Lymphatic System

Question 1

immune system

Answer 1

a system of diverse defenses against disease, not an organ system in itself, but an inclusive term for defensive units of multiple organ systems; includes leukocytes & immune cells, defense chemicals, and physical barriers like skin & mucous membranes

Question 2

B lymphocytes

Answer 2

(B cells)
- lymphocytes which mature in the bone marrow and that are involved in the production of antibodies
- carry out humoral immunity

Question 3

T lymphocytes

Answer 3

• lymphocytes that mature in the thymus and act directly against antigens in cell-mediated immune responses
• carry out cellular/cell-mediated immunity

Question 4

antigen-presenting cells

Answer 4

• dendritic cells, macrophages (monocytes), B cells
• chop up or process foreign antigens and display fragments of them on the cell surface to alert the immune system to the presence of a pathogen

Question 5

which formed elements are most responsible for humoral immunity?

Answer 5

B lymphocytes (B cells)

Question 6

2 largest lymphatic vessels

Answer 6

1. thoracic duct
   - origin: begins just below the diaphragm and ascends alongside the aorta
   - location of termination: empties into left subclavian vein
2. right lymphatic duct
   - origin: receives drainage from the right upper limb and the right side of the thorax and head
   - location of termination: empties into right subclavian vein

Question 7

histological property of larger lymphatic vessels

Question 8

germinal centers

Answer 8

• in the centers of lymphatic nodules, in the cortex of lymph nodes
• primary locations where B lymphocytes reproduce and proliferate

Question 9

thymus

Answer 9

• location: located between the sternum and aortic arch in the upper mediastinum
• fxn: the site where T cells differentiate and become immunocompetent, houses developing lymphocytes and secretes hormones that regulate their later activity