Chapter: Histology & Embryology; Topic: Thymus; Subtopic: Structure and Development
Keyword Definitions:
Thymus: Primary lymphoid organ responsible for T-cell maturation.
Cortex: Outer region of thymic lobules densely packed with immature T-lymphocytes.
Medulla: Inner region containing mature T-cells and characteristic Hassall’s corpuscles.
Hassall’s Corpuscles: Eosinophilic, concentric epithelial structures found only in thymic medulla.
Pharyngeal Pouches: Endodermal outpouchings forming several endocrine and lymphoid organs; thymus arises from 3rd pouch.
1) Lead Question – 2016
All of the following are true about thymus except?
A) The cortical portion is mainly composed of lymphocytes
B) The medulla contains Hassall's Corpuscles
C) It is derived from the fourth Pharyngeal pouch
D) It undergoes atrophy puberty onwards
Answer: C) It is derived from the fourth Pharyngeal pouch
Explanation: The thymus plays a critical role in T-cell maturation. The cortex contains densely packed immature lymphocytes, and the medulla contains Hassall’s corpuscles, both of which are correct statements. The thymus undergoes physiological involution beginning at puberty, another true statement. However, embryologically, the thymus develops from the third pharyngeal pouch (ventral wing), not the fourth pouch. Hence, option C is false and therefore the correct answer. Understanding thymic microanatomy and development is essential for appreciating immunodeficiencies and congenital anomalies such as DiGeorge syndrome.
2) The thymus is primarily responsible for maturation of–
A) B-lymphocytes
B) Plasma cells
C) T-lymphocytes
D) NK cells
Answer: C) T-lymphocytes
Explanation: The thymus is the central lymphoid organ for T-cell maturation. B-cells mature in bone marrow. Thus, C is correct.
3) Hassall’s corpuscles are composed of–
A) Degenerating lymphocytes
B) Concentric epithelial cells
C) Fibroblasts
D) Reticular fibers
Answer: B) Concentric epithelial cells
Explanation: These eosinophilic medullary structures consist of keratinized epithelial cells. Thus, B is correct.
4) In DiGeorge syndrome, thymic aplasia results from failure of development of–
A) 1st pouch
B) 2nd pouch
C) 3rd and 4th pouches
D) 2nd and 3rd pouches
Answer: C) 3rd and 4th pouches
Explanation: Thymus (3rd pouch) and parathyroids (3rd & 4th) fail to develop in DiGeorge. Thus, C is correct.
5) Which cell type is responsible for positive selection of T-cells?
A) Dendritic cells
B) Macrophages
C) Thymic epithelial cells
D) Endothelial cells
Answer: C) Thymic epithelial cells
Explanation: Cortical thymic epithelial cells conduct positive selection by testing MHC recognition. Thus, C is correct.
6) A newborn with recurrent infections shows profound T-cell deficiency. The most likely organ affected is–
A) Spleen
B) Thymus
C) Liver
D) Bone marrow
Answer: B) Thymus
Explanation: Absent or defective thymus leads to T-cell deficiency, producing severe immunodeficiency. Thus, B is correct.
7) Thymus differs from lymph nodes because it lacks–
A) Cortex
B) Medulla
C) Afferent lymphatics
D) Efferent lymphatics
Answer: C) Afferent lymphatics
Explanation: Thymus contains no afferent lymphatics, distinguishing it from lymph nodes. Thus, C is correct.
8) Thymic epithelial cells arise from which germ layer?
A) Endoderm
B) Mesoderm
C) Ectoderm
D) Neural crest
Answer: A) Endoderm
Explanation: Thymic epithelium derives from endoderm of the 3rd pharyngeal pouch. Thus, A is correct.
9) Which hormone is secreted by the thymus to aid T-cell development?
A) Thymosin
B) Renin
C) Calcitonin
D) Glucagon
Answer: A) Thymosin
Explanation: Thymosin supports T-cell differentiation. Other options are unrelated. Thus, A is correct.
10) The blood-thymus barrier is found in which region?
A) Medulla
B) Cortex
C) Capsule
D) Septa
Answer: B) Cortex
Explanation: The barrier protects developing T-cells in the cortex from antigen exposure. Thus, B is correct.
11) Age-related thymic involution results in replacement by–
A) Smooth muscle
B) Bone marrow
C) Adipose tissue
D) Hyaline cartilage
Answer: C) Adipose tissue
Explanation: Thymus undergoes fatty replacement after puberty. Thus, C is correct.
Chapter: Histology; Topic: Gastrointestinal Tract; Subtopic: Enteric Nervous System (Auerbach’s & Meissner’s Plexus)
Keyword Definitions:
Auerbach’s (Myenteric) Plexus: Neural plexus located between circular and longitudinal muscle layers; controls GI motility.
Meissner’s Plexus: Submucosal plexus controlling glandular secretion and local blood flow.
Enteric Nervous System: Intrinsic autonomic system regulating gastrointestinal functions independent of CNS input.
GI Motility: Coordinated contraction of smooth muscle mediated largely by myenteric plexus.
Muscularis Externa: GI layer containing inner circular and outer longitudinal muscle layers with Auerbach’s plexus between them.
1) Lead Question – 2016
Auerbach’s plexus is present in the–
A) Colon
B) Esophagus
C) Stomach
D) All of the above
Answer: D) All of the above
Explanation: Auerbach’s plexus (myenteric plexus) is present throughout the entire gastrointestinal tract, extending from the esophagus to the anal canal. It is located between the circular and longitudinal muscle layers of the muscularis externa. Its primary function is to regulate peristalsis and coordinated smooth muscle contraction. Because it is found in the esophagus, stomach, small intestine, and colon, the correct answer is D. Damage to this plexus, as in achalasia, significantly affects GI motility.
2) Auerbach’s plexus is located between–
A) Mucosa and submucosa
B) Serosa and adventitia
C) Circular and longitudinal muscle layers
D) Muscularis mucosae and mucosa
Answer: C) Circular and longitudinal muscle layers
Explanation: The myenteric plexus lies between the two layers of muscularis externa. Thus, C is correct.
3) Destruction of Auerbach’s plexus is characteristic of–
A) Hirschsprung disease
B) Achalasia
C) Crohn disease
D) Peptic ulcer
Answer: B) Achalasia
Explanation: Achalasia involves degeneration of myenteric plexus in esophagus, impairing peristalsis and LES relaxation. Thus, B is correct.
4) Which plexus primarily controls glandular secretion in GI tract?
A) Auerbach’s plexus
B) Meissner’s plexus
C) Subserosal plexus
D) Muscular plexus
Answer: B) Meissner’s plexus
Explanation: Meissner’s plexus lies in submucosa and regulates secretions and local blood flow. Thus, B is correct.
5) A patient with congenital aganglionic colon lacks which structure?
A) Only Meissner’s plexus
B) Only Auerbach’s plexus
C) Both Auerbach’s and Meissner’s plexus
D) Only vagal fibers
Answer: C) Both Auerbach’s and Meissner’s plexus
Explanation: Hirschsprung disease involves absence of both plexuses due to neural crest migration failure. Thus, C is correct.
6) Stomach motility is impaired in a lesion of–
A) Myenteric plexus
B) Submucosal plexus
C) Gastric glands
D) Parietal cells
Answer: A) Myenteric plexus
Explanation: Myenteric plexus orchestrates stomach peristalsis; damage reduces motility. Thus, A is correct.
7) Myenteric plexus receives input from which nerve?
A) Phrenic nerve
B) Vagus nerve
C) Accessory nerve
D) Facial nerve
Answer: B) Vagus nerve
Explanation: Parasympathetic innervation from the vagus enhances GI motility via myenteric plexus. Thus, B is correct.
8) Interstitial cells of Cajal serve as–
A) Immune cells
B) Pacemaker cells
C) Hormone-secreting cells
D) Fibroblasts
Answer: B) Pacemaker cells
Explanation: ICC generate slow waves regulating GI motility and interact with Auerbach’s plexus. Thus, B is correct.
9) In which layer of GI wall are Meissner’s and Auerbach’s plexuses respectively located?
A) Submucosa; muscularis externa
B) Muscularis mucosae; mucosa
C) Serosa; mucosa
D) Adventitia; submucosa
Answer: A) Submucosa; muscularis externa
Explanation: Meissner’s in submucosa, Auerbach’s between muscle layers. Thus, A is correct.
10) A man with long-standing achalasia shows dilation of esophagus. The underlying cause is loss of–
A) Parietal cells
B) Myenteric ganglion cells
C) Endocrine cells
D) Basal cells
Answer: B) Myenteric ganglion cells
Explanation: Loss of Auerbach’s plexus causes aperistalsis and dilation. Thus, B is correct.
11) Which GI segment has skeletal muscle but still contains Auerbach’s plexus?
A) Upper esophagus
B) Jejunum
C) Appendix
D) Rectum
Answer: A) Upper esophagus
Explanation: Upper esophagus contains skeletal muscle but retains enteric plexuses including Auerbach’s. Thus, A is correct.
Chapter: Histology; Topic: Gastrointestinal Tract; Subtopic: Esophageal Wall Layers
Keyword Definitions:
Mucosa: Innermost layer consisting of epithelium, lamina propria, and muscularis mucosae.
Muscularis Propria: Major smooth muscle layer responsible for peristalsis.
Adventitia: Outer connective tissue covering of structures not enclosed by peritoneum.
Serosa: Outer serous membrane present only in intraperitoneal organs; absent in thoracic esophagus.
Submucosa: Dense connective tissue containing glands, vessels, and Meissner’s plexus.
1) Lead Question – 2016
Which of the following layer is absent in the esophagus?
A) Adventitia
B) Serosa
C) Muscularis propria
D) Mucosa
Answer: B) Serosa
Explanation: The esophagus is primarily a retroperitoneal and thoracic structure; hence it lacks a serosa and is instead covered by adventitia. The mucosa with its stratified squamous epithelium, the muscularis propria with skeletal and smooth muscle components, and the submucosa with esophageal glands are all present. Only the abdominal portion has a partial serosal covering, but histologically the esophagus is considered to lack a true serosa. Therefore, the correct answer is B. This distinction is clinically important in understanding esophageal mobility, spread of infections, and surgical considerations.
2) The esophageal epithelium is classified as–
A) Simple columnar
B) Stratified squamous non-keratinized
C) Stratified cuboidal
D) Pseudostratified columnar
Answer: B) Stratified squamous non-keratinized
Explanation: The esophagus requires protection from mechanical injury during swallowing; hence it is lined by non-keratinized stratified squamous epithelium. This differentiates it sharply from the stomach, which has simple columnar epithelium. Therefore, B is correct.
3) Esophageal glands proper are located in the–
A) Mucosa
B) Muscularis propria
C) Submucosa
D) Serosa
Answer: C) Submucosa
Explanation: The submucosa of the esophagus contains mucous glands responsible for lubrication of the lumen. The mucosa itself has only small cardiac glands near the gastroesophageal junction. Thus, C is correct.
4) The transition from skeletal to smooth muscle in esophagus occurs at approximately–
A) Upper third
B) Middle third
C) Lower third
D) GE junction only
Answer: B) Middle third
Explanation: The upper third contains skeletal muscle, middle third mixed muscle, and lower third smooth muscle. Thus, B is correct.
5) A patient with severe GERD shows metaplasia of esophageal epithelium to–
A) Keratinized squamous
B) Simple cuboidal
C) Columnar with goblet cells
D) Transitional epithelium
Answer: C) Columnar with goblet cells
Explanation: Barrett’s esophagus is characterized by intestinal metaplasia with goblet cells. Thus, C is correct.
6) The esophagus differs from the rest of the GI tract by presence of–
A) Meissner’s plexus
B) Auerbach’s plexus
C) Skeletal muscle
D) Serosa
Answer: C) Skeletal muscle
Explanation: Upper esophagus uniquely contains skeletal muscle. Thus, C is correct.
7) A lesion compressing the esophagus in the posterior mediastinum will most affect which wall layer first?
A) Serosa
B) Adventitia
C) Mucosa
D) Submucosa
Answer: B) Adventitia
Explanation: Because esophagus lacks serosa, external compression acts directly on adventitia. Thus, B is correct.
8) Which nerve plexus is responsible for peristalsis in esophagus?
A) Meissner’s
B) Auerbach’s
C) Sympathetic chain
D) Phrenic nerve
Answer: B) Auerbach’s
Explanation: Myenteric (Auerbach’s) plexus controls motility in all GI segments. Thus, B is correct.
9) In achalasia, which layer of esophagus is primarily affected?
A) Mucosa
B) Submucosa
C) Muscularis propria
D) Adventitia
Answer: C) Muscularis propria
Explanation: Loss of myenteric neurons affects muscularis propria, impairing LES relaxation. Thus, C is correct.
10) Which part of esophagus has a serosal covering?
A) Cervical part
B) Thoracic part
C) Abdominal part
D) Entire esophagus
Answer: C) Abdominal part
Explanation: Only the short abdominal segment has peritoneal covering. Thus, C is correct.
11) A biopsy from esophagus reveals thickened muscularis mucosae. This layer lies between–
A) Epithelium and lamina propria
B) Lamina propria and submucosa
C) Submucosa and muscularis propria
D) Muscularis propria and adventitia
Answer: B) Lamina propria and submucosa
Explanation: Muscularis mucosae marks the boundary between mucosa and submucosa. Thus, B is correct.
Chapter: Histology; Topic: Connective Tissues; Subtopic: Cartilage Types and Distribution
Keyword Definitions:
Hyaline Cartilage: Most abundant cartilage; found in nose, trachea, bronchi, articular surfaces.
Elastic Cartilage: Cartilage rich in elastic fibers; found in pinna, epiglottis.
Fibrocartilage: Strongest cartilage; found in intervertebral discs and pubic symphysis.
Chondrocytes: Cartilage cells residing in lacunae producing matrix.
Cartilage Matrix: Extracellular material rich in type II collagen and proteoglycans.
1) Lead Question – 2016
Which is the most abundant cartilage–
A) Hyaline cartilage
B) Elastic cartilage
C) Fibrocartilage
D) None
Answer: A) Hyaline cartilage
Explanation: Hyaline cartilage is the most abundant type of cartilage in the human body. It forms the fetal skeleton, costal cartilages, articular surfaces, nasal cartilages, and supportive framework for respiratory passages. Its matrix contains type II collagen and high water content, allowing smooth movement and shock absorption. Elastic cartilage is less common and limited to flexible structures like pinna and epiglottis; fibrocartilage appears only where strength and resistance to compression are needed. Therefore, option A is correct.
2) Hyaline cartilage primarily contains which collagen type?
A) Type I
B) Type II
C) Type III
D) Type IV
Answer: B) Type II
Explanation: Hyaline cartilage matrix is dominated by type II collagen, giving it its glassy appearance and resilience. Thus, B is correct.
3) A patient with a fractured tracheal ring shows damage to which cartilage?
A) Elastic
B) Hyaline
C) Fibrocartilage
D) Calcified cartilage
Answer: B) Hyaline
Explanation: Tracheal rings are composed of hyaline cartilage, enabling airway patency. Thus, B is correct.
4) Elastic cartilage is found in which structure?
A) Articular surfaces
B) Epiglottis
C) Costal cartilage
D) Trachea
Answer: B) Epiglottis
Explanation: Epiglottis requires flexibility and contains elastic cartilage. Thus, B is correct.
5) Fibrocartilage is present in–
A) External ear
B) Nasal septum
C) Intervertebral discs
D) Laryngeal cartilages
Answer: C) Intervertebral discs
Explanation: Fibrocartilage provides tensile strength in intervertebral discs and pubic symphysis. Thus, C is correct.
6) Articular cartilage lacks–
A) Blood vessels
B) Chondrocytes
C) Matrix
D) Type II collagen
Answer: A) Blood vessels
Explanation: Articular cartilage is avascular; nutrients diffuse through synovial fluid. Thus, A is correct.
7) A child with laryngomalacia has weakness of which cartilage?
A) Elastic
B) Hyaline
C) Fibrocartilage
D) Bone cartilage
Answer: A) Elastic
Explanation: Epiglottis and arytenoid cartilages contain elastic cartilage; laxity causes laryngomalacia. Thus, A is correct.
8) Fibrocartilage differs from hyaline cartilage because it contains–
A) Type II collagen only
B) Type I collagen
C) No collagen
D) Elastic fibers
Answer: B) Type I collagen
Explanation: Fibrocartilage has abundant type I collagen for tensile strength. Thus, B is correct.
9) The perichondrium is absent in–
A) Nasal cartilage
B) Costal cartilage
C) Articular cartilage
D) Epiglottis
Answer: C) Articular cartilage
Explanation: Articular cartilage lacks perichondrium to allow smooth joint movement. Thus, C is correct.
10) Cartilage grows by which mechanism?
A) Interstitial growth
B) Appositional growth
C) Both interstitial and appositional growth
D) No growth after birth
Answer: C) Both interstitial and appositional growth
Explanation: Cartilage expands internally (interstitial) and from perichondrium (appositional). Thus, C is correct.
11) A meniscal tear involves which cartilage type?
A) Hyaline
B) Fibrocartilage
C) Elastic
D) Calcified cartilage
Answer: B) Fibrocartilage
Explanation: Knee menisci contain fibrocartilage, making B correct.
Chapter: Histology & GI Anatomy; Topic: Large Intestine; Subtopic: Colonic Wall Specializations
Keyword Definitions:
Haustrations: Sacculations of colon formed by tonic contractions of teniae coli.
Teniae Coli: Three longitudinal muscle bands present only in colon.
Plicae Circulares: Circular folds found in jejunum > ileum; absent in colon.
Colonic Crypts: Straight tubular glands containing numerous goblet cells.
Colonic Motility: Segmental contractions generating haustral patterns.
1) Lead Question – 2016
Haustrations are present in–
A) Duodenum
B) Ileum
C) Jejunum
D) Colon
Answer: D) Colon
Explanation: Haustrations are sacculations formed by the segmentation of the colon due to the presence of teniae coli—longitudinal muscle bands unique to the large intestine. These features are absent in the small intestine, where plicae circulares dominate, especially in the jejunum. The colon lacks villi and has hallmark haustra that help in water absorption and fecal storage. Therefore, the correct answer is D. Recognizing haustra helps differentiate colon from small intestine on radiological and anatomical examinations.
2) Teniae coli are present in which organ?
A) Jejunum
B) Ileum
C) Colon
D) Duodenum
Answer: C) Colon
Explanation: Teniae coli are exclusive to the colon and responsible for forming haustrations. Thus, C is correct.
3) Plicae circulares are most prominent in the–
A) Colon
B) Duodenum
C) Jejunum
D) Appendix
Answer: C) Jejunum
Explanation: Jejunum has the tallest and most numerous plicae circulares aiding absorption. Thus, C is correct.
4) A CT scan shows haustral markings; this indicates the patient’s sample is from–
A) Ileum
B) Colon
C) Duodenum
D) Stomach
Answer: B) Colon
Explanation: Haustral folds on imaging are specific to colon. Thus, B is correct.
5) Goblet cells are most numerous in the–
A) Jejunum
B) Ileum
C) Colon
D) Duodenum
Answer: C) Colon
Explanation: Colon contains the maximum goblet cells for lubrication of feces. Thus, C is correct.
6) Which of the following lacks villi?
A) Jejunum
B) Ileum
C) Duodenum
D) Colon
Answer: D) Colon
Explanation: Colon has no villi, only crypts. Thus, D is correct.
7) Appendices epiploicae are characteristic of–
A) Duodenum
B) Jejunum
C) Ileum
D) Colon
Answer: D) Colon
Explanation: Fat-filled epiploic appendages are exclusive to colon. Thus, D is correct.
8) Colonic mucosa contains abundant–
A) Paneth cells
B) Chief cells
C) Goblet cells
D) Parietal cells
Answer: C) Goblet cells
Explanation: Goblet cells increase distally in colon. Thus, C is correct.
9) A patient with chronic constipation has reduced segmental contractions. The affected structure is–
A) Plicae circulares
B) Teniae coli
C) Brunner's glands
D) Peyer’s patches
Answer: B) Teniae coli
Explanation: Teniae coli generate haustral contractions; dysfunction reduces motility. Thus, B is correct.
10) The major function of haustrations is–
A) Enzyme secretion
B) Absorption of fats
C) Mixing and slow propulsion
D) Protein digestion
Answer: C) Mixing and slow propulsion
Explanation: Haustrations aid in segmental mixing and water absorption. Thus, C is correct.
11) Colonic identification on histology is confirmed by–
A) Presence of villi
B) Tall plicae
C) Straight tubular crypts
D) Teniae coli inside mucosa
Answer: C) Straight tubular crypts
Explanation: Colon has numerous straight crypts without villi. Thus, C is correct.
Chapter: Histology; Topic: Exocrine Glands; Subtopic: Lacrimal Gland Structure
Keyword Definitions:
Lacrimal Gland: A serous, tubuloacinar gland producing tears.
Serous Cells: Pyramidal secretory cells with round basal nuclei and apical secretory granules.
Acini/Alveoli: Secretory units lined by serous pyramidal cells arranged around a lumen.
Myoepithelial Cells: Contractile cells lying between basement membrane and secretory cells, aiding secretion.
Duct System: Intercalated and striated ducts conducting lacrimal secretion to ocular surface.
1) Lead Question – 2016
What is the lining of the lacrimal gland alveoli?
A) Ciliated columnar cells
B) Pyramidal cells
C) Non-keratinizing squamous epithelium
D) None
Answer: B) Pyramidal cells
Explanation: Lacrimal glands are serous tubuloacinar glands whose secretory alveoli are lined by serous pyramidal cells. These cells have a basally located round nucleus, abundant rough endoplasmic reticulum, and apically stored secretory granules. They secrete the watery component of tears. Ciliated columnar epithelium lines respiratory structures, not lacrimal alveoli. Squamous epithelium is not found in lacrimal glands. Therefore, option B is correct. Recognizing serous pyramidal cells helps identify lacrimal gland histology and differentiate it from mixed glands like salivary glands.
2) Lacrimal gland secretion is primarily–
A) Mucous
B) Serous
C) Mixed
D) Keratinous
Answer: B) Serous
Explanation: Lacrimal gland is purely serous, producing watery tears with lysozyme and IgA. Thus, B is correct.
3) Which nerve provides parasympathetic supply to lacrimal gland?
A) Glossopharyngeal nerve
B) Facial nerve
C) Trigeminal nerve
D) Vagus nerve
Answer: B) Facial nerve
Explanation: Parasympathetic fibers arise from facial nerve via greater petrosal nerve. Thus, B is correct.
4) Myoepithelial cells in lacrimal glands lie between–
A) Duct epithelium and lumen
B) Basement membrane and secretory cells
C) Stroma and ducts
D) Lumen and stroma
Answer: B) Basement membrane and secretory cells
Explanation: Myoepithelial cells assist secretion by contracting around acini. Thus, B is correct.
5) A patient with Sjögren syndrome typically shows–
A) Destruction of lacrimal gland acini
B) Hyperplasia of lacrimal ducts
C) Increase in mucus secretion
D) Normal tear secretion
Answer: A) Destruction of lacrimal gland acini
Explanation: Autoimmune attack destroys serous acini causing dry eyes. Thus, A is correct.
6) The lacrimal gland resembles which salivary gland histologically?
A) Sublingual
B) Submandibular
C) Parotid
D) Von Ebner's glands
Answer: C) Parotid
Explanation: Both parotid and lacrimal glands are purely serous with similar acini. Thus, C is correct.
7) Which Ig is predominantly secreted in lacrimal fluid?
A) IgE
B) IgA
C) IgM
D) IgD
Answer: B) IgA
Explanation: IgA provides mucosal immunity in tears. Thus, B is correct.
8) Tear fluid drains first into which structure?
A) Nasolacrimal duct
B) Lacrimal sac
C) Canaliculi
D) Puncta
Answer: D) Puncta
Explanation: Tears enter puncta before canaliculi and lacrimal sac. Thus, D is correct.
9) Serous cells contain abundant–
A) Mucin granules
B) Zymogen granules
C) Lipid droplets
D) Keratohyalin granules
Answer: B) Zymogen granules
Explanation: Serous cells store protein-rich secretory granules. Thus, B is correct.
10) Lacrimal gland acini are surrounded by–
A) Dense irregular connective tissue
B) Smooth muscle bundles
C) Myoepithelial cells
D) Stratified squamous epithelium
Answer: C) Myoepithelial cells
Explanation: Myoepithelial cells facilitate tear secretion. Thus, C is correct.
11) Which duct drains lacrimal gland secretions into conjunctival sac?
A) Interlobular duct
B) Striated duct
C) Excretory duct
D) Collecting duct
Answer: C) Excretory duct
Explanation: Lacrimal gland excretory ducts open into superior fornix of conjunctiva. Thus, C is correct.
Chapter: Upper Limb Anatomy; Topic: Intrinsic Muscles of the Hand; Subtopic: Lumbricals (Structure & Function)
Keyword Definitions:
Lumbricals: Intrinsic hand muscles arising from FDP tendons and inserting into extensor expansions.
Unipennate Muscle: Fibers attach to one side of a tendon.
Bipennate Muscle: Fibers attach to both sides of a central tendon.
Multipennate Muscle: Muscle with multiple feather-like fascicles converging onto several tendons.
Extensor Expansion: Triangular aponeurosis on the dorsum of fingers receiving lumbrical insertion.
1) Lead Question – 2016
What type of muscles are medial two lumbricals?
A) Unipennate
B) Bipennate
C) Multipennate
D) None
Answer: B) Bipennate
Explanation: The medial two lumbricals (3rd and 4th) of the hand are bipennate muscles. They arise from the adjacent sides of the tendons of the flexor digitorum profundus, giving them a two-headed or bipennate configuration. In contrast, the lateral two lumbricals (1st and 2nd) are unipennate. These muscles flex the metacarpophalangeal joints and extend the interphalangeal joints via the extensor expansion. Recognizing their pennation is important for understanding their strength, function, and involvement in neuropathies such as ulnar nerve palsy, which impairs medial lumbricals.
2) The medial two lumbricals are supplied by–
A) Median nerve
B) Ulnar nerve
C) Radial nerve
D) Musculocutaneous nerve
Answer: B) Ulnar nerve
Explanation: The medial lumbricals (3rd & 4th) receive innervation from the deep branch of the ulnar nerve, unlike the lateral lumbricals supplied by the median nerve. Thus, B is correct.
3) Lumbricals produce which combined action?
A) Flex MCP & Flex IP
B) Extend MCP & Flex IP
C) Flex MCP & Extend IP
D) Extend MCP & Extend IP
Answer: C) Flex MCP & Extend IP
Explanation: Lumbricals flex the metacarpophalangeal joints and extend the interphalangeal joints via the extensor expansion. Thus, C is correct.
4) In ulnar nerve palsy, which lumbricals lose function?
A) 1st & 2nd
B) 2nd & 3rd
C) 3rd & 4th
D) All
Answer: C) 3rd & 4th
Explanation: The ulnar nerve supplies medial lumbricals; their paralysis contributes to clawing. Thus, C is correct.
5) Lumbricals originate from which structure?
A) Flexor digitorum superficialis tendons
B) Flexor digitorum profundus tendons
C) Interossei tendons
D) Extensor digitorum tendons
Answer: B) Flexor digitorum profundus tendons
Explanation: All lumbricals arise from FDP tendons; medial lumbricals arise from adjacent tendons. Thus, B is correct.
6) A patient presents with difficulty extending IP joints of ring and little fingers. This suggests dysfunction of–
A) Lateral lumbricals
B) Medial lumbricals
C) Palmar interossei
D) Dorsal interossei
Answer: B) Medial lumbricals
Explanation: Medial lumbricals extend IP joints of digits 4 and 5. Thus, B is correct.
7) Lumbricals insert into–
A) Base of proximal phalanx
B) FDP tendon
C) Extensor expansion
D) Metacarpal head
Answer: C) Extensor expansion
Explanation: Their insertion into the extensor expansion allows extension of IP joints. Thus, C is correct.
8) Which muscle group assists lumbricals in IP extension?
A) Interossei
B) Thenar muscles
C) Hypothenar muscles
D) Brachioradialis
Answer: A) Interossei
Explanation: Interossei and lumbricals act synergistically to extend IP joints. Thus, A is correct.
9) Bipennate muscles typically provide–
A) More force
B) Less force
C) No mechanical advantage
D) Only precision movement
Answer: A) More force
Explanation: Bipennate arrangement increases physiological cross-sectional area, enhancing force production. Thus, A is correct.
10) Which lumbricals are unipennate?
A) 1st & 2nd
B) 2nd & 3rd
C) 3rd & 4th
D) All four
Answer: A) 1st & 2nd
Explanation: Lateral lumbricals are unipennate and median-nerve–supplied. Thus, A is correct.
11) A hand injury damaging FDP tendons to digits 4 & 5 will affect which lumbricals most?
A) 1st & 2nd
B) 2nd & 3rd
C) 3rd & 4th
D) All
Answer: C) 3rd & 4th
Explanation: Since lumbricals originate from FDP tendons, injury to FDP of digits 4–5 impairs the medial two lumbricals. Thus, C is correct.
Chapter: Histology; Topic: Renal Tubule System; Subtopic: Loop of Henle (Ansa Nephroni)
Keyword Definitions:
Ansa Nephroni (Loop of Henle): U-shaped part of nephron consisting of descending limb, thin limb, and thick ascending limb.
Thin Limb Epithelium: Simple squamous epithelium allowing passive water movement.
Thick Ascending Limb: Cuboidal to low columnar epithelium performing active ion transport.
Juxtamedullary Nephron: Nephrons with long loops of Henle contributing to urine concentration.
Countercurrent Mechanism: Passive and active transport system enhancing medullary osmotic gradient.
1) Lead Question – 2016
Ansa nephroni is lined by?
A) Columnar
B) Squamous epithelium
C) Cuboidal and columnar epithelium
D) Stratified squamous epithelium
Answer: C) Cuboidal and columnar epithelium
Explanation: The Loop of Henle (Ansa nephroni) has different epithelial linings depending on the segment. The thin descending and thin ascending limbs are lined by simple squamous epithelium, facilitating passive movement of water and solutes. However, the thick ascending limb—an essential component of Ansa nephroni—is lined by simple cuboidal to low columnar epithelium responsible for active Na⁺/K⁺/Cl⁻ transport. Because the thick segment is the functional component emphasized in exam questions, the best answer is option C, representing the cuboidal/columnar lining of the thick limb.
2) The thin descending limb of Loop of Henle is highly permeable to–
A) Sodium
B) Water
C) Urea
D) Glucose
Answer: B) Water
Explanation: Simple squamous epithelium of thin descending limb allows passive water movement, concentrating tubular fluid. Thus, B is correct.
3) The thick ascending limb is impermeable to–
A) Sodium
B) Potassium
C) Water
D) Chloride
Answer: C) Water
Explanation: The thick ascending limb actively reabsorbs ions but is water-impermeable, crucial for countercurrent multiplication. Thus, C is correct.
4) Which transporter is characteristic of thick ascending limb?
A) Na⁺/Cl⁻ cotransporter
B) NKCC2 transporter
C) Aquaporin-2
D) ENaC channels
Answer: B) NKCC2 transporter
Explanation: NKCC2 is responsible for Na⁺/K⁺/2Cl⁻ reabsorption in thick ascending limb. Thus, B is correct.
5) A patient taking loop diuretics has blockade of which nephron segment?
A) Proximal tubule
B) Thin descending limb
C) Thick ascending limb
D) Collecting duct
Answer: C) Thick ascending limb
Explanation: Loop diuretics inhibit NKCC2 transporter in thick ascending limb. Thus, C is correct.
6) Which epithelium lines the proximal convoluted tubule?
A) Simple squamous
B) Simple cuboidal with brush border
C) Stratified columnar
D) Transitional epithelium
Answer: B) Simple cuboidal with brush border
Explanation: PCT has dense microvilli for reabsorption. Thus, B is correct.
7) Medullary osmotic gradient is primarily generated by–
A) PCT
B) Loop of Henle
C) Collecting duct
D) Renal corpuscle
Answer: B) Loop of Henle
Explanation: Countercurrent multiplier in Loop of Henle generates gradient. Thus, B is correct.
8) Vasa recta capillaries run parallel to–
A) PCT
B) DCT
C) Loop of Henle
D) Collecting duct
Answer: C) Loop of Henle
Explanation: Vasa recta maintain medullary osmotic gradient by countercurrent exchange. Thus, C is correct.
9) The longest loop of Henle is found in–
A) Cortical nephrons
B) Juxtamedullary nephrons
C) Medullary rays
D) Renal sinus
Answer: B) Juxtamedullary nephrons
Explanation: These nephrons create concentrated urine. Thus, B is correct.
10) Which part of nephron has macula densa?
A) PCT
B) Thick ascending limb
C) Thin descending limb
D) Bowman’s capsule
Answer: B) Thick ascending limb
Explanation: Macula densa detects NaCl concentration and regulates GFR. Thus, B is correct.
11) A biopsy shows simple squamous epithelium in nephron. This is most likely–
A) PCT
B) Thick ascending limb
C) Thin limb of Loop of Henle
D) Collecting duct
Answer: C) Thin limb of Loop of Henle
Explanation: Thin limbs are lined by simple squamous cells for passive exchange. Thus, C is correct.
Chapter: Upper Limb Anatomy; Topic: Development of Hand; Subtopic: Ossification of Carpal Bones
Keyword Definitions:
Carpal Bones: Eight small bones of the wrist arranged in proximal and distal rows.
Ossification Centers: Sites where bone tissue begins to develop; carpal bones ossify postnatally.
Capitate & Hamate: First carpal bones to ossify, appearing in the first year of life.
Carpal Ossification Sequence: A predictable pattern used clinically to assess bone age.
Bone Age Assessment: Radiographic evaluation comparing ossification with chronological standards.
1) Lead Question – 2016
Four carpal bones are present at what age?
A) 3 years
B) 4 years
C) 5 years
D) 6 years
Answer: A) 3 years
Explanation: Carpal bones ossify in a specific chronological sequence. Capitate and hamate appear first within the first year of life. By 2–3 years of age, two additional carpal bones typically ossify, bringing the total to four. Radiological evaluation of wrist ossification assists in assessing delayed growth or endocrine abnormalities. By this standard timeline, four ossified carpal bones are present at approximately 3 years of age, making option A the correct answer. Understanding carpal bone ossification is crucial for pediatric age estimation and orthopedic assessments.
2) Which carpal bone ossifies first?
A) Pisiform
B) Hamate
C) Capitate
D) Scaphoid
Answer: C) Capitate
Explanation: Capitate ossifies first, followed closely by hamate, both within the first year. Thus, C is correct.
3) The last carpal bone to ossify is–
A) Triquetrum
B) Pisiform
C) Lunate
D) Trapezium
Answer: B) Pisiform
Explanation: Pisiform ossifies around 9–12 years, making it the last carpal bone. Thus, B is correct.
4) A 1-year-old child's wrist x-ray commonly shows which carpal bones?
A) Capitate & hamate
B) Scaphoid & lunate
C) Trapezoid only
D) Triquetrum only
Answer: A) Capitate & hamate
Explanation: These two bones ossify first. Thus, A is correct.
5) In a 5-year-old child, the number of ossified carpal bones expected is–
A) 2
B) 4
C) 6
D) 8
Answer: C) 6
Explanation: By 5 years, about six carpal bones appear radiographically. Thus, C is correct.
6) Carpal ossification helps diagnose–
A) Diabetes mellitus
B) Growth delay
C) Pneumonia
D) Appendicitis
Answer: B) Growth delay
Explanation: Bone age assessment via carpal ossification is essential in endocrinology. Thus, B is correct.
7) Pisiform is considered a–
A) Long bone
B) Sesamoid bone
C) Flat bone
D) Irregular bone
Answer: B) Sesamoid bone
Explanation: Pisiform is a sesamoid bone within flexor carpi ulnaris tendon. Thus, B is correct.
8) Scaphoid receives blood supply mainly from–
A) Volar vessels
B) Dorsal carpal branch
C) Ulnar artery
D) Radial recurrent artery
Answer: B) Dorsal carpal branch
Explanation: Scaphoid vascularity is predominantly dorsal, explaining AVN risk. Thus, B is correct.
9) A triquetral fracture is commonly detected by–
A) MRI
B) Lateral wrist x-ray
C) Ultrasound
D) AP wrist x-ray
Answer: B) Lateral wrist x-ray
Explanation: Triquetral fractures show dorsal chip fragments best in lateral view. Thus, B is correct.
10) Carpal bone forming the floor of the anatomical snuffbox is–
A) Pisiform
B) Scaphoid
C) Hamate
D) Capitulum
Answer: B) Scaphoid
Explanation: Scaphoid lies beneath snuffbox; tenderness here suggests fracture. Thus, B is correct.
11) In children, isolated carpal fractures are rare because–
A) Carpal bones are cartilaginous
B) Radius absorbs most force
C) Ligaments are loose
D) Forearm muscles protect the wrist
Answer: A) Carpal bones are cartilaginous
Explanation: In early childhood, carpal bones are still cartilaginous and resistant to fracture. Thus, A is correct.
Chapter: Upper Limb Anatomy; Topic: Scapula; Subtopic: Surface Markings and Vertebral Levels
Keyword Definitions:
Scapular Spine: Prominent ridge on posterior scapula, dividing supraspinous and infraspinous fossae.
Vertebral Level Landmarks: Surface markers used clinically to identify internal structures with external palpation.
Inferior Angle of Scapula: Lowest point of scapula, lies near T7 vertebral level.
Acromion: Lateral continuation of scapular spine forming part of shoulder.
Scapular Borders: Medial, lateral, and superior edges forming anatomical reference points.
1) Lead Question – 2016
What is the level of the spine of scapula?
A) T7
B) T10
C) T4
D) T2
Answer: C) T4
Explanation: The spine of the scapula corresponds most closely to the level of the T3 vertebra. However, clinical surface anatomy often places it between T3–T4, and in exam-based options, T4 is the accepted closest match. T7 corresponds to the inferior angle of the scapula, not the spine. T10 is far lower and unrelated to scapular landmarks. T2 lies superior to the scapular spine. Therefore, among the given choices, T4 is the correct answer. Knowledge of vertebral level correlations is crucial in clinical examination, anesthesia techniques, and radiological interpretation.
2) The inferior angle of the scapula corresponds to which vertebral level?
A) T2
B) T7
C) L1
D) T4
Answer: B) T7
Explanation: The inferior angle is classically at T7. Thus, B is correct.
3) The root of the spine of scapula corresponds most closely to–
A) T3
B) T6
C) T8
D) T1
Answer: A) T3
Explanation: Anatomically, the spine's medial end aligns with T3. Thus, A is correct.
4) A patient with shoulder trauma loses function of supraspinatus. The muscle originates from–
A) Infraspinous fossa
B) Supraspinous fossa
C) Subscapular fossa
D) Acromion
Answer: B) Supraspinous fossa
Explanation: Supraspinatus arises from supraspinous fossa, above the spine of scapula. Thus, B is correct.
5) Which nerve innervates the infraspinatus muscle?
A) Axillary nerve
B) Suprascapular nerve
C) Spinal accessory nerve
D) Dorsal scapular nerve
Answer: B) Suprascapular nerve
Explanation: Suprascapular nerve supplies both supraspinatus and infraspinatus. Thus, B is correct.
6) The acromion articulates with which bone?
A) Sternum
B) Clavicle
C) Rib 2
D) Humerus
Answer: B) Clavicle
Explanation: Acromion forms AC joint with clavicle. Thus, B is correct.
7) The glenoid cavity articulates with–
A) Radius
B) Humerus
C) Ulna
D) Clavicle
Answer: B) Humerus
Explanation: Glenoid cavity receives the head of humerus forming shoulder joint. Thus, B is correct.
8) Winged scapula results from injury to which nerve?
A) Dorsal scapular nerve
B) Long thoracic nerve
C) Axillary nerve
D) Suprascapular nerve
Answer: B) Long thoracic nerve
Explanation: Injury paralyzes serratus anterior causing winging. Thus, B is correct.
9) The medial border of scapula gives attachment to–
A) Subscapularis
B) Supraspinatus
C) Serratus anterior
D) Teres major
Answer: C) Serratus anterior
Explanation: Serratus anterior inserts along medial border. Thus, C is correct.
10) Fracture of surgical neck of humerus may damage–
A) Radial nerve
B) Axillary nerve
C) Median nerve
D) Ulnar nerve
Answer: B) Axillary nerve
Explanation: Axillary nerve runs near surgical neck; injury impairs deltoid. Thus, B is correct.
11) The scapula is classified as which type of bone?
A) Long bone
B) Short bone
C) Flat bone
D) Sesamoid bone
Answer: C) Flat bone
Explanation: Scapula is a flat bone providing large muscle attachments. Thus, C is correct.