Lymphatic and Immune Systems Flashcards
Red Bone Marrow
Site for the origin of all types of blood cells
What are the four functions of the lymphatic system?
Lymphatic capillaries absorb excess tissue fluid and return it to the bloodstream
Lymphatic capillaries in the small intestine absorb fats associated with proteins
Lymphatic System works in the production, maintenance, and distribution of lymphocytes in the body
Helps in defense against pathogens
Thymus
Lymphatic tissue where T lymphocytes mature and learn to tell “self” from “nonself”
Spleen
Cleanses the blood of cellular debris and bacteria, while resident lymphocytes respond to the presence of antigens
Name the four components of the Lymphatic System.
Red Bone Marrow
Thymus
Spleen
Lymphatic Vessels & Lymph Nodes
Lacteals
Lymphatic capillaries in the small intestine
Lymph
Fluid in the lymphatic system that passes through the one-way valve system
What is the function of lymphatic vessels?
Lymphatic vessels function is to return tissue fluid (which includes water, solutes, and cell products) to the bloodstream.
Name the two primary lymphatic organs.
Red bone marrow
Thymus
Name the two secondary lymphatic organs.
Lymph nodes
Spleen
What is red bone marrow the site of?
Red bone marrow is the site of blood cell production, and produces many types of white blood cells, including lymphocytes (B cells and T cells).
Where do B cells mature?
B cells mature in the red bone marrow.
Where do T cells mature?
T cells mature in the thymus.
Where is the thymus located in the body?
The thymus is a bilobed gland located in the thoracic cavity superior to the heart.
Do children or adults have more red bone marrow?
Children have more bones with red marrow.
Is the thymus larger or smaller in children?
Larger.
About how many of the T lymphocytes will be put to work after maturing?
About 5% of the T lymphocytes will pass the final test and be put to work in one’s body.
What are lymph nodes?
Small, oval-shaped structures found along the lymphatic vessels.
What are lymph nodes filled with?
Lymph nodes are filled with B cells, T cells, and macrophages.
Where are lymph nodes commonly found?
Lymph nodes are common in the neck, armpit, and groin regions.
Where is the spleen located?
The spleen is located in the upper left region of the abdominal cavity.
What does the spleen contain?
The spleen is filled with white pulp, which contains lymphocytes, and red pulp, which is involved with filtering the blood.
Name the two parts of the first line of defense.
Physical and chemical barriers to entry.
Name the three parts of the second line of defense.
Phagocytic white blood cells
Inflammatory Response
Protective Proteins
Name four physical barriers to entry.
Skin, and then tears, saliva, and urine all flush out microbes.
What lines the respiratory, digestive, reproductive, and urinary tracts?
Mucous membranes.
What is the function of the resident bacteria and flora that inhabit the body?
The normal flora use available nutrients and space, thus preventing pathogens from taking up residence.
Lysozyme
Antibacterial enzyme
Name three chemical barriers.
The secretions of the oil glands (sweat, oil on face and hair)
Lysozyme
The acidic pH of the stomach and vagina
What is the purpose of the phagocytic white blood cells?
Phagocytic white blood cells leave circulation and move into tissue, and are important in the inflammatory response.
What do the phagocytic white blood cells include?
Phagocytic white blood cells include neutrophils and macrophages.
Name four hallmark symptoms of the inflammatory response.
Heat, swelling, redness, and pain.
Mast cells do what?
Release histamine.
Histamine does what?
Histamine causes the capillaries to dilate and become more permeable to phagocytic white blood cells.
What causes the heat in the inflammatory response, and what is the purpose of this?
Increased blood flow to an area raises the temperature, and this inhibits some pathogens.
What does increased blood flow do in the inflammatory response?
Increased blood flow increases warmth, and brings more white blood cells to an injured area.
What do neutrophils do in the inflammatory response?
Neutrophils are the first scouts to kill pathogens.
What do cytokines do if the neutrophils cannot control the damage right away?
Cytokines will initiate recruitment of more white blood cells, including macrophages, if the neutrophils can’t control the damage at the injured spot.
Name two types of protective proteins.
Complement (system)
Interferons
What are complement (system) proteins?
Complement proteins are a group of blood plasma proteins.
How are complement proteins involved in the inflammatory response?
Complement proteins are involved in the inflammatory response by binding to mast cells, causing them to release histamine.
Outside of the inflammatory response, what do complement proteins do?
Complement proteins attract phagocytes to pathogens by binding them, and they form a membrane attack complex that makes holes in some bacteria and viruses, causing them to burst.
What are interferons, and what do they do?
Interferons are proteins produced by virus-infected cells and sent out to warn neighboring healthy cells.
The third line of defense is called what?
Adaptive, or specific, defense.
What does adaptive defense do?
Adaptive defense helps protect us against specific pathogens when nonspecific defenses fail, and helps to protect us against cancer. It depends on the action of B cells and T cells.
Two types of lymphocytes
B cells and T cells
B cells do what?
B cells produce plasma cells and memory cells.
T Cells do what?
T cells regulate immune response, and produce various types of T cells.
Name the three types of T cells.
Cytotoxic T cells
Helper T cells
Memory T cells
What do plasma cells produce?
Plasma cells produce specific antibodies.
Antibodies
Y shaped proteins that bind with specific antigens
Antigens
A cell or foreign substance (e.g. protein, bacterium, etc.) that stimulates an immune system response.
What do memory cells do?
Memory cells produce antibodies in the future, allowing them to kill in the future.
What do cytotoxic T cells do?
Cytotoxic T cells kill virus-infected and cancer cells.
What do helper T cells do?
Helper T cells regulate immunity and produce cytokines.
What is the B cell receptor called, and what does it do?
BCR, and it binds a specific antigen.
What type of immunity is given by B cells?
B cells give antibody-mediated immunity.
What does the BCR binding to a specific antigen trigger?
Binding triggers production of cytokines from T cells, which then initiate clonal expansion.
What is clonal expansion?
In clonal expansion, the B cell makes copies of itself.
Clonal expansion produces what types of cells?
Clonal expansion produces primarily plasma cells that secrete monoclonal antibodies, but also produces memory cells which result in long-term immunity.
Monoclonal Antibodies
Antibodies that all bind to the same antigen
What happens to plasma cells after an infection has passed?
After an infection has passed, plasma cells undergo apoptosis.
What is apoptosis?
Apoptosis is programmed cell death.
What type of immunity is granted by T cells?
T cells grant cell-mediated immunity.
T cells’ receptors are called what, and what do they do?
T cells’ receptors are called TCRs, and they recognize a piece of an antigen with the help of an antigen-presenting cell.
How does an antigen-presenting cell (APC) help a T cell recognize an antigen?
An APC engulfs an antigen, breaks it down, and presents it on its surface in association with a membrane protein (called human leukocyte antigens in humans, or HLA) then presents it to T cells in the lymph node or spleen. The T cell then specifically recognizes the combination of the HLA protein and piece of the antigen.
Give four characteristics of B cells.
Produced and mature in bone marrow
Antibody-mediated immunity against pathogens
Directly recognize antigen and then undergo clonal selection (expansion)
Clonal expansion produces antibody-secreting plasma cells as well as memory B cells
Name five characteristics of T cells.
Produced in bone marrow; mature in thymus
Cell-mediated immunity against virus-infected cells and cancer cells
Antigen must be presented via HLA molecule in APCs
Cytotoxic T cells destroy virus-infected and cancer cells
Helper T cells secrete cytokines that control the immune response
Immunity
The ability to combat diseases and cancer
What two ways can immunity be brought about?
Naturally and Artificially
How is natural immunity brought about?
Natural immunity is brought about through an infection.
How is artificial immunity brought about?
Artificial immunity is brought about through medical intervention.
Name the two types of immunity.
Active and passive immunity.
Active Immunity
Individual produces antibodies alone.
Passive immunity
Individual is given prepared antibodies.
How is active immunity produced?
Active immunity can be produced during natural infection or through immunization involving vaccines.
Describe primary response and secondary response of active immunity.
Primary response or exposure is slower and shorter-lived, while a secondary response or exposure often involves a rapid, strong response (hence why vaccines often require a follow up).
Is active immunity short or long lasting?
Active immunity is usually long-lasting, but it depends on memory B and T cells.
Is passive immunity long or short-lived?
Passive immunity is short-lived.
Can passive immunity happen naturally, and if so, how?
Passive immunity can happen naturally as antibodies are passed across the placenta or during breastfeeding.
How can passive immunity occur artificially?
A person can be injected with antibodies.
Name three ways in which the immune system can harm the body.
Allergies
Tissue Rejection
Immune System Disorders
Allergies
Hypersensitivities to harmless substances such as pollen, food, or animal hair (allergens)
Allergens
Antigens that are typically not harmful to the body
What happens in an immediate allergic response?
In an immediate allergic response, allergens bind to antibodies and cause the release of histamine. The subject then exhibits allergy symptoms. An immediate allergic response that can occur when the allergen enters the bloodstream is anaphylactic shock.
Anaphylactic Shock
The blood pressure drops and is life-threatening.
What initiates delayed allergic responses?
Memory T cells - e.g., reaction to poison ivy, TB test.
When can tissue rejection occur?
Tissue rejection can occur when cytotoxic T cells respond to tissue that is not recognized as “self.”
How can tissue rejection be prevented or controlled?
Patients can be given immunosuppressive drugs and organs that have the same HLA proteins as the recipient can be transplanted. We are also trying to grow organs in the lab that can be transplanted with less rejection.
Autoimmune Disease
A disease in which cytotoxic T cells or antibodies attack the body’s own cells as if they were foreign.
Give a few examples of autoimmune disease.
Multiple sclerosis, Chron’s/UC, myasthenia gravis, and rheumatoid arthritis
Immunodeficiency Disease
A disease in which the immune system is compromised and thus unable to defend the body against disease.
Give two examples of immunodeficiency disease.
SCID, severe combined immunodeficiency
AIDS, due to HIV infection
