The enlarged portion of the thoracic duct is called the:

A. Lacteals are specialized lymphatic capillaries located in the villi of the small intestine. They absorb digested fats (in the form of chylomicrons) and transport them into the lymphatic system, eventually entering the bloodstream.
B. Peyer patches are clusters of lymphoid tissue found in the small intestine, important for immune surveillance, but they are not involved in fat absorption.
C. Kupffer cells are specialized macrophages in the liver that filter blood, not involved in lymphatic fat transport.
D. Lymph capillaries generally collect interstitial fluid to form lymph, but lacteals are the specific type of lymph capillary responsible for absorbing dietary fats.

A. Blood contains various types of cells, such as red blood cells and white blood cells, but dust cells are not found in the blood.
B. Dust cells are a type of macrophage found in the lungs. They are responsible for engulfing and clearing inhaled particles, dust, and pathogens from the respiratory system.
C. The liver contains Kupffer cells, which are macrophages that filter blood, but dust cells are not found in the liver.
D. The small intestine contains various immune cells, but dust cells are not among them. The small intestine has its own specialized immune cells like Peyer's patches.