Histology Practice Questions

Q: Intercalated discs are seen in which of the following tissues?

Cardiac muscle. **Explanation:** **Intercalated discs** are specialized junctional complexes found exclusively in **cardiac muscle** (Option B) [1]. They represent the interface between adjacent cardiomyocytes and are essential for the heart's function as a functional syncytium. **Why Cardiac Muscle is Correct:** Intercalated discs consist of three types of cell junctions: 1. **Fascia Adherens:** The most prominent component; it anchors actin filaments of the sarcomere. 2. **Desmosomes (Macula Adherens):** Provide mechanical stability by preventing cells from pulling apart during contraction. 3. **Gap Junctions:** Provide low-resistance electrical coupling, allowing rapid spread of action potentials across the myocardium for synchronized contraction [2]. **Analysis of Incorrect Options:** * **Option A (Iris):** Contains smooth muscle (sphincter and dilator pupillae). Smooth muscle cells are connected by gap junctions but lack the organized, thick intercalated discs seen in cardiac tissue [3]. * **Option C (Musculotendinous endings):** This is the junction where skeletal muscle fibers taper and connect to tendon collagen (Golgi tendon organs are located here). It lacks intercalated discs. * **Option D (Nerve bundles):** These consist of axons, Schwann cells, and connective tissue layers (epi/peri/endoneurium). Communication occurs via synapses or saltatory conduction, not intercalated discs. **High-Yield Clinical Pearls for NEET-PG:** * **Microscopic Appearance:** On H&E staining, intercalated discs appear as dark, transverse lines perpendicular to the muscle fibers. * **Functional Syncytium:** This term refers to the heart's ability to contract as a single unit due to the gap junctions within the discs [2]. * **Comparison:** Unlike skeletal muscle, cardiac muscle is **involuntary, striated, and branched** with a **central nucleus**.

Q: Which of the following is present in the colon?

Goblet cells. ### Explanation The correct answer is **D. Goblet cells**. **1. Why Goblet Cells are Correct:** The colon (large intestine) is primarily responsible for water absorption and the lubrication of fecal matter. To facilitate this, its mucosa is lined by simple columnar epithelium containing a high density of **Goblet cells** [1]. These unicellular glands secrete mucus, which protects the intestinal lining from mechanical trauma and acidity produced by bacterial fermentation. A high-yield histological feature of the colon is the presence of straight, tubular **Crypts of Lieberkühn** packed with Goblet cells, but notably **lacking villi**. **2. Why the Other Options are Incorrect:** * **Parietal cells (Option A):** These are found in the gastric glands of the **stomach** (primarily the body and fundus) [2]. They secrete hydrochloric acid (HCl) and intrinsic factor. * **Chief cells (Option B):** Also known as peptic cells, these are located in the basal regions of the **gastric glands** [2]. They secrete pepsinogen and gastric lipase. * **Brunner's glands (Option C):** These are characteristic histological markers of the **duodenum**. Located in the submucosa, they secrete alkaline mucus to neutralize acidic chyme entering from the stomach. **3. NEET-PG High-Yield Pearls:** * **Gradient of Goblet Cells:** The number of Goblet cells increases progressively from the duodenum to the sigmoid colon (highest concentration is in the distal large intestine). * **Histological Distinction:** The absence of **villi** and **plicae circulares** distinguishes the colon from the small intestine. * **Teniae Coli:** The outer longitudinal muscle layer of the colon is not continuous but is gathered into three thick bands called teniae coli. * **Clinical Correlation:** In **Ulcerative Colitis**, a classic histological finding is

Q: Which part of the female genital tract is known to have 'peg cells'?

Fallopian Tubes. The correct answer is **D. Fallopian Tubes** [1] (Uterine tubes/Salpinx). The mucosal lining of the fallopian tube consists of a **simple columnar epithelium** [1] composed of two distinct types of cells: 1. **Ciliated cells:** These are most numerous in the infundibulum and ampulla. Their cilia beat toward the uterus, assisting in the transport of the ovum or zygote [1]. 2. **Peg cells (Non-ciliated cells):** These are secretory cells. They are called "peg cells" because they are often squeezed between ciliated cells, giving them a narrow, peg-like appearance. They provide a nutrient-rich environment (containing glycogen and proteins) for the spermatozoa, the oocyte, and the developing zygote. **Why other options are incorrect:** * **Vagina:** Lined by **non-keratinized stratified squamous epithelium**. It lacks glands; lubrication is provided by cervical mucus and transudate. * **Vulva:** Covered by **stratified squamous epithelium** (keratinized on the labia majora). * **Ovary:** Covered by a single layer of cuboidal cells known as **germinal epithelium** [2] (modified mesothelium), not peg cells. **High-Yield Clinical Pearls for NEET-PG:** * **Cyclic Changes:** The height of the epithelium and the activity of peg cells are **estrogen-dependent**. They reach their maximum height/activity during the periovulatory phase. * **Kartagener Syndrome:** Dysfunctional cilia in the fallopian tubes can lead to **ectopic pregnancy** or infertility. * **Histology Tip:** The fallopian tube is most folded in the **Ampulla** [3] (the most common site for fertilization and ectopic pregnancy).

Q: The Space of Disse is located in which organ?

Liver. **Explanation:** The **Space of Disse** (also known as the perisinusoidal space) is a critical anatomical and functional area located in the **Liver**. It is the narrow gap situated between the fenestrated endothelial cells of the hepatic sinusoids and the plasma membrane of the hepatocytes [1]. **Why Liver is Correct:** The Space of Disse plays a vital role in nutrient exchange [1]. It contains blood plasma that filters through the sinusoidal fenestrations, allowing hepatocytes to process nutrients, proteins, and toxins. Crucially, it houses **Ito cells** (hepatic stellate cells), which store Vitamin A and, in pathological states, transform into myofibroblasts that produce collagen, leading to liver cirrhosis. **Why Other Options are Incorrect:** * **Spleen:** Contains the Red Pulp (sinusoids and Cords of Billroth) and White Pulp (lymphoid tissue), but no Space of Disse. * **Lymph node:** Characterized by subcapsular, trabecular, and medullary sinuses, but lacks this specific perisinusoidal structure. * **Bone:** Contains the Haversian system and Volkmann’s canals; while bone marrow has sinusoids, the specific "Space of Disse" is unique to hepatic architecture. **High-Yield Clinical Pearls for NEET-PG:** * **Ito Cells:** Located in the Space of Disse; primary site for **Vitamin A storage**. * **Cirrhosis Pathogenesis:** Activation of Ito cells in the Space of Disse is the key event in hepatic fibrosis. * **Lymph Formation:** Approximately 50% of the body’s lymph is formed in the Space of Disse. * **Kupffer Cells:** These are specialized macrophages found *inside* the hepatic sinusoids, not in the Space of Disse itself.

Q: Elastic cartilage is present in which of the following structures?

Epiglottis. ### Explanation **Correct Answer: B. Epiglottis** The cartilages of the larynx are divided into two types based on their histological composition: **Hyaline** and **Elastic**. The **Epiglottis** is composed of **elastic cartilage**. This histological structure provides the necessary flexibility for the epiglottis to bend and seal the laryngeal inlet during deglutition, preventing aspiration. Unlike hyaline cartilage, elastic cartilage contains a dense network of branching elastic fibers and **does not undergo calcification or ossification** with age. #### Analysis of Incorrect Options: * **A. Thyroid Cartilage:** This is the largest laryngeal cartilage and is composed of **hyaline cartilage**. It typically begins to ossify after the age of 20-25. * **C. Cricoid Cartilage:** This is a complete ring of **hyaline cartilage**. Like the thyroid, it is prone to calcification and ossification in older individuals, which can be seen on X-rays. * **D. Arytenoid Cartilage:** This is a mixed cartilage. The **base and muscular process** are made of **hyaline cartilage**, while the **vocal process** and the apex are made of **elastic cartilage**. Since the majority of the bulk is hyaline, it is generally classified as such in broad contexts. --- ### NEET-PG High-Yield Pearls: 1. **Mnemonic for Elastic Cartilages in ENT:** Remember the **"3 E's"**: **E**piglottis, **E**xternal Ear (Pinna & External Auditory Canal), and **E**ustachian tube (cartilaginous part). 2. **Laryngeal Elastic Cartilages:** Epiglottis, Coriniculate, Cuneiform, and the **Apex/Vocal process** of the Arytenoid. 3. **Clinical Significance:** Hyaline cartilages (Thyroid, Cricoid, Base of Arytenoid) can be visualized on imaging in the elderly due to ossification, whereas the Epiglottis remains radiolucent unless diseased.

Q: Which of the following is not a component of the pulmonary acinus?

Pulmonary lobule. ### Explanation The **pulmonary acinus** is the functional unit of the lung, defined as the portion of the lung distal to the **terminal bronchiole**. It is the site where gas exchange actually occurs. #### Why "Pulmonary Lobule" is the Correct Answer: The **pulmonary lobule** (specifically the Secondary Pulmonary Lobule) is a larger structural unit. It is composed of a cluster of **3 to 12 pulmonary acini**. Therefore, the acinus is a *component* of the lobule, not the other way around. The lobule is the smallest unit of lung tissue surrounded by connective tissue septa [1]. #### Analysis of Incorrect Options: * **B. Respiratory Bronchioles:** These are the first components of the acinus [1]. They arise from the terminal bronchioles and are characterized by the presence of occasional alveoli in their walls [1]. * **C. Alveolar Ducts:** These are thin-walled tubes arising from respiratory bronchioles, completely lined with alveoli [1]. * **D. Alveolar Sacs:** These are the terminal clusters of alveoli at the end of the alveolar ducts [1]. #### NEET-PG High-Yield Pearls: * **Terminal Bronchiole:** This is the last part of the **conducting zone** (no gas exchange) [1]. * **Respiratory Bronchiole:** This marks the beginning of the **respiratory zone** and the pulmonary acinus. * **Blood Supply:** The pulmonary acinus receives deoxygenated blood via the pulmonary artery branches and oxygenated blood is carried away by pulmonary veins (which travel in the interlobular septa). * **Centriacinar vs. Panacinar Emphysema:** In smoking-related emphysema, the damage is primarily at the respiratory bronchiole level (**centriacinar**), whereas in $\alpha_1$-antitrypsin deficiency, the entire acinus is involved (**panacinar**).

Q: Which of the following is NOT a neuroglial cell in the Central Nervous System?

Kupffer cells. The nervous system contains two types of cells: neurons and neuroglia (supporting cells). Neuroglia are further divided into those found in the Central Nervous System (CNS) and the Peripheral Nervous System (PNS) [1]. **Why Kupffer cells are the correct answer:** **Kupffer cells** are specialized macrophages located in the **liver** (lining the sinusoids). They are part of the Mononuclear Phagocyte System, not the nervous system. Therefore, they are not neuroglial cells. **Analysis of incorrect options (CNS Neuroglia):** * **Oligodendrocytes:** These are responsible for the **myelination** of axons within the CNS [2]. A single oligodendrocyte can myelinate multiple axon segments [1]. * **Microglia:** These are the resident macrophages of the CNS. They are unique because they are derived from the **mesoderm** (yolk sac), unlike other glial cells which are neuroectodermal in origin [1]. They respond to injury by proliferating and forming aggregates or rod cells [2]. * **Astrocytes:** The most numerous glial cells. They provide structural support, form the **Blood-Brain Barrier (BBB)**, and regulate the chemical environment (potassium buffering). **High-Yield Clinical Pearls for NEET-PG:** * **Origin:** All CNS neuroglia (Astrocytes, Oligodendrocytes, Ependymal cells) are derived from **Neuroectoderm**, EXCEPT **Microglia**, which are **Mesodermal** [1]. * **PNS Neuroglia:** The primary glial cells in the PNS are **Schwann cells** (myelination) and **Satellite cells** (support) [1]. * **Pathology:** In Multiple Sclerosis, oligodendrocytes are targeted; in Guillain-Barré Syndrome, Schwann cells are affected [2]. * **Marker:** **GFAP** (Glial Fibrillary Acidic Protein) is a high-yield marker for Astrocytes and tumors arising from them (Astrocytomas).

Q: What are the supporting cells of the testes?

Sertoli cells. **Explanation:** The correct answer is **C. Sertoli cells**. Sertoli cells are the large, columnar "nurse cells" located within the germinal epithelium of the seminiferous tubules [1]. They are considered the **supporting cells** of the testes because they provide structural integrity, nutrition, and protection to developing germ cells [1], [2]. They are also responsible for forming the **blood-testis barrier** via tight junctions, protecting sperm from the immune system [1]. **Analysis of Options:** * **Spermatogonia (A):** These are the undifferentiated male germ cells (stem cells) located on the basement membrane [1]. They are the precursors to sperm, not supporting cells. * **Leydig cells (B):** Also known as interstitial cells, these are found in the connective tissue *between* seminiferous tubules. Their primary function is the endocrine production of **Testosterone** in response to LH [3]. * **Spermatids (D):** These are haploid male germ cells derived from secondary spermatocytes. They represent a late stage of spermatogenesis before undergoing spermiogenesis to become mature spermatozoa [2]. **High-Yield Facts for NEET-PG:** * **Secretions:** Sertoli cells secrete **Inhibin B** (inhibits FSH), **Androgen Binding Protein (ABP)** (maintains high local testosterone), and **Anti-Müllerian Hormone (AMH)** during fetal development [2], [3]. * **Regulation:** Sertoli cells are stimulated by **FSH**, whereas Leydig cells are stimulated by **LH** (Mnemonic: **L**H acts on **L**eydig cells) [3]. * **Phagocytosis:** Sertoli cells phagocytose the excess cytoplasm (residual bodies) shed by spermatids during spermiogenesis. * **Tumor Marker:** Sertoli cells contain **Charcot-Böttcher crystals** (spindle-shaped cytoplasmic inclusions), which are pathognomonic.

Question 1

Intercalated discs are seen in which of the following tissues?

Accepted Answer

Cardiac muscle

Answer

Iris

Answer

Musculotendinous endings

Answer

Nerve bundles

Question 2

Structurally, what type of neurons function as sensory neurons?

Accepted Answer

Pseudounipolar

Answer

Unipolar

Answer

Bipolar

Answer

Multipolar

Question 3

Which of the following is present in the colon?

Accepted Answer

Goblet cells

Answer

Parietal cells

Answer

Chief cells

Answer

Brunner's glands

Question 4

Which part of the female genital tract is known to have 'peg cells'?

Accepted Answer

Fallopian Tubes

Answer

Vagina

Answer

Vulva

Answer

Ovary

Question 5

The Space of Disse is located in which organ?

Accepted Answer

Liver

Answer

Spleen

Answer

Lymph node

Answer

Bone

Question 6

Elastic cartilage is present in which of the following structures?

Accepted Answer

Epiglottis

Answer

Thyroid cartilage

Answer

Cricoid cartilage

Answer

Arytenoid cartilage

Question 7

Which of the following is not a component of the pulmonary acinus?

Accepted Answer

Pulmonary lobule

Answer

Respiratory bronchioles

Answer

Alveolar ducts

Answer

Alveolar sac

Question 8

Which of the following is NOT a neuroglial cell in the Central Nervous System?

Accepted Answer

Kupffer cells

Answer

Oligodendrocytes

Answer

Microglia

Answer

Astrocytes

Question 9

What are the supporting cells of the testes?

Accepted Answer

Sertoli cells

Answer

Spermatogonia

Answer

Leydig cells

Answer

Spermatids

Question 10

Which of the following statements concerning skin melanocytes is true?

Accepted Answer

They synthesize a pigment that protects against damage caused by UV radiation.

Answer

They are located only in the dermis.

Answer

They produce keratohyalin granules.

Answer

They may give rise to basal cell carcinoma.

Histology — MCQs

Histology — MCQs

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