Host Defenses I

Immune response

physiological process coordinated by the immune system to eliminate foreign
substances (antigens)

antigens

any substance that can provoke a response from the immune system, causing it to produce antibodies against it

Innate barriers 

the body's first line of defense against pathogens, which can be physical (like the skin and mucous membranes) or chemical (like tears, saliva, and stomach acid)

innate immunity 

the body's first, non-specific line of defense against pathogens that is present from birth

lymphatic system

a circulatory system made up of lymph vessels, which are much like blood vessels

edema

tissue swelling 

MALT

Mucosa-associated lymphoid tissue; a network of immune cells located in the mucous membranes lining various body systems

granulocytes

a type of white blood cell (leukocyte) that contain granules in their cytoplasm. They play a crucial role in the immune system by fighting infections and allergic reactions. 

agranulocytes

a type of white blood cell that lack granules in their cytoplasm and include two main types: lymphocytes and monocytes

erythrocytes

red blood cella

leukocytes

white blood cells

neutrophils

highly phagocytic; fight many invaders, especially bacteria and viruses; fast migration 

eosinophils

moderately phagocytic; attack allergens and parasites

basophils

attack allergens and parasites 

phagocytosis

the process by which a cell engulfs and ingests solid particles, such as microorganisms, foreign substances, or dead cells, through a cellular eating mechanism

neutrophil extracellular traps (NETs)

web-like DNA structures combined with histones and antimicrobial proteins that are released from stimulated neutrophils

mast cells

phagocytic; typically stationed near body openings; play a crucial role in the immune system and allergic reaction

granules

Histamine, heparin, AMPs, pro-inflammatory enzymes

piecemeal degranulation

a slow releasing process mediated by vesicular transport of stored secretory granule contents

anaphylatic degranulation

the rapid release of inflammatory mediators from mast cells and basophils, triggered by an allergic reaction, such as in anaphylaxis

cutaneous allergic responses

an immune reaction in the skin to an allergen, causing symptoms like redness, itching, swelling, and rashes

mucosal allergic response

an overreaction of the immune system to a harmless substance (allergen) in areas with mucous membranes, such as the nose, throat, and gut

monocytes

largest agranular white blood cell; highly phagocytic once they mature into macrophages (which can be fixed or wandering); activate adaptive immune responses

monocytes

chronic infections, inflammation, disorders, certain cancers

maccrophages

mature monocytes; migrated out of circulatory system

macrophages 

a type of white blood cell that acts as a "big eater" of the immune system, responsible for identifying, engulfing, and destroying pathogens like bacteria, damaged cells, and cancer cells

dendritic cells

highly phagocytic; important role in activating adaptive immune system; found in most body tissue- areas with exposure to environment

lymphocytes

B cells and T cells

interferon

What type of pathogen would illicit a cell to produce large amounts of interfero

neutrophils

which cells of the innate immune response are typically the first responders to a wound or infection?

pyrogens

What molecules are responsible for inducing a fever response during an infection?

opsonization, cytolysis, inflammation

Describe 3 outcomes of successful activation of the complement cascade.

adaptive immunity

the body's specialized immune response that targets specific pathogens and builds long-term "immunological memory" through B cells and T cells

stomach acid, lysozyme in tears and AMPs

Give one example of an innate chemical barrier defense of the human body.

natural killer cells

a type of white blood cell in the innate immune system that identifies and kills abnormal cells, such as virus-infected cells and tumor cells

cytotoxic

release specialized proteins; proteins that incapacitate cells structurally and functionally and trigger an inflammatory response

apoptosis

programmed cell death, a natural process where a cell triggers its own death to eliminate unnecessary or damaged cells for the health of the organism

defense and signaling molecules

Eliminate the invading pathogen or limit its spread until the adaptive immune system responds

cytokines

small proteins secreted by immune and other cells that act as chemical messengers to coordinate and regulate immune responses

chemokines

signaling molecules; attract WBCs

chemotaxis

cell movement in response to chemical stimuli

chemokines

subset of cytokines that primarily act as a "call to action," attracting and guiding immune cells to a specific location

interleukins

key communicators in the immune system, regulating immune responses by promoting or suppressing inflammation, activating immune cells, and influencing their growth and differentiation

hematopoiesis

production of new blood cella and platelets

interferons(IFNs)

“interfere” with viral replication; activated innate and adaptive immune reponses to other pathogens

IFN-y

produced by NK cells and certain T cella to activate macrophages

IFN-a and IFN-B

made by virus infected cells

tumor necrosis factor (TNFs)

regulate immune cells and inflammation; capable of killing tumor cells

TNF-a

produced mainly by macrophages, induces inflammation

classical pathway 

complement proteins activated when antibodies bind to a pathogen 

alternative pathway

complement proteins activated by directly interacting with pathogen

lectin pathway

complement proteins activated when mannose-binding lectin (MBL) binds to pathogen

opsonization

complement protein tags pathogen for phagocytosis

cytolysis

complement proteins form membrane attack complex (MAC) in pathogen’s plasma membrane. Water and ions rush through MAC and lyse cell

inflammation

complement proteins recruit leukocytes, releasing signals that cause ________

inflammation

innate immune response that develops after tissue damage

recruit immune defenses to injured site, limit spread of infectious agents, deliver oxygen, nutrients and chemical factors required for tissue recovery

why does our immune system employ inflammation

redness, pain, localized heat, swelling, and sometimes loss of function

what are some cardial signs of inflammation 

vascular changes

chemical alarm signals released by damaged cells and leukocytes increase blood flow and vessel permeability 

leukocyte recruitment

cytokines recruit leukocytes. Neutrophils arrive first, followed by monocytes, which mature into macrophages. Neutrophils and macrophages phagocytize invaders and recruit other leukocytes 

resolution

inflammation signals decrease; tissue repair initiated

vasodilation

the widening of blood vessels, which increases blood flow

exudate

a fluid that leaks from blood vessels into nearby tissues, composed of cells, proteins, and other solid materials; associated with inflammation

vasoactive molecules

substances that cause blood vessels to widen (dilate) or narrow (constrict), influencing vascular tone and permeability; pro-inflammatory/active pain receptors

chemoattractants

chemical substances that induce directional movement in cells, guiding them toward higher concentrations of the substance

margination

leukocytes slow as they roll along vessel wall; eventually leukpcytes adhere to vessel wall

diapedesis

leukocytes change shape; leukocytes squeeze out of vessel

macrophage maturation

inflammation- resolution

return of capillaries to normal state; damaged vessels repaired

angiogenesis

the natural process of forming new blood vessels from existing ones

fever

abnormally high systemic body temp

pyrogens

fever-inducing agents

hypothalamus

what do cytokines signal to raise body temp

low grade fever

enhances antiviral effects of interferons, promotes tissue repair, limits growth of certain pathogens

interferon

cell infected by virus releases ________

interferon

signals uninfected neighboring cells to decrease protein synthesis, preventing viral replication

interferon

triggers apoptosis of infected neighboring cells

interferon

activates leukocytes