BIOL 252 Human Anatomy and Physiology II:
Module 5 Lymphatic System and Immunity
Comprehensive Exam
SECTION I: ANATOMY OF LYMPHATIC VESSELS AND LYMPH CIRCULATION
1. What is the composition of lymph and how is it formed?
Answer: Lymph is a clear fluid similar to blood plasma but with lower protein
concentration. It is formed when interstitial fluid is absorbed into lymphatic capillaries.
2. Describe the unique anatomical structure of lymphatic capillaries that allows them to
absorb interstitial fluid.
Answer: They are blind-ended tubes with endothelial cells that overlap like roof
shingles, acting as one-way microvalves held in place by collagen anchoring filaments.
3. Explain how edema occurs if lymphatic drainage is blocked.
Answer: Interstitial fluid accumulation exceeds the rate of lymphatic drainage, causing
the tissue space to swell with fluid and plasma proteins.
4. What specialized lymphatic capillaries are located in the villi of the small intestines,
and what do they absorb?
Answer: Lacteals; they absorb digested dietary lipids.
5. What is chyle?
, Answer: A milky-white, fatty lymph fluid collected from the digestive tract by the lacteals.
6. Contrast the drainage areas of the right lymphatic duct and the thoracic duct.
Answer: The right lymphatic duct drains the upper right quadrant of the body; the
thoracic duct drains the left side of the head, neck, thorax, left upper extremity, and the
entire lower body.
7. What is the cisterna chyli and where is it located?
Answer: A dilated sac at the base of the thoracic duct in the abdominal cavity that
receives fatty lymph from the intestinal trunk.
8. Into which specific blood vessels does the lymphatic system empty its contents?
Answer: At the junction of the internal jugular and subclavian veins.
9. Name three mechanisms that assist in the movement of lymph through lymphatic
vessels against gravity.
Answer: The skeletal muscle pump, the respiratory pump, and one-way valves.
10. What effect does physical exercise have on lymphatic flow?
Answer: Exercise increases muscle contraction and respiratory depth, which rapidly
accelerates lymphatic return to the venous system.
SECTION II: LYMPHOID ORGANS AND TISSUES
11. Differentiate between primary and secondary lymphoid organs.
Answer: Primary organs are where lymphocytes mature (red bone marrow and thymus);
secondary organs are where lymphocytes encounter antigens and are activated (lymph
nodes, spleen, tonsils, MALT).
Module 5 Lymphatic System and Immunity
Comprehensive Exam
SECTION I: ANATOMY OF LYMPHATIC VESSELS AND LYMPH CIRCULATION
1. What is the composition of lymph and how is it formed?
Answer: Lymph is a clear fluid similar to blood plasma but with lower protein
concentration. It is formed when interstitial fluid is absorbed into lymphatic capillaries.
2. Describe the unique anatomical structure of lymphatic capillaries that allows them to
absorb interstitial fluid.
Answer: They are blind-ended tubes with endothelial cells that overlap like roof
shingles, acting as one-way microvalves held in place by collagen anchoring filaments.
3. Explain how edema occurs if lymphatic drainage is blocked.
Answer: Interstitial fluid accumulation exceeds the rate of lymphatic drainage, causing
the tissue space to swell with fluid and plasma proteins.
4. What specialized lymphatic capillaries are located in the villi of the small intestines,
and what do they absorb?
Answer: Lacteals; they absorb digested dietary lipids.
5. What is chyle?
, Answer: A milky-white, fatty lymph fluid collected from the digestive tract by the lacteals.
6. Contrast the drainage areas of the right lymphatic duct and the thoracic duct.
Answer: The right lymphatic duct drains the upper right quadrant of the body; the
thoracic duct drains the left side of the head, neck, thorax, left upper extremity, and the
entire lower body.
7. What is the cisterna chyli and where is it located?
Answer: A dilated sac at the base of the thoracic duct in the abdominal cavity that
receives fatty lymph from the intestinal trunk.
8. Into which specific blood vessels does the lymphatic system empty its contents?
Answer: At the junction of the internal jugular and subclavian veins.
9. Name three mechanisms that assist in the movement of lymph through lymphatic
vessels against gravity.
Answer: The skeletal muscle pump, the respiratory pump, and one-way valves.
10. What effect does physical exercise have on lymphatic flow?
Answer: Exercise increases muscle contraction and respiratory depth, which rapidly
accelerates lymphatic return to the venous system.
SECTION II: LYMPHOID ORGANS AND TISSUES
11. Differentiate between primary and secondary lymphoid organs.
Answer: Primary organs are where lymphocytes mature (red bone marrow and thymus);
secondary organs are where lymphocytes encounter antigens and are activated (lymph
nodes, spleen, tonsils, MALT).
