Lymphatic System Chapter 22

Why are the walls of the lymphatic vessels so thin, like veins?

The pressure in lymphatic vessels is low.

Lymphatic System Functions? (3)

1) Draining excess interstitial fluid and plasma proteins from tissue spaces 2) Transporting dietary lipids and vitamins from G1 track (small intestine) to the blood. 3) Facilitating immune responses-- recognizing microbes or abnormal cells and responding by killing.

What are the 3 stages of inflammation?

1) Vasodilation and increased permeability of blood vessels. 2) Emigration of phagocytes from the blood to interstitial fluid. 3) Tissue repair.

What is Immunity?

Activation of specific lymphocytes that combat a particular pathogen or other foreign substance. The ability of the body to defend itself against specific invading agents.

Bacteria and viruses in infected tissues easily enter lymph vessels. Explain why?

Bacteria and viruses can be picked up by lymphatic capillaries that have large openings to drain interstitial fluid. From here, microbes enter the lymphatic vessels.

A patient has enlarged right inguinal lymph nodes that are very tender to the touch. Examination of the feet reveals a small cut between the 3rd and 4th toes, which are warm and red. What would your initial impression be, and why are the lymph nodes enlarged?

Bacteria entered the body through the small cut between the toes and traveled up the lymphatic vessels of the leg into the inguinal lymph nodes. Lymph travels through the lymph nodes slowly, allowing phagocytosis to occur by macrophages. The increased number of bacteria in the lymph nodes causes swelling.

What would be missing in lymph exiting a lymph node, compared with lymph entering the node?

Bacteria, viruses, worn out cells, and other debris engulfed by macrophages.

What is Nonspecific Resistance?

Defense mechanisms that provides general protection against invasion by a wide range of pathogens.

What is Inflammation?

It is what occurs when cells are damaged by microbes, physical agents, or chemical agents.

What is Susceptibility?

Lack of resistance.

Secondary Lymphatic Organs?

Lymph nodes and the spleen.

How do lymphatic capillaries differ from blood capillaries?

Lymphatic capillaries are slightly larger in diameter than blood capillaries and have one-way openings that drain interstitial fluid into them. In addition, they are attached to surrounding tissues by anchoring filaments and they are closed at one end.

If you look into a child's mouth, there are

Palatine tonsils

Primary Lymphatic organs?

Red bone marrow and the thymus gland that produces B and T cells.

Would you describe the flow of lymph through lymph through lymph nodes as being fast or slow, compared with blood capillaries?

Slower than blood capillaries due to the lymph node structure. Each lymph node has more afferent vessels entering it than efferent vessels leaving it. This slows lymph flow through the node.

What are the distinguishing properties of immunity?

Specificity and memory.

What is Resistance?

The ability to ward off the pathogens that produce disease.

What is the Lymphatic System?

The body system that carries out immune responses.

What is Immunology?

The branch of science that deals with the responses of the body when challenged by antigens.

How would the lymph that is leaving the cisterna chyli differ from lymph draining into the right lymphatic duct?

The lacteals (lymphatic capillaries) in the small intestine absorb dietary lipids (chylomicrons) and lipid soluble vitamins into the lymph. Lacteals drain into the cisterna chyli, that in turn drains into the thoracic duct. The right lymphatic duct does not receive any lymph from the small intestine so it would not contain any dietary fat.

What are antigens?

The substances recognized as foreign by the immune responses.

If you dissected a fetal pig or a young cat, what difference would you expect in the thymus compared to the adult?

The thymus of the fetal pig or young cat is very large compared to an adult. The thymus regresses with age and is replaced by adipose tissue.

If a woman had a radial mastectomy (removal of a cancerous breast, surrounding tissues with axillary lymph nodes, and anterior thoracic muscles), would you expect the arm on that side to be edematous (have edema)? Explain.

Yes, Lymph nodes have lymphatic vessels leading into them that would drain the axillary area around the lymph nodes of excess interstitial fluid. When these structures are removed, excess interstitial fluid may build up.