Lymphatic System (Unit 4)

Describe the formation of lymph and its drainage pattern back into the circulatory system:

1.Lymph originates as plasma (the fluid portion of blood). The arterial blood, which flows out of the heart, slows as it moves through a capillary bed. This slowing allows some plasma to leave the arterioles (small arteries) and flow into the tissues where it becomes tissue fluid. 2. Arterial blood carries oxygen, nutrients, and hormones for the cells. To reach these cells it leaves the small arteries and flows into the tissues. This fluid is now known as interstitial fluid and it delivers its nourshing products to the cells. Then it leaves the cell and removes waste products.After this task is complete, 90% of this fluid returns to the circulatory system as venous blood.

Correlate the location and function of Peyer's Patches:

Another secondary lymphatic organ are the Peyer patches. Peyer's patches are lymphatic nodules found in the intestinal wall and the appendix. They are considered nodules since they lack the capsule found in nodes. They work to protect the body against pathogens that may have entered the body through the digestive tract.

Correlate the location and function of Lymph nodes:

Lymph nodes are secondary lymphatic organs. They are found all along the lymphatic vessels and are small and oval in structure. Connective tissue covers the outer capsule and a nodule is found in compartments throughout the nodes that have B and T lymphocytes packed within them. As the lymphatic fluid flows through the nodes, they are filtered by macrophages (phagocytic white blood cells) as well as come into contact with the Tcells as well. Nodes can either be superficial, near the surface of the body or deeper in the body.

Correlate the location and function of the Primary Lymphatic Organs:

Lymphatic organs have large numbers of white blood cells and therefore very important for the body's immune system. The primary lymphatic organs are the thymus gland and the red bone marrow. Lymphocytes originate and/or mature in these primary organs.

Other than produce T cells what else does the thymus do?

Produces other cells and thymic hormones that enable T cells to become immunologically competent and able to recognize foreign antigens and provide immunity

List the functions of the lymphatic system:

Produces, maintains and distributes T cells, B cells and NK cell

Correlate the location and function of the Red Bone Marrow:

The red bone marrow is found in the medullary cavity of bone and is where blood cells are produced. In adults the red bone marrow is found in the sternum, vertebrae, ribs, skull, pelvic girdle and the proximal part of the humerus and femur. Children, however, have red bone marrow in most of the bones. Lymphocytes, among the other blood cells form here. Lymphocytes B lymphocytes and T lymphocytes both originate here. B lymphocytes will mature in the red bone marrow while the T lymphocytes will travel to the thymus gland to mature.

Correlate the location and function of the spleen:

The spleen is the largest lymphatic organ and is located in the upper left region of the abdominal cavity. It sits posterior to the stomach and also filters the lymphatic fluid. The connective tissue forms compartments called white or red pulp. The white pulp has the lymphocytes and the red pulp are found near the venous sinuses. The red pulp works to filter the blood. The spleen is important in both the immune system as well as removing old, worn out red blood cells from circulation. Since the outer layer of the spleen is very thin, it is susceptible to rupture with impact or trauma. The lymphatic function can then be carried out by the rest of the lymphatic system if the spleen must be removed, however they typically live with a greater risk of infection the rest of their lives.

Correlate the location and function of Tonsils:

The tonsils are the last secondary lymphatic organs. There are 3 pairs of them in the posterior pharynx: the palatine, pharyngeal and lingual tonsils. They are also considered nodules due to the absence of the protective capsule. However, they function very similar to the nodes and are typically the first to encounter a pathogen or antigen that enters the body either through the mouth or nose.

What are the types of Tonsils:

a. Palatine- The palatine tonsils are in the posterior oral cavity. b. Pharyngeal- The pharyngeal tonsil, sometimes called the adenoid, is found in the Nasopharynx. c. Lingual- The lingual are located at the base of the tongue.

What does the Thymus do?

produces T cells and hormones necessary for the maturation of the immune system

Correlate the location and function of the Thymus:

what is the thymus? an organ made of lymphatic tissue located inferior to the thyroid gland -large in fetus and shrinks over aging