the jugular foramen by the continuation of the **sigmoid sinus**, and it exits the skull through this foramen. - It is one of the primary venous drainage pathways for the brain.
Question 344: Which of the following is NOT a content of the occipital triangle?
- A. Lesser occipital nerve
- B. Occipital artery
- C. Suprascapular nerve (Correct Answer)
- D. Great auricular nerve
Explanation: Suprascapular nerve - The **suprascapular nerve** originates from the brachial plexus and supplies the supraspinatus and infraspinatus muscles; it travels through the suprascapular notch and is not found within the occipital triangle. - Its primary course and innervation are associated with the shoulder, entirely separate from the neck region defining the occipital triangle. *Great auricular nerve* - The **great auricular nerve** emerges from the cervical plexus and supplies sensory innervation to the skin over the parotid gland, mastoid process, and auricle, courses superficially across the sternocleidomastoid in the region of the occipital triangle. - It is a recognized content of the posterior triangle of the neck, which encompasses the occipital triangle. *Lesser occipital nerve* - The **lesser occipital nerve** arises from the cervical plexus at C2 and C3, providing sensory innervation to the skin of the neck and scalp posterior to the auricle. - It ascends along the posterior border of the sternocleidomastoid muscle, placing it within the boundaries of the occipital triangle. *Occipital artery* - The **occipital artery** is a branch of the external carotid artery that supplies blood to the posterior scalp. - It traverses the apex of the posterior triangle (including the occipital triangle) as it ascends to the back of the head.
Question 345: The roof of the olfactory region is formed by?
- A. Nasal bone
- B. Sphenoid
- C. Temporal bone
- D. Cribriform plate of ethmoid (Correct Answer)
Explanation: ***Cribriform plate of ethmoid*** - The **cribriform plate** of the ethmoid bone forms the superior boundary, or roof, of the nasal cavity specifically in the olfactory region [1]. - It is perforated by numerous **olfactory foramina** through which the olfactory nerves pass from the nasal cavity to the olfactory bulb of the brain [2]. *Nasal bone* - The **nasal bones** form part of the bridge of the nose and contribute to the anterior part of the bony framework of the external nose. - They do not form the roof of the olfactory region within the nasal cavity. *Sphenoid* - The **sphenoid bone** is a complex bone at the base of the skull, contributing to the posterior wall of the nasal cavity and parts of the cranial floor. - It does not directly form the roof of the olfactory region. *Temporal bone* - The **temporal bones** are located on the sides and base of the skull, housing structures related to hearing and balance. - They are not involved in forming the roof of the nasal cavity or the olfactory region.
Question 346: Which muscle is the deepest in the anterior neck region?
- A. Sternocleidomastoid
- B. Platysma
- C. Longus colli (Correct Answer)
- D. Trapezius
Explanation: ***Longus colli*** - The **longus colli** muscle is the **deepest muscle** located in the anterior neck region, running along the front of the cervical vertebral column from C1 to T3. - It lies in the **prevertebral layer**, deep to all other anterior neck structures including the carotid sheath, visceral compartment, and superficial muscles. - Its position directly anterior to the vertebral bodies makes it the deepest anterior neck muscle. *Platysma* - The platysma is the **most superficial muscle** of the neck, located just beneath the skin in the superficial fascia. - It is not a deep muscle and lies superficial to all other neck muscles. *Sternocleidomastoid* - The sternocleidomastoid is enclosed within the **investing layer of deep cervical fascia**, making it relatively superficial. - While prominent in the anterior and lateral neck, it is not the deepest anterior neck muscle. *Trapezius* - The trapezius is a large, **superficial muscle of the back and posterior neck**. - It is not located in the anterior neck and is a superficial, not deep, muscle.
Biochemistry
3 questionsWhich of the following is activated by calmodulin?
What is the half-life of Prealbumin?
What is the approximate half-life of albumin in the human body?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 341: Which of the following is activated by calmodulin?
- A. Muscle phosphorylase
- B. Calcium/calmodulin-dependent protein kinase (Correct Answer)
- C. Phospholipase C
- D. Adenylyl cyclase
Explanation: ***Calcium/calmodulin-dependent protein kinase*** - **Calmodulin** is a **calcium-binding messenger protein** that, when bound to calcium, undergoes a conformational change allowing it to activate various enzymes, including **calcium/calmodulin-dependent protein kinases** (CaMKs). - CaMKs play crucial roles in many cellular processes, including **metabolism**, **gene expression**, and **neurotransmission**, by phosphorylating target proteins. *Muscle phosphorylase* - **Muscle phosphorylase** (glycogen phosphorylase) is primarily activated by **epinephrine**, **AMP**, and **nerve stimulation** (via calcium), but not directly by calmodulin. - Its activation leads to the breakdown of **glycogen** into glucose-1-phosphate. *Phospholipase C* - **Phospholipase C (PLC)** is typically activated by **G protein-coupled receptors** and **tyrosine kinase receptors**, leading to the production of **inositol trisphosphate (IP3)** and **diacylglycerol (DAG)**. - While it plays a role in calcium signaling upstream (releasing calcium from stores), it is not directly activated by calmodulin. *Adenylyl cyclase* - **Adenylyl cyclase (AC)** is a key enzyme in generating **cyclic AMP (cAMP)**, and is commonly regulated by **G proteins** (specifically Gs and Gi subunits). - While certain isoforms (AC1, AC3, AC8) can be directly activated by calcium/calmodulin, **CaMK** remains the most classical and direct example of calmodulin activation.
Question 342: What is the half-life of Prealbumin?
- A. 2 days (Correct Answer)
- B. 10 days
- C. 20 days
- D. 40 days
Explanation: ***2 days*** - Prealbumin, also known as transthyretin, has a **short half-life** of approximately 2-3 days, making it a sensitive indicator of recent changes in **nutritional status**. - Its rapid turnover allows for prompt reflection of improvement or deterioration in protein synthesis. *10 days* - A half-life of 10 days would make prealbumin less responsive to acute changes in nutrition compared to its actual turnover rate. - This duration is longer than the typical half-life of proteins used to monitor **short-term nutritional status**. *20 days* - A 20-day half-life would indicate a protein with a much slower turnover, unsuitable for monitoring **acute nutritional interventions**. - Proteins with such long half-lives, like **albumin**, reflect more chronic states rather than rapid changes. *40 days* - A half-life of 40 days is characteristic of proteins like **albumin**, which are influenced by longer-term nutritional and inflammatory processes. - Such a long half-life would not be useful for assessing immediate responses to **nutritional support** or acute disease states.
Question 343: What is the approximate half-life of albumin in the human body?
- A. 30 days
- B. 20 days (Correct Answer)
- C. 3 days
- D. 7 days
Explanation: ***20 days*** - The **half-life of albumin** in the human body is approximately **20 days**, reflecting the time it takes for half of the circulating albumin to be catabolized or excreted. - This relatively long half-life means that changes in albumin levels, such as those due to malnutrition or liver disease, may take several weeks to become evident. *3 days* - A half-life of 3 days is too short for albumin, which is a major, long-lasting plasma protein. - Proteins with such a short half-life typically include more rapidly turnover proteins or small peptides. *7 days* - A half-life of 7 days is also too short for albumin, which plays a critical role in maintaining plasma oncotic pressure and transporting various substances. - While some proteins have a 7-day half-life, albumin's is considerably longer. *30 days* - A half-life of 30 days is longer than the typical half-life of albumin. - While some proteins may have half-lives in this range, 20 days is the more commonly accepted value for albumin.
Pathology
1 questionsThe MOST COMMON cause of concentric hypertrophy of left ventricle is?
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 341: The MOST COMMON cause of concentric hypertrophy of left ventricle is?
- A. Hypertension (Correct Answer)
- B. Aortic stenosis
- C. Mitral stenosis
- D. Aortic regurgitation
Explanation: ***Hypertension*** - Chronic **hypertension** is the most common cause of **pressure overload** on the left ventricle, leading to concentric hypertrophy [1]. - In response to the increased afterload, the ventricular wall thickens uniformly inward, reducing the chamber size while maintaining normal wall stress [2]. - Due to its high prevalence (30-40% of adults), hypertension is epidemiologically the most frequent cause of concentric LVH [1]. *Aortic stenosis* - While **aortic stenosis** is the classic pathological cause of **pressure overload** and concentric hypertrophy [2], **hypertension** is more prevalent in the population. - Aortic stenosis causes fixed outflow obstruction, leading to significant pressure work for the left ventricle. - This is the second most common cause but occurs in only 2-5% of elderly patients. *Mitral stenosis* - **Mitral stenosis** primarily causes pressure overload on the **left atrium** and **pulmonary circulation**, not the left ventricle. - It doesn't typically lead to **left ventricular hypertrophy** directly; instead, it causes left atrial enlargement and right ventricular hypertrophy. *Aortic regurgitation* - **Aortic regurgitation** results in **volume overload** of the left ventricle due to blood flowing back into the chamber during diastole. - This typically leads to **eccentric hypertrophy**, where the chamber dilates and the wall thickens proportionally, rather than concentric hypertrophy [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 560-562. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 536.