Primary and secondary palates are divided by
All are derived from ectoderm except for which of the following?
Primordial germ cells are derived from:
Pituicytes are seen in ?
What is the anatomical significance of the Rhinion in relation to the osseocartilaginous junction?
What are the main types of cells found in the cerebellar cortex?
Which lymph nodes are involved in the lymphatic drainage of the lateral wall of the nose?
Rouviere nodes are situated in?
All are lateral branches of the abdominal aorta, EXCEPT which of the following?
Which of the following is NOT a surface marking of the oblique fissure of the lung?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 31: Primary and secondary palates are divided by
- A. Greater palatine foramen
- B. Canine teeth
- C. Alveolar arch
- D. Incisive foramen (Correct Answer)
Explanation: ***Incisive foramen*** - The **incisive foramen** is an anatomical landmark located just posterior to the central incisors, and it marks the boundary between the developmentally distinct primary and secondary palates. - The **primary palate** develops from the median palatine process, while the **secondary palate** develops from the palatal shelves of the maxillary prominences [1]. *Greater palatine foramen* - The **greater palatine foramen** is located near the posterior border of the hard palate, transmitting the greater palatine nerve and vessels. - It lies within the **secondary palate** and does not delineate the boundary between the primary and secondary palatal structures. *Canine teeth* - The **canine teeth** are part of the dental arch and play a role in mastication. - While located in the anterior part of the oral cavity, they are not a developmental or anatomical boundary marker for palatal divisions [1]. *Alveolar arch* - The **alveolar arch** is the bone that supports the teeth, forming the curved ridge of the maxilla and mandible [1]. - It is distinct from the palate and does not serve as a divider between the primary and secondary palatal components.
Question 32: All are derived from ectoderm except for which of the following?
- A. Hair follicles
- B. Nails
- C. Lens of the eye
- D. Adrenal cortex (Correct Answer)
Explanation: ***Adrenal cortex*** - The adrenal cortex is derived from the **intermediate mesoderm**, specifically from the cells lining the posterior abdominal wall. The cells migrate to develop into the adrenal cortex. - It produces various steroid hormones, including **aldosterone**, **cortisol**, and **androgens**, which regulate diverse bodily functions. *Lens of the eye* - The lens of the eye is derived from the **surface ectoderm**. It forms from an invagination of the surface ectoderm called the lens placode. - Its primary function is to **focus light** onto the retina. *Hair follicles* - Hair follicles develop from the **surface ectoderm** [1]; they are invaginations of the epidermis that extend into the dermis. - They produce hair, which provides **insulation** and **protection** [1]. *Nails* - Nails are also derivatives of the **surface ectoderm**, forming thickened plates on the dorsal surface of the distal phalanges. - They provide **protection** to the fingertips and aid in grasping objects.
Question 33: Primordial germ cells are derived from:
- A. Neural crest
- B. Genital ridge
- C. Somatopleuritic mesoderm
- D. Yolk sac (Correct Answer)
Explanation: ***Yolk sac*** - **Primordial germ cells (PGCs)** arise from **epiblast** cells but are first identifiable in the wall of the **yolk sac** during the **3rd week** of development. - From the yolk sac, they migrate during the **4th-6th week** through the dorsal mesentery to reach the developing **genital ridges** (gonads) where they form **gametes** [2]. - The yolk sac is considered the site where PGCs are recognized and begin their journey to the gonads. *Neural crest* - Neural crest cells are multipotent cells that migrate to various locations and differentiate into structures like **neurons**, **glial cells**, **melanocytes**, and **facial cartilage**, not germ cells. - They arise from the dorsal part of the **neural tube** during neurulation. *Genital ridge* - The genital ridge is the embryonic structure that develops into the **gonads** (testes or ovaries) [1]. - Primordial germ cells migrate *to* the genital ridge, but they do not originate *from* it — it is their destination, not their source. *Somatopleuritic mesoderm* - **Somatopleuritic mesoderm** (somatic mesoderm) forms the **parietal layer** of serous membranes, the dermis of the body wall, and the skeletal elements of the limbs. - It does not give rise to **primordial germ cells**.
Question 34: Pituicytes are seen in ?
- A. Anterior lobe
- B. Posterior lobe (Correct Answer)
- C. Intermediate lobe
- D. All of the options
Explanation: ***Posterior lobe*** - **Pituicytes** are specialized glial cells found exclusively in the **posterior pituitary** (neurohypophysis). [1] - They provide structural support and regulation for the nerve terminals that release **antidiuretic hormone (ADH)** and **oxytocin**. [1] *Anterior lobe* - The anterior pituitary, or **adenohypophysis**, consists of glandular epithelial cells that synthesize and secrete various hormones. [2] - It does not contain pituicytes, which are glial cells. [2] *Intermediate lobe* - The intermediate lobe is a rudimentary part of the pituitary gland in humans, primarily producing **melanocyte-stimulating hormone (MSH)**. [1] - While it is part of the pituitary, it does not contain pituicytes. *All of the options* - Pituicytes are specific to the posterior pituitary, so they are not found in all parts of the gland. - Different lobes of the pituitary gland have distinct cellular compositions and functions.
Question 35: What is the anatomical significance of the Rhinion in relation to the osseocartilaginous junction?
- A. Nasion
- B. Rhinion (Correct Answer)
- C. Radix
- D. Columella
Explanation: ***Correct Answer: Rhinion*** - The **rhinion** is the **most prominent anterior point of the nasal bone**, often palpable as a slight bump or angulation on the dorsum of the nose. - It marks the anatomical location of the **osseocartilaginous junction** of the nasal dorsum, where the bony nasal framework transitions to the cartilaginous framework. - This is the key anatomical landmark that defines the transition from bone to cartilage in the external nose. *Incorrect: Nasion* - The **nasion** is located at the **root of the nose**, specifically at the most anterior and superior point of the nasofrontal suture. - It is a bony landmark and does not directly relate to the osseocartilaginous junction of the nasal dorsum. *Incorrect: Radix* - The **radix** (or nasal root) refers to the **uppermost part of the nose**, corresponding to the nasion. - It defines the point where the nose begins to project from the forehead and is a bony landmark, not directly related to the osseocartilaginous junction. *Incorrect: Columella* - The **columella** is the **fleshy, narrow strip of tissue that separates the nostrils**. - It forms the inferior segment of the nasal septum and is composed of skin, soft tissue, and the medial crura of the alar cartilages, thus having no direct relation to the osseocartilaginous junction of the nasal dorsum.
Question 36: What are the main types of cells found in the cerebellar cortex?
- A. Purkinje cells, granule cells, and molecular layer interneurons (Correct Answer)
- B. Glomus cells
- C. Principal cells
- D. Intercalated cells
Explanation: **Purkinje cells, granule cells, and molecular layer interneurons** - The **cerebellar cortex** is characterized by distinct layers housing these cell types: **Purkinje cells** (large, inhibitory neurons), **granule cells** (small, excitatory neurons), and **molecular layer interneurons** (stellate and basket cells, inhibitory) [1]. - These cells work in concert to process motor information, with Purkinje cells serving as the sole output of the cerebellar cortex [1]. *Glomus cells* - **Glomus cells** are primarily found in the **carotid and aortic bodies**, where they act as chemoreceptors sensing changes in blood oxygen, carbon dioxide, and pH. - They are not a characteristic cell type of the cerebellar cortex. *Principal cells* - **Principal cells** is a general term often used to describe the main excitatory neurons of a brain region, such as **pyramidal cells in the cerebral cortex** or CA3 neurons in the hippocampus [2]. - While granule cells are excitatory in the cerebellum, "principal cells" is not a specific or exclusive term for cerebellar cortical cell types. *Intercalated cells* - **Intercalated cells** are specialized cells found in various locations, such as the **collecting ducts of the kidney** where they regulate acid-base balance, or in the **amygdala** as a type of inhibitory interneuron. - They do not represent a primary cell type of the cerebellar cortex.
Question 37: Which lymph nodes are involved in the lymphatic drainage of the lateral wall of the nose?
- A. Deep cervical nodes
- B. Retropharyngeal nodes
- C. Submandibular nodes
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - The lymphatic drainage from the **lateral wall of the nose** follows a sequential pathway involving **submandibular nodes**, **retropharyngeal nodes**, and ultimately the **deep cervical nodes**. - This question tests understanding of the complete lymphatic drainage pathway, not just the primary drainage site. - All three node groups are anatomically involved in draining lymph from the lateral nasal wall. **Drainage Pathway:** - **Submandibular nodes** (Primary): The anterior and middle portions of the lateral nasal wall drain primarily to the submandibular lymph nodes. - **Retropharyngeal nodes** (Secondary): The posterior portions of the lateral wall and areas near the nasal pharynx drain to retropharyngeal nodes. - **Deep cervical nodes** (Final pathway): Lymph from both submandibular and retropharyngeal nodes eventually drains into the deep cervical chain, particularly the jugulodigastric and juguloomohyoid nodes. *Why not just one node group?* - The lateral wall of the nose has an extensive lymphatic network with multiple drainage routes. - Different regions of the lateral wall have preferential drainage to different node groups. - Understanding the complete drainage pathway is clinically important for assessing spread of infections and malignancies from the nasal cavity.
Question 38: Rouviere nodes are situated in?
- A. Retropharynx (Correct Answer)
- B. Nasopharyngeal region
- C. Oral region
- D. Supraclavicular region
Explanation: ***Retropharynx*** - Rouviere nodes are a group of **retropharyngeal lymph nodes** located in the space behind the pharynx. - They are clinically significant as they are the **first station of lymphatic drainage** for the nasopharynx and can be involved in cancers of that region. *Nasopharyngeal region* - While Rouviere nodes drain the nasopharynx, they are **located *behind* the nasopharynx** in the retropharyngeal space, not within the nasopharyngeal region itself. - The nasopharynx is the superior part of the pharynx, above the soft palate. *Oral region* - The oral cavity drainage primarily involves **submandibular, submental, and deep cervical lymph nodes**. - Rouviere nodes are not typically involved in the initial lymphatic drainage of the oral region. *Supraclavicular region* - **Supraclavicular nodes** are located above the clavicle in the supraclavicular fossa and represent a distant drainage site. - Involvement of these nodes usually indicates more **advanced disease** or drainage from organs in the chest or abdomen.
Question 39: All are lateral branches of the abdominal aorta, EXCEPT which of the following?
- A. Right testicular artery
- B. Left renal artery
- C. Middle suprarenal artery
- D. Celiac trunk (Correct Answer)
Explanation: ***Celiac trunk*** - The **celiac trunk** is an anterior branch of the abdominal aorta, supplying the foregut derivatives. - It arises from the ventral aspect of the aorta, distinguishing it from lateral branches. *Right testicular artery* - The **testicular arteries** (gonadal arteries) are paired lateral branches of the abdominal aorta. - They arise inferior to the renal arteries and descend to supply the testes in males. *Left renal artery* - The **renal arteries** [1] [3] are large paired lateral branches of the abdominal aorta. - They supply the kidneys [2] and typically arise just inferior to the superior mesenteric artery. *Middle suprarenal artery* - The **middle suprarenal arteries** are paired lateral branches, typically arising directly from the abdominal aorta. - They supply the suprarenal (adrenal) glands [2].
Question 40: Which of the following is NOT a surface marking of the oblique fissure of the lung?
- A. 6th costal cartilage
- B. T3
- C. 5th rib
- D. 7th rib (Correct Answer)
Explanation: ***7th rib*** - The **oblique fissure** typically extends from the spine at approximately the **T3 vertebral level** anteriorly to the **6th costal cartilage**. [1] - The **7th rib** is generally inferior to the typical anterior termination point of the oblique fissure. [1] *T3* - The **oblique fissure** begins posteriorly at the level of the **spinous process of T3**. [1] - This marks the superior-posterior extent of the fissure on the surface. *5th rib* - The **oblique fissure** crosses the **5th intercostal space** on the lateral chest wall. [1] - This point helps map the fissure's path between its posterior and anterior endpoints. *6th costal cartilage* - The **oblique fissure** terminates anteriorly near the **6th costal cartilage** in the midclavicular line. [1] - This represents the inferior-anterior most point of the fissure on the chest wall.