Exam Review | Latest Update 2026/2027 | 200 Practice
Questions & Detailed Answers | Lymphatic System &
Immunity | LockDown Browser Ready | A+ Graded
1. What is the primary function of the lymphatic system regarding fluid balance?
A) Transport of oxygen
B) Return of interstitial fluid to the blood
C) Production of red blood cells
D) Synthesis of vitamin D
Answer: B) Return of interstitial fluid to the blood
Explanation: The lymphatic system collects excess interstitial fluid that leaks from blood capillaries and
returns it to the bloodstream via lymphatic vessels and ducts, preventing edema and maintaining fluid
homeostasis.
2. Where does lymph reenter the cardiovascular system?
A) Cisterna chyli
B) Jugular veins
C) Subclavian veins
D) Aorta
Answer: C) Subclavian veins
Explanation: Lymph is returned to the bloodstream at the junction of the internal jugular and subclavian
veins. The right lymphatic duct and thoracic duct empty into the right and left subclavian veins
respectively.
,3. Lacteals, a type of lymphatic capillary, are found in the intestine and absorb fats.
A) True
B) False
Answer: A) True
Explanation: Lacteals are specialized lymphatic capillaries located in the villi of the small intestine. They
absorb dietary lipids and fatsoluble vitamins, forming chyle, which gives lymph a milky appearance.
4. Which of the following is NOT a primary lymphatic organ?
A) Lymph nodes
B) Thymus
C) Bone marrow
D) Red bone marrow
Answer: A) Lymph nodes
Explanation: Primary lymphatic organs are where lymphocytes mature. The thymus and bone marrow
are primary organs. Lymph nodes are secondary lymphatic organs where immune responses are
initiated.
5. The thoracic duct drains lymph from all of the following EXCEPT:
A) Left lower extremity
B) Left upper extremity
C) Left side of the head and neck
D) Right upper extremity
,Answer: D) Right upper extremity
Explanation: The thoracic duct drains lymph from the entire body below the diaphragm and the left side
of the body above the diaphragm. The right upper extremity drains into the right lymphatic duct.
6. Lymphatic capillaries differ from blood capillaries in that they:
A) Are more permeable and have overlapping endothelial cells
B) Contain red blood cells
C) Have thicker walls
D) Are surrounded by smooth muscle
Answer: A) Are more permeable and have overlapping endothelial cells
Explanation: Lymphatic capillaries are highly permeable due to overlapping endothelial cells that act as
"minivalves," allowing interstitial fluid, proteins, and even large particles to enter.
7. What structure prevents backflow of lymph?
A) Valves
B) Sphincters
C) Septa
D) Fenestrations
Answer: A) Valves
Explanation: Lymphatic vessels contain oneway valves similar to those in veins. These valves prevent
backward flow of lymph, ensuring unidirectional movement toward the heart.
, 8. The spleen is located in the:
A) Right upper quadrant
B) Left upper quadrant
C) Right lower quadrant
D) Left lower quadrant
Answer: B) Left upper quadrant
Explanation: The spleen is located in the left upper quadrant of the abdomen, just below the diaphragm
and posterior to the stomach.
9. Which of the following cells is responsible for producing antibodies?
A) Cytotoxic T cells
B) Plasma B cells
C) Natural killer cells
D) Macrophages
Answer: B) Plasma B cells
Explanation: Plasma B cells are differentiated B lymphocytes that produce and secrete antibodies
(immunoglobulins) specific to antigens. Each plasma cell produces antibodies against a specific antigen.
10. Which type of immunity involves the production of antibodies by B cells?
A) Humoral immunity
B) Cellmediated immunity
C) Innate immunity