Neuroanatomy Practice Questions

Q: Which of the following cells contain organelles needed for the secretion of a proteinaceous product?

Pyramidal cells of the pancreatic acini. **Explanation:** The question focuses on the histological characteristics of cells specialized for **protein synthesis and secretion**. Cells that secrete proteinaceous products (like digestive enzymes) are characterized by an abundance of **Rough Endoplasmic Reticulum (RER)** at the base, a prominent **Golgi apparatus**, and apical **zymogen granules**. [1] **1. Why Option A is Correct:** The **Pyramidal cells of the pancreatic acini** are the classic example of protein-secreting cells. They produce various digestive enzymes (trypsinogen, lipase, amylase). [2], [4] Under a microscope, they exhibit intense basal basophilia (due to dense RER) and acidophilic apical granules (zymogen granules), reflecting their high metabolic activity in protein production. **2. Analysis of Other Options:** * **B & C (Chief cells and Serous cells):** These cells **also** contain organelles for protein secretion (pepsinogen in chief cells; amylase in parotid cells). [4] However, in the context of standard medical entrance exams, if a question asks for the "most representative" or "classic" example of a pyramidal-shaped protein-secreting cell, the **Pancreatic Acinar cell** is the gold standard. * **D (Fibroblasts):** While fibroblasts secrete collagen (a protein), they are spindle-shaped and primarily involved in maintaining the extracellular matrix rather than the rapid, regulated secretion of enzymes seen in glandular epithelium. [3] **NEET-PG High-Yield Pearls:** * **Basal Basophilia:** Always indicates a high concentration of RER (RNA), typical of protein-secreting cells. [1] * **Nissl Bodies:** In neuroanatomy, these are specialized RER found in neurons (like Pyramidal cells of the cortex), also used for protein synthesis. * **Golgi Apparatus:** Best visualized using **Silver Stains** (e.g., Golgi's method); it is the site for post-translational modification.

Q: Fructose is transported by which GLUT transporter?

GLUT 5. **Explanation:** The correct answer is **GLUT 5** [2]. Glucose transporters (GLUT) are a family of membrane proteins that facilitate the transport of glucose and other sugars across cell membranes via facilitated diffusion [2]. **Why GLUT 5 is correct:** GLUT 5 is unique among the GLUT family because it has a high affinity specifically for **fructose** [2]. It is primarily expressed in the apical membrane of enterocytes in the small intestine, where it facilitates the absorption of dietary fructose [1]. It is also found in the spermatozoa and kidneys [2]. **Analysis of Incorrect Options:** * **GLUT 1:** This is a high-affinity glucose transporter found in almost all tissues. It is most abundant in **Red Blood Cells (RBCs)** and the **Blood-Brain Barrier (BBB)** [2]. It provides a basal level of glucose uptake. * **GLUT 2:** This is a high-capacity, low-affinity bidirectional transporter. It is found in the **Liver, Pancreatic beta cells, and Basolateral membrane of the small intestine** [1],[2]. It acts as a "glucose sensor." * **GLUT 4:** This is the only **insulin-dependent** transporter. It is primarily located in **Skeletal muscle and Adipose tissue** [2]. In the presence of insulin, GLUT 4 translocates from intracellular vesicles to the cell membrane to increase glucose uptake. **High-Yield Clinical Pearls for NEET-PG:** * **SGLT-1 vs. GLUT 5:** Glucose and Galactose are absorbed in the intestine via SGLT-1 (active transport), whereas Fructose is absorbed via GLUT 5 (facilitated diffusion) [1]. * **Spermatozoa:** Fructose is the primary energy source for sperm, making GLUT 5 clinically significant in male fertility [2]. * **GLUT 3:** Primarily found in **Neurons** (highest affinity for glucose to ensure brain supply during hypoglycemia) [2]. * **Mnemonic:** "GLUT **5** is for **F**ructose" (F is the 6th letter, but think of **F**ructose and **F**ive).

Q: A 4-month-old infant, who underwent surgical treatment for myelomeningocele, presents with progressive hydrocephalus. A CT scan at birth revealed herniation of the cerebellar tonsils through the foramen magnum, consistent with Arnold-Chiari malformation. Which of the following is also commonly associated with this syndrome?

Abnormal elongation of the medulla and lower cranial nerves. Explanation: **Arnold-Chiari Malformation (Type II)** is a congenital anomaly of the hindbrain characterized by the downward displacement of the cerebellar tonsils, vermis, and brainstem through the foramen magnum [2]. **Why Option C is Correct:** The hallmark of Chiari Type II is the caudal displacement of the medulla oblongata and the fourth ventricle into the cervical spinal canal [4]. This mechanical "dragging" or downward shift results in the **abnormal elongation of the medulla** and the stretching of the **lower cranial nerves** (CN IX, X, XI, and XII) as they must travel superiorly to exit their respective cranial foramina. This displacement often leads to obstructive hydrocephalus due to the narrowing of the aqueduct of Sylvius or obstruction of the fourth ventricle outlets [2]. **Why Incorrect Options are Wrong:** * **Option A & B:** Holoprosencephaly (failure of prosencephalon cleavage) and fusion of lobes are defects of the **forebrain** (prosencephalon). Arnold-Chiari is a defect of the **hindbrain** (rhombencephalon). * **Option D:** Pituitary gland abnormalities are associated with midline defects like Septo-optic dysplasia, not typically with the hindbrain herniation seen in Chiari malformations. **NEET-PG High-Yield Pearls:** * **Chiari Type I:** Downward herniation of cerebellar tonsils only; often asymptomatic until adulthood; associated with **syringomyelia** [3]. * **Chiari Type II:** Herniation of tonsils, vermis, and medulla; almost always associated with **lumbar myelomeningocele** and hydrocephalus [1], [2]. * **Radiological Sign:** "Beaked midbrain" (tectal plate peaking) and a small posterior fossa [2]. * **Clinical Presentation:** In infants, it may present with stridor, weak cry, and feeding difficulties due to lower cranial nerve stretching.

Q: Which one of the following structures is a part of the diencephalon?

Thalamus. **Explanation:** The brain develops from three primary vesicles: the forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon). The prosencephalon further divides into the **telencephalon** and the **diencephalon**. **Why Thalamus is Correct:** The **diencephalon** forms the central core of the brain and consists of four main components: the **thalamus**, hypothalamus, epithalamus, and subthalamus [1]. The thalamus acts as the major relay station for almost all sensory information (except olfaction) heading to the cerebral cortex [1]. **Why Other Options are Incorrect:** * **Caudate Nucleus:** This is a component of the **basal ganglia**, which develops from the **telencephalon** [2]. * **Cerebral Hemispheres:** These represent the largest part of the brain and are derived entirely from the **telencephalon**. * **Hippocampus:** Part of the limbic system located in the temporal lobe, the hippocampus is a **telencephalic** structure. **High-Yield NEET-PG Pearls:** 1. **Cavity Association:** The cavity of the diencephalon is the **third ventricle**. 2. **Boundary:** The boundary between the telencephalon and diencephalon is the *foramen of Monro* (interventricular foramen). 3. **Optic Nerve:** Interestingly, the **optic nerve (CN II)** and retina are embryologically outgrowths of the diencephalon; thus, the optic nerve is considered a tract of the CNS rather than a true peripheral nerve. 4. **Internal Capsule:** The diencephalon is separated from the lentiform nucleus by the posterior limb of the internal capsule.

Q: Which muscle does not have a dual nerve supply?

Thyrohyoid. The concept of **dual nerve supply** (hybrid muscles) refers to muscles innervated by two different nerves, often reflecting their complex embryological origins. ### **Why Thyrohyoid is the Correct Answer** The **Thyrohyoid** is a unique infrahyoid muscle. Unlike other muscles in this region, it is supplied **solely by the C1 nerve fibers** traveling via the **Hypoglossal nerve (CN XII)**. It does not receive a second nerve supply, nor is it supplied by the Ansa cervicalis (which supplies the Omohyoid, Sternohyoid, and Sternothyroid). ### **Analysis of Incorrect Options** * **Digastric:** This is a classic hybrid muscle. The **Anterior belly** is derived from the 1st pharyngeal arch (Nerve to Mylohyoid, CN V3), while the **Posterior belly** is derived from the 2nd arch (Facial nerve, CN VII). * **Trapezius:** It receives a dual supply: **Spinal accessory nerve (CN XI)** provides motor innervation, while the **ventral rami of C3 and C4** provide sensory (proprioceptive) fibers. * **Adductor Magnus:** This is a "hybrid" muscle of the lower limb. The **Adductor part** is supplied by the **Obturator nerve**, and the **Hamstring part** is supplied by the **Tibial component of the Sciatic nerve**. ### **High-Yield NEET-PG Pearls** * **Geniohyoid:** Like the Thyrohyoid, it is also supplied exclusively by **C1 via CN XII**. * **Pectineus:** Often considered a hybrid muscle, supplied by the **Femoral nerve** and occasionally the **Obturator nerve**. * **Brachialis:** Supplied by the **Musculocutaneous nerve** (motor) and the **Radial nerve** (proprioceptive). * **Flexor Digitorum Profundus:** Medial half by the **Ulnar nerve**, lateral half by the **Median nerve** (Anterior Interosseous Nerve).

Question 1

Which of the following cells contain organelles needed for the secretion of a proteinaceous product?

Accepted Answer

Pyramidal cells of the pancreatic acini

Answer

Chief cells of the stomach

Answer

Serous-secreting cells of the parotid gland

Answer

Fibroblasts

Question 2

Fructose is transported by which GLUT transporter?

Accepted Answer

GLUT 5

Answer

GLUT 1

Answer

GLUT 2

Answer

GLUT 4

Question 3

A 4-month-old infant, who underwent surgical treatment for myelomeningocele, presents with progressive hydrocephalus. A CT scan at birth revealed herniation of the cerebellar tonsils through the foramen magnum, consistent with Arnold-Chiari malformation. Which of the following is also commonly associated with this syndrome?

Accepted Answer

Abnormal elongation of the medulla and lower cranial nerves

Answer

Holoprosencephaly (fusion of the frontal lobes)

Answer

Observed fusion of the temporal, parietal, and occipital lobes

Answer

Partial or complete absence of the pituitary gland

Question 4

Which one of the following structures is a part of the diencephalon?

Accepted Answer

Thalamus

Answer

Caudate nucleus

Answer

Cerebral hemispheres

Answer

Hippocampus

Question 5

Which muscle does not have a dual nerve supply?

Accepted Answer

Thyrohyoid

Answer

Digastric

Answer

Trapezius

Answer

Adductor magnus

Neuroanatomy — MCQs

Neuroanatomy — MCQs

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