Question

question 3
1 pts
about half of the lymph flowing through the thoracic duct comes from the:
liver.
small intestine.
spleen.
both a and b are correct.
question 4
1 pts
lymphatics resemble veins except that lymphatics:
have thinner walls.
contain more valves.
contain lymph nodes located at certain intervals along their course.
all of the above are correct.

Explanation:

• Question 3: The thoracic duct receives lymph from the lower limbs, abdomen, left side of the thorax, left upper limb, and left side of the head and neck. The liver and small intestine are major contributors to the lymph flow in the abdominal region. The spleen's contribution is relatively smaller compared to the liver and small intestine.
• Question 4: Lymphatics have thinner walls than veins (due to less smooth muscle and elastic fibers). They also have more valves to prevent backflow of lymph (since lymphatic flow is often against gravity and pressure is low). Lymph nodes are located at intervals along lymphatic vessels, which is not a feature of veins.

Answer:

• Question 3: Both A and B are correct.
• Question 4: All of the above are correct.