Chapter 22 study guide

What is a pathogen?

any microorganism or agent that can cause disease in its host

Define immunity.

the ability to resist infection and disease

What is the compositional difference between lymph and plasma?

Lymph has significantly less proteins, no red blood cells, and more white blood cells

Name the two primary lymph tissues/organs.

bone marrow and thymus

Name four secondary lymphoid tissues/organs

tonsils, mucosa associated lymphatic tissue (MALT), lymph nodes, and the spleen

What is the function of lymphatic vessels?

carry lymph from peripheral tissues to the venous system

Lymphatic capillaries have overlapping endothelial cells that act as one-way valves. Regarding pathogens, what is the importance of valves in immune function?

It permits fluids and solutes (including proteins) to enter, along with viruses, bacteria, and cell debris, but it prevents them from returning to the intercellular spaces.

What feature do lymphatic vessels share with veins that allows lymph to flow in only one direction?

one-way valves

Define lymphedema.

produced by obstruction of lymphatic vessels, causes swelling, especially in subcutaneous tissues

List two types of phagocytes associated with immune function.

macrophages and microphages

List three classes of lymphocytes that circulate in blood

T (thymus-dependent) cells

B (bone marrow–derived) cells

NK (natural killer) cells

What are tonsils?

are large lymphoid nodules in the walls of the pharynx

Which tonsils are usually inflamed when a patient experiences tonsillitis?

the palatine tonsils

What does the acronym MALT stand for, and where is MALT located in the body?

mucosa associated lymphoid tissue

The collection of lymphoid tissues that protect the epithelia of the digestive, respiratory, urinary, and reproductive systems

Lists three examples of MALT.

tonsils, peyer’s patches, appendix

Where are Peyer’s patches located?

deep to the epithelial lining of the intestine

What is the functional difference between afferent and efferent lymphatic vessels?

afferens, bringing towards

efferens, carrying out

Which cells located in the subcapsular space of a lymph node initiate the immune response?

dendritic cells

What is the function of lymph nodes?

purifies lymph before it reaches the veins.

How are lymph nodes like early warning systems?

Any infection or other abnormality in a peripheral tissue puts antigens into the interstitial fluid, and thus into the lymph leaving the area. These antigens then stimulate macrophages and lymphocytes in nearby lymph nodes

What are thymosins and why are they important?

thymic hormones that are an extract from the thymus that promotes the development and maturation of T cells

List three functions of the spleen.

removing abnormal blood cells and other blood components by phagocytosis

storing iron recycled from red blood cells

initiating immune responses by B cells and T cells in response to antigens in circulating blood.

contains large quantities of red blood cells

red pulp

resembled lymphoid nodules

white pulp

Why is innate immunity considered nonspecific?

it does not distinguish one potential threat from another.

What lymphocytes are involved in innate immunity?

NK cells

What lymphocytes are involved in adaptive immunity?

B cells and T cells

Define lymphocytopoiesis.

process by which the body produces new lymphocytes

Where do B cells develop and mature?

red bone marrow

Where do T cells develop and mature?

thymus

Where do NK cells develop and mature?

bone marrow

Are first line defenses innate or adaptive?

innate

True or False. If the statement is False, correct it. Adaptive immune defenses deny pathogens access to the body or destroy them without distinguishing among specific types.

False, adaptive immune defenses are highly specific

describe the function of the following innate defenses: Physical barriers

keeps hazardous organisms and materials outside the body

describe the function of the following innate defenses: Phagocytes

engulf pathogens and cell debris

describe the function of the following innate defenses: Immune surveillance

is the destruction of abnormal cells by NK cells in peripheral tissue

describe the function of the following innate defenses: Interferons

are chemical messengers that coordinate the defenses against viral infections

describe the function of the following innate defenses: Complement

is a system of circulating proteins that assist antibodies in the destruction of pathogens. It also lyses cells, and enhances phagocytosis and inflammation.

describe the function of the following innate defenses: Inflammation

is a localized, tissue-level response that tends to limit the spread of an injury or infection

describe the function of the following innate defenses: Fever

is an elevation of body temperature that speeds up tissue metabolism and the activity of defenses

Name two physical barriers.

skin

mucous membrane

What two bactericidal molecules are found in sweat that reduce pathogen numbers on epidermal surfaces?

Name two kinds of microphages.

neutrophils

eosinophils

Give two examples of fixed macrophages

stellate macrophages

alveolar macrophages

What occurs during emigration?

microphages and free macrophages move through capillary walls by squeezing between adjacent endothelial cells

Define chemotaxis.

microphages and free macrophages may be attracted to chemicals, or both may be repelled by chemicals in the surrounding fluids

What molecules are made and released after NK cell activation? What is their function?

What are interferons?

are small proteins release by activated lymphocytes and macrophages and by tissue cells infected with viruses

What does a rise in levels of interferons suggest?

your body is activating a defense against an invader or viral infection

What proteins interact with one another in chain reactions known as cascades?

complete proteins

How is the classical complement pathway activated?

begins with the binding of complement protein C1 to two nearby antibodies already attached to its specific antigen, such as a bacterial cell wall.

How is the lectin complement pathway activated?

by the binding of the protein mannose-binding lectin (MBL) to carbohydrates on pathogen surfaces, such as bacterial cell walls

How is the alternative complement pathway activated?

begins when several complement proteins—including properdin (factor P), factor B, and factor D—interact in the plasma. This interaction is triggered by exposure to foreign materials, such as the cell wall of a bacterium.

Complement activation using any of the three pathways produces three results. What are they?

killing of the pathogen by cell lysis, enhanced phagocytosis (opsonization), and enhanced inflammation (histamine release).

What is a MAC complex and what is its function?

immune system effector to puncture holes in cell membrane

What is opsonization?

An effect of coating an object with antibodies; the attraction and enhancement of phagocytosis.

What specific chemical is released by mast cells and basophils that increases the degree of local inflammation?

histamine

What are the four cardinal signs and symptoms of inflammation?

redness, swelling, heat, and pain

Once neutrophils are activated, they undergo a respiratory burst. What two reactive chemicals do activated neutrophils produce? What is the outcome of their release?

superoxide anions (O₂^-) and hydrogen peroxide (H₂O₂)

outcome is pathogen destruction, collateral tissue damage, immune signaling

What is necrosis?

The tissue destruction that occurs after cells have been injured or destroyed

What is an abscess?

An accumulation of pus in an enclosed tissue space

What are pyrogens?

fever inducing agents

How do pyrogens work?

raise body temperature by stimulating the temperature control area of the pre-optic nucleus of the hypothalamus.

cytotoxic T cells

are involved in direct cellular attack. These cells enter peripheral tissues and attack antigens physically and chemically.

helper T cells

stimulate the responses of both T cells and B cells. Are vital to the immune response because they must activate B cells before the B cells can produce antibodies.

regulatory T cells

are a subset of T cells that moderate the immune response.

memory T cells

respond to antigens they have already encountered by the cloning (producing identical cellular copies) of more lymphocytes to ward off the invader.

What are stimulated B cells called? What do they secrete?

Define antigen.

What are three additional organic molecules that can act as antigens?

True or False. If the statement is False, correct it. Clones of the same activated lymphocyte are sensitive to the same specific antigen.

Describe the four types of adaptive immunity and explain how the immunity is acquired.

What type of adaptive immunity occurs by contracting SARS-CoV-2, the causative agent of COVID-19, from your brother?

What form of adaptive immunity occurs when a person is vaccination against SARS-CoV-2?

Patients who have COVID-19 can be treated with laboratory-produced antibodies against the SARS-CoV-2 spike protein. What type of adaptive immunity is this?

Women who produced antibodies against SARS-CoV-2 while pregnant or from a previous exposure can transfer a certain isotype of antibody across the placenta to protect her unborn child. What type of adaptive immunity is this?

Adaptive immunity is specific. What does this mean?

What is immune tolerance?

Define apoptosis?

What are APCs and what are their function?

What are MHCs? What is another name they are known by? What is their importance?

What must be recognized for antigen presentation to occur?

What blood group is considered the universal donor? Why?

What blood group is considered the universal recipient? Why?

What do tissue typing tests determine?

What do cross matching tests determine?

Which cells have MHC Class 1 proteins?

What triggers antigen presentation by class I MHC proteins?

What triggers antigen presentation by class II MHC proteins?

Which cells have MHC Class 1I proteins?

List three examples of phagocytic antigen-presenting cells.

Name one example of non-phagocytic antigen-presenting cells. Where are they found?

Which cells have CD8 markers? Antigen bound to which MHC class do they detect?

Which cells have CD4 markers? Antigen bound to which MHC class do they detect?

What is costimulation and what is its function?

What is the function of regulatory T cells?

What molecules are produced by T helper cells that function to coordinate specific and nonspecific defenses and stimulate cell-mediated and antibody-mediated immunities.

A sensitized B cell does not undergo activation unless it receives the “OK” from which type of cell?

What are the two pairs of polypeptide chains of a Y-shaped antibody molecule called?

The specificity of an antibody molecule depends on the amino acid sequence of which region of the antibody?