chapter 21 Q&A

What are the three main functions of the lymphatic system?

Fluid recovery, immunity, and lipid absorption.

What percentage of water and plasma proteins are recovered by the lymphatic system daily?

15% (2 to 4 L/day).

What is lymph?

The recovered fluid that is usually clear and colorless, similar to blood plasma but low in protein.

What are lymphatic vessels?

Structures that transport lymph, beginning with lymphatic capillaries that converge into larger collecting vessels.

Where do lymphatic trunks empty into?

They empty into two collecting ducts, the right lymphatic duct and the thoracic duct.

What are the main lymphatic organs, w/ their anatomy and functions?

Red bone marrow: soft, highly vascular material that’s involved in hemopoiesis and immunity

thymus: bilobed organ located in sup. mediastinum. Where T&B cells become immunocompetent

lymph nodes: numerous lymphatic organs, 450 in adults. the bottleneck that slows down lymph flow and cleanses foreign matter

tonsils: patches of lymphatic tissue located at the entrance to the phyranx

spleen: the body’s largest lymphatic organ, 12 cm long, 160 g. Blood production in fetus, blood reservoir, RBC disposal, and white pulp monitors blood for foreign antigens

What is the role of the thymus?

The site where T and B cells become immunocompetent.

What do lymph nodes do?

They cleanse lymph by removing foreign matter and act as a site for T and B cell activation.

What are tonsils?

Patches of lymphatic tissue located at the entrance to the pharynx that guard against ingested or inhaled pathogens.

What is the spleen's function?

Blood production in the fetus, blood reservoir, disposal of RBCs, and monitoring blood for foreign antigens.

What are the three lines of defense in the immune system?

External barriers, other nonspecific resistance mechanisms, and specific immunity.

What characterizes the first line of defense?

External barriers such as skin and mucous membranes that provide nonspecific resistance.

What is the role of the skin in immune defense?

It acts as a mechanical and chemical barrier against pathogens.

What do mucous membranes do?

They trap microbes and contain lysozyme which destroys bacterial cell walls.

What types of protective cells are involved in the second line of defense?

Leukocytes and macrophages.

What are neutrophils responsible for?

Wandering in connective tissue and killing bacteria.

What is the primary function of eosinophils?

They guard against parasites, allergens, and other pathogens.

What is the role of basophils in immune response?

Secreting chemicals that aid the mobility and action of other leukocytes.

What are interferons?

Proteins secreted by virus-infected cells that protect neighboring cells from infection.

What distinguishes the third line of defense from the first two?

It involves specific immunity.

What is humoral immunity?

Antibody-mediated immunity that involves B cells and targets extracellular pathogens.

What do B cells do in humoral immunity?

They create and release antibodies that tag pathogens for destruction.

What is cellular immunity?

T cell-mediated immunity that directly attacks and destroys infected or diseased host cells.

What is the role of memory cells in immunity?

They allow for a rapid response upon re-exposure to a pathogen.

How do helper T cells assist in the immune response?

They secrete interleukins to attract and activate other immune cells.

What is the relationship between lymph nodes and metastatic cancer?

Cancer cells can spread to nearby lymph nodes, indicating disease progression.

What is tonsillitis?

Inflammation of the tonsils, often due to infection.

What is the acid mantle of the skin?

A protective layer formed by lactic acid from sweat that inhibits bacterial growth.

What is dermicidin?

An antibacterial peptide found in sweat that helps destroy pathogens.

How do mucus membranes contribute to the immune defense?

They trap microbes in the digestive, respiratory, urinary, and reproductive tracts using mucus.

What is the purpose of immunological memory?

To allow the body to mount a faster and more effective response to previously encountered pathogens.

what line(s) of defense are called non-specific resistance

First and Second line

What are the three categories of the second line of defense in the immune system?

Protective cells, protective proteins, and protective processes.

What are the key stages of humoral immunity?

1. Recognize: Antigen recongntion

   -B cells recognize and bind to antigens.

2. antigen presentation

   - b cell and t cells binds to b cell adn secretes interleukin

3. clonal selelction

   - interluekin stims b cell to divide and form clone

4. Remember: deffereintion

   • some cells of clone become mmeory b cells, mst differ into plasma cells

5. React: Attack

   • plasma cells synthesize adn secret antibody. antibody

What role do B cells play in humoral immunity?

B cells create and release antibodies to tag pathogens for destruction; they primarily target extracellular pathogens.

What is cellular immunity?

Cell-mediated immunity that involves T cells directly attacking and destroying foreign or diseased cells.

What are the key stages of cellular immunity?

1. Recognize: Antigen-Presenting Cells (APCs) present antigens to T cells.

2. React: T cells carry out the attack on infected cells.

3. Remember: Memory T cells provide a rapid response to re-exposure.

What are the roles of cytotoxic T cells?

Cytotoxic T cells directly attack infected or foreign cells by recognizing antigen-MHC-I complexes and releasing chemicals to destroy them.

How do helper T cells assist in the immune response?

Helper T cells secrete interleukins that attract and activate other immune cells, such as neutrophils, macrophages, T cells, and B cells.

What is lymphadenitis?

Lymphadenitis is the inflammation of lymph nodes, often due to infection.

How does lymphadenopathy differ from lymphadenitis?

Lymphadenopathy refers to the enlargement of lymph nodes, while lymphadenitis specifically involves inflammation.

What is the relationship between lymph nodes and metastatic cancer?

Cancer cells can spread through the lymphatic system to nearby lymph nodes, which may indicate disease progression.

What is the condition of tonsillitis?

Tonsillitis is the inflammation of the tonsils, typically caused by viruses or bacteria.

What characterizes Severe Combined Immunodeficiency Disease (SCID)?

SCID is a genetic disorder marked by a severely compromised immune system, affecting both T and B cell functions.

What happens in Acquired Immunodeficiency Syndrome (AIDS)?

AIDS is a disease caused by the HIV virus that progressively damages the immune system, leading to increased vulnerability to infections.

What are the 4 forms of specific resitance immunity?

natural active immunity

artificial active immunity

natural passive immunity

artificial passive immunity.

What is natural active immunity?

the prodction of ones own antibodies or t cells as a result of natural exposure to an antigen

What is artificial active immunity?

produciton of antibodies from vaccination from disease like, flu, tetanus or smallpox

What is natural passive immunity?

temporary immunity resulting from acquiring antibodies produced by another person

What is artificial passive immunity?

temporary immunity resultoing from injection of immue serum obtained from another person or animals that have antibodies against pathogen.

Where do B and T lymphocytes mature and become immunocompetent?

B lymphocytes mature in the bone marrow, while T lymphocytes mature in the thymus.

What is an antigen?

substance that triggers the body's immune system to produce antibodies.

What is a pathogen?

a microorganism that can cause disease

If either of the collecting ducts become obstructed, what kind of edema would result?

lymphedema

What are the Six Lymphatic trunks?

Subclavian, Jugular, bronchomediastinal, intercostal, Lumbar, and Intestinal