Histology Practice Questions

Q: A 9-year-old boy is brought to the emergency department by ambulance due to difficulty breathing. On presentation he is found to be straining to breathe. Physical exam reveals bilateral prolonged expiratory wheezing, difficulty speaking, and belly breathing. Radiographs also reveal hyperinflation of the lungs. He is given oxygen as well as albuterol, which begins to reverse the flow limitation in the airway segments of this patient. The airway segment that is most susceptible to this type of flow limitation has which of the following characteristics?

Distal most extent of smooth muscle. ***Distal most extent of smooth muscle*** - The symptoms described (wheezing, difficulty breathing, hyperinflation) are characteristic of **asthma**, which primarily affects the **small airways** (bronchioles) where smooth muscle contraction causes significant narrowing. - The **terminal bronchioles** are the most susceptible to flow limitation in asthma because they are the smallest airways with significant amounts of smooth muscle, and their lack of cartilage makes them prone to collapse during spasm. - These airways represent the **distal-most extent of smooth muscle** in the respiratory tree, making them the primary site of bronchoconstriction in asthma. *Contains mucous producing goblet cells* - While **goblet cells** are present in the larger airways (trachea and bronchi) and contribute to mucus production in asthma, they are less prevalent or absent in the terminal bronchioles most affected by bronchoconstriction. - Mucus production is a contributing factor to airway obstruction but is not the primary characteristic defining the most susceptible airway segment for acute flow limitation. *Contains c-shaped hyaline cartilage rings* - **C-shaped cartilage rings** are characteristic of the **trachea** and large bronchi, which are rigid and less susceptible to the type of acute bronchoconstriction seen in asthma. - The lack of cartilage in the terminal bronchioles makes them more prone to collapse during smooth muscle contraction, highlighting them as the main site of flow limitation. *Lined by type I and type II pneumocytes* - **Type I and type II pneumocytes** line the **alveoli**, which are the gas exchange units and not the primary site of airway flow limitation and bronchoconstriction in asthma. - While hypoxemia can result from alveolar dysfunction due to poor ventilation, the initial pathology in asthma is in the conducting airways, specifically the terminal bronchioles.

Q: Cords of Billroth in spleen are found in

Red pulp. ***Correct: Red pulp*** - The **cords of Billroth** (or splenic cords) are a distinctive histological feature of the **red pulp** of the spleen. - These cords consist of a meshwork of reticular cells and reticular fibers, packed with macrophages, lymphocytes, plasma cells, and abundant red blood cells. *Incorrect: White pulp* - The **white pulp** is primarily involved in immune functions, containing lymphoid follicles rich in lymphocytes. - It is organized around central arterioles and does not contain the cords of Billroth. *Incorrect: Trabecular zone* - The **trabecular zone** consists of connective tissue septa that extend inward from the splenic capsule, carrying blood vessels and nerves. - It provides structural support to the spleen but is not where the cords of Billroth are located. *Incorrect: Mantle zone* - The **mantle zone** is a region within the **white pulp**, surrounding the germinal centers of lymphoid follicles. - It is composed mainly of naive B lymphocytes and is distinct from the cords of Billroth.

Q: Protein making up the bulk of keratohyaline granules in stratum granulosum of keratinized epithelium is

Filaggrin. ***Filaggrin*** - **Filaggrin** is a key protein derived from **profilaggrin** found in **keratohyaline granules** within the stratum granulosum. - Its primary role is to aggregate **keratin filaments** into tight bundles, contributing to the formation of the skin barrier. *Nectin* - **Nectins** are **cell adhesion molecules** involved in cell-cell junctions and signaling pathways, particularly in adherens junctions and tight junctions. - They are not the primary protein component of **keratohyaline granules** in the stratum granulosum. *Vinculin* - **Vinculin** is a **cytoskeletal protein** associated with **focal adhesions** and **adherens junctions**, linking integrins and cadherins to the actin cytoskeleton. - It plays a role in cell adhesion and mechanotransduction but is not found in **keratohyaline granules**. *Involucrin* - **Involucrin** is a precursor protein for the **cornified envelope** in the stratum corneum, cross-linked by transglutaminases to other proteins like loricrin. - While important for skin barrier function, it is not the bulk protein of **keratohyaline granules** themselves, which primarily contain profilaggrin/filaggrin.

Q: Arrange coverings on peripheral nerve from inner to outer

Endoneurium, Perineurium, Epineurium. The endoneurium is the innermost delicate connective tissue sheath that surrounds individual nerve fibers (axons), providing structural support and maintaining the microenvironment [1]. The perineurium is a stronger, protective sheath that encircles bundles of nerve fibers, called fascicles, forming a crucial barrier [2]. The epineurium is the outermost, toughest connective tissue layer that surrounds the entire peripheral nerve, encompassing multiple fascicles and their surrounding perineurium.

Q: Basophilic thyrotroph cells of pituitary secrete:

TSH. ***TSH*** - **Basophilic thyrotroph cells** of the anterior pituitary gland are responsible for synthesizing and secreting **Thyroid-Stimulating Hormone (TSH)**. - TSH then acts on the thyroid gland, stimulating it to produce **thyroid hormones (T3 and T4)**. *GH* - **Growth Hormone (GH)** is secreted by **acidophilic somatotroph cells** in the anterior pituitary, not basophilic thyrotrophs. - GH plays a crucial role in growth, metabolism, and body composition. *LH* - **Luteinizing Hormone (LH)** is secreted by **basophilic gonadotrophs** of the anterior pituitary, which also secrete Follicle-Stimulating Hormone (FSH). - LH is involved in reproductive functions in both males and females. *Prolactin* - **Prolactin** is produced by **acidophilic lactotroph (mammotroph) cells** in the anterior pituitary, not basophilic thyrotrophs. - Its primary function is to stimulate milk production in mammary glands.

Q: Gland that secretes an oily substance is:

Meibomian gland. ***Meibomian gland*** - These glands secrete **oily lipids** (meibum) that form the outermost layer of the tear film, preventing evaporation. - They are a type of **sebaceous gland** located within the eyelids. *Sweat gland* - Sweat glands produce a watery solution of electrolytes and metabolic waste products, primarily for **thermoregulation**. - They do not secrete an **oily substance**, but rather a clear, aqueous fluid. *Lacrimal gland* - The lacrimal gland produces the **aqueous layer of tears**, primarily for lubrication, washing away debris, and providing oxygen to the cornea. - Its secretion is predominantly **watery**, not oily. *Salivary gland* - Salivary glands produce **saliva**, a fluid containing enzymes (like amylase), mucins, and antibodies, important for digestion, lubrication, and oral hygiene. - Saliva is a **mucoserous or aqueous substance**, not an oily secretion.

Q: Elastic cartilage is present in

Epiglottis. ***Epiglottis*** - The **epiglottis** is composed of **elastic cartilage**, which provides flexibility to fold over the glottis during swallowing, preventing food from entering the trachea. - This type of cartilage is characterized by a dense network of **elastic fibers** within its matrix, allowing it to spring back to its original shape. *Cricoid* - The **cricoid cartilage** is a ring-shaped cartilage that forms the inferior wall of the larynx and is composed of **hyaline cartilage**. - **Hyaline cartilage** provides structural support and maintains the patency of the airway, but lacks the flexibility of elastic cartilage. *Arytenoid cartilage* - The **arytenoid cartilages** are small, paired cartilages that sit atop the cricoid cartilage and are primarily composed of **hyaline cartilage**. - They play a crucial role in the movement of the **vocal cords**, but their limited flexibility is not characteristic of elastic cartilage. *Thyroid cartilage* - The **thyroid cartilage**, the largest laryngeal cartilage, forms the "Adam's apple" and is made of **hyaline cartilage**. - Its rigid structure provides protection for the vocal cords and maintains the shape of the larynx, which is a function of hyaline rather than elastic cartilage.

Q: Nutrient and oxygen reach the chondrocytes across perichondrium by

Diffusion. ***Diffusion*** - **Cartilage** is an **avascular tissue**, meaning it lacks its own direct blood supply. - Nutrients and oxygen from the capillaries in the surrounding **perichondrium** move into chondrocytes via **simple diffusion** through the extracellular matrix. *Along neurons* - **Neurons** are responsible for transmitting electrical signals and are not involved in the transport of nutrients and oxygen to chondrocytes. - Cartilage itself is also an **aneural tissue**, meaning it lacks nerve innervation. *Active transport* - While active transport is a mechanism for moving substances across cell membranes, it requires energy and specifically transports substances against their **concentration gradient**. - The primary mechanism for bulk nutrient and oxygen delivery from the perichondrium to chondrocytes due to the concentration gradient is **diffusion**. *Capillaries* - **Capillaries** are indeed the source of nutrients and oxygen, but they are located within the **perichondrium**, not directly within the **avascular cartilage** itself. - Nutrients must leave the capillaries and then **diffuse** through the perichondrium and cartilage matrix to reach the chondrocytes.

Q: Merkel cells are found in which of the following tissues?

Epidermis. ***Epidermis*** - **Merkel cells** are specialized **neuroendocrine cells** located in the **stratum basale** (deepest layer) of the epidermis [1]. - They function as **mechanoreceptors**, playing a crucial role in **touch sensation**, particularly light touch and discrimination of shapes and textures [1]. *Reticular layer of dermis* - The **reticular layer** is the deeper, thicker layer of the dermis, composed of dense irregular connective tissue. - It primarily contains **collagen and elastic fibers** and is involved in the skin's strength and elasticity, not housing mechanoreceptors like Merkel cells. *Hypodermis* - The **hypodermis** (or superficial fascia) is the layer beneath the dermis, primarily composed of **adipose tissue** and loose connective tissue. - Its main functions include **insulation**, energy storage, and shock absorption; it does not contain Merkel cells. *Papillary layer of dermis* - The **papillary layer** is the superficial layer of the **dermis**, characterized by dermal papillae that interdigitate with the epidermis. - While it contains touch receptors like **Meissner's corpuscles**, it does not contain Merkel cells, which are epidermal.

Q: The slide of the testis is shown below. The supporting cells of the testis are:

Sertoli cells. ***Sertoli cells*** - **Sertoli cells** are also known as **nurse cells** because they provide structural and nutritional support to developing sperm cells (**spermatogonia, spermatocytes, and spermatids**). - They also form the **blood-testis barrier** and secrete hormones like **inhibin** and **androgen-binding protein**. *Spermatids* - **Spermatids** are immature male gametes that undergo spermiogenesis to mature into spermatozoa (sperm). - They are one of the types of cells being supported, not the supporting cells themselves. *Spermatogonia* - **Spermatogonia** are stem cells located at the base of the seminiferous tubules that initiate spermatogenesis. - These are the precursors to sperm cells and require support from Sertoli cells for their development. *Leydig cells* - **Leydig cells** are interstitial cells located between the seminiferous tubules and are responsible for producing and secreting **testosterone**. - While crucial for male reproductive function, they do not directly support the developing germ cells within the tubules.

Question 1

A 9-year-old boy is brought to the emergency department by ambulance due to difficulty breathing. On presentation he is found to be straining to breathe. Physical exam reveals bilateral prolonged expiratory wheezing, difficulty speaking, and belly breathing. Radiographs also reveal hyperinflation of the lungs. He is given oxygen as well as albuterol, which begins to reverse the flow limitation in the airway segments of this patient. The airway segment that is most susceptible to this type of flow limitation has which of the following characteristics?

Accepted Answer

Distal most extent of smooth muscle

Answer

Contains mucous producing goblet cells

Answer

Contains c-shaped hyaline cartilage rings

Answer

Lined by type I and type II pneumocytes

Question 2

Cords of Billroth in spleen are found in

Accepted Answer

Red pulp

Answer

White pulp

Answer

Trabecular zone

Answer

Mantle zone

Question 3

Protein making up the bulk of keratohyaline granules in stratum granulosum of keratinized epithelium is

Accepted Answer

Filaggrin

Answer

Nectin

Answer

Vinculin

Answer

Involucrin

Question 4

Arrange coverings on peripheral nerve from inner to outer

Accepted Answer

Endoneurium, Perineurium, Epineurium

Answer

Endoneurium, Epineurium, Perineurium

Answer

Epineurium, Endoneurium, Perineurium

Answer

Perineurium, Endoneurium, Epineurium

Question 5

Basophilic thyrotroph cells of pituitary secrete:

Accepted Answer

TSH

Answer

GH

Answer

LH

Answer

Prolactin

Question 6

Gland that secretes an oily substance is:

Accepted Answer

Meibomian gland

Answer

Sweat gland

Answer

Lacrimal gland

Answer

Salivary gland

Question 7

Elastic cartilage is present in

Accepted Answer

Epiglottis

Answer

Cricoid

Answer

Arytenoid cartilage

Answer

Thyroid cartilage

Question 8

Nutrient and oxygen reach the chondrocytes across perichondrium by

Accepted Answer

Diffusion

Answer

Along neurons

Answer

Active transport

Answer

Capillaries

Question 9

Merkel cells are found in which of the following tissues?

Accepted Answer

Epidermis

Answer

Reticular layer of dermis

Answer

Hypodermis

Answer

Papillary layer of dermis

Question 10

The slide of the testis is shown below. The supporting cells of the testis are:

Accepted Answer

Sertoli cells

Answer

Spermatids

Answer

Spermatogonia

Answer

Leydig cells

Histology — MCQs

Histology — MCQs

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