question

Host defenses involving anatomical barriers, sensor systems that recognize patterns associated with microbes or tissue damage, phagocytic cells, and the inflammatory response.

answer

Innate immunity

question

What is a substance that causes an immune response called?

answer

An antigen

question

Y-shaped proteins that bind to antigens and are an important part of adaptive immune response.

answer

antibodies

question

What is the specialized defense system that vertabrates have evolved?

answer

adaptive immunity

question

What are the initial obstacles that microbes must overcome to invade tissues? (They include skin, mucous membranes and can be bathed in secretions that have antimicrobial properties.)

answer

First-line defenses

question

How does the body recognize when first-line defenses have been breached?

answer

Certain cells (called sentinel cells) have pattern recognition receptors (PRRs) on their surface and within their endosomes and phagosomes.

question

What are the series of proteins always present in the blood and tissue fluids collectively called?

answer

the complement system

question

How does the complement system work?

answer

it acts in combination with the adaptive immune defenses as a sensor and communicates with other cells.

question

During this response, cells that line local blood vessels undergo changes that allow complement system components and other proteins to leak out into the tissue. Phagocytes also accumulate in the tissues.

answer

inflammatory response

question

What cells specialize in engulfing and digesting microbes and cell debris?

answer

Phagocytes

question

What are two roles phagocytes can play?

answer

1. destroying invaders
2. communicate with cells of the adaptive immune system.

question

Many cells have _____ _______ _______ in their cytoplasm, allowing them to recognize when they have been invaded by a microbe.

answer

PRRs (Pattern recognition receptors)

question

ciliated cells in the respiratory tract that beat in an upwards motion, moving materials away from the lings to the throat where they can be swallowed.

answer

mucociliary escalator

question

contraction of the intestinal tract that helps remove microbes

answer

peristalsis

question

What are some of the antimicrobial substances found on the body?

answer

1. saltiness of evaporated sweat
2. lysomzyme (in tears, saliva and mucous, and also phagocytic cells, blood and fluid that bathes tissues)
3. peroxidase enzymes (saliva and milk)
4. Lactoferrin
5. transferrin
6. defensins

question

What are short antimicrobial peptides produced by neutrophils and epithelial cells that insert into bacteria membranes that form pores and damage cells?

answer

Defensins

question

An iron-binding protein in saliva, mucous , and milk (and some types of phagocytes)

answer

Lactoferrin

question

Why does iron-binding help defend against microbes?

answer

Because iron is one of the major elements and withholding it prevents microbial growth.

question

What iron-binding mechanism is found in the blood and tissues?

answer

transferrin

question

How does the normal microbiota provide prtoection from pathogens?

answer

1. by covering binding sites where pathogens may otherwise use for attachment
2. producing compounds toxic to other bacteria

question

The formation and development of blood cells is called what?

answer

hematopoiesis

question

All blood cells, including those important to the body's defense originate from what cell type?

answer

the hematopoietic stem cell

question

What induces hematopoietic stem cells to develop into various types of blood cells?

answer

A group of proteins called colony-stimulating factors (CSFs)

question

Erythrocytes are what type of blood cell?

answer

Red blood cells that carry oxygen

question

White blood cells are also called what?

answer

Leukocytes

question

What are the four groups of leukocytes?

answer

1. granulocytes
2. mononuclear phagocytes
3. dendritic cells
4. lymphocytes

question

What are the three types of granulocytes?

answer

1. neutrophils
2. basophils
3. eosinophils

question

How do you distinguish between the three types of granulocytes?

answer

The staining properties of their granules

question

These efficiently engulf and destroy bacteria and other material. Their granules stain poorly. They normally make up more than half of the circulation white blood cells

answer

neutrophils

question

What are other name of neutrophils?

answer

PMNs polymorphonuclear neutrophilic leukocytes

question

These are a type of granulocytes involved in allergic reactions and inflammation. Their granules stain dark purple-ish blue contain histamine and other chemicals that increase capillary permeability during inflammation.

answer

basophils

question

These are similar in appearance and function to basophils, but are found in tissues rather than blood.

answer

Mast Cells (responsible for many allergic reactions)

question

These are granulocytes that are thought to be primarily involved in ridding the body of parasitic worms.

answer

Eosinophils

question

mononuclear phagocytes that circulate in the blood

answer

monocytes

question

sentinel cells that function as "scouts". they engulf material in tissues and bring them in to the cells of the adaptive immune system for "inspection"

answer

dendritic cells

question

These are responsible for adaptive immunity.

answer

lymphocytes

question

What are the two major groups of lymphocytes?

answer

B cells and T cells

question

These cells are responsible for adaptive immunity and are highly specific in their recognition of antigen.

answer

B cells and T cells

question

These cells are part of adaptive immunity that are not specific in their anitgen recognition.

answer

Natural Killer cells (NK)

question

Where do lymphocytes usually reside?

answer

lymph nodes and lymphatic tissues

question

Differentiated forms of monocytes, meaning that they have gained specialized properties

answer

Macrophages

question

How are macrophages related to monocytes?

answer

Monocytes circulate in the blood, but enter different areas of the body and become different forms of monocytes called macrophages, that have specialized properties. They are called different things depending on where thwy end up in the body.

question

The eyes and ears of a cell that are usually proteins that span the plasma membrane connecting the outside of the cell to the inside and allow the cell to sense and respond to external signals.

answer

surface receptors

question

The voices of the cell. a _____ produced by one cell diffuses to another and binds to the appropriate ______ _______.

answer

Cytokine
cytokine receptor

question

Binding of a cytokine to its receptor causes what?

answer

Changes in the cell such as
1.growth
2.differentiation
3.movement
4.cell death

question

cytokines important in chemotaxis of immune cells.

answer

chemokines

question

These are important in the multiplication and differentiation of leukocytes. (type of cytokine)

answer

Colony-stimulating Factors (CSFs)

question

These are important in the control of viral infections. They are antiviral, and help regulate function of cells in inflammatory response. They adjust certain roles in adaptive immunity.

answer

Interferons (IFNs)

question

These are cytokines produced by leukocytes and have diverse, often over-lapping functions. They are important in innate and adaptive immunity.

answer

Interleukins (ILs)

question

These are cytokines that have multiple roles. They help initiate the inflammatory response that triggers cell death.(apoptosis)

answer

Tumor Necrosis Factor (TNF)

question

One example of a group of cytokines that act together to generate a specific response are ___-__________ ________. (

answer

Pro-inflammatory cytokines (TNF, IL-1, IL-6, and others)

question

These, on the surface of cells, allow those cells to "grab" other cells.(They are produced by the cells) Ex: they are used by the endothelial cells that line the blood vessels to bind to passing phagocytic cells allowing them to leave the blood stream.

answer

Adhesion molecules

question

What is the function of a CSF? (colony-stimulating factor)

answer

To multiply and differentiate leukocytes into what they need to be and where they need to be by adaptive immunity.

question

What is a ligand?

answer

A molecule that binds to a specific receptor

question

generic microbe-associated patterns that are recognized by PRRs (Pattern Recognition receptors) They are common in all microbes, not just pathogens.

answer

Pathogen-associated molecular patterns (PAMPs) or microbe-associated molecular patterns (MAMPs)

question

WHat are some examples of PAMPs?

answer

various cell wall components(lipopolysacharride, peptidoglycan, lipoteichoic acid, and lipotproteins), flagellen subunits, and RNA molecules that characterize viruses.

question

Molecules that indicate host cell damage

answer

Danger-associated molecular patterns (DAMPs)

question

This type of PRRs are anchored in membranes of sentinel cells such as macrophages, dendritic cells, and cells that line sterile body sites.

answer

Toll-like receptors(TLRs)

question

There are at least 10 different types of these in humans, and they each recognize a distinct compound or group of compounds in microbes.

answer

Toll-like receptors(TLRs)

question

When this type of PRR detects a compound, a signal is transmitted to the cells' nucleus, causing certain genes to be expressed. Its response can be tailored to the situation and category of pathogen.

answer

A toll-like receptor(TLRs)

question

Thess type of PRRs are cytoplasmic proteins that detect bacterial components, allowing the cell to recognize when its' own borders have been breached.

answer

NOD-like receptors (NLRs)

question

At least 23 of these have been described in the human body.

answer

NLRs (NOD-like receptors)

question

When an NLR detects PAMPs or DAMPs what happens?

answer

They unleash a series of events to protect the cell, sometimes at the expense of the cell itself.

question

In macrophages, some NLRs can join with other proteins in the cytoplasm to form what?

answer

inflammasome.

question

What is inflammasome?

answer

A complex that activates a potent pro-inflammatory cytokine, thus initiating an inflammatory response.

question

an enclosed compartment full of extracellular material, brought into the cell during phagocytosis

answer

a phagosome

question

A membrane bound compartment formed during pinocytosis which then fuses with the digestive organelles called lysosomes.

answer

an endosome

question

These type of PRRs are cytoplasmic proteins that detect viral RNA. Allows the cell to detect that it has been invaded.

answer

Rig-like receptors (RLRs)

question

What are the two types of PRRs that are cytoplasmic proteins?

answer

NLRs and RLRs (NOD-like receptors and Rig-like receptors)

question

What type of PRR is anchored in the membranes of sentinel cells?

answer

Toll-like receptors (TLRs)

question

How do RLRs detect viral RNA from the cells own RNA?

answer

There are two differences btwn viral RNA and the cells own RNA.
1.Viral RNA often has 3 phosphates at the 5' end. Capping of cellular RNA hides its' phosphates
2. Viral RNA is often double stranded

question

What occurs when the cells' RLRs detect viral RNA?

answer

Interferons are synthesized and secreted by the cell. These proteins attach to specific receptors on the the infected cell and the neighboring cells, causing the cells to express inactive "suicide" enzymes that ultimately can be activated to degrade mRNA and stop protein synthesis, leading to apoptosis.

question

What are iAVPs?

answer

inactive antiviral proteins (interferons)

question

what are AVPs

answer

antiviral proteins(interferons)

question

When are iAVPs activated?

answer

When the cell recognizes via the RLRs that it has been breached by viral RNA.

question

If a cell produces antiviral proteins, what happens to that cell when those proteins encounter long dsRNA?

answer

IAVPs are activated by dsRNA. Thus, when cells bind interferon, only the infected cells are sacrificed.

question

This is a series of proteins that circulate the blood and the fluid that bathes the tissues.

answer

The complement system

question

These "complement" the function of antibodies.

answer

The complement system

question

What are the three pathways that lead to the complement system activation?

answer

1.Alternative pathway
2.Lectin pathway
3.Classical pathway

question

what are the three outcomes of the activation of the complement system?

answer

1.The inflammatory response
2.Lysis of foreign cells
3.Opsonization

question

When is the alternative pathway triggered?

answer

When C3b binds to foreign cell surfaces

question

What are the nine major proteins of the complement system named?

answer

C1 through C9

question

When do the three pathways of the complement system converge?

answer

When a complex called C3 convertase is formed.

question

When C3 convertase splits C3, what ocurrs?

answer

additional steps of the activation cascade.

question

How can C3b be both a product of complement activation and an activator of the complement system?

answer

Because C3 is somewhat unstable, and spontaneously splits to C3a and C3b at a low rate even when the complement system has not been activated.

question

What happens to C3a and C3b formed by C3's spontaneous splitting?

answer

It is rapidly inactivated by regulatory proteins, but some C3b is always present to trigger the alternative pathway when it is needed.

question

What triggers the lectin pathway of the complement system?

answer

The binding of pattern recognition molecules called Mannose-binding lectins (MBLs) to certain arrangements of multiple mannose molecules that characterize microbial cells.

question

What does C3 convertase do?

answer

It splits C3 into C3a and C3b so that it can be used in the 3 different outcomes of the complement system.

question

How is the classical pathway activated?

answer

When antibodies bind to an antigen forming an immune complex. (Antibodies bind to microbial invaders)

question

What are the three major protective outcomes of the complement system?

answer

1.Opsonization
2.inflammatory response
3.lysis of foreign cells

question

What are the two effects when C3b concentration increases substantially when the complement system is activated?

answer

1.Continued complement activation via the alternative pathway
2.opsonization

question

What does opsonization mean? (Think of it as coating a microbe with one layer of velcro, with phagocytes having the opposing layer on their surface.)

answer

It has been "prepared for eating", and it is easier for phagocytes to bind to and engulf because phagocyted have receptors that attach specifically to opsonin. (C3b)

question

This is a complement component that is a potent chemoattractant, drawing phagocytes to the area where the complement system has been activated.

answer

C5a

question

What do C3a and C5a do in the inflammatory response?

answer

they induce changes in the endothelial cells that line blood vessels, contributing to vascular permeablility associated with inflammation.

question

complexes of complement system proteins that assemble in cell membranes, creating pores in the membrane and disrupt the integrity of the cell.

answer

Membrane Attack complexes (MACs)

question

Do MACs have much effect on gram-positive bacteria?

answer

No, because the peptidoglycan layer of these cells prevents CSCs (complement sytem components)from reaching their cytoplasmic membranes.

question

What are opsonins?

answer

secreted proteins that tag particles for phagocytosis

question

A phagosome fused with a lysosome

answer

phagolysosome

question

a phenomenon called respiratory burst enables what? (when oxygen consumption increases in a phagolysosome)

answer

it allows an enzyme to produce reactive oxygen species (ROS)which are toxic.

question

Describe the digestion process of a lysosome in phagocytosis.

answer

1.O2 consumption increases, creating ROS
2.another enzyme make nitirc oxide which reacts with ROS to produce more toxic cmpds
3.special pumps pump protons into the phagolysosome, lowering the pH
4.The degradation of the peptidoglycan layer occurs.
5.defensins damage membranes of invader
6.transferrins tie up iron

question

concentrated groups of macrophages, giant cells and T cells that wall off and retain organisms or other material that cannot be destroyed.

answer

Granulomas

question

when pahocytes fuse together, they form what?

answer

Giant cells

question

When are giant cells and granulomas formed?

answer

When activated macrophages fail to destroy microbes

question

What is the problem with granulomas?

answer

although they protect from the spread of microbes to other cells, they also harm the host because they interfere with normal tissue function.

question

scavengers and sentries that are routinely phagocytizing dead cells and debris, but ready to destroy invaders and call in reinforcment when needed.

answer

Macrophages

question

The rapid response team quick to move into the area of trouble and ready to eliminate the invaders.

answer

Neutrophils

question

How long can macrophages live?

answer

a few weeks to a few months

question

How long to neutrophils usually live?

answer

1 to 2 days

question

What is the benefit and weakness of neutrophils?

answer

They have more killing power that macrophages, but they have a limited lifespan

question

In what ways do nuetrophils kill microbes?

answer

1.phagocytosis
2.They also release their granules along with DNA to form neutrophil extracellular traps (NETs)

question

How do the NETs of neutrophils kill microbes?

answer

The DNA strands in the NET ensnare microbes, allowing the granule contents (enzymes and peptides) to destroy them.

question

This type of programmed self-destruction triggers an inflammatory response

answer

pyroptosis

question

What are the two major events that can initiate inflammation?

answer

1.Microbes
2.Tissue damage

question

cytokines and other fever inducing substances

answer

pyrogens

question

What are fever-inducing cytokines made by the body?

answer

endogenous pyrogens

question

What are fever-inducing pyrogens that are introduced from external sources such as bacteria?

answer

exogenous pyrogens

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