Anatomy C2: lymphatic system

MALT

Mucosa-associated lymphoid tissue.

Differentiate between blood capillaries and lymphatic capillaries.

-Lymphatic capillaries are slightly larger in diameter than blood capillaries, and have closed ends (unlike the loop structure of blood capillaries). -Lymph capillaries have a greater internal pressure than blood capillaries, due to the greater concentration of plasma proteins in the lymph.

Distinguish between blood capillaries and lymphatic capillaries.

-Lymphatic capillaries are slightly larger in diameter than blood capillaries, and have closed ends (unlike the loop structure of blood capillaries). -Their unique structure permits interstitial fluid to flow into them but not out. The ends of the endothelial cells that make up the wall of a lymphatic capillary overlap.

Explain the different functional roles of the primary and secondary lymphoid organs and list each structure included within each group.

-Primary lymphoid tissues (thymus, fetal liver and bone marrow) nurture lymphocyte development, whereas secondary lymphoid organs support lymphocyte maturation, survival and activation. Secondary lymphoid organs are distributed strategically throughout the body and drain antigenic material from tissues and organs.

Describe the major function of the lymphatic system and how it is functionally relate to the cardiovascular and immune systems.

-Return fluids that have leaked from the vascular system back to the blood. -Oxygenated blood being pumped from lungs to the heart and to the rest of the body via arteries. -Deoxygenated blood returning from the body via veins to the heart to the lungs. -Lymphatic vessels that are intertwined throughout the capillary beds and sending lymph's to the heart.

List additional substances carried by the lymph to the heart through the lymphatic vessels.

-The blood capillaries absorb most nutrients, but the fats and fat-soluble vitamins are absorbed by the lacteals. The lymph in the lacteals has a milky appearance due to its high fat content and is called chyle.

Defend the claim that the lymph nodes are the most critical structures in the lymphatic system.

-The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.

T cells

Cells created in the thymus that produce substances that attack infected cells in the body.

B cells

Cells manufactured in the bone marrow that create antibodies for isolating and destroying invading bacteria and viruses.

Lymphatic trunk

Drains lymph from specific body areas.

Describe the source of lymph and summarize how it is transported through the body, including where it ends up.

Form a one way system - Lymph only flows towards the heart - Begins in microscopic lymphatic capillaries, interwoven between tissue cells and blood capillaries.

Lymphatic vessels

Large vessels with valves, which collect and carry lymph to lymph nodes.

List and define three types of cells that make up lymphoid tissues and organs.

Primary lymphoid organs: Red bone marrow and the thymus -B Cells are made and mature in the red bone marrow. -T Cells are made in the red bone marrow and mature in Lymph the thymus. Secondary lymphoid organs: lymph nodes, spleen, and mucosa associated lymphoid tissue patches (MALT, which includes the appendix). • Where mature lymphocytes are activated.

Lymph nodes

Small oval clumps of lymphatic tissue located at grouped intervals along lymphatic vessels.

Lacteals

Specialized lymph vessels in the small intestine that absorb fat into the bloodstream.

Summarize the roles of the thymus nodes, spleen, tonsils, Peyer's patches, and appendix in the lymphatic and or immune system.

Thymus nodes- Where T cells mature so that they can actually defend us against pathogens when activated in an immune response - Key role early in life. Spleen- Cleanses blood and removes aged/defective RBCs, debris, and foreign substances in the red pulp tissue. -Activates and proliferates lymphocytes in the white pulp tissue. Tonsils- a ring of MALT around the entrance of the pharynx that gathers and tries to remove any pathogens from food or inhaled air before they can enter the GI tract or lungs. Peyer's patches- clusters of lymphoid tissue in the ileum of the small intestine that monitor intestinal bacteria populations and prevent the growth of pathogenic bacteria. Appendix- contains a bunch of lymphoid tissue to prevent bacteria from breaching the intestinal wall and generating "memory" lymphocytes for establishing long-term immunity.

Lymph

Watery fluid.