Line of Defense -First (Barriers) -Second -Third
(First line of Defense) – Physical or Anatomical Barriers >>Skin and mucous membranes of respiratory, urogenital, eyes, and digestive tracts -Mucous coat impedes attachment and entry of bacteria - Nasal hair traps larger particles *tears and skin – Chemical Barriers Lysozyme & Defensins -produced by saliva and tears – Genetic Resistance
(Second line of Defense)
– protective cells and
fluids; inflammation, phagocytosis, INF, Complement
*WBC produced>inflamation occurs
(Third line of Defense)
– Third line of defense – acquired with exposure to
foreign substance; produces protective antibodies
and creates memory cells – specific disease
*Relies on lymphocytes (T,B) & antibodies
How does inflammation occur
Why does inflammation occur
(HOW) WBC's have Patter recognizing receptors (PRR) -kinases -lectins -mannose-type molecule -toll-like receptors
can recognize Pattern associated molecular patterns (PAMP)
Nonspecific Diseases
- Sebaceous secretions
- Lysozyme, an enzyme that hydrolyzes the cell
wall of bacteria, in tears - High lactic acid and electrolyte concentration in
sweat - Skin’s acidic pH
- Hydrochloric acid in stomach
- Digestive juices and bile of intestines
- Semen contains an antimicrobial chemical
- Vagina has acidic pH
Immune System
>Subdivisions(4)
immunology
-The study of the body’s
second and third lines of
defense
*Skin is The major organ in the body
-Large, complex, and diffuse network of cells
and fluids that penetrate into every organ
and tissue
- Subdivisions of immune system:
1. Reticuloendothelial system (RES)
2. Extracellular fluid (ECF)
3. Bloodstream
4. Lymphatic system
Functions of a healthy immune system(3)
self-normal cells of body
nonself-foreign material
Functions of a healthy immune system: 1. Surveillance of the body 2. Recognition of foreign material 3. Destruction of entities deemed to be foreign
PAMP
-
Reticuloendothelial System (RES)
Phagocytic cells – mononuclear phagocyte system
Network of connective tissue fibers that interconnects other cells and meshes with the connective tissue network surrounding organs
Origin, Composition, and
Functions of the Blood
Whole blood-
Serum – is the liquid portion of the blood after a clot has
formed – minus clotting factors
Hemopoiesis – production of blood cells
(Whole blood)
- plasma
- blood cells/ formed elements
> > Plasma – 92% water, metabolic proteins, globulins,
clotting factors, hormones, and all other chemicals and
gases to support normal physiological functions
>>Blood cells – -Stem cells – undifferentiated cells, precursor of new blood cells -Leukocytes – White blood cells Granulocytes: lobed nucleus Agranulocytes: unlobed, rounded nucleus -Erythrocytes –develop from bone marrow stem cells, lose nucleus, simple biconcave sacs of hemoglobin
leukocytes
-granulocytes
»Neutophil, Basophil, Acidophil
found in blood and tissues
- *stimulated by
1. Pathogen presence
2. Damaged Host cells
3. T lymphocytes - Secrete
(granulocytes)
>Neutrophils
-most common phagocyte
secrete: peroxide
> Basophil (mast cell in tissue)
- rare in blood. ~~common in tissue as mast cell~~
secrete: histamine - cause leaky capilaries–water out of blood vessels (Inflammation)
> Eosinophil
- good at fightin eukaryotic pathogens~~(inhibit parasites-worms)
secrete: histamine & peroxide
Leukocytes
-agranulocytes
»>Lymphocytes
(Helper T cells, Cytotoxic T cell, Suppressor Tcells)
(B cells, Plasma cells)
(Natural Killer cells)
(T-Lymphocytes) >Helper T cells (CD4) ---stimulate inflammation ---stimulate B cells ---stimulate Cytotoxic T cells
> Cytotoxic T cells
-directly destroy infected cells
> Suppressor/Regulatory T cells
-inhibit further immune response
(B-Lymphocytes)–>Plasma cell
- make and secrete antibodies
- inhibit pathogenic activity
(Natural Killer cells)
- stimulate sick cells in body to preform apoptosis
- activate w/o antigen
Leukocytes
-agranulocytes
»>Antigen-presenting cells(APC)
(Dendritic cells)
(Macrophage)
(Dendritic cells)
-present things to Helper T cell
~~Activated immunity if T cell is Presented to Helper Tcells~~~
(Macrophage)
-engulf antibody encrusted pathogens
Lymphatic system
1. Provides an auxiliary route for return of extracellular fluid to the circulatory system 2. Acts as a drain-off system for the inflammatory response 3. Renders surveillance, recognition, and protection against foreign material
Lymphatic fluid
Lymph
a plasma-like liquid carried by
lymphatic circulation
- Formed when blood components move out of
blood vessels into extracellular spaces - Made up of water, dissolved salts, 2-5%
proteins - Transports white blood cells, fats, cellular
debris, and infectious agents
Lymphatic Vessles
Lymphatic capillaries
permeate all parts of the body except the CNS, bone, placenta, and thymus
- Thin walls easily permeated by extracellular fluid which
is then moved through
contraction of skeletal
muscles
Functions to return lymph to circulation; flow is one direction
– toward the heart
– eventually returning to blood stream
Lymphoid Organs and Tissues
(Primary lymphoid organs)
sites:
- Thymus
- Bone marrow
(Secondary lymphoid organs) >circulatory-based locations -Spleen -Lymph nodes >collections of cells distributed throughout body tissues – skin and mucous membranes – SALT, GALT, MALT
Lymphoid Organs
Primary:
-Thymus
Secondary:
- Spleen
- Lymph nodes
(Thymus)
located in the thoracic cavity
-high rate of growth and activity
»site of T-cell maturation
(Lymph nodes)
serves as a filter for lymph
(Spleen)
serves as a filter for blood
function:
move worn out rbc from circulation
(Assocated Lymphoid tissue) >MALT - >SALT - >GALT -Peyer's patch
Secondary line of defense
– protective cells and
fluids; inflammation and phagocytosis – nonspecific disease
*WBC produced>inflamation occurs
Actions of Secondary line of defense
Recognition Inflammation Phagocytosis Interferon Complement
Inflammation-
Functions
Chemical Mediators(6)
(Inflammation)
-a reaction to any traumatic event in the tissues that restores homeostasis
»Functions:
1.mobilize & attract immune components to site of injury
2. set in motion mechanism to repair tissue damage
3.destroy and block microbes from further invasion
(Chemical Mediators) - - - - - -
Major Events in Inflation(4)
Injury/Immediate Responses
Vascular Changes
Edema
Resolution/Scar formation
Injury/Immediate Responses(4-5)
Rubor-redness >inc circul&vasodilation Calor-Warmth >heat via increased blood flow Tumor-Swelling >edema, pus forms, prevents spread of infection Dolor-Pain >stimulation of nerve ends LOSS OF FUNCTION
Vascular Changes
Vasodilation
(Vasodilation)
-increase flow of blood into area
»Causes Rubor and Calor
Edema
Exudate
(Edema)
(Diapedesis)
(Chemotaxis)
(exudate)
-fluid part that escapes into tissues. may contain RBC or pus
(edema)
-when accumulation of fluid gives rise to Swelling and Hardness
(Diapedesis)
-WBC migrate out of blood into tissue spaces
(Chemotaxis)
- cells migrate in response to chemical stimulus released @site of injury
- cells swarm to cell
Fever
-Definition
- Pyrogens
- Phagocytosis
(Fever)
-an abnormality elevated body temperature
(Pyrogens) -substance causing elevated body temp >Exogenous pyrogens -prod of infectious agents >Endogenous pyrogens -pyrogens released by macrophages,monocytes, neutrophils during phagocytosis 1. IL-2 2. TNF
(Phagocytosis)
1 Surveillance
2Engulf and eliminate
3Extract immunogenic information(antigen) from foreign
Resolution/Scar formation
-Phagocytosis(5)
(Stages of Phagocytosis)
- chemotaxis
- ingestion
- phagolysome formation
- destruction
- elimination
(Chemotaxis)
- cells migrate in response to chemical stimulus released @site of injury
- cells swarm to cell
TLR hooks to PAMP and meets with 2nd TLR to encase the PAMP molecule
–stimulates intracellular process and release of chemical mediators
»Ingestion
(Phagolysome formation)
-lysomes fuse with phagosome
-antimicrobial chemicals go into Phagolysome
»Destruction of microbes
Interferon
(Interferon)
-Small protein produced by certain WBCs and tissue cells
Interferon alpha – lymphocytes and macrophages
Interferon beta – fibroblasts and epithelial cells
Interferon gamma – T cells
Complement Cascade
- Classical
- Lectin
- Alternative
(Classical)
– activated by the presence of antibody bound to microorganism
(Lectin)
– nonspecific reaction of a host serum
(Alternative)
– begins when complement proteins bind to normal cell wall and surface components of microorganisms
4 Stages of the Complement Cascade
- Initiation
- Amplification&cascade
- Polymerization
- Membrane attack
(Initiation)
(Amplification&cascade)
(Polymerization)
(Membrane attack)