Lymphatic System

What is MALT? List several components of MALT.

(Mucosa-associated lymphoid tissue): is a lymphoid tissue found in the mucosa of the digestive, respiratory, and genitourinary tracts. It includes tonsils, Peyer's patches, and the appendix.

The _______ ____ _____ keeps blood-bourne antigens out of the thymus.

*blood thymus barrier*

The _____ _____ and tissues provide the structural basis of the immune system.

*lymphoid organs and tissues*

Lymphoid tissue comes in various "packages"

-Diffuse lymphoid tissue -Lymphoid follicles

What are the main functions of the *lymphoid tissue*

-Houses and provides proliferation sites for lymphocytes -Lymphocytes and macrophages as they filter through lymph.

3 important functions of the Spleen:

-Recycles the breakdown products of red blood cells for later reuse. it releases the breakdown products to the blood for processing by the liver and stores some of the iron salvaged from hemoglobin. -Stores blood platelets and monocytes for release into the blood when needed. -Site of erythrocyte production in fetus

List several functions of the spleen:

-The spleen cleanses the blood, recycles breakdown products of RBCs, stores iron, stores platelets and monocytes, and is thought to be a site of erythrocyte production in the fetus.

Lymph Nodes have 2 basic protective functions:

1. Cleansing the lymph 2. Immune system activation

The Appendix is in an ideal position to (1.) ____________, and (2) ________.

1. Prevent bacteria (present in large numbers in the intestine) from breaching the intestinal wall. 2. Generate many "memory" lymphocytes for long-term immunity.

The Thymus is primarily lymphoid organ and differs from secondary lymphoid organs in three important ways.

1. The thymus has no follicles because it lacks B cells 2. The thymus does not directlly fight antigens. Instead, the thymus functions strictly as a maturation site for T lymphocyte precursors. These precursors must be kept isolated from foreign antigens to prevent their premature activation. 3. The stroma of the thymus consists of epithelial cells rather than reticular fibers. These epithelial cells provide the physical and chemical environment in which T lymphocytes mature.

The *lymphatic system* consists of 3 parts.

1. a meandering network of lymphatic vessels 2. Lymph, the fluid contained in those vessels 3. Lymph nodes that cleanse the lymph as it passes through them.

MALT: Mucosa-associated lymphoid tissues.

A set of distributed lymphoid tissues strategically located in mucous membranes throughout the body.

What are the primary lymphoid organs and what makes them special?

Are the red bone marrow and thymus. Primary lymphoid organs are the organs where lymphocytes originate and mature.

T Cells mature in the Thymus. Where do B cells mature?

B Cells mature in the bone marrow

Thymus:

Bilobed lymphoid organ found in inferior neck.

The enlarged terminus of the thoracic duct that receives lymph from the digestive viscera is called the ______.

Cisterna chyli

Lymphoid Tissue is largely composed of _____ ______.

Connective tissue

*(T/F)* Spleen contain follicles w/ germinal centers and scattered lymphocytes.

False (Tonsils)

*(T/F)* Lymph system is a high-pressure system like venous system.

False (it is a low-pressure system like the venous system)

Tonsils:

Form a ring of lymphoid tissue around the entrance to the pharynx (throat), where they appear as swellings of the mucosa.

lymphocytes differentiate in different lymphoid organs into B cells and T cels. A major functional difference between the two is that B cells ______.

Form antibody-producing plasma cells.

What is the benefit of having fewer efferent than afferent lymphatics in lymph nodes?

Having fewer efferents causes lymph to accumulate in lymph nodes, allowing more time for its cleansing.

A notable anatomical feature of the lymph node is that ______.

It has more afferent vessels than efferent vessels.

_____ is delivered from trunks into one of two large *lymphatic ducts.*

Lymph (right lymphatic duct drains right upper arm and right side of head and thorax) (Thoracic duct drains rest of body)

What is lymph? Where does it come from?

Lymph is the fluid inside lymphatic vessels. It enters lymphatic vessels from interstitial fluid. Interstitial fluid, in turn, is a filtrate of blood plasma.

What is the driving force for lymph movement ?

Lymph movement is driven by the contraction of adjacent skeletal muscles, pressure changes in the thorax during breathing, the pulsations of nearby arteries, and contraction of smooth muscle in the lymphatic vessel walls.

The bean shaped organs that cluster along the lymphatic vessels of the body and filter lymphatic fluid are known as _______.

Lymph nodes

______ are the main warriors of the immune system.

Lymphocytes

What is a lymphoid follicle? what type of lymphocyte predominates in follicles, especially in their germinal centers.

Lymphoid follicles are solid, spherical bodies consisting of tightly packed reticular fibers and lymphoid cells, often with a lighter-staining central region. Region where *B cells* predominate.

Antibodies are composed of one or more _______, each of which is made up of four protein chains connected by disulfide bridges.

Monomers

An antibody can bind to ______.

Only one specific antigen

_______ tonsils are located on either side at the *posterior end of the oral cavity*. Largest tonsils and the ones most often infected.

Palatine

_____ patches, or *aggregated lymphod nodules*, are large clusters of lymphoid follicles, structurally similar to the tonsils.

Peyer's `

The _____ tonsil is in the posterior wall of the nasopharynx.

Pharyngeal

Macrophages....

Play a crucial role in body protection and the immune response by phagocytizing foreign substances and by helping to activate T cells.

Functional categories of the *Lymphoid Organs*

Primary lymphoid organs Secondary lymphoid organs

The ____ lymphoid organs are where mature lymphocytes first encounter their antigens and are activated.

Secondary

In which organ of the lymphatic system do you find red and white pulp?

Spleen

Name two lymphatic ducts and indicate the body regions usually drained by each.

The right lymphatic duct receives lymph from the right upper arm and the right side of the head and thorax. The thoracic duct drains lymph from the rest of the body.

The bilobed _____ has important functions primarily during the early years of life. Found in the inferior neck and extends into the superior thorax, where it partially overlies the heart deep to the sternum.

Thymus

______ functions as lymphoid organ where T cells mature.

Thymus

The ____ gather and remove many of the pathogens entering the pharynx in food or in inhaled air.

Tonsils

The functions of the lymphatic system include all of the following EXCEPT:

Transporting oxygen and nutrients to tissues.

*(T/F)* Tonsils are the simplest lymphoid organs.

True

*(T/F)* Certain T cells directly destroy infected cells and are therefore said to mediate cellular immunity.

True

The tine ____ tonsils surround the openings of the auditory tubes into the pharynx.

Tubal

The _____ is a tubular offshoot of the first par of the large intestine and contains a high concentration of lymphoid follicles.

appendix

The lymphatic system works closely with the _____ system.

cardiovascular

Lymphatic vessels, or *lymphatics*:

elaborate networks of drainage vessels that collect the excess protein-containing interstitial fluid and return it to the blood stream.

Tonsils function is to...

gather and remove pathogens in food or air.

Important characteristic of the spleen is that it..

has blood-cleansing functions.

The lymphatic system contains key cells that work in the development of the body's defense system, also called the _______.

immune system.

The spleen is located:

in the left side of the abdominal cavity, just beneath the diaphragm, it curls around the anterior aspect of the stomach.

Physical activity ______ flow of lymph (immobilization of area keeps needed inflammatory material in area for faster healing)

increases

The _____ tonsil is the collective term for a lumpy collection of lymphoid follicles at the base of the tongue.

lingual

The ______ system return leaked fluid that have leaked from the vascular system back to the blood.

lymphatic

Appendix:

offshoot of first part of large intestine

The _____ lymphoid organs are where B and T cells mature- the *red bone marrow* and the *thymus*.

primary

T cells and B cells...

protect the body against antigens

The ____ provides a site for lymphocyte proliferation and immune surveillance.

spleen

The soft, blood-rich ______ is about the size of a fist and is the largest lymphoid organ.

spleen

Spleen:

stores iron and blood platelets