Nonspecific Host Defenses Flashcards
3 lines of defense
first, second, third
first line of defense
block the microbe from entering the body/portal of entry (nonspecific and innate)
second line of defense
through the entire body/systemic (nonspecific, innate)
eg. of second line of defense
phagocytosis, interferons
third line of defense
systemic, acquired, specific
characteristics of third line of defense
Changes throughout lifetime,
Specific to a strain of microbe,
B and T lymphocytes, antibodies, cytotoxins
first line of defense mechanisms
Physical or anatomical barriers, chemical defense layers, genetic defenses
Physical or anatomical barriers
skin, mucus membranes, respiratory tract
skin
thick keratin layer
how does skin remove microbes
keratin, hairshaft, sweating
keratin
thick insoluble layer that prevents microbes from entering
hair-shaft
hair sheds removing microbes
sweating
removes mircobes
mucus membranes
moist permeable layer which gets flushed with fluid to remove microbes
where are mucus membranes present?
Gi tract, Respiratory tract, urinary tract
Respiratory tract
nasal hairs that trap large particles, cilia actively brush mucus out of respiratory tract
chemical defense layer
lysozyme, defensins, stomach pH
lysozyme
breaks down peptidogylcan
defensins
small proteins that are found in bodily fluids that insert into the cell membrane of microbes causing leaks
genetic defenses eg.
Cat HIV, sickle cell anemia against anemia
Components of Second and Third Lines of Defense
system wide defense, white blood cells
component of second line of defense
PRRs, PAMPs
component of third line of defense
antibodies, antigens
system wide defense
constantly look and recognize if microbe is foreign
white blood cells
recognize what does not belong by cell surface markers made of proteins/sugars
PRRs
recognize molecular patterns that are recognized as foreign
PAMPs
molecular patterns
eg. PAMPs
LPS, peptidoglycan, flagellin, ds RNA, techoic acid, chtin
Systems involved in immune defenses
extracellular fluid, Reticuloendotheial system (RES), bloodstream
Reticuloendotheial system (RES)
network of connective tissue that surrounds organs; Way to prevent microbes from attacking important organs
bloodstream includes
plasma, granulocytes, agranulocytes,
hematopoiesis
process of blood cell production
hematopoiesis produces
leukocytes, erythrocytes, platelets
blood plasma
fluid of blood
blood plasma includes
sugars, dissolved gasses, antibodies, platelets, clotting factors
granulocytes
pokadots (organelles) in white blood cell; found by using multiple dyes
types of granulocytes
Neutrophils, Eosinophils, Basophils
neutrophil
Most common phagocyte in the body and WBC/act as phagocytes
eosinophil
Fight worm infections and fungal infections by binding to the larger microbe and releasing digestive enzyme
basophils
Involved in histamine and inflammation production and regulates sleep wake cycles
mast cells
Found in connective tissue and involved in anaphylaxis
Agranulocytes
unstained organelles
types of agranulocytes
lymphocytes, monocytes
lymphocytes
smaller and have no cytoplasm
types of lymphocytes
T cells, B cells
T cells
fight off infections; cell mediated immunity
B cells
make antibodies; humoral immunity
types of monocytes
macrophages, dendritic cells
macrophages
blood stream
dendritic cells
connective tissues
are macrophages and dendritic cells phagocytes?
yes and Involved in antigen processing and antigen presenting
lymphatic fluid
contains all components blood has except for RBC
major functions of lymphatic system
return leaked fluid, draining off inflammatory fluid, surveillance/recognition/destruction of foreign cells
Lymphatic vessels move
only inwards; through skeletal muscle movements
what prevents backflow?
valves
Lymph organs
thymus, lymph nodes, spleen
thymus
where t cells mature
lymph nodes
filters moving from extremities back to bloodstream
Region of lymph node clusters
neck, maxillary/armpits, abdominal region
Spleen
filter out dead blood cells
MALT/GALT
mucus membrane, gut tissue
cause of swollen lymph nodes
white blood cells gathering, metastasis cancer cells
activation of innate immunity caused by
PRRs and PAMPs, TLRs
toll like receptors (TLR)
pattern recognition receptor in phagocytes; Bind to PAMPs
Dimerization
bind to same PAMP
Cytokines
molecule to communicate to other cells of the body
interleukins
molecule made to communicate with other white blood cells
Inflammatory response
any response to tissue damage
Purpose of inflammatory response
to draw fluid and white blood cells to the site of healing to prevent foreign material from entering body and draw fluid
stages of Inflammatory response
- Injury
- Rubor/calor: redness/heat
- Tumor: swelling
- Dolor: pain
- Loss of function: scab
Inflammatory response microscopic
- Damaged cells will be picked up and sensed by white blood cells
- White blood cells send cytokines to cause blood cells to constrict; prevents bacteria from entering and decrease blood loss
- Send cytokines for blood cells to dialate; Allow more movement of blood and Causes adeema (buildup of fluid) + pus formation
Histamine
help release fluid
CRP/C-reactive protein
PRRs important in enhancing phagocytosis and complement system function; promote inflammation
Diapedesis
white blood cells leaving the bloodstream; creates pus
Pyrogens
cause fever; slow cell division
purpose of fevers
promote t cell development/cell division, improves ethicacy of t cell production and speeds up maturation, brings iron into the macrophages
mechanisms of phagocytes
- Chemotaxis: microbe using TLR to recognize pathogen/foreign debris and chases after it
- Adhesion:
Uses PAMP to attach - Engulfment: endocytosis; brings into cell vacuole
Phagosome: cell vacuole - Phagolysosome forming: phagosome fuses with lysosome
- Killing infastructure
Goes through antigen processing if dendrtic/neturophil
interferons are produced by
white blood cells that detect the presence of viruses/cancer cells
interferons purpose
Sent to other white blood cells to become specialized to fight viruses/cancer cells
interferons
White blood cell detects virus and produces/releases interferons as the virus is synthesizing and then other white blood cell recieves interferons and creates DNases and becomes antiviral cell
interferon types
made by t cells, macrophages, specific white blood cells
complement system
component of second line of defense; collection of proteins that work together in a cascade to create a hole in the membrane of pathogens