Histology Practice Questions

Q: The area marked as $X$ is called:

Spiral canal of modiolus. ***Spiral canal of modiolus*** - The image shows a cross-section of the **organ of Corti** within the cochlea. Modiolus is the central bony pillar of the cochlea, and the **spiral canal of modiolus** contains the **spiral ganglion**, which consists of the cell bodies of the auditory nerve. The arrow points to a collection of neurons, clearly indicating this structure. - The spiral ganglion neurons receive input from the hair cells and transmit auditory information to the brain. *Endolymphatic sac* - The **endolymphatic sac** is located within the dura mater of the posterior cranial fossa and is involved in the absorption and regulation of **endolymph** fluid. - It is not depicted in this image, which focuses on the sensory structures of the **cochlea**. *Tunnel of Corti* - The **tunnel of Corti** is a triangular-shaped space within the organ of Corti, formed by the inner and outer pillar cells. It is filled with **cortilymph**. - While present in the organ of Corti, the area marked 'X' is clearly positioned to indicate the collection of **neuronal cell bodies** (ganglion) rather than this specific extracellular space. *Scala tympani* - The **scala tympani** is one of the three fluid-filled chambers of the cochlea, located below the basilar membrane. It contains **perilymph** and transmits sound vibrations. - The marked area 'X' indicates a cellular structure (spiral ganglion) within the modiolus, not a fluid-filled chamber of the cochlea.

Q: Which of the following layers has abundance of desmosomes? (AIIMS Nov 2017)

C. ***C*** - Layer C represents the **stratum spinosum** (prickle cell layer) of the epidermis, which is characterized by abundant **desmosomes**. - These desmosomes give the cells a **prickly appearance** when stained, as the cells shrink but the desmosomal attachments remain, pulling on the cell membranes. *A* - Layer A represents the **stratum corneum**, which is the outermost layer consisting of flattened, anucleated cells filled with **keratin**. - While desmosomes are present deeper in the epidermis, this layer is primarily involved in **protection** and shedding of dead cells. *B* - Layer B represents the **stratum granulosum**, characterized by cells containing **keratohyalin granules**. - These granules are precursors to keratin, and while desmosomes connect cells here, they are less prominent than in the stratum spinosum. *D* - Layer D represents the **stratum basale** (basal layer), which is the deepest epidermal layer of cuboidal or columnar cells. - These cells are responsible for **cell proliferation** and connect to the basement membrane via **hemidesmosomes**, and to each other via desmosomes, but not as abundantly as in the stratum spinosum.

Q: Which of the following layers contains Odland bodies?

B. ***B*** - The layer indicated by **B** is the **stratum granulosum**, which is characterized by the presence of **keratohyalin granules** and **Odland bodies** (lamellar bodies). - **Odland bodies** are crucial for forming the **epidermal water barrier** as they release lipids and enzymes into the intercellular space. *A* - The layer indicated by **A** is the **stratum corneum**, which consists of dead, flattened keratinocytes. - This layer is primarily involved in protection and does not contain Odland bodies, which are found in deeper layers. *C* - The layer indicated by **C** is the **stratum spinosum**, characterized by many **desmosomes** giving a "spiny" appearance. - While cells in this layer are metabolically active and produce keratin, Odland bodies primarily form and are extruded in the stratum granulosum. *D* - The layer indicated by **D** is the **stratum basale** (or stratum germinativum), the deepest layer of the epidermis. - This layer contains **stem cells** that are constantly dividing to replenish the epidermal layers and is also where melanocytes are located; it does not contain Odland bodies.

Q: Which of the following area is marked in the histology of lymph node? (AIIMS May 2017)

Germinal center. ***Germinal center*** - The image illustrates a **germinal center**, characterized by its **lighter staining** and a distinct network of cells (likely follicular dendritic cells) which are responsible for B-cell proliferation and differentiation. - The pointer indicates the surrounding, more basophilic lymphocytes, often seen adjacent to the paler germinal center. *Mantle zone* - The mantle zone surrounds the germinal center and consists of **small, inactive B-lymphocytes** that stain more densely (darker) than the cells within the germinal center. - It would be seen as a darker ring immediately outside the lighter germinal center. *Marginal zone* - The marginal zone is typically found in the **spleen** and is a region of B cells that surrounds the white pulp. - It is not a primary structural component identified within the follicular architecture of a lymph node in the manner depicted. *Paracortical area* - The paracortex is primarily a **T-cell zone**, located between the follicles and the medulla within the lymph node. - It would not exhibit the distinct follicular structure with a light center and surrounding darker cells as shown.

Q: Which one of the following is the myelinating cell of Central Nervous System?

Oligodendrocyte. ***Oligodendrocyte*** - **Oligodendrocytes** are the primary cells responsible for producing and maintaining the **myelin sheath** around axons in the **Central Nervous System (CNS)** [2], [3]. - Each oligodendrocyte can myelinate multiple axons or multiple segments of the same axon [3]. *Astrocyte* - **Astrocytes** are star-shaped glial cells that provide structural and metabolic support to neurons in the CNS [1]. - They are involved in forming the **blood-brain barrier** and regulating the chemical environment around neurons, but they do not produce myelin. *Microglia* - **Microglia** are the resident **immune cells** of the CNS, functioning as macrophages [1]. - They are primarily involved in immune surveillance, phagocytosis of cellular debris and pathogens, and inflammatory responses, not myelination [1]. *Schwann cell* - **Schwann cells** are the myelinating cells of the **Peripheral Nervous System (PNS)** [2], [3]. - Unlike oligodendrocytes, each Schwann cell typically myelinates only a single axon segment [3].

Q: Identify which of the following structure is a sebaceous gland:

2. ***Correct: (2) Sebaceous gland*** - The structure labeled (2) is a **sebaceous gland**, characterized by its **multicellular alveolar structure** typically associated with a hair follicle - Sebaceous glands are **holocrine glands** where the entire cell disintegrates to release sebum (oily secretion) - These glands are found throughout the body except on palms and soles, and produce **sebum for lubrication** of hair and skin - Histologically identified by **grape-like clusters of cells** with foamy cytoplasm due to lipid content *Incorrect: (3) Inner root sheath* - The structure labeled (3) represents the **inner root sheath** of the hair follicle - This is a **structural component**, not a glandular structure - Functions to provide support and guidance to the developing hair shaft - Composed of three layers: Henle's layer, Huxley's layer, and the cuticle *Incorrect: (4) Hair matrix* - The structure labeled (4) indicates the **hair matrix**, located at the base of the hair follicle - This is a **proliferative zone** with actively dividing cells responsible for hair growth - Not a glandular structure, but rather the germinative region where hair cells differentiate - Contains melanocytes that provide pigment to the growing hair *Incorrect: (1) Hair shaft* - The structure labeled (1) is the **hair shaft**, the visible keratinized portion of the hair - This is the **final product** of the hair follicle, composed of dead, keratinized cells - Not a glandular structure, but rather a modified epidermal structure - Extends from the hair follicle through the skin surface

Q: Identify the cell marked in the image below

Mast cell. ***Mast cell*** - The cell indicated by the arrow displays characteristic features of a **mast cell**, including its large size, prominent central nucleus, and cytoplasm densely packed with numerous large, basophilic (darkly stained) granules. - These granules contain powerful inflammatory mediators like **histamine** and **heparin**, which are key in allergic reactions and inflammation. *Macrophage* - Macrophages are typically larger than mast cells with an **irregular shape**, a kidney-shaped nucleus, and often contain phagocytosed material in their cytoplasm, which is not clearly visible here. - While they are also immune cells, they lack the characteristic dense, uniform basophilic granulation seen in the indicated cell. *Plasma cell* - Plasma cells are characterized by an **eccentric nucleus** with **chromatin clumping** (cartwheel or clock-face appearance) and a prominent Golgi apparatus (perinuclear halo), none of which are evident in the marked cell. - Their cytoplasm is typically basophilic but lacks the distinct large granules. *Fibroblast* - Fibroblasts are typically **spindle-shaped** or stellate cells with elongated nuclei and a sparse cytoplasm, responsible for producing extracellular matrix. - They do not possess the abundant, dense cytoplasmic granules that are a hallmark of the cell shown.

Q: Arrange the cells according to their positions from the basal layer towards the lumen in the seminiferous tubules:- 1. Spermatogonia 2. Primary spermatocyte 3. Spermatid 4. Spermatozoa

1,2,3,4. ***1,2,3,4*** - This sequence accurately represents the **developmental progression of male germ cells** from the basal lamina towards the lumen of the seminiferous tubule [1], [2]. - **Spermatogonia** are stem cells located near the basal lamina [1], which then differentiate into **primary spermatocytes**, followed by **spermatids**, and finally maturing into **spermatozoa** that are released into the lumen [2]. *2,1,3,4* - This order is incorrect because **primary spermatocytes** develop from spermatogonia [2], meaning spermatogonia should precede primary spermatocytes in the sequence. - The initial cell in the spermatogenic lineage is the **spermatogonium**, found at the base of the tubule [1]. *1,3,2,4* - This sequence is incorrect as **primary spermatocytes** undergo meiosis to form secondary spermatocytes, which then become spermatids [2]. - Therefore, **spermatids** develop *after* primary spermatocytes, not before them. *4,3,2,1* - This order is a reversal of the actual developmental process and spatial arrangement within the seminiferous tubule. - **Spermatozoa** are the most mature cells and are found closest to the lumen [1], while **spermatogonia** are located at the basal layer [1].

Q: A pathologist examining a tissue sample notes the presence of pseudostratified columnar epithelium with goblet cells and cilia. This tissue was most likely obtained from which of the following locations?

Bronchi. ***Bronchi*** - The **bronchi**, as part of the respiratory tract, are lined with **pseudostratified columnar epithelium** that contains abundant **goblet cells** and **cilia** [1]. - **Cilia** help propel mucus and trapped particles out of the respiratory system, while **goblet cells** produce mucus to trap foreign substances [1]. *Small intestine* - The small intestine is lined with **simple columnar epithelium** with **microvilli** (forming a brush border) and goblet cells, but it lacks **cilia**. - Its primary function is nutrient absorption, not particulate clearance. *Skin* - The skin is covered by **stratified squamous epithelium**, specifically **keratinized stratified squamous epithelium**, which provides protection against abrasion and dehydration. - It does not contain **goblet cells**, **cilia**, or **pseudostratified columnar epithelium**. *Esophagus* - The esophagus is lined with **non-keratinized stratified squamous epithelium**, designed to protect against mechanical abrasion during food passage. - It lacks **goblet cells**, **cilia**, and **pseudostratified columnar epithelium**.

Question 1

The area marked as $X$ is called:

Accepted Answer

Spiral canal of modiolus

Answer

Endolymphatic sac

Answer

Tunnel of Corti

Answer

Scala tympani

Question 2

Which of the following layers has abundance of desmosomes? (AIIMS Nov 2017)

Accepted Answer

C

Answer

A

Answer

B

Answer

D

Question 3

Which of the following layers contains Odland bodies?

Accepted Answer

B

Answer

A

Answer

C

Answer

D

Question 4

Which of the following area is marked in the histology of lymph node? (AIIMS May 2017)

Accepted Answer

Germinal center

Answer

Mantle zone

Answer

Marginal zone

Answer

Paracortical area

Question 5

Which one of the following is the myelinating cell of Central Nervous System?

Accepted Answer

Oligodendrocyte

Answer

Astrocyte

Answer

Microglia

Answer

Schwann cell

Question 6

Identify the structures labeled A, B, C, and D in the given histological section of skin

Accepted Answer

A: Sebaceous gland; B: Arrector pili muscle; C: Apocrine gland; D: Eccrine gland

Answer

A: Eccrine gland; B: Arrector pili muscle; C: Sebaceous gland; D: Apocrine gland

Answer

A: Sebaceous gland; B: Apocrine gland; C: Eccrine gland; D: Arrector pili muscle

Answer

A: Apocrine gland; B: Eccrine gland; C: Sebaceous gland; D: Arrector pili muscle

Question 7

Identify which of the following structure is a sebaceous gland:

Accepted Answer

2

Answer

3

Answer

4

Answer

1

Question 8

Identify the cell marked in the image below

Accepted Answer

Mast cell

Answer

Macrophage

Answer

Plasma cell

Answer

Fibroblast

Question 9

Arrange the cells according to their positions from the basal layer towards the lumen in the seminiferous tubules:-

1. Spermatogonia
2. Primary spermatocyte
3. Spermatid
4. Spermatozoa

Accepted Answer

1,2,3,4

Answer

2,1,3,4

Answer

1,3,2,4

Answer

4,3,2,1

Question 10

A pathologist examining a tissue sample notes the presence of pseudostratified columnar epithelium with goblet cells and cilia. This tissue was most likely obtained from which of the following locations?

Accepted Answer

Bronchi

Answer

Small intestine

Answer

Skin

Answer

Esophagus

Answer

Urinary bladder

Histology — MCQs

Histology — MCQs

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