Chapter 21 Study Guide

Question 1

What are the three main functions of the lymphatic system? What is a lacteal?

Answer 1

1) Fluid recovery, immunity, and lipid absorption
2) Lacteals are lymphatic vessels in the small intestine that absorb dietary lipids that are not absorbed by the blood capillaries

Question 2

What 4 structures make up the lymphatic system? How much fluid enters the lymphatic system?

Answer 2

1) Lymph, lymphatic vessels, lymphatic tissues, and lymphatic organs
2) 15% (~3 L/day) of fluid enters the lymphatic system

Question 3

How does lymph form and what’s it color? What fluid is lymph most similar to?

Answer 3

1) It’s colorless and forms when interstitial fluid enters the lymphatic capillaries.
2) Most similar to interstitial fluid, which is similar to plasma but has less protein.

Question 4

List the order of the flow of lymph

Answer 4

1) Lymphatic capillaries take in interstitial fluid, which becomes lymph
2) Lymphatic collecting vessels
3) Lymphatic trunks
4) Lymphatic ducts

Question 5

Are lymphatic vessels more similar to an artery, vein or capillary? Why?

Answer 5

Veins, because they both have unidirectional valves and thin walls

Question 6

Can you tell the difference between lymphatic capillaries and blood capillaries?

Answer 6

Yes; Unlike blood capillaries, fluid can flow into lymph capillaries but can’t flow out through the cell walls

Question 7

Do blood capillaries or lymph capillaries have valves? Which is more permeable?

Answer 7

Lymphatic capillaries have valves formed by overlapping endothelial cells; they’re more permeable than blood capillaries.

Question 8

What structure starts the thoracic duct, where does it empty into and what parts of the body does it drain?

Answer 8

The cisterna chyli starts the thoracic duct, which empties into the lefts subclavian vein. It drains the right and left abdomen, right and left legs, left arm and upper body, left thoracic region

Question 9

What drains the upper part of the right side of the body and where does it empty into?

Answer 9

The right lymphatic duct drains the right head, neck, thorax, and arm. It drains into the right subclavian vein.

Question 10

Can you name the six major cells of the lymphatic tissues and what functions they perform?

Answer 10

1) Natural Killer/ NK cells: large lymphocytes that attack bacteria, transplanted tissue, viral-infected cells, or cancer
2) T-lymphocytes (T-cells): Each T-cell develops unique antigen receptors that correspond to a specific antigen while in the thymus; once given these receptors they’re activated, which means they can recognize antigens presented to them.
3) B-lymphocytes (B-cells): Activation causes proliferation and differentiation into plasma cells that produce antibodies
4) Macrophages: large phagocytes that develop from monocytes; work as antigen-presenting cells for T-cells
5) Dendritic cells: branched, mobile antigen-presenting cells found in the epidermis, mucosal membranes, and lymphatic organs
6) Reticular cells: form the stroma (soft skeleton) of a lymphatic organ

Question 11

List the 4 types of T-cells and describe what they do

Answer 11

1) Cytotoxic T cells: attack enemy cells.
2) Helper T cells: promote cytotoxic t-cell and b-cell activation.
3) Regulatory T cells: inhibit multiplication and cytokine secretion by other T cells and limit immune response.
4) Memory T cells: are responsible for memory and cellular immunity.

Question 12

1) Which lymphatic cell type matures in the thymus?
2) Which lymphatic cell gives rise to plasma cells that produce antibodies?
3) Which lymphatic cell is capable of attacking cancerous cells or an organ transplant recipient?

Answer 12

1) T-cells mature in the thymus
2) B-cells
3) NK cells

Question 13

What type of lymphatic cell forms the soft skeleton of the lymphatic organ?

Answer 13

Reticular cells

Question 14

What are the two primary lymphatic organs? Why are they the only two considered to be primary lymphatic organs?

Answer 14

1) Red bone marrow and thymus.
2) There are only two because those are the only two places where lymphatic cells are ‘made and educated’

Question 15

1) What are three secondary lymphatic organs?
2) What does it mean if a cell is immunocompetent?

Answer 15

1) Lymph nodes, tonsils, and the spleen.
2)Immunocompetent cells have receptors for an antigen and are able to recognize and respond to it

Question 16

Describe the structure and function of the red bone marrow and thymus

Answer 16

1) Red bone marrow:
a) Structure: Soft, loosely organized, highly vascular material that’s separated from osseous tissue by the endosteum of bone
b) Function: Hemopoiesis and immunity
2) Thymus:
a) Structure: A bilobed organ located in the superior mediastinum that shows degeneration with age. The lobules are divided into cortex and medulla.
b) Function: T-lymphocytes develop in the cortex and move to the medulla. Produces signaling molecules thymosin, thymopoietin, thymulin, interleukins, and interferon.

Question 17

Describe the structure and function of the lymph nodes and tonsils

Answer 17

1) Lymph nodes:
a) Structure: An elongated, bean-shaped structure with a hilum that’s enclosed with a fibrous capsule with trabeculae that divide its interior into compartments. Its two regions are cortex and medulla.
b) Functions: Cleanse the lymph and act as a site of T and B cell activation.
2) Tonsils:
a) Structure: Patches of lymphatic tissue located at the entrance to the pharynx that are covered with epithelium and have deep pits (tonsillar crypts) which are lined with lymphatic nodules.
b) Function: Guard against ingested or inhaled pathogens.

Question 18

Describe the structure and function of the spleen

Answer 18

1) Structure: The largest lymphatic organ; made up of red and white pulp. Red pulp are sinuses filled with RBCs, and white pulp is lymphocytes and macrophages surrounding the small branches of the splenic artery.
2) Function: Produces RBCs in fetuses and breaks down old RBCs, stabilizes blood volume through plasma transfers to the lymphatic system, and white pulp monitors for foreign antigens and keeps an army of monocytes for release when needed.

Question 19

What is metastasis and why is this a concern?

Answer 19

1) Metastasis is when cancerous cells break free from the original tumor, travel to other sites in the body, and establish new tumors
2) It’s a concern for the lymphatic system because metastasizing cells easily enter lymph vessels and get lodged in the first lymph nodes they encounter. They then multiply in the lymph node and destroy it, and swim on to the next node.

Question 20

1) Define pathogen
2) Is our immune system an organ system? Why or why not?

Answer 20

1) Pathogens are defined as agents capable of producing disease. Includes bacteria, viruses, and fungi.
2) Our immune system is an organ system because its made up of the functions of multiple organs and vessels.

Question 21

What is the composition of the first line of defense and what’s its purpose?

Answer 21

1) Composition: Skin and mucous membranes; acid mantle and fluid flow
2) Purpose: Keep pathogens out of the body

Question 22

What is the composition of the second line of defense and what’s its purpose?

Answer 22

1) Composition: Protective cells (leukocytes, macrophages, NK cells), protective proteins (interferons and complement proteins), and protective responses (fever and inflammation)
2) Purpose: Keep the pathogen from replicating and spreading throughout the body

Question 23

1) What is the purpose of histamine and which cell types produce this substance?
2) What is the purpose of heparin and what cell types produce this substance?
3) What is the difference between a fixed and a wandering macrophage?

Answer 23

1) Basophils secrete histamine which promotes inflammation.
2) Basophils secrete heparin which inhibits clot formation.
3) Wandering macrophages seek out pathogens, whereas fixed macrophages only kill pathogens that come to them.

Question 24

1) Why does an NK cell release perforins?
2) What does an NK cell secrete to cause death?
3) Which leukocyte does phagocytosis on the enemy cell?

Answer 24

1) NK cells release perforins to create pores in the cell
2) NK cells secrete granzymes to induce apoptosis (programmed cell death)
3) Neutrophils can kill bacteria using phagocytosis and digestion

Question 25

Which cells release interferon and what ends of happening to that cell? Which cells benefit from interferon being released?

Answer 25

Interferon is secreted by certain cells infected by viruses to alert neighboring cells, doesn’t benefit the cell itself. Activates NK cells and macrophages and causes the alerted cell to synthesize anti-viral proteins

Question 26

List the 4 methods that the complement system uses and describe them

Answer 26

1) Inflammation: Stimulates mast cells and basophils to secrete histamine; activates and attracts neutrophils and macrophages
2) Immune clearance: Binds with antigen–antibody (Ag-Ab) complexes to red blood cells, so when they circulate through liver and spleen, macrophages strip off and destroy the Ag–Ab complexes leaving RBCs unharmed. Principal means of clearing foreign antigens from the bloodstream.
3) Phagocytosis: Assists phagocytes by opsonization (coating microbial cells)
4) Cytolysis: Forms a Membrane Attack Complex, which forms a hole in the target cell. This causes electrolytes to leak out, water to flow in rapidly, and the cell to rupture

Question 27

What organ controls elevation of body temperature? What protein is released?

Answer 27

1) The hypothalamus of the brain controls the elevation of body temperature
2) Promotes interferon activity

Question 28

Are all fevers beneficial? Why or why not? What are the 4 signs of inflammation?

Answer 28

1) Moderate fevers are helpful because they promote interferon activity, elevate metabolic rate and accelerates tissue repair, and inhibits reproduction of bacteria and viruses.High temperatures are harmful because we can cause brain damage and denature our own proteins.
2) Heat, pain, redness, swelling

Question 29

Can you correctly order the steps in the mobilization of defenses?

Answer 29

1) Step 1: Release of inflammatory chemicals such Histamine and other cytokines (from basophils, mast cells, damaged cells, toxins, etc.)
2) Step 2: The chemicals cause Vasodilation, which increases blood flow (local hyperemia). Hyperemia helps washes toxins and metabolic waste from area
3) Step 3: The chemicals increase capillary permeability. Fluid, leukocytes, and plasma proteins leave blood. Edema occurs
4) Step 4: Neutrophils leave bloodstream to injury site; accumulate within an hour. Margination, diapedesis, and chemotaxis occur.
5) Step 5: Fibrinogen (and other clotting factors) released in interstitial fluid clots to wall off microbes.

Question 30

Define margination, diapedesis, and chemotaxis

Answer 30

1) Margination: Selectins cause leukocytes to adhere to blood vessel walls
2) Diapedesis (emigration): Leukocytes squeeze between endothelial cells into tissue space
3) Use chemotaxis to guide them to the injury site.

Question 31

What do edema and hyperemia do?

Answer 31

1) Edema contributes to tissue cleanup; forces more fluid into lymphatic system
2) Hyperemia delivers oxygen, amino acids, and other necessities for protein synthesis

Question 32

What leukocyte arrives first to bacterial infections? What is the primary agent of tissue cleanup?

Answer 32

1) Neutrophils typically arrive first to a bacterial infection.
2) Monocytes are the primary agents of tissue cleanup and repair.

Question 33

What are the three characteristics that distinguish adaptive immunity from innate immunity?

Answer 33

1) Systemic effect: throughout the body
2) Specificity: immunity directed against a particular pathogen
3) Memory: when reexposed to the same pathogen, the body reacts so quickly that there is no noticeable illness

Question 34

What is the difference between cellular immunity and humoral immunity and which is better on extracellular pathogens and which is better for intracellular pathogens?

Answer 34

1) Cellular (cell-mediated) immunity: T-Cells directly attack and destroy foreign cells or diseased host cells and gets rid of intracellular pathogens by killing the cell
2) Humoral (antibody-mediated) immunity: B-Cells turn into plasma cells which secrete antibodies. Antibodies do not directly destroy a pathogen but tag it for destruction; works on extracellular stages of infections

Question 35

What’s the difference between natural immunity and artificial immunity? What’s the difference between active and passive immunity?

Answer 35

1) Natural immunity means you got sick
2) Active immunity means your body made the antibodies

Question 36

Can you define antigen, epitope, hapten and relate to how an antibody would react?

Answer 36

1) Antigen: any molecule that triggers an immune response
-An antibody would bind to it
2) Epitope: a fragment of an antigen presented by an antigen-presenting cell
-This is directed at T-cells, not antibodies.
3) Hapten: things that can trigger an immune response by combining with a host macromolecule and creating a complex that the body recognizes as foreign, but they’re too small to be antigenic in themselves. Afterwards, haptens alone can trigger a response.
-An antibody would bind to it if it has combined with a host macromolecule

Question 37

What are the three classes of lymphocytes? Which are third line of defense and which are second?

Answer 37

1) T-lymphocytes: third line of defense
2) B-lymphocytes: third line of defense
3) Natural Killer (NK) cells: second line of defense

Question 38

What are the three stages in a T cell’s life? What organs/tissues are involved in each stage of a T cell’s life cycle?

Answer 38

1) Born in bone marrow
2) Educated in thymus
3) Deployed to carry out immune function in lymphatic tissues and organs

Question 39

Can you explain what it means to be in a naïve lymphocyte pool or what deployment means?

Answer 39

1) Naive lymphocyte pool: immunocompetent T cells that have not yet encountered foreign antigens
2) Deployment: Naive T cells leave thymus and colonize lymphatic tissues and organs everywhere in the body

Question 40

What are the three stages in a B cell’s life? What organs/tissues are involved in each stage of a B cell’s life cycle?

Answer 40

1) Born in red bone marrow
2) Educated in red bone marrow
3) Deployed to same lymphatic tissues and organs as T cells

Question 41

Why does a T cell need an antigen presenting cell? What four cells are antigen presenting cells? What protein class acts as an identification tag?

Answer 41

1) T-cells cannot recognize antigens on their own
2) Dendritic cells, macrophages, reticular cells, and B cells
3) Major histocompatibility (MHC) complex proteins

Question 42

What does an antigen presenting cell display in the grooves of the class of protein that acts as an identification tag? What organelle helps antigen presenting cells process foreign antigens?

Answer 42

1) Epitopes are displayed in the grooves of the MHC protein.
2) Phagolysosomes

Question 43

What will a T cell do if the antigen presenting cell is displaying a self-antigen? A nonself-antigen?

Answer 43

Ignores self-antigens, attacks nonself-antigens

Question 44

What is cellular mediated immunity? What do the T lymphocytes do? Do you directly attack and kill with cellular immunity?

Answer 44

Cellular mediated immunity is when T lymphocytes directly attack and destroy diseased or foreign cells. Then the immune system remembers the antigens and prevents them from causing disease in the future

Question 45

Which is the effector T cell of cellular immunity? What type helps in both innate and adaptive immunity? Which helps prevent the body from overreacting i.e., limits your immune response?

Answer 45

1) Cytotoxic T-cells
2) Helper T-cells
3) Regulatory T-cells

Question 46

Can you explain the three Rs of immunity- recognize, react and remember?

Answer 46

Recognition: Recognize
Attack: React
Memory: Remember

Question 47

What is the purpose of costimulation for a T cell?

Answer 47

Costimulation is important because it helps ensure the immune system does not launch an attack in the absence of an enemy, in which case it would turn against one’s own body and injure our tissues

Question 48

A T cell releases perforin and granzymes just like ______________________.
What happens to the T cell after releasing chemicals, does it die?

Answer 48

1) NK cells
2) They undergo repeated mitosis

Question 49

What is the T cell recall response?

Answer 49

The idea that upon re-exposure to same pathogen later in life, memory cells launch a quick attack so that no noticeable illness occur. The person is immune to the disease

Question 50

1) What is humoral immunity; do you directly attack and kill with humoral immunity?
2) Which type of T cell helps B cells get activated?
3) What do we call a B cell that has come in contact with its specific antigen?

Answer 50

1) B lymphocytes produce antibodies that bind to antigens and tag them for destruction by other means; you do not directly attack and kill.
2) Helper T cells: bind to a Ag–MHC protein complex and secretes interleukins that activate B cell
3)Immunocompetent

Question 51

1) What is clonal selection?
2) What type of cell is the B cell differentiating into?
3) What will that cell secrete, and what 2 organelles do you expect that cell to have a lot of?

Answer 51

1) Clonal selection is when interleukins secreted by a helper T cell triggers a B cell to quickly replicate
2) Plasma cells
3) Plasma cells secrete antibodies, so you’d expect them to have a lot of rough ER.

Question 52

Define immunoglobulin. What letter of the alphabet does an antibody look like?

Answer 52

1) Immunoglobulin (IG): an antibody; a defensive gamma globulin found in blood plasma, tissue fluids, body secretions, and some leukocyte membranes
2) Antibodies are shaped like the letter Y

Question 53

Can you differentiate between the five classes of antibodies?

Answer 53

1) IgG: 80% of total; a monomer; most abundant and diverse; crosses placenta to fetus; secreted in secondary immune response; complement fixation
2) IgA: 10-15% of total; monomer in plasma; dimer in secretions (mucus, saliva, tears, breast milk, and intestinal secretions; too large to cross placenta.) Prevents pathogen adherence to epithelia and penetrating underlying tissues
3) IgM: 5-10% of total, pentamer; secreted in primary immune response (indicates a current infection); agglutination during ABO incompatibility; complement fixation
4) IgD: 0.02% of total, monomer; B cell transmembrane antigen receptor. Thought to function in B cell activation by antigens
5) IgE: 0.002% of total, monomer; transmembrane protein on basophils and mast cells causing release of histamine when activated.

Question 54

1) Which immunoglobin type crosses the placenta to the fetus?
2) Which type is in body secretions?
3) Which type is a pentamer and indicates a current infection?
4) Which helps in B cell activation?
5) Which is on basophils or masts cells?

Answer 54

1) IgG crosses placenta to fetus
2) IgA is in body secretions
3) IgM is a pentamer and indicates infection
4) IgD helps in B-cell activation
5) IgE is on basophils and mast cells

Question 55

Can you briefly explain how antibodies work? What is neutralization? What is complement fixation and what does it lead to? What is agglutination? What is precipitation?

Answer 55

Antibodies have 4 mechanisms of attack against antigens:
1) Neutralization: Antibodies mask pathogenic region of antigen
2) Complement fixation: Leads to inflammation, phagocytosis, immune clearance, or cytolysis
3) Agglutination: Antibody has 2 to 10 binding sites; binds to multiple enemy cells, immobilizing them from spreading. Enhances phagocytosis by creating “bigger bites”
4) Precipitation: Antibody binds antigen molecules (not cells); creates antigen–antibody complex that precipitates, allowing them to be removed by immune clearance or phagocytized by eosinophils.

Question 56

1) Can you explain the primary immune response?
2) Which antibody class appears first?
3) What is going on with your health during the lag time of the primary immune response; why is there lag time?

Answer 56

1) Primary immune response: The immune reaction brought about by the first exposure to an antigen. Has a lag period (3-6 days) while naive B cells multiply and differentiate into plasma cells. As plasma cells produce antibodies, the antibody titer (level in the blood plasma) rises
2) IgM appears first, peaks in about 10 days, soon declines
3) During the lag period, which is needed for naive B cells to multiply and differentiate into plasma cells, you get sick.

Question 57

1) If you have the IgG antibody present, what does that indicate?
2) Is there a lag if you have secondary response? What is going on with your health during the secondary immune response?

Answer 57

1) If you have the IgG antibody, the you were either sick during the lag time of primary immune response about 11-14 days ago, or you’ve been re-exposed to an antigen and have long-term immunity
2) No lag time in secondary response; totally healthy

Question 58

Compare and contrast what cellular and humoral immunity are best for, their effector cells, and their memory

Answer 58

1) Cellular Immunity:
a) Best for: Intracellular pathogens, cancer cells, transplanted tissues
b) Effector cells: Cytotoxic T cells (helped by Helper T cells)
c) Memory: usually last life-time
2) Humoral Immunity:
a) Best for: extracellular pathogens, toxins, venoms, allergens, mismatched RBCs
b) Effector cells: Plasma cells (develop from B cells and helped by Helper T cells)
c) Memory: does not last as long as cellular immunity

Question 59

Can you define hypersensitivity, alloimmunity, autoimmunity, allergen, allergy, and anaphylaxis?

Answer 59

1)Hypersensitivity: an excessive immune reaction against antigens that most people tolerate. Includes alloimmunity, autoimmunity, and allergies.
2) Alloimmunity: Transplanted organs
3) Autoimmunity: When your body uses immune responses against itself
4) Allergen: A particle that can cause a type 1 hypersensitivity reaction
5) Allergy: A type I hypersensitivity reaction
6) Anaphylaxis: an immediate, severe type I reaction; local anaphylaxis can be relieved with antihistamines

Question 60

What are the four types of hyper sensitivity? Which is T cell based? Which are antibody based?

Answer 60

1) Type I acute (immediate) hypersensitivity
-Very rapid response
-Based on antibodies
2) Type II and Type III subacute hypersensitivity
-Slower onset (1 to 3 hours after exposure)
-Last longer (10 to 15 hours)
-Based on antibodies
3) Type IV: delayed cell-mediated response
-Signs appear 12 to 72 hours after exposure
-Cosmetics, poison ivy, graft rejection, TB skin test
-T-cell based

Question 61

1) In a type 1 reaction, what contact causes the person to have symptoms; is it the first, second or all exposures to the allergen?
2) If you have a reaction to poison ivy, this is what type of hypersensitivity?

Answer 61

1) In type I (acute), the initial contact is asymptomatic but sensitizes person. The second contact causes symptoms.
2) Poison ivy is type IV hypersensitivity.

Question 62

What treatment would be prescribed for a person going into anaphylactic shock and why?

Answer 62

-Antihistamines are inadequate by themselves
-Epinephrine relieves the symptoms by dilating bronchioles, increasing cardiac output, and restoring blood pressure
-Fluid therapy and respiratory support are sometimes required

Question 63

AIDs is caused by what virus? What T cells is destroyed by the virus?

Answer 63

1) Human immunodeficiency virus (HIV)
2) Helper T-cells

Question 64

1) What are common signs and symptoms of HIV/AIDS?
2) How is the virus transmitted? 3) What does the virus do to the immune system?

Answer 64

1) Early symptoms: flu-like symptoms of chills and fever. Progresses to night sweats, fatigue, headache, extreme weight loss, lymphadenitis. Susceptibility to opportunistic infections, candida (thrush), kaposi sarcoma (cancer)
2) HIV is transmitted through blood, semen, vaginal secretions, breast milk, or across the placenta. By sexual intercourse (vaginal, anal, oral), contaminated blood products, and contaminated needles; not by casual contact.
3) By destroying TH cells, HIV strikes at the central coordinating agent of innate defense, humoral immunity, and cellular immunity