Lecture Exam 2 - Lymphatic System Study Guide Flashcards Preview

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Terminology and Structure --

Define: Immunity

The body is continually exposed to toxins and pathogens (disease-inducing substances) including viruses, bacteria and environmental pollutants.

Our immune system allows us to defend against these harmful substances.


Terminology and Structure --

Define: resistance

The ability to ward off the pathogens that produce disease


Terminology and Structure --

Define: Susceptibility

Lack of resistance to pathogens that produce disease


Terminology and Structure --

Define: lymphatic system

The body system that carries out immune responses is the lymphatic system.


Terminology and Structure --

Define: non-specific (innate) immunity

Nonspecific resistance to disease includes
defense mechanisms that provide general
protection against invasion by a wide range of


Terminology and Structure --

Define: specific immunity.

What are the two types of specific immunity?

Immunity involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance.

Specific resistance or immunity is ability to fight a specific pathogen. Two types of immunity:
– cell-mediated immunity
– antibody-mediated immunity


Lymphatic System Structure --

What is the name of the fluid that flows through the lymphatic system?

Lymph -- very similar to interstitial fluid


Lymphatic System Structure --

Where are lymphocytes produced?

Bone Marrow


Lymphatic System Structure --

What are the main functions of the lymphatic system?

1) Draining excess interstitial fluid & plasma proteins from tissue spaces

2) Transporting dietary lipids &
vitamins from GI tract to the blood

3) Facilitating immune responses –recognize microbes or abnormal cells & responding by killing them directly or secreting antibodies that cause their destruction


Lymphatic System Structure --

Name the primary lymphatic organs.

Primary lymphatic organs

– provide environment for stem cells to divide & mature into B and T lymphocytes
• red bone marrow gives rise to mature B cells
• thymus is site where pre-T cells from red marrow mature


Lymphatic System Structure --

Name the secondary lymphatic organs.

Secondary lymphatic organs & tissues
– site where most immune responses occur
• lymph nodes, spleen & lymphatic nodules


Lymphatic System Structure --

Describe the differences between lymphatic vessels and blood vessels.

Lymphatic capillaries have a slightly larger diameter than blood capillaries and have overlapping endothelial cells which work as one-way valves for fluid to enter the lymphatic


Lymphatic System Structure --

What are lacteals and where are they located?

A lymphatic capillary in the villus of the small intestine is the lacteal. It functions to transport digested fats from the small intestine into blood.


Lymph Ducts --

What are the names of the two major lymphatic ducts and what parts of the body do they drain?

the right lymphatic duct and the thoracic duct.

The thoracic duct receives lymph from the left side of the head, neck, and chest, the left upper extremity, and the entire body below the ribs.

• It drains lymph into venous blood via the left subclavian vein.

• The Right side head, arm & chest empty into right lymphatic
duct and rest of body empties into thoracic duct

• Lymph is dumped directly into left & right subclavian veins.


Thymus Gland --

Where in the body is the thymus gland located?

2 lobed organ located in mediastinum (superior and anterior to the heart)


Thymus Gland --

What cells are found in the thymic cortex?

tightly packed T lymphocytes & macrophages


Thymus Gland --

What cells are found in the thymic medulla?

-- reticular epithelial cells produces thymic hormones
– Hassall’s corpuscles (possible sites of T cell death)


Thymus Gland --

What are Hassall’s corpuscles?

possible sites of T cell death


Thymus Gland --

What is the major function of the thymus?

thymus is site where pre-T cells from red marrow mature


Thymus Gland --

What is the difference in thymus size and function in the newborn compared to an adult?

Large organ in infants (70 g) but atrophied as adult (3 g).


Lymph Nodes --

Describe the structure and function of lymph nodes.

Lymph nodes are encapsulated oval structures located along lymphatic vessels.

• They contain some T cells, macrophages, follicular dendritic cells, and B cells.

• Lymph enters nodes through afferent lymphatic vessels, is filtered to remove damaged cells and microorganisms, and exits through efferent lymphatic vessels.

• Foreign substances filtered by the lymph nodes are trapped by nodal reticular fibers.

• Macrophages then destroy some foreign substances by phagocytosis and lymphocytes bring about the destruction of others by immune responses.

• Lymph nodes are the site of proliferation of plasma cells (mature B cells) and T cells.


Spleen --

What is found in the white pulp?
What is found in the red pulp?

Parenchyma consists of white pulp and red pulp:

– white is lymphatic tissue (lymphocytes & macrophages) around branches of splenic artery

– red pulp is venous sinuses filled with blood & splenic tissue (splenic cords)


Spleen --

What role does the spleen play in pregnancy that is does not usually perform?



Spleen --

What are trabeculae?



Lymphatic nodules --

Describe where MALT is found.

Where are the tonsils?

Where is the appendix?



Malignant Tumors --

What does the term metastasis mean? How does a tumor metastasize? What is the difference between a primary and secondary tumor?



Malignant Tumors --

What is the difference in the feel of a cancerous lymph node compared to an inflamed/infected lymph node.



Non-Specific (Innate) immunity --

1) First line of defense (skin and mucous membranes).

Describe methods of mechanical and chemical protection in the skin and mucous



Non-Specific (Innate) immunity --

2) Second line of defense (internal defenses)

Antimicrobial proteins: interferons, complement, defensins.
Natural killer cells.


Non-Specific (Innate) immunity --

What cells are phagocytic?
Describe 5 phases of phagocytosis.

Phagocytes (neutrophils & macrophages)

– ingest microbes or particulate matter

– macrophages developed from monocytes

• fixed macrophages stand guard in specific tissues
– histiocytes in the skin, kupffer cells in the liver, alveolar
macrophages in the lungs, microglia in the brain &
macrophages in spleen, red marrow & lymph nodes

• wandering macrophages also enter and exit tissues

– The phases of phagocytosis are:


Non-Specific (Innate) immunity --

What mechanisms do microbes use to evade phagocytosis?

Capsule formation

Toxin production

Interference with lysozyme secretion

Ability to counter oxidants produced by the phagocytes.


Non-Specific (Innate) immunity --

What is the function of inflammation?

Function is to trap microbes, toxins or foreign material
& begin tissue repair


Non-Specific (Innate) immunity --

What are the clinical signs of inflammation?
What are the major stages of inflammation?

Signs of inflammation
– redness
– heat
– swelling
– pain
– Loss of function may be a fifth symptom, depending on the site
and extent of the injury.

The three basic stages of inflammation are:
1) Vasodilation and increased permeability of blood vessels
2) Phagocyte migration (neutrophils and macrophages)
3) Tissue repair


Non-Specific (Innate) immunity --

Define abscess, ulcer, fever. What cytokine is the major inducer of fever?

Abscess: accumulation of pus in a confined space not open to the outside (pimples and boils)

Ulcer: Open sore

Fever: Abnormally high body temperature that occurs because the hypothalamic thermostat is reset

Fever occurs during infection & inflammation
– bacterial toxins trigger release of fever-causing
cytokines such as interleukin-1


Specific Immunity --

Define: specificity, memory, antigen, antibody.

Specificity: recognizes self & non-self

Memory: 2nd encounter produces even more vigorous

Antigens: substances recognized as foreign by the immune response

Antibody: a protein that can combine specifically with the antigenic determinant on the antigen (epitope) that triggered its production.


Specific Immunity --

How does specific immunity differ from non-specific immunity?

-- specificity----recognizes self & non-self
– memory----2nd encounter produces even more vigorous


Specific Immunity --

Where are pre-T cells formed?
Where do T cells mature?
What type of invaders are T cells most able to combat?

Where are pre-T cells formed?
Bone Marrow

Where do T cells mature?

What type of invaders are T cells most able to combat?
effective against fungi, viruses, parasites, cancer, and
tissue transplants


Specific Immunity --

Where do B cells develop?
What type of invader are B cells most able to combat?

Where do B cells develop?
Bone Marrow

What type of invader are B cells most able to combat?


Specific Immunity --

Define: antigen, epitope, hapten.

Antigens are large, complex molecules, usually proteins
– substances with simple repeating subunits are not usually antigenic (plastics in joint replacements)
– only a small part of the antigen that triggers the immune response - called an epitope

• Haptens are smaller substance that cannot trigger an immune
response unless attached to
body protein
e.g. the lipid of poison ivy


Major Histocompatibility Complex Antigens --

What is an MHC antigen?
What is the difference between class I and class II MHC antigens?

All our cells have thousands of molecules that are unique surface markers.
– integral membrane proteins called HLA antigens (human leukocyte antigens)

• MHC-I molecules are built into cell membrane of all cells except red blood cells

• MHC-II markers are seen only on membrane of antigen presenting cells (macrophages, B cells, thymus cells)


Major Histocompatibility Complex Antigens --

What is the function of MHC antigens?
Where are MHC class I and class II antigens found?

MHC antigens help a T cell recognize whether something is foreign to the body or not.

MHC-I are found in the cell membrane of all cells except RBCs

MHC-II are seen on the membrane of antigen presenting cells (macrophages, B cells, thymus cells)


Major Histocompatibility Complex Antigens --

What is histocompatibility testing?
In what circumstances is histocompatibility testing useful?

Histocompatibility is a similarity of MHC antigens on body cells of different individuals

– tissue typing must be done before any organ transplant.

– can help identify biological parents.


Antigen-presenting cells --

What cell-types can present antigen?
What is the purpose of antigen presentation?

Cells called antigen-presenting cells (APCs) process exogenous antigens (antigens formed outside the body) and present them together with MHC class II molecules to T cells.

• APCs include macrophages, B cells, and dendritic cells.

• The presentation of exogenous antigens together with MHCII molecules on antigen presenting cells alerts T cells that “intruders are present”.


Cytokines --

Define: cytokine, interleukin, interferon. Know which cytokines are most important in costimulation of T cells and B cells and in activation of macrophages.

Cytokines are small protein local mediators involved in immune responses
– mostly secreted by lymphocytes and antigen
presenting cells
-Interleukin and interferon are cytokines

Proliferation of T cells requires costimulation,
by cytokines such as interleukin-1 (IL-1) and
interleukin-2 (IL-2)/


Cell-mediated Immunity --

What type of lymphocytes are important in cell-mediated immunity?

In a cell-mediated immune response:

1) An antigen is recognized (bound).

2) A small number of specific T cells proliferate and differentiate into a clone of effector cells (a population of
identical cells that can recognize the same antigen and carry out some aspect of the immune attack).

3) The antigen (intruder) is eliminated.


Cell-mediated Immunity --

Know the key roles of cytotoxic T cells, helper T cells and memory T cells in cell-mediated immunity.



Cell-mediated Immunity --

Know the different names used for cytotoxic and helper T cells.



Cell-mediated Immunity --

Know the processes of activation, proliferation and differentiation of cytotoxic and helper T cells.



Cell-mediated Immunity --

Know how activated cytotoxic T cells ultimately attack and destroy invaders.



Graft rejection --

What is meant by the term graft rejection?
What precautions will make it most likely that a transplant surgery will succeed?



Tumor antigens --

What is a tumor antigen?
What is meant by the term immunological surveillance?



Antibody-mediated immunity --

What cells are responsible for antibody-mediated immunity?



Antibody-mediated immunity --

Where in the lymphatic system does antigen come in contact with B cells?
What are B cells called when they become differentiated antibody-secreting cells?



Antibody-mediated immunity --

Understand the important steps in the activation, differentiation and proliferation of B



Antibodies --

Know the structure of antibodies (focusing on the IgG sub-type).



Antibodies --

Know the five different classes of antibodies and the specific functions of each class.



Antibodies --

What is a monoclonal antibody?
How are monoclonal antibodies produced?



Antibodies --

Describe clinical applications of monoclonal antibodies.



The Complement System --

What are the important roles of the complement in microbe destruction?



Immunological Memory --

Memory T cells and memory B cells provide immunological memory. Some antibodies also
survive for a long time.

Understand the different immunoglobulin responses after a primary and secondary immune response.



Immunological Memory --

What is meant by the term antibody titer?
How do the titers of IgM and IgG differ? See Fig. 22.19.

The amount of an antibody in a person’s blood is called the antibody titer.


Aging and the immune response --

In what ways does immune system function decrease with age?

T cells less responsive to antigens
– age-related atrophy of thymus
– decreased production of thymic hormones
B cells less responsive
– production of antibodies is slowed


Hypersensitivity Reactions --
Define the terms: hypersensitivity, allergy, allergen.

A person who is overly reactive to a substance that is tolerated by most others is said to be hypersensitive (allergic).

Whenever an allergic reaction occurs, there is inflammation. The antigens that induce an allergic reaction are called allergens.


Hypersensitivity Reactions --

Know the features of the 4 basic types of hypersensitivity reactions.

Type I (anaphylaxis) reactions are the most common and occur with a few minutes after a person sensitized to an allergen is reexposed to it.

Type II (cytotoxic) reactions are caused by antibodies (IgG or IgM) directed against a person’s blood cells or tissue cells.

Type III (immune complex) reactions involve antigens
(not part of a host tissue cell), antibodies (IgA or IgM),
and complement.

Type IV (cell-mediated) reactions or delayed hypersensitivity reactions usually appear 12-72 hours after exposure to an allergen.


Types of Immunity --
Understand the classification of immunity into naturally or artificially acquired and actively or passively acquired.



Specific Immunity --

What are the major characteristics of antigens?

• Required characteristics to be considered an antigen
– immunogenicity = ability to provoke immune response
– reactivity = ability to react to cells or antibodies it caused to be formed


Specific Immunity --

Why can the immune system recognize and respond to so many different epitopes?

• Explanation for great diversity of receptors is genetic recombination of a few hundred small gene segments.

• Each B or T cell has its own unique set of gene segments that codes its unique antigen receptor in the cell membrane.