3.2 Innate Immunity Study Guide REDO

The immune system is divided into two response mechanisms

Innate immunity and adaptive immunity

The innate immune response is present and functional at birth? True or False

True

Immune response during first 2 hours

Innate defenses detect pathogen and release cytokines while phagocytes like macrophages and neutrophils are recruited

Phagocyte

A white blood cell that engulfs and digests pathogens and debris

Receptor

A protein on the cell surface that recognizes and binds to molecules like PAMPs on pathogens

Antigen

A foreign substance that triggers an immune response and antibody production

Immune response after 4 hours

Inflammation begins and cytokines increase blood flow to attract immune cells

Immune response after 6 hours

Phagocytes engulf and destroy pathogens while adaptive immunity begins activating

Apoptosis

Programmed cell death that prevents viral replication and limits infection spread

10 hours after infection

Adaptive immune cells activate and produce antibodies

Which of the following terms is used to describe the innate immune response?

Non-specific

Sweating

Flushes microbes and contains antimicrobial substances

Mucus

Traps pathogens in respiratory and digestive tracts

Tears

Contain lysozyme that breaks down bacterial cell walls

Mucociliary escalator

Moves trapped microbes out of the airway

Urine

Flushes microbes from the urinary tract

Microbiota

Competes with pathogens and prevents colonization

Lysozyme

Enzyme that destroys bacterial cell walls

Sebum

Oily secretion that lowers skin pH and inhibits bacterial growth

Not part of first line of defense

Production of antibodies

Lymph

Clear fluid that transports white blood cells and removes waste

Lymph node

Filters lymph and houses immune cells that detect pathogens

MALT

Mucosa-Associated Lymphoid Tissue in mucous membranes

Importance of mucosal lymphoid tissue

Provides immune defense where pathogens enter

GALT

Gut-Associated Lymphoid Tissue such as Peyer’s patches that protect intestines

Monocytes develop into

Dendritic cells and macrophages

Leukocyte component of pus

Neutrophil

Which white blood cells are professional antigen presenting cells?

Macrophages, dendritic cells, and B cells

Mononuclear phagocytic system

Network of phagocytes like monocytes and macrophages in tissues and lymphatic organs

PAMP

Pathogen-Associated Molecular Patterns

Who displays PAMPs

Pathogens

PRR stands for what?

Pattern Recognition Receptors

Who displays PRRs

Immune cells

Relationship between PRR and PAMP

PRRs are receptors and PAMPs are antigens

Difference between first and second lines of defense

First is barriers like skin and mucus; second is internal responses like inflammation and phagocytosis

Chemical that directs phagocytes

Cytokines

Phagocyte super sensor is a PAMP or PRR?

PRR

Why would the binding of PRR to PAMP of a pathogen cause the release of cytokines?

It signals immune defenses and recruits more immune cells

Phagosome

Vesicle inside a phagocyte that encloses an ingested pathogen

Phagolysosome

Fusion of phagosome and lysosome where enzymes destroy the pathogen

What attaches to MHC

A fragment of the digested antigen

Phagocytic cell displaying antigen

Antigen-presenting cell (APC)

Four signs of inflammation

Redness, heat, swelling, pain

First step in inflammation

Vasoconstriction

Function of prostaglandins and histamines

Increase blood flow and vessel permeability

How vasodilation helps

Allows immune cells and proteins to reach tissue faster

Purpose of neutrophils

First responders that engulf and destroy pathogens

Diapedesis

Movement of white blood cells through vessel walls to infection site

NSAIDs

Nonsteroidal anti-inflammatory drugs

Mechanism of NSAIDs

Inhibit prostaglandin synthesis by blocking COX enzymes

Part of brain regulating temperature

Hypothalamus

99°F considered fever

False

Temperature causing organ damage

Above 104°F or 40°C

Why chills occur during fever

Body raises temperature set point making you feel cold

Benefits of fever

Inhibits pathogen growth

Interferons

Proteins that warn neighboring cells and inhibit viral replication

Complement system

Group of blood proteins that enhance immune responses and destroy pathogens

Why complement is innate

Acts quickly and non-specifically

How complement works

Protein cascade leading to inflammation

Antimicrobial peptides

Small proteins that damage pathogen membranes or interfere with function