Keyword Definitions
• Sinus venosus – Embryonic structure that collects blood from veins and directs it into primitive atrium.
• Vitelline veins – Carry nutrient-rich blood from yolk sac to sinus venosus.
• Umbilical veins – Carry oxygenated blood from placenta to sinus venosus.
• Common cardinal veins – Return deoxygenated blood from body to sinus venosus.
• Subcardinal veins – Contribute to formation of inferior vena cava, renal veins, not directly to sinus venosus.
• Sinuatrial node – Pacemaker tissue develops near right sinus venosus.
• Right horn of sinus venosus – Becomes part of right atrium and smooth-walled portion (sinus venarum).
• Left horn of sinus venosus – Forms coronary sinus and oblique vein of left atrium.
• Embryonic veins – Vitelline, umbilical, cardinal, subcardinal, sacrocardinal systems in fetal circulation.
• Clinical relevance – Abnormal venous development causes persistent left superior vena cava or venous anomalies.
Chapter: Embryology
Topic: Cardiovascular System Development
Subtopic: Development of Venous System
Lead Question – 2013
Sinus venosus receives blood from all except?
a) Vitelline vein
b) Umbilical vein
c) Common cardinal vein
d) Subcardinal vein
Explanation: The sinus venosus receives blood from vitelline, umbilical, and common cardinal veins. Subcardinal veins do not directly drain into sinus venosus; they contribute to the formation of the inferior vena cava. Correct answer: Subcardinal vein. Clinically, abnormal venous connections may lead to persistent left superior vena cava or systemic venous anomalies.
Guessed Questions for NEET PG
1) The right horn of sinus venosus contributes to:
a) Right atrium smooth part
b) Left atrium
c) Ventricular septum
d) Pulmonary veins
Explanation: The right horn becomes the smooth-walled portion of the right atrium (sinus venarum). Correct answer: Right atrium smooth part. Clinically, defects here may alter atrial conduction pathways.
2) Left horn of sinus venosus forms:
a) Coronary sinus
b) Inferior vena cava
c) Superior vena cava
d) Right atrial appendage
Explanation: The left horn becomes the coronary sinus and oblique vein of left atrium. Correct answer: Coronary sinus. Abnormal development can result in persistent left superior vena cava.
3) Vitelline veins contribute to:
a) Portal vein
b) Pulmonary veins
c) Subclavian veins
d) Coronary sinus
Explanation: Vitelline veins form portal vein, part of inferior vena cava, and hepatic veins. Correct answer: Portal vein. Clinical: vitelline anomalies can cause portal vein malformations.
4) Umbilical vein develops into:
a) Ligamentum teres hepatis
b) Superior vena cava
c) Subclavian vein
d) Inferior vena cava
Explanation: The left umbilical vein persists and becomes ligamentum teres hepatis after birth. Correct answer: Ligamentum teres hepatis. Clinical: failure of obliteration causes patent umbilical vein in neonates.
5) Common cardinal veins form:
a) Superior vena cava
b) Inferior vena cava
c) Pulmonary vein
d) Coronary sinus
Explanation: Common cardinal veins drain into sinus venosus and contribute to SVC and part of IVC. Correct answer: Superior vena cava. Clinical: anomalies can cause SVC duplication.
6) Subcardinal veins contribute to formation of:
a) Inferior vena cava
b) Superior vena cava
c) Coronary sinus
d) Pulmonary veins
Explanation: Subcardinal veins form the renal segment of IVC and renal veins. Correct answer: Inferior vena cava. Abnormalities may lead to retrocaval ureter.
7) Sacrocardinal veins contribute to:
a) Inferior vena cava lower portion
b) Superior vena cava
c) Pulmonary veins
d) Coronary sinus
Explanation: Sacrocardinal veins form the distal IVC and common iliac veins. Correct answer: Inferior vena cava lower portion. Clinical: anomalies cause double IVC.
8) Sinuatrial node develops near:
a) Right sinus venosus
b) Left atrium
c) Left horn
d) Right ventricle
Explanation: SA node develops near right sinus venosus at junction with primitive atrium. Correct answer: Right sinus venosus. Clinical: congenital arrhythmias can arise from SA node maldevelopment.
9) Persistent left superior vena cava results from:
a) Left common cardinal vein
b) Right cardinal vein
c) Subcardinal vein
d) Vitelline vein
Explanation: Persistent left SVC occurs when left common cardinal vein fails to regress. Correct answer: Left common cardinal vein. Clinically relevant in central line placement and cardiac surgery.
10) Portal vein forms from:
a) Vitelline veins
b) Umbilical veins
c) Subcardinal veins
d) Common cardinal veins
Explanation: Portal vein originates from vitelline veins during embryogenesis. Correct answer: Vitelline veins. Clinical: anomalies lead to portal vein agenesis or malformations, affecting hepatic blood flow.
Keyword Definitions
• Epiphysis – Secondary ossification center at the end of long or irregular bones.
• Traction epiphysis – Develops at site of muscle or tendon attachment; ossification influenced by pulling forces.
• Pressure epiphysis – Forms at sites subjected to articular pressure, e.g., head of femur.
• Atavistic epiphysis – Rare, evolutionary remnant epiphysis; may not appear in all individuals.
• Aberrant epiphysis – Epiphysis occurring at unusual location, not typically present.
• Mastoid process – Part of temporal bone; develops as traction epiphysis for sternocleidomastoid attachment.
• Ossification – Process of bone formation, primary and secondary centers.
• Clinical relevance – Abnormal development leads to delayed ossification or deformity; relevant in surgery or trauma.
• Sternocleidomastoid – Muscle inserting on mastoid process; traction epiphysis responds to muscular forces.
• Embryology of skull – Bones form by intramembranous and endochondral ossification.
Chapter: Embryology
Topic: Skeletal System Development
Subtopic: Epiphysis Types and Development
Lead Question – 2013
Mastoid process is which type of epiphysis?
a) Pressure
b) Aberrant
c) Atavistic
d) Traction
Explanation: The mastoid process develops as a traction epiphysis where the sternocleidomastoid muscle attaches. Correct answer: Traction. Traction epiphyses form under tensile forces, unlike pressure epiphyses which develop under joint loading. Clinical relevance: mastoiditis or congenital hypoplasia can affect muscle function and cranial anatomy.
Guessed Questions for NEET PG
1) Head of femur is which epiphysis?
a) Traction
b) Pressure
c) Aberrant
d) Atavistic
Explanation: Head of femur is a pressure epiphysis, forming under joint load to articulate with acetabulum. Correct answer: Pressure. Clinical: Slipped capital femoral epiphysis occurs in adolescents due to weak epiphyseal plate.
2) Greater trochanter of femur is:
a) Traction epiphysis
b) Pressure epiphysis
c) Atavistic epiphysis
d) Aberrant epiphysis
Explanation: Greater trochanter forms a traction epiphysis at muscle attachment sites. Correct answer: Traction. Clinical: avulsion fractures may occur in athletic adolescents.
3) Sesamoid bones are considered:
a) Traction epiphysis
b) Aberrant epiphysis
c) Pressure epiphysis
d) Atavistic epiphysis
Explanation: Sesamoid bones (e.g., patella) develop under mechanical stress at tendon insertions, thus traction epiphyses. Correct answer: Traction epiphysis. Clinical: sesamoiditis causes forefoot pain.
4) Os trigonum of ankle is which type?
a) Aberrant
b) Atavistic
c) Pressure
d) Traction
Explanation: Os trigonum is an atavistic epiphysis, present in some individuals as a remnant accessory bone. Correct answer: Atavistic. Clinical: may cause posterior ankle impingement.
5) Calcaneal tuberosity is:
a) Pressure epiphysis
b) Traction epiphysis
c) Aberrant
d) Atavistic
Explanation: Calcaneal tuberosity is a traction epiphysis for Achilles tendon attachment. Correct answer: Traction. Clinical: Sever’s disease occurs here in adolescents with repetitive stress.
6) Epiphysis of distal tibia articulating with talus is:
a) Pressure
b) Traction
c) Aberrant
d) Atavistic
Explanation: The distal tibial epiphysis is a pressure epiphysis forming the ankle joint. Correct answer: Pressure. Clinical: trauma can cause growth disturbances leading to angular deformity.
7) Pisiform is classified as:
a) Traction
b) Pressure
c) Aberrant
d) Atavistic
Explanation: Pisiform is a traction epiphysis within tendon of flexor carpi ulnaris. Correct answer: Traction. Clinical: pisiform fractures are rare but affect wrist function.
8) Epiphysis absent in most individuals and variable is:
a) Atavistic
b) Traction
c) Pressure
d) Aberrant
Explanation: Atavistic epiphyses are evolutionary remnants, variable in occurrence. Correct answer: Atavistic. Clinical: accessory bones may be mistaken for fractures on X-ray.
9) Clavicular epiphysis in late adolescence is:
a) Traction
b) Pressure
c) Aberrant
d) Atavistic
Explanation: Clavicular epiphysis is a traction epiphysis forming for sternocleidomastoid and trapezius attachment. Correct answer: Traction. Clinical: delayed ossification may mimic fracture on imaging.
10) Patella develops as:
a) Traction epiphysis
b) Aberrant
c) Pressure epiphysis
d) Atavistic
Explanation: Patella is a traction epiphysis within quadriceps tendon. Correct answer: Traction. Clinical: Osgood-Schlatter-like stress affects traction epiphyses in lower limb.
Keyword Definitions
• Cartilage – Flexible connective tissue present in joints, rib cage, ear, nose, and respiratory tract.
• Hyaline cartilage – Most common cartilage; glassy matrix, found in nose, trachea, larynx, fetal skeleton, articular surfaces.
• Collagen types – Structural proteins; provide tensile strength. Type I (bone, tendon), Type II (cartilage), Type III (reticular), Type IV (basement membrane), Type V (cell surfaces).
• Type II collagen – Predominant in hyaline and elastic cartilage; forms fibrils providing resilience.
• Chondrocytes – Cartilage cells producing extracellular matrix including collagen and proteoglycans.
• Extracellular matrix – Gel-like substance containing collagen, proteoglycans, water; gives cartilage strength and elasticity.
• Articular cartilage – Covers joint surfaces; reduces friction; primarily hyaline cartilage.
• Clinical relevance – Collagen defects lead to skeletal dysplasia, osteoarthritis, or cartilage degeneration.
• Endochondral ossification – Process where hyaline cartilage is replaced by bone during fetal development.
• Cartilage repair – Limited due to avascularity; relies on chondrocytes and diffusion.
Chapter: Histology / Embryology
Topic: Connective Tissue
Subtopic: Cartilage Structure and Collagen Types
Lead Question – 2013
Collagen found in hyaline cartilage is?
a) Type I
b) Type II
c) Type IV
d) Type V
Explanation: Hyaline cartilage primarily contains type II collagen, forming fibrils that provide tensile strength and resilience to the extracellular matrix. Correct answer: Type II. Type I is in bone and tendon, Type IV in basement membrane, Type V in cell surfaces. Collagen defects can cause skeletal abnormalities or early osteoarthritis.
Guessed Questions for NEET PG
1) Elastic cartilage contains which type of collagen?
a) Type I
b) Type II
c) Type IV
d) Type V
Explanation: Elastic cartilage contains type II collagen along with abundant elastin fibers. Correct answer: Type II. Found in ear pinna and epiglottis. Clinical: defects in type II collagen lead to structural weakness and potential deformities.
2) Fibrocartilage contains predominant collagen:
a) Type I
b) Type II
c) Type IV
d) Type V
Explanation: Fibrocartilage is rich in type I collagen, giving it high tensile strength for intervertebral discs, menisci, and pubic symphysis. Correct answer: Type I. Clinical: degeneration leads to disc herniation and joint instability.
3) Articular cartilage in joints is primarily:
a) Hyaline
b) Elastic
c) Fibrocartilage
d) Atavistic
Explanation: Articular cartilage is hyaline type with type II collagen. Correct answer: Hyaline. Provides low-friction, resilient surfaces. Damage leads to osteoarthritis.
4) Collagen in basement membrane is:
a) Type I
b) Type II
c) Type IV
d) Type V
Explanation: Type IV collagen forms non-fibrillar network in basement membranes. Correct answer: Type IV. Clinical: defects cause Alport syndrome and kidney dysfunction.
5) Type II collagen defect causes:
a) Chondrodysplasia
b) Osteogenesis imperfecta
c) Ehlers-Danlos
d) Marfan
Explanation: Type II collagen mutation leads to chondrodysplasia, skeletal abnormalities, and early-onset osteoarthritis. Correct answer: Chondrodysplasia.
6) Proteoglycan in hyaline cartilage:
a) Aggrecan
b) Decorin
c) Fibronectin
d) Laminin
Explanation: Aggrecan is the major proteoglycan in hyaline cartilage, binding water and contributing to compressive strength. Correct answer: Aggrecan. Clinical: degradation leads to cartilage wear in arthritis.
7) Chondrocytes reside in:
a) Lacunae
b) Canaliculi
c) Haversian canals
d) Interstitial spaces
Explanation: Chondrocytes are housed in lacunae within the cartilage matrix. Correct answer: Lacunae. Clinical: chondrocyte death contributes to cartilage degeneration.
8) Cartilage avascularity implies:
a) Nutrients diffuse from perichondrium
b) Blood vessels penetrate matrix
c) Direct innervation
d) Lymphatic supply
Explanation: Cartilage receives nutrients by diffusion from the perichondrium. Correct answer: Nutrients diffuse from perichondrium. Clinical: slow healing of cartilage injuries.
9) Endochondral ossification replaces:
a) Hyaline cartilage
b) Fibrocartilage
c) Elastic cartilage
d) Bone marrow
Explanation: Hyaline cartilage serves as a template in endochondral ossification. Correct answer: Hyaline cartilage. Clinical: disturbances lead to growth plate disorders and short stature.
10) Nasal septum cartilage is:
a) Hyaline
b) Elastic
c) Fibrocartilage
d) Atavistic
Explanation: Nasal septum is hyaline cartilage with type II collagen. Correct answer: Hyaline. Clinical: trauma or septal perforation affects airflow and nasal support.
Keyword Definitions
• Spleen – Lymphoid organ in left upper abdomen; filters blood, immune surveillance, stores blood.
• White pulp – Lymphoid tissue surrounding central arteries; contains lymphocytes; immune function.
• Red pulp – Vascular sinusoids and cords; removes aged RBCs, stores platelets.
• Billroth’s cords – Also called splenic cords; connective tissue strands in red pulp containing macrophages, lymphocytes, and plasma cells.
• Central artery – Penetrates white pulp; surrounded by periarteriolar lymphoid sheath (PALS).
• Splenic sinusoids – Vascular channels in red pulp; allow filtration of blood cells.
• Capsule – Dense connective tissue surrounding spleen; provides protection and structure.
• Clinical relevance – Splenic injury affects hematological and immune function; red pulp disorders cause anemia.
• Embryology – Spleen develops from mesenchymal cells in dorsal mesogastrium during 5th week.
• Histology – Red pulp: cords and sinusoids; White pulp: lymphoid follicles with germinal centers.
Chapter: Histology / Embryology
Topic: Lymphoid Organs
Subtopic: Spleen Structure and Components
Lead Question – 2013
Billroth's cord are present in which part of spleen?
a) White pulp
b) Red pulp
c) Both
d) Capsule
Explanation: Billroth’s cords are connective tissue strands found in the red pulp of the spleen, containing macrophages, lymphocytes, plasma cells, and reticular fibers. Correct answer: Red pulp. They function in filtration and immune surveillance. White pulp contains lymphoid follicles; capsule is protective connective tissue. Damage can impair hematological and immune functions.
Guessed Questions for NEET PG
1) Central arteries are found in:
a) White pulp
b) Red pulp
c) Both
d) Capsule
Explanation: Central arteries pass through white pulp surrounded by periarteriolar lymphoid sheath (PALS). Correct answer: White pulp. Clinical: arterial occlusion can reduce immune cell activation.
2) Splenic sinusoids are located in:
a) Red pulp
b) White pulp
c) Capsule
d) Trabeculae
Explanation: Sinusoids are vascular channels in red pulp facilitating filtration of aged or damaged RBCs. Correct answer: Red pulp. Clinical: sinusoidal damage can lead to hemolytic anemia.
3) Periarteriolar lymphoid sheath (PALS) surrounds:
a) Central arteries
b) Red pulp cords
c) Capsule
d) Sinusoids
Explanation: PALS consists of T-lymphocytes surrounding central arteries in white pulp. Correct answer: Central arteries. Clinical: immune deficiencies can impair T-cell mediated responses.
4) Germinal centers are present in:
a) White pulp follicles
b) Red pulp
c) Capsule
d) Sinusoids
Explanation: Germinal centers in white pulp follicles are sites of B-cell proliferation and differentiation. Correct answer: White pulp. Clinical: germinal center hyperplasia occurs in infections or autoimmune diseases.
5) Trabeculae of spleen contain:
a) Connective tissue and vessels
b) White pulp only
c) Red pulp only
d) Sinusoids only
Explanation: Trabeculae provide structural support, carrying arteries and veins into spleen. Correct answer: Connective tissue and vessels. Clinical: trauma can rupture trabeculae, causing hemorrhage.
6) Macrophages in red pulp function to:
a) Phagocytose aged RBCs
b) Produce antibodies
c) Secrete collagen
d) Form germinal centers
Explanation: Macrophages in Billroth’s cords phagocytose old erythrocytes and pathogens. Correct answer: Phagocytose aged RBCs. Clinical: macrophage dysfunction leads to splenomegaly and anemia.
7) White pulp is rich in:
a) Lymphocytes
b) Erythrocytes
c) Platelets
d) Sinusoids
Explanation: White pulp contains lymphocytes around central arteries for immune surveillance. Correct answer: Lymphocytes. Clinical: loss leads to immunodeficiency.
8) Red pulp ratio to white pulp is approximately:
a) 3:1
b) 1:1
c) 1:3
d) 2:1
Explanation: Red pulp constitutes roughly 3/4 of splenic volume, responsible for filtration and blood storage. Correct answer: 3:1. Clinical: splenomegaly increases red pulp proportion causing anemia.
9) Capsule of spleen is composed of:
a) Dense connective tissue
b) Lymphoid tissue
c) Sinusoids
d) Cartilage
Explanation: Capsule is dense connective tissue surrounding spleen, providing protection and support. Correct answer: Dense connective tissue. Clinical: splenic rupture involves capsule laceration.
10) Accessory spleens are usually located near:
a) Hilum
b) Red pulp
c) White pulp
d) Capsule
Explanation: Accessory spleens develop near hilum, containing red and white pulp. Correct answer: Hilum. Clinically important in splenectomy to remove all functional splenic tissue.
Keyword Definitions
• Spleen – Lymphoid organ in the left upper abdomen; filters blood, stores blood, and provides immune surveillance.
• White pulp – Lymphoid tissue surrounding central arteries; mainly composed of lymphocytes; site of immune responses.
• Red pulp – Vascular tissue with sinusoids and cords (Billroth’s cords); removes aged red blood cells and pathogens.
• B-cells – Lymphocytes responsible for humoral immunity; produce antibodies; primarily located in white pulp follicles.
• T-cells – Lymphocytes involved in cell-mediated immunity; mainly found in periarteriolar lymphoid sheath (PALS).
• Germinal centers – Sites of B-cell proliferation and differentiation within white pulp follicles.
• Central artery – Artery surrounded by PALS in white pulp.
• Billroth’s cords – Structures in red pulp containing macrophages, lymphocytes, and plasma cells.
• Capsule – Dense connective tissue surrounding spleen; provides protection.
• Clinical relevance – B-cell deficiencies lead to poor humoral response; splenectomy affects antibody production.
Chapter: Histology / Immunology
Topic: Lymphoid Organs
Subtopic: Spleen Cell Distribution
Lead Question – 2013
B-cells are dispersed in which part of spleen?
a) White pulp
b) Red pulp
c) Capsule
d) None
Explanation: B-cells are primarily located in the follicles of white pulp surrounding central arteries. They form germinal centers upon antigen stimulation and produce antibodies. Correct answer: White pulp. Red pulp contains mainly macrophages and plasma cells. Clinical relevance: B-cell deficiencies reduce humoral immunity, increasing susceptibility to infections.
Guessed Questions for NEET PG
1) T-cells are concentrated in:
a) PALS of white pulp
b) Red pulp
c) Capsule
d) Sinusoids
Explanation: T-cells mainly surround central arteries in PALS within white pulp. Correct answer: PALS of white pulp. Clinical: T-cell defects impair cell-mediated immunity, predisposing to viral infections.
2) Germinal centers are found in:
a) White pulp follicles
b) Red pulp cords
c) Capsule
d) Sinusoids
Explanation: B-cells proliferate and differentiate in germinal centers of white pulp follicles. Correct answer: White pulp follicles. Clinical: hyperactive germinal centers can occur in autoimmune diseases.
3) Plasma cells are abundant in:
a) Red pulp
b) White pulp
c) Capsule
d) PALS
Explanation: Plasma cells derived from B-cells are mainly in Billroth’s cords of red pulp. Correct answer: Red pulp. Clinical: splenic damage reduces antibody production.
4) Marginal zone of spleen contains:
a) Specialized B-cells
b) T-cells
c) Macrophages only
d) Capsule fibroblasts
Explanation: Marginal zone surrounds white pulp and contains specialized B-cells and macrophages. Correct answer: Specialized B-cells. Clinical: marginal zone lymphoma arises from these B-cells.
5) White pulp to red pulp ratio is approximately:
a) 1:3
b) 3:1
c) 1:1
d) 2:1
Explanation: Red pulp predominates (~3:1) over white pulp. Correct answer: 1:3. Clinical: splenomegaly increases red pulp proportion, affecting blood filtration.
6) Spleen's immune response to blood-borne antigens is mediated by:
a) White pulp B-cells
b) Red pulp macrophages
c) Capsule fibroblasts
d) Sinusoids
Explanation: White pulp B-cells produce antibodies in response to blood-borne antigens. Correct answer: White pulp B-cells. Clinical: asplenic patients have impaired humoral immunity.
7) Central arteries in spleen are surrounded by:
a) PALS
b) Billroth’s cords
c) Capsule
d) Sinusoids
Explanation: Central arteries are encircled by T-cell rich PALS in white pulp. Correct answer: PALS. Clinical: PALS destruction may impair cell-mediated immunity.
8) Billroth’s cords contain:
a) Macrophages, plasma cells, lymphocytes
b) Only erythrocytes
c) Fibroblasts only
d) Collagen fibers only
Explanation: Billroth’s cords in red pulp contain macrophages, plasma cells, and lymphocytes. Correct answer: Macrophages, plasma cells, lymphocytes. Clinical: damage to cords impairs clearance of aged RBCs.
9) Spleen functions include all except:
a) Filtering blood
b) Producing antibodies
c) Hematopoiesis in adult
d) Destroying aged RBCs
Explanation: Spleen filters blood, produces antibodies, and removes aged RBCs. Adult hematopoiesis is minimal. Correct answer: Hematopoiesis in adult. Clinical: extramedullary hematopoiesis can occur in disease.
10) Accessory spleens contain:
a) Both white and red pulp
b) Only white pulp
c) Only red pulp
d) Capsule only
Explanation: Accessory spleens contain both red and white pulp, functioning like main spleen. Correct answer: Both white and red pulp. Clinical: important in splenectomy to prevent recurrence of hematologic disease.
Keyword Definitions
• Lymph node – Small encapsulated lymphoid organ along lymphatic vessels; filters lymph and initiates immune responses.
• Cortex – Outer portion of lymph node containing lymphoid follicles; mainly B-cell areas.
• Medulla – Inner portion of lymph node; contains medullary cords and sinuses; plasma cells reside here.
• Follicles – Spherical aggregates of lymphocytes within cortex; primary follicles are inactive, secondary follicles contain germinal centers.
• Germinal center – Site of B-cell proliferation, differentiation, and somatic hypermutation after antigen stimulation.
• Paracortex – Area between cortex and medulla; rich in T-cells surrounding high endothelial venules (HEVs).
• Lymphatic sinuses – Channels within node for lymph flow; subcapsular, trabecular, and medullary sinuses.
• High endothelial venules (HEVs) – Specialized vessels allowing lymphocyte entry into lymph nodes.
• Clinical relevance – Follicular hyperplasia indicates infection or immune activation; neoplasms like follicular lymphoma arise from follicles.
• Embryology – Lymph nodes develop from mesenchymal cells; colonize by lymphocytes in late fetal life.
Chapter: Histology / Immunology
Topic: Lymphoid Organs
Subtopic: Lymph Node Structure
Lead Question – 2013
Follicles are present in which part of lymph nodes?
a) Red pulp
b) White pulp
c) Cortex
d) Medulla
Explanation: Lymphoid follicles are present in the cortex of lymph nodes, forming B-cell rich zones. Primary follicles are inactive, while secondary follicles contain germinal centers after antigen exposure. Correct answer: Cortex. Medulla contains plasma cells, and red/white pulp refer to spleen. Follicular hyperplasia occurs in infections or autoimmune conditions.
Guessed Questions for NEET PG
1) Paracortex of lymph node contains:
a) T-cells
b) B-cells
c) Plasma cells
d) Fibroblasts
Explanation: Paracortex is rich in T-lymphocytes surrounding HEVs. Correct answer: T-cells. Clinical: T-cell deficiency affects cell-mediated immunity and lymph node structure.
2) Medullary cords contain:
a) Plasma cells
b) T-cells
c) B-cells in follicles
d) Red pulp
Explanation: Medullary cords in lymph node medulla contain plasma cells and macrophages. Correct answer: Plasma cells. Clinical: antibody production is concentrated here.
3) Subcapsular sinus is located:
a) Beneath capsule
b) Cortex
c) Medulla
d) Follicles
Explanation: Subcapsular sinus lies just below the lymph node capsule, allowing lymph to flow into trabecular sinuses. Correct answer: Beneath capsule. Clinical: site for metastatic cancer cell entry.
4) Secondary follicles contain:
a) Germinal centers
b) T-cells only
c) Medullary cords
d) Capsule fibroblasts
Explanation: Secondary follicles develop germinal centers after antigen stimulation. Correct answer: Germinal centers. Clinical: hyperactive germinal centers appear in infections and autoimmune disease.
5) High endothelial venules (HEVs) are in:
a) Paracortex
b) Cortex follicles
c) Medullary cords
d) Sinuses
Explanation: HEVs in paracortex allow lymphocyte migration from blood to lymph node. Correct answer: Paracortex. Clinical: impaired HEV function reduces lymphocyte homing.
6) Primary follicles are:
a) Inactive B-cell clusters
b) Germinal centers
c) Medullary cords
d) Paracortex T-cells
Explanation: Primary follicles are small, inactive B-cell clusters in cortex. Correct answer: Inactive B-cell clusters. Clinical: may enlarge in early immune response.
7) Lymph node capsule is composed of:
a) Dense connective tissue
b) B-cell follicles
c) Medullary cords
d) Paracortex
Explanation: Capsule is dense connective tissue providing protection and structure. Correct answer: Dense connective tissue. Clinical: capsule rupture can spread infection or metastasis.
8) Trabeculae of lymph nodes carry:
a) Blood vessels and lymphatics
b) Only sinuses
c) Only follicles
d) Red pulp
Explanation: Trabeculae carry vessels and lymph channels from capsule into interior. Correct answer: Blood vessels and lymphatics. Clinical: obstruction can impair lymph flow.
9) Medullary sinuses drain into:
a) Efferent lymphatics
b) Afferent lymphatics
c) Capsule
d) Paracortex
Explanation: Medullary sinuses drain lymph into efferent lymphatic vessels. Correct answer: Efferent lymphatics. Clinical: blockage leads to lymph node swelling.
10) Follicular lymphoma arises from:
a) B-cell follicles
b) T-cell paracortex
c) Medullary cords
d) Capsule
Explanation: Follicular lymphoma is a B-cell malignancy originating from cortical follicles. Correct answer: B-cell follicles. Clinical: presents as painless lymphadenopathy and may involve multiple lymph nodes.
Keyword Definitions
• Hyoid bone – U-shaped bone in anterior neck; supports tongue and serves as attachment for muscles of swallowing and speech.
• Cervical vertebrae – Seven vertebrae in neck region, labeled C1–C7; provide support and mobility for head and neck.
• C3 – Third cervical vertebra; anterior to it lies the body of hyoid bone.
• Suprahyoid muscles – Muscles above hyoid, elevate it during swallowing; include digastric, stylohyoid, mylohyoid, geniohyoid.
• Infrahyoid muscles – Muscles below hyoid, depress it; include sternohyoid, omohyoid, thyrohyoid, sternothyroid.
• Thyroid cartilage – Cartilage inferior to hyoid; forms Adam’s apple; attachment for laryngeal muscles.
• Clinical relevance – Hyoid fractures suggest strangulation; landmarks for neck surgery and radiology; level of airway structures.
• Embryology – Hyoid develops from second and third pharyngeal arches; lesser horn from 2nd, greater horn from 3rd.
• Laryngeal inlet – Located inferior to hyoid; opens into pharynx; important in intubation.
• Anatomical landmarks – Hyoid at C3; thyroid cartilage at C4–C5; cricoid cartilage at C6.
Chapter: Anatomy / Osteology
Topic: Cervical Region
Subtopic: Hyoid Bone and Neck Landmarks
Lead Question – 2013
Hyoid lies at the level of?
a) C3
b) C5
c) C7
d) T2
Explanation: The hyoid bone is positioned at the level of the third cervical vertebra (C3) in the neck. It is U-shaped, supports the tongue, and serves as an attachment for suprahyoid and infrahyoid muscles. Correct answer: C3. Clinical relevance includes neck surgery landmarks, airway management, and forensic assessment of strangulation.
Guessed Questions for NEET PG
1) Thyroid cartilage lies at the level of:
a) C3–C4
b) C4–C5
c) C5–C6
d) C6–C7
Explanation: Thyroid cartilage, forming the Adam’s apple, is located at C4–C5. Correct answer: C4–C5. Clinical: important landmark for cricothyrotomy and neck surgery.
2) Cricoid cartilage lies at the level of:
a) C4
b) C6
c) C7
d) T1
Explanation: Cricoid cartilage is complete ring below thyroid cartilage at C6. Correct answer: C6. Clinical: landmark for tracheostomy and endotracheal tube placement.
3) Greater horn of hyoid arises from:
a) 2nd pharyngeal arch
b) 3rd pharyngeal arch
c) 1st pharyngeal arch
d) 4th pharyngeal arch
Explanation: The greater horn of hyoid develops from the 3rd pharyngeal arch. Correct answer: 3rd pharyngeal arch. Clinical: anomalies may affect swallowing or neck mobility.
4) Lesser horn of hyoid arises from:
a) 2nd pharyngeal arch
b) 3rd pharyngeal arch
c) 1st pharyngeal arch
d) 4th pharyngeal arch
Explanation: Lesser horn of hyoid develops from the 2nd pharyngeal arch. Correct answer: 2nd pharyngeal arch. Clinical: variations may be seen on imaging.
5) Suprahyoid muscles function to:
a) Elevate hyoid
b) Depress hyoid
c) Rotate hyoid
d) Stabilize vertebrae
Explanation: Suprahyoid muscles elevate the hyoid during swallowing and speech. Correct answer: Elevate hyoid. Clinical: paralysis affects swallowing.
6) Infrahyoid muscles function to:
a) Depress hyoid
b) Elevate hyoid
c) Flex cervical spine
d) Extend cervical spine
Explanation: Infrahyoid muscles depress the hyoid and larynx. Correct answer: Depress hyoid. Clinical: injury may affect voice and swallowing.
7) Fracture of hyoid bone suggests:
a) Strangulation
b) Fall from height
c) Sports injury
d) Osteoporosis
Explanation: Hyoid fractures commonly indicate manual strangulation. Correct answer: Strangulation. Clinical: forensic marker in neck trauma cases.
8) Hyoid is U-shaped and located:
a) Anterior neck
b) Posterior neck
c) Lateral neck
d) Mediastinum
Explanation: Hyoid bone is U-shaped in anterior neck at C3, supporting tongue and neck muscles. Correct answer: Anterior neck. Clinical: important landmark for airway and neck surgery.
9) The hyoid does not articulate with any other bone:
a) True
b) False
Explanation: Hyoid is a floating bone, not articulating with other bones; it is anchored by muscles and ligaments. Correct answer: True. Clinical: allows mobility for swallowing and speech.
10) Hyoid bone serves as attachment for:
a) Suprahyoid and infrahyoid muscles
b) Only neck flexors
c) Only tongue muscles
d) Sternocleidomastoid only
Explanation: Hyoid provides attachment for both suprahyoid and infrahyoid muscles, facilitating swallowing and speech. Correct answer: Suprahyoid and infrahyoid muscles. Clinical: fractures impair these functions and may indicate trauma.
Keyword Definitions
• Pubic symphysis – Midline cartilaginous joint between left and right pubic bones; allows limited movement.
• Joint types – Fibrous (immovable), cartilaginous (primary/secondary), synovial (freely movable).
• Fibrous joint – Bones united by dense connective tissue; minimal or no movement.
• Primary cartilaginous (synchondrosis) – Bones joined by hyaline cartilage; temporary in growth plates.
• Secondary cartilaginous (symphysis) – Bones joined by fibrocartilage; allows limited movement; found in pubic symphysis and intervertebral discs.
• Fibrocartilage – Dense cartilage with type I collagen; provides strength and shock absorption.
• Pelvic mobility – During childbirth, pubic symphysis slightly widens to facilitate delivery.
• Clinical relevance – Pubic symphysis injury or separation causes pain and gait disturbance; osteitis pubis is inflammation of this joint.
• Embryology – Forms from mesenchyme between pubic bones; fibrocartilaginous disc develops in early childhood.
• Anatomy – Located anteriorly in pelvis; superior and inferior pubic ligaments reinforce it.
Chapter: Anatomy / Osteology
Topic: Pelvic Girdle
Subtopic: Pubic Symphysis and Joint Types
Lead Question – 2013
Pubic symphysis is which type of joint?
a) Gomphosis
b) Fibrous joint
c) Primary cartilaginous
d) Secondary cartilaginous
Explanation: Pubic symphysis is a secondary cartilaginous joint (symphysis), consisting of fibrocartilage between the pubic bones, allowing limited movement. Correct answer: Secondary cartilaginous. Fibrous joints like gomphoses are immobile; primary cartilaginous joints are temporary (growth plates). Clinically, separation or inflammation affects gait and childbirth.
Guessed Questions for NEET PG
1) Intervertebral discs are examples of:
a) Secondary cartilaginous joints
b) Primary cartilaginous joints
c) Synovial joints
d) Fibrous joints
Explanation: Intervertebral discs are secondary cartilaginous joints (symphyses) with fibrocartilage, allowing slight movement. Correct answer: Secondary cartilaginous joints. Clinical: disc degeneration leads to back pain.
2) Epiphyseal plates are:
a) Primary cartilaginous joints
b) Secondary cartilaginous joints
c) Fibrous joints
d) Synovial joints
Explanation: Epiphyseal plates are primary cartilaginous joints (hyaline cartilage) temporarily present during growth. Correct answer: Primary cartilaginous. Clinical: fractures through growth plates affect bone length.
3) Sutures of skull are examples of:
a) Fibrous joints
b) Cartilaginous joints
c) Synovial joints
d) Symphyses
Explanation: Skull sutures are fibrous joints (immovable) united by dense connective tissue. Correct answer: Fibrous joints. Clinical: premature fusion (craniosynostosis) affects skull shape.
4) Gomphosis is a type of:
a) Fibrous joint
b) Cartilaginous joint
c) Synovial joint
d) Symphysis
Explanation: Gomphosis is a peg-and-socket fibrous joint, e.g., tooth in alveolar socket. Correct answer: Fibrous joint. Clinical: periodontal disease affects this joint.
5) Superior and inferior pubic ligaments reinforce:
a) Pubic symphysis
b) Sacroiliac joint
c) Hip joint
d) Knee joint
Explanation: Superior and inferior ligaments strengthen pubic symphysis. Correct answer: Pubic symphysis. Clinical: ligament injury can cause pelvic instability.
6) Fibrocartilage in pubic symphysis contains:
a) Type I collagen
b) Type II collagen
c) Elastic fibers only
d) Hyaline cartilage only
Explanation: Fibrocartilage in secondary cartilaginous joints contains type I collagen for tensile strength. Correct answer: Type I collagen. Clinical: degeneration causes pain and reduced mobility.
7) During childbirth, pubic symphysis:
a) Widens slightly
b) Becomes rigid
c) Fuses permanently
d) Fractures routinely
Explanation: Pubic symphysis widens slightly due to relaxin hormone, facilitating vaginal delivery. Correct answer: Widens slightly. Clinical: excessive separation causes symphyseal diastasis.
8) Osteitis pubis is inflammation of:
a) Pubic symphysis
b) Hip joint
c) Sacroiliac joint
d) Knee joint
Explanation: Osteitis pubis is inflammation of pubic symphysis, often post-surgery or in athletes. Correct answer: Pubic symphysis. Clinical: presents as pain in groin and pubic region.
9) Fibrocartilaginous disc of pubic symphysis functions to:
a) Absorb shock and allow slight movement
b) Produce synovial fluid
c) Form growth plate
d) Connect ligaments only
Explanation: Fibrocartilaginous disc absorbs mechanical stress and allows limited movement. Correct answer: Absorb shock and allow slight movement. Clinical: disc injury impairs pelvic stability.
10) Separation of pubic symphysis may occur due to:
a) Trauma or childbirth
b) Osteoporosis only
c) Infection of hip joint
d) Vertebral fracture
Explanation: Pubic symphysis separation can occur during traumatic injury or childbirth. Correct answer: Trauma or childbirth. Clinical: causes pain, difficulty walking, and may require surgical stabilization.
Keyword Definitions
• Urinary bladder – Hollow muscular organ storing urine temporarily; located in pelvis; wall consists of mucosa, muscularis, and serosa/adventitia.
• Epithelium – Tissue covering surfaces and cavities; provides protection, absorption, secretion, or stretching.
• Transitional epithelium (urothelium) – Specialized epithelium in urinary tract; allows distension and contraction; cells appear cuboidal when relaxed, squamous when stretched.
• Mucosa – Inner lining of bladder including epithelium and underlying lamina propria.
• Lamina propria – Connective tissue beneath epithelium; supports epithelium, contains blood vessels and nerves.
• Muscularis (detrusor) – Smooth muscle layer in bladder wall; contracts during micturition.
• Clinical relevance – Transitional epithelium resists urine toxicity; urothelial carcinoma arises from this lining.
• Urothelium – Another term for transitional epithelium lining ureters, bladder, and proximal urethra.
• Distension – Ability of bladder to stretch during filling; provided by transitional epithelium.
• Embryology – Bladder epithelium derived from endoderm of urogenital sinus; smooth muscle from splanchnic mesoderm.
Chapter: Histology / Urogenital System
Topic: Urinary Bladder
Subtopic: Epithelium and Wall Structure
Lead Question – 2013
Epithelial lining of urinary bladder?
a) Squamous
b) Transitional
c) Cuboidal
d) Columnar
Explanation: The urinary bladder is lined by transitional epithelium, allowing expansion and contraction as it fills and empties. Correct answer: Transitional. Squamous, cuboidal, and columnar are seen in other organs. Clinically, urothelial carcinoma arises from this lining, and its integrity protects against urine toxicity.
Guessed Questions for NEET PG
1) Ureters are lined by:
a) Transitional epithelium
b) Squamous epithelium
c) Columnar epithelium
d) Cuboidal epithelium
Explanation: Ureters are lined by transitional epithelium to allow distension during urine flow. Correct answer: Transitional epithelium. Clinical: obstruction or stones can damage urothelium.
2) Proximal urethra epithelium is:
a) Transitional epithelium
b) Stratified squamous epithelium
c) Simple cuboidal
d) Simple columnar
Explanation: Proximal urethra retains transitional epithelium, while distal urethra gradually becomes stratified squamous. Correct answer: Transitional epithelium. Clinical: infections often begin in distal urethra but can ascend.
3) Bladder mucosa contains:
a) Epithelium + lamina propria
b) Epithelium only
c) Muscularis only
d) Adventitia only
Explanation: Mucosa includes epithelium and underlying lamina propria. Correct answer: Epithelium + lamina propria. Clinical: inflammation affects both layers (cystitis).
4) Detrusor muscle of bladder is composed of:
a) Smooth muscle
b) Skeletal muscle
c) Cardiac muscle
d) Fibrocartilage
Explanation: Muscularis of bladder (detrusor) is smooth muscle, allowing involuntary contraction during urination. Correct answer: Smooth muscle. Clinical: detrusor instability causes urinary incontinence.
5) Urothelial carcinoma arises from:
a) Transitional epithelium
b) Squamous epithelium
c) Cuboidal epithelium
d) Columnar epithelium
Explanation: Malignancy of bladder most often arises from transitional epithelium. Correct answer: Transitional epithelium. Clinical: presents with hematuria and may require cystoscopic intervention.
6) Bladder epithelium appearance when stretched:
a) Squamous-like
b) Cuboidal
c) Columnar
d) Pseudostratified
Explanation: Transitional epithelium flattens and appears squamous-like during bladder distension. Correct answer: Squamous-like. Clinical: allows large urine volumes without tearing epithelium.
7) Bladder epithelium originates embryologically from:
a) Endoderm
b) Ectoderm
c) Mesoderm
d) Neural crest
Explanation: Bladder epithelium develops from endoderm of the urogenital sinus. Correct answer: Endoderm. Clinical: congenital anomalies may involve endodermal derivatives.
8) Lamina propria of bladder contains:
a) Blood vessels, nerves, connective tissue
b) Only epithelium
c) Only smooth muscle
d) Cartilage
Explanation: Lamina propria is connective tissue supporting epithelium with vessels and nerves. Correct answer: Blood vessels, nerves, connective tissue. Clinical: inflammation can cause edema and pain.
9) Protective function of urothelium:
a) Resists urine toxicity
b) Absorbs urine
c) Secretes digestive enzymes
d) Stores bile
Explanation: Transitional epithelium protects underlying tissues from toxic urine components. Correct answer: Resists urine toxicity. Clinical: barrier breakdown leads to cystitis.
10) Transitional epithelium in bladder allows:
a) Expansion and contraction
b) Only absorption
c) Only secretion
d) Only filtration
Explanation: Transitional epithelium stretches and recoils during filling and emptying. Correct answer: Expansion and contraction. Clinical: loss of elasticity causes urinary dysfunction.
Keyword Definitions
• Cardiac muscle – Specialized involuntary muscle forming the myocardium; responsible for heart contractions.
• Myocardium – Thick middle layer of heart wall made of cardiac muscle; contracts to pump blood.
• Intercalated discs – Specialized junctions connecting cardiac muscle cells; contain desmosomes and gap junctions.
• Gap junctions – Channels allowing electrical coupling between cardiac myocytes for synchronized contraction.
• Nucleus – Cardiac muscle cells typically have one centrally located nucleus; occasionally two.
• Striations – Alternating light and dark bands in cardiac muscle due to organized sarcomeres.
• Sheet arrangement – Cardiac muscle fibers arranged in branching sheets for efficient contraction.
• Spindle-shaped – Characteristic of smooth muscle, not cardiac muscle.
• Clinical relevance – Dysfunction of cardiac muscle leads to arrhythmias, heart failure, or cardiomyopathies.
• Histology – Cardiac muscle cells are short, branched, striated, with intercalated discs and central nuclei.
Chapter: Histology / Muscular System
Topic: Cardiac Muscle
Subtopic: Structure, Histology, and Clinical Relevance
Lead Question – 2013
True about cardiac muscle is?
a) Spindle shaped
b) Large central nucleus
c) No gap junctions
d) Arranged in sheets
Explanation: Cardiac muscle fibers are arranged in branching sheets, enabling coordinated contractions. Correct answer: Arranged in sheets. They are striated, short, branched, with one central nucleus and intercalated discs containing gap junctions. Spindle-shaped is smooth muscle. Clinically, the sheet arrangement ensures synchronized myocardial contraction and efficient blood pumping.
Guessed Questions for NEET PG
1) Cardiac muscle fibers are:
a) Striated
b) Non-striated
c) Voluntary
d) Spindle-shaped
Explanation: Cardiac muscle is striated due to sarcomere organization. Correct answer: Striated. Clinical: Striations are essential for contraction; histological changes indicate cardiomyopathies.
2) Intercalated discs contain:
a) Desmosomes and gap junctions
b) Tight junctions only
c) Hemidesmosomes only
d) None
Explanation: Intercalated discs connect cardiac myocytes via desmosomes for mechanical strength and gap junctions for electrical coupling. Correct answer: Desmosomes and gap junctions. Clinical: defects cause arrhythmias.
3) Nucleus in cardiac myocytes is typically:
a) Single and central
b) Multiple and peripheral
c) Absent
d) Peripheral only
Explanation: Cardiac myocytes usually have a single centrally located nucleus. Correct answer: Single and central. Clinical: nuclear abnormalities may indicate hypertrophy or cardiomyopathy.
4) Cardiac muscle is controlled by:
a) Autonomic nervous system
b) Somatic nervous system
c) Hormones only
d) Voluntary control
Explanation: Cardiac muscle contracts involuntarily under autonomic nervous system regulation. Correct answer: Autonomic nervous system. Clinical: autonomic dysfunction affects heart rate and rhythm.
5) Branching of cardiac fibers allows:
a) Efficient force distribution
b) Limited contraction
c) No contraction
d) Smooth movement only
Explanation: Branching ensures synchronized contraction and effective pumping. Correct answer: Efficient force distribution. Clinical: branching abnormalities reduce cardiac efficiency.
6) Gap junctions allow:
a) Electrical coupling
b) Structural support only
c) Nutrient diffusion only
d) No function
Explanation: Gap junctions permit ion flow between cardiac cells for coordinated contraction. Correct answer: Electrical coupling. Clinical: defective gap junctions cause arrhythmias.
7) Spindle-shaped cells are characteristic of:
a) Smooth muscle
b) Cardiac muscle
c) Skeletal muscle
d) Connective tissue
Explanation: Spindle-shaped cells belong to smooth muscle. Correct answer: Smooth muscle. Cardiac cells are branched. Clinical: smooth muscle pathology affects vessel tone.
8) Clinical significance of cardiac muscle sheets:
a) Coordinated contraction of myocardium
b) Voluntary movements
c) Endocrine secretion
d) Filtration
Explanation: Sheet arrangement allows synchronized myocardial contraction. Correct answer: Coordinated contraction of myocardium. Clinical: disruption leads to inefficient pumping and heart failure.
9) Cardiac muscle striations are due to:
a) Sarcomeres
b) Fibrocartilage
c) Elastic fibers
d) Gap junctions
Explanation: Striations arise from organized sarcomeres with actin and myosin filaments. Correct answer: Sarcomeres. Clinical: sarcomere disruption occurs in cardiomyopathy.
10) Cardiac muscle differs from skeletal muscle in:
a) Branching and intercalated discs
b) Voluntary control
c) Peripheral nuclei
d) Non-striated appearance
Explanation: Cardiac muscle is branched, striated, and has intercalated discs, unlike skeletal muscle which is unbranched, striated, and multinucleated. Correct answer: Branching and intercalated discs. Clinical: these features enable synchronized contractions and resistance to mechanical stress.