a&p ch 20: lymphatic system immunity (innate immunity)

How does innate immunity protect us from disease?

- physical barriers (ex: skin) - phagocytes that engulf pathogens - immune surveillance of abnormal cells - interferons to defend from viruses - complement to assist antibodies - inflammation to limit the spread of infection - fever

What are the steps of the compliment alternate pathway?

1. A group of compliment proteins (Properdin, Factor B, Factor D) interact following exposure to foreign materials 2. Interaction catalyzed C3 into C3a and C3b 3. C3a activates an inflammatory response and C3b binds to the bacterial surface and enhances phagocytosis

What are the steps of the compliment classic pathway?

1. Antibody binds bacteria cell wall 2. Compliment protein C1 is activated when it binds to 2 antibodies 3. C1 catalyzes C3 into C3a and C3b 4. C3a activates an inflammatory response & C3b binds to the bacterial surface and enhances phagocytosis

Name the 3 pathways of compliment proteins.

Classic Lectin Alternate

Distinguish between innate immunity and adaptive immunity.

Innate immunity is nonspecific & doesn't distinguish one type of threat from another adaptive immunity is specific & protects against particular threats

How does HCl contribute to innate immunity?

helps destroy microorganisms in stomach

A child falls off her bike and skins her knee. Which form of immunity will be activated immediately?

innate (nonspecific) immunity

What are the 2 types of immunity?

innate (nonspecific) immunity adaptive (specific) immunity

What are the 3 types of interferons?

interferon alpha interferon beta interferon gamma

How do interferons trigger the production of antiviral proteins?

interferons bind to receptors on normal cells use 2nd messenger to trigger production of antiviral proteins in the cytoplasm antiviral proteins only work once the virus enters the cell bc fxn = interfer w viral replication

What are the 3 results of complement activation?

killing of pathogen through membrane attack complex (MAC) enhanced phagocytosis through opsonization inflammation (histamine response)

How do mucous membranes contribute to innate immunity?

line digestive, respiratory, urinary, & reproductive tracts fxn to trap microorganisms/debris to prevent them from entering the circulatory sys

What is inflammation/inflammatory response?

localized tissue response to injury

What do interferons stimulate?

macrophages NK cells

What are macrophages derived from? What does the term macrophage apply to?

monocytes in blood phagocytes in tissues

What is the effect of histamine release?

Histamine release by mast cells and basophils in tissues increases local inflammation, thereby accelerating blood flow to the region.

Which phagocytes are abundant, mobile, & quick to phagocytize cell debris or invading bacteria?

neutrophils

Identify the types of phagocytes in the body, and differentiate between fixed macrophages and free macrophages.

neutrophils, eosinophils, macrophages fixed macrophages = scattered among CTs & don't move free macrophages = mobile & reach injury sites by migrating through adjacent tissues or travelling in the BS

Define chemotaxis.

phagocyte movement in response to chemical stimuli released by body cells or pathogens

What is the function of eosinophils?

phagocytose foreign substances/pathogens coated w antibodies

How is interferon alpha produced? What does it do?

produced by cells infected w virus attracts & stimulates NK cells enhances resistance to viral infection

How do pyrogens increase body T?

pyrogens reset hypothalamus to increase body temp

What are the 4 cardinal signs of inflammation/inflammatory response?

redness, swelling, heat, pain

How is interferon gamma produced? What does it do?

secreted by T cells & NK cells stimulates macrophage activity

How is interferon beta produced? What does it do?

secreted by fibroblasts slows inflammation in damaged areas

How does the integumentary system protect the body? (textbook)

skin/physical barrier - 1st line of defense in preventing pathogens & toxins from entering the body skin secretions - flush the surface hair - protects against physical abrasion multiple layers of the skin's epithelium = interlocking barrier

Define interferons. What do they trigger?

small proteins released by activated lymphocytes, macrophages, & cells infected w viruses trigger production of antiviral proteins that interfere w viral replication w/in tissue cells

A rise in the level of interferons in the body suggests what kind of infection?

viral infection

What is a membrane attack complex (MAC)? How is it forms? What is its function?

when C3b binds to other compliment proteins to form a structure in the pathogen membrane that helps destroy through cell lysis

What is a fever? What induces it?

when body T is above 99F / 37.2C pyrogens

What is immunological escape?

when cancer cells mutate to be undetectable & destroyed by NK cells

What is emigration?

when phagocytes leave capillaries by squeezing bw adjacent endothelial cells

What is the impact of a fever on immunity?

↑ T may destroy some bacteria ↑ metabolic rate ↑s by 1 °C (results in 10% ↑ in metabolic rate which results in mobilization of tissue defenses & repair mechanisms)

What effect do pyrogens have in the body?

↑ body T (fever) which mobilizes defenses, accelerates repairs, & inhibits pathogens

What are the steps of the compliment lectin pathway?

1. Mannose-binding lectin (MBL) binds to carbohydrates on bacteria cell wall 2. MBL catalyzed C3 into C3a and C3b 3. C3a activates an inflammatory response & C3b binds to the bacterial surface & enhances phagocytosis

How do NK cell destroy cancer cells?

1. NK cells recognize abnormal cell & attaches to it 2. Golgi apparatus moves until the maturing face points towards the abnormal cell & produces secretory vessels containing perforins 3. perforins are released by exocytosis & diffuse towards the target cell 4. perforins generate pores in target cell, making it unable to maintain its internal environment & disintegrates

Where are neutrophils found? What is their function?

BS, peripheral tissues, sites of injury/infection (abundant, quick, mobile) phagocytose cell debris & bacteria

What is immunity?

Body's ability to resist infections from disease & damage from foreign substances & harmful chemicals

What is the difference bw C3a and C3b?

C3a activates an inflammatory response C3b binds to the bacterial surface & enhances phagocytosis

How do NK cells detect cancer cells?

NK cells recognize unusual proteins, called tumor-specific antigens, on the plasma membranes of cancer cells. When these antigens are detected, the NK cells then destroy the abnormal cells.

Describe innate immunity. What is another name for this type of immunity? What does it provide?

Prevent/slow the entry of pathogens or attacks them immediately following entry. Same responses regardless of the pathogen (can't distinguish threats) AKA Nonspecific Immunity Provides nonspecific resistance

Describe adaptive immunity. What is another name for this type of immunity? What does it provide?

Protects against specific threats (Ex: defend against 1 pathogen but no others) Involves lymphocytes AKA Specific Immunity Provides specific resistance

How are the skin & its components contribute to innate immunity?

SKIN - Mechanical barrier to pathogens & toxins - keratinized cells & adjacent cells = tightly locked ACID MANTLE - acidic pH - inhibits bacterial growth SEBUM - antifungal/bacterial properties TEARS/SALIVA - lysozyme attacks & destroys bacteria

What are the physical barriers of innate immunity?

Skin Hair Mucous membranes MALT Mucus Urine HCl

Can normal cellular division generate an abnormal cell?

YES

When do phagocytes begin to function as a result of innate immunity?

after the physical barrier is breached

What is adhesion? Explain. What happens after adhesion?

attachment of phagocyte to its target 1st step of phagocytosis receptors on the phagocyte's plasma mem bind to surface of target after adhesion, phagocyte may destroy target itself or promote destruction by activating specific defenses

What is the function of histamine & heporin?

attract phagocytotes, which clean up bacteria, debris, & activate specific immune response

How does hair contribute to innate immunity?

barrier against physical abrasions prevents organisms/chemicals from reaching skin

If NK cells are engaged in immune sur

cancer cells can mutate to not display tumor-specific antigens or they secrete chems that can destroy NK cells

What triggers inflammation? What cells are involved?

changes in interstitial environment (alters chem enviro) mast cells & basophils release histamine & heporin

What are cytokines?

chem signals released by cells to coordinate local activities some can act as hormones

Where are complement proteins located and what do they do?

circulate in BS interact w antibodies to destroy pathogens

Which compliment pathway is the most rapid and effective?

classic

Briefly explain the role of complement proteins.

complement proteins of the complement system interact with each other in chain reactions that ultimately produce activated forms that target bacterial cell walls & plasma membranes, stimulate inflammation, attract phagocytes, or enhance phagocytosis

Define immune surveill

constant monitoring of normal tissues by NK cells sensitive to abnormal antigens on the surfaces of cells.

How does mucus contribute to innate immunity?

contains acids

Explain how inflammation accelerates blood flow to a region.

dilate BVs = ↑ blood flow ↑ permeability of BV initiate clotting

What are the functional characteristics of phagocytes?

emigration chemotaxis adhesion

What is opsonization? Why does it occur?

enhancement of phagocytosis occurs bc macrophage membranes contain receptors which detect & bind compliment-antibody bound complexes