Module 13 AP224

True Interstitial fluid and blood plasma together constitute lymph. It is about 95% water, with the remainder consisting of plasma proteins and tissue fluid.

Lymph is derived from blood and tissue fluid.

True Lymph nodes mechanically filtrate by physically stopping particles from progressing in the body. They biologically filtrate by using processes such as phagocytosis to destroy particles.

Lymph nodes provide both biological and mechanical filtration.

small intestine Lymphatic vessels, often simply called lymphatics, originate as microscopic blind-end vessels called lymphatic capillaries. Those originating in the villi of the small intestine are called lacteals.

Lymph capillaries called lacteals are located in the:

False Lymph does not contain platelets and does not clot.

Lymph contains platelets, which allow clots to form in lymphatic vessels.

afferent lymph vessels Efferent lymph vessels

Lymph enters a node via: Lymph Exits via:

A single lymph vessel Lymph exits a node through a single efferent lymph vessel. Although there are four afferent lymph vessels that allow lymph to enter the lymph node for cleansing, a single efferent lymphatic vessel accommodates the exit flow of lymph.

Lymph exits a node through:

left hypochondriac region

the spleen is located

True As one ages, the thymus atrophies until, in advanced old age, it may be largely replaced by fat, weigh less than 10 g, and be barely recognizable. This process of shrinking is known as involution.

As one ages, the thymus decreases in size. This process is called involution.

False With the exception of comparatively few single nodes, most lymph nodes occur in groups, or clusters, in certain areas.

Even though some lymph nodes occur in clusters, most occur as single nodes.

splenomegaly Splenomegaly, an enlargement of the spleen, is often caused by infectious diseases such as scarlet fever, typhoid fever, and syphilis

Infectious diseases such as scarlet fever, typhoid fever, and syphilis may cause:

True Once lymph enters the node, it "percolates" slowly through the spaces known as sinuses before draining into the single efferent exit vessel so microorganisms and particulate matter can be phagocytized.

One function of lymph nodes is to slow the lymph flow so microorganisms and particulate matter can be phagocytized.

False The thymus serves as the final site of lymphocyte development before birth. The fetal bone marrow forms immature lymphocytes, which then move to the thymus.

The fetal thymus forms immature lymphocytes, which then move to the bone marrow for the final stages of lymphocyte development before birth.

False The lymphatic system is not a closed system of vessels like the circulatory system. Instead, lymph fluid flows through the lymphatic vessels and eventually empties into the circulatory system at the junction of the internal jugular and subclavian veins.

The lymphatic system, like the circulatory system, is a closed circuit.

thoracic duct Lymph drained from approximately three fourths of the body eventually collects in the thoracic duct. Lymph from the upper right quadrant of the body empties into the right lymphatic duct.

The majority of the body's lymph is drained by the:

Thymus Soon after birth the thymus begins secreting a group of hormones (collectively called thymosin) and other regulators that enable lymphocytes to develop into mature T cells.

The part of the lymphatic system that secretes a hormone is the:

True The red pulp of the spleen is made up of a network of fine reticular fibers submerged in blood that comes from nearby arterioles.

The red pulp of the spleen is red because it contains a great deal of blood.

Thymosin The thymus secretes a group of hormones collectively called thymosin, which is vital to the body's T-cell development and the immune system.

The thymus secretes:

Palatine The palatine tonsils are the tonsils usually removed during a tonsillectomy. The pharyngeal tonsils, known as adenoids, usually atrophy during adolescence and then no longer require removal during a tonsillectomy. The lingual tonsils are near the base of the tongue. It is not necessary to remove them during a tonsillectomy because they are rarely involved.

The tonsils are sometimes removed surgically if antibiotic therapy is not successful or if swelling impairs breathing. When a tonsillectomy is performed, which tonsils are usually removed?

Tonsils The tonsils are the mass of lymphatic tissue—or lymph nodes—located in the mouth and back of the throat. They filter tissue fluid contaminated by pathogens that enter the body through the nose or mouth or both.

What is the name of the lymph nodes that are located in the mouth and back of the throat?

Pharyngeal The pharyngeal tonsils are also known as adenoids, particularly when they become swollen. They are located near the posterior opening of the nasal cavity and tend to atrophy beginning during adolescence.

Which tonsils are known as adenoids, especially when they become swollen?