Chapter 31: Immunology: Animal Defense Systems Flashcards
pathogens
harmful organisms and viruses that can cause disease
immunity
the ability to avoid disease when invaded by a pathogen
Innate Immunity
Nonspecific
deployed against/targets a wide variety of invasive organisms
Barriers and phagocytes
Can be there all of the time or just activated by an invasion/injury
Super quick
Most animals have this
Adaptive Immunity
Specific distinguishes between self and nonself involves antibody proteins and other proteins that recognize, bind to, and help destroy specific invaders Slow Long lasting JUST VERTEBRATES
Innate, nonspecific 1st line
barriers (skin and organ lining) Dryness, low pH mucus lysozymes, defensins 1st 4 hours after pathogen infection
Innate, nonspecific (second line)
Inflammation phagocytosis Natural Killer Cells Complement System Interferons 4-96 hours after infection by pathogen
Adaptive, specific
Humoral immunity (B cells, antibodies) Cellular Immunity (T cells) More than 96 hours after infection
self
substances made by organism
nonself
substances that are not part of the organism
T or F: In mammals and other vertebrates, specific and nonspecific mechanisms work together as a coordinated defense system, usually in sequence
True
T or F: The major players in immunity are specific cells and proteins
True
T or F: There are more white blood cells than red blood cells in human blood
False, there are more red than white blood cells
White blood cells
cells in the blood that are specialized for various functions in the immune system
two major kinds
Lymphocytes and Phagocytes
Phagocytes
LARGE CELLS [large font to help remember]
engulf pathogens [p to help remember] and other substances by phagocytosis [cell eating]
Innate and Adaptive Immunity
type of WBC
ex. macrophage
Lymphocytes
type of WBC
ex. B cells and T cells
adaptive immunity
Antibodies
Proteins that bind to specific substances identified as nonself
This can be inactivate and DESTROY microorganisms and toxins
OR
it can function as a tag/marker, making it easier for other immune cells to attack
produced by B cells
Major Histocompatibility Complex (MHC)
proteins found in two classes (I and II)
MHC proteins act as labels and present antigens to T cells
MHC I proteins
found on most cells in mammals
self-identifying labels
present antigens to cytotoxic T cells
MHC II proteins
found on macrophages, B cells, and dendritic cells
self-identifying labels
present antigens to helper T cells
coordinate interactions between lymphocytes and macrophages
T Cell receptores
integral membrane proteins on the surfaces of T cells
Recognize and bind to the substances presented by the MHC proteins on other cells
Cytokines
soluble signaling proteins released by many cell types
bind to surface receptors and alter target cell action
Activate or inactivate B cells, macrophages, and T cells
like an on and off switch for immune cells
Skin
Physical barrier: rarely penetrated by bacteria when INTACT
Saltiness: usually not hospitable to bacteria growth
Presence of Normal Flora: the bacteria and fungi that are normally just chilling out on the skin take up space and nutrients, causing competition
Mucus
slippery secretion by mucous membranes
traps microorganisms that are super duper tiny so that they can be removed by the motion of the cilia
Mucous membranes
line body cavities that are exposed to the external environment
Lysozyme
enzyme made by mucous membranes
breaks the bonds in the cell walls of bacterias, causing them to lyse (break open), hence the name
Defensins
made by (guess what?) Mucous membranes
peptides
Have hydrophobic domains
toxic to a wide range of pathogens, like bacteria, microbial eukaryotes, and enveloped viruses
insert selves into plasma membranes and make the membranes freely permeable to everything, killing the invader
DefenseIN: INsert themselves IN membrane
also made in phagocytes to kill pathogens
Plants also use these
enveloped viruses
membrane-enclosed viruses
Harsh internal conditions
kill pathogens
ex. stomach #gastricjuice
Phagocytes
Recognize pathogens and ingest them by phagocytosis
Once inside the pathogen, the invader is killed by hydrolysis within lysosomes or by defensins
Natural Killer Cells
A class of lymphocytes
can tell the difference between healthy body cells and infected/cancerous cells
Initiate apoptosis in the infected/cancerous cells
also interact with adaptive immune by lysing the cells labeled by antibodies
apoptosis
programmed cell death
Complement Proteins
In blood
more than 20 types
once initiated, proteins function in a cascade
system can be initiated by innate and adaptive immune responses
In adaptive, the bonding of a complement protein to an antibody starts the cascade
Steps in complement Protein sequence
- A protein binds to components on surface of invading cell, helping phagocytes recognize and destroy the invader
- Another protein starts inflammation response and attracts phagocytes
- Other proteins lyse the invading cell
Interferons
Signaling proteins/ class of cytokines
produced by an infected cell
helps increase resistance of nearby cells
induced by various molecules, such as viral RNA bind to receptors on plasma membrane of uninfected cells– creating a signaling pathway that prevents viral reproduction if the cell becomes infected, which is less likely because it stimulates cells to hydrolyze bacteria/viruses, a step in adaptive immunity
Inflammation
The redness, swelling, and localized heat caused by tissue damage due to infection or injury
can become painful
can happen almost anywhere in the body
Why is inflammation important
isolates the infected area to prevent spread of damage
recruits cells and molecules to the area that could be useful in destroying any pathogens that could be there
and promotes healing
Mast Cells
one of the first responders to tissue damage
adhere to skin and linings of organs
Release lots of chemical signals
Tumor Necrosis Factor
a chemical signal produced by mast cells
a cytokine protein that kills target cells and activates immune cells
Prostglandins
chemical signal produced by mast cells
fatty acid DERIVATIVES that play roles in like multiple immune responses, but apparently, the only one worth mentioning is the initiation of inflammation in nearby tissues
gland—>glad—->happy—->heyyy—-> aaaayyyy —> a —-> acid—-> fatty acid
Histamine
chemical signal produced by mast glands
an amino acid DERIVATIVE that increases the permeability of blood vessels to white blood cells and molecules so that they can act in nearby tissues.
What causes the redness and heat of inflammation?
The dilation of blood vessels in the affected/injured area
What molecules/cells are responsible for the healing associated with inflammation?
Phagocytes and Neutrophils
How/why is a fever produced in the inflammatory response?
Phagocytes and neutrophils produce cytokines, which signal the brain to turn up the heat in the body
This heat accelerates lymphocyte production and phagocytosis, accelerating the immune response.
Additionally, some phagocytes are picky about temperate and can have their growth inhibited by fever