IMMUNOLOGY

Detailed explanation-1: -Lymph flows in the body through its intercellular spaces into the capillaries at the base of the neck. The lymphatic system does not have the circulatory system like the heart to send it in all directions. Lymph flows in one direction only i.e, from tissues to the heart.

Detailed explanation-2: -The lymphatic vessels drain into collecting ducts, which empty their contents into the two subclavian veins, located under the collarbones. These veins join to form the superior vena cava, the large vein that drains blood from the upper body into the heart.

Detailed explanation-3: -This fluid is then transported back into the bloodstream via the lymph vessels. Lymph only moves in one direction, toward the heart.

Detailed explanation-4: -Lymphatic fluid flows from the lower extremities–the liver and intestine–to the thoracic duct, which is the main channel for lymphatic drainage. In most people the thoracic duct drains into the subclavian vein on the left side.

Detailed explanation-5: -There is no pump in the lymphatic system like the heart in the cardiovascular system. The pressure gradients to move lymph through the vessels come from the skeletal muscle action, respiratory movement, and contraction of smooth muscle in vessel walls.

Detailed explanation-6: -The correct answer is option d because the lymphatic system is not a closed-loop like the circulatory system, it starts with lymphatic capillaries that drain into successively larger vessels that eventually drain out the lymphatic system through two lymph ducts into veins that lead towards the heart.