Lecture 16 - Innate Immunity Flashcards
immunity
the body’s ability to fight off diseases
innate immunity AKA
nonspecific immunity
adaptive immunity AKA
specific or acquired immunity
Difference between Innate and Adaptive Immunity
innate immunity is our broad lines of defense which one is born with protects us from any kind of pathogen whereas adaptive immunity is acquired throughout one’s lifetime and works to protect us from specific pathogens
epidermis
the superficial portion of the skin
dermis
the deep portion of the skin
What makes skin waterproof?
keratin
tinea pedis AKA
athlete’s foot
Why is skin considered to be stratified epithelium?
skin is composed of epithelial cells which are stacked on top of each other in several layers
Name 4 primary areas of the body where mucous membranes are found:
- GI Tract
- Genitourinary Tract
-Respiratory Tract - Lining of the Eyes
What type of cells secrete mucous?
Goblet Cells
What is the Lacrimal Gland?
the gland located above the eye which produces tears and moisture to keep the eye wet and clean. Also contains lysozyme - an antimicrobial enzyme.
Which two body fluids are particularly rich in lysozyme?
Tears & Saliva
mucociliary escalator
cilia on epithelial cells lining the respiratory tract sweep mucus with trapped debris up and away from the lungs
cilia
hair-like projections on a cell
lysozyme
an enzyme which attacks peptigoglycan in cells walls
Is lysozyme more effective against Gram-Positive or Gram-Negative bacteria?
Gram-Positive
Gram-Positive Bacteria stains ____.
Purple
Gram-Negative Bacteria stains ______.
Pink
Discovered Lysozyme
Alexander Flemming
Oil Glands AKA
Sebaceous Glands
sebum
oil
Why are many areas of the body acidic?
The acidic environment make it harder for harmful bacteria to survive
pH of gastric juice
1.2 - 3.0
pH of saliva
6.55 - 8.55
pH of urine
6
pH of vagina
3-5
pH of earwax
3-5
Why should one be cautious of taking antacids?
antacids neutralize the pH of the stomah which could increase one’s risk of infection
bacteria species frequently causing stomach ulcers
H. pylori
competetive inhibition AKA microbial antagonism
normal bacteria protect against harmful microorganisms simply by taking up space (and sometimes by also creating bacteriocins) so that there is no room for harmful microorganisms to easily take up residence and cause adverse effects
bacteriocins
enzymes produced by bacteria which are harmful to other types of bacteria
Examples of the Body’s First Line of Defense Against Pathogens.
- skin
- mucous membranes
- acidic environment
- normal flow of body fluids
Examples of the Body’s Second Line of Defense Against Pathogens
- Phagocytosis
- Fever
- Inflammation
plasma
the the fluid portion of blood
platelets
fragments of megakaryocytes from the bone marrow and are important in blood clotting
WBC
White Blood Cells
RBC
Red Blood Cells
thrombocytes AKA
platelets
coagulation
the formation of blood clots
Platelets are well-known for their role in blood clotting, but what else are they also important for?
production of antimicrobial peptides
Leukocytes
White Blood Cells (WBC)
leuko-
white
-cyte
cell
Function of Neutrophils
Phagocytosis
neutrophils can leave the blood and enter tissues during the early stages of an infection to “eat” the pathogens
How can exercise help support neutrophils in the body and consequently immunity?
Neutrophils will sometimes “hangout” in the larger veins of the body. Moderate excercise increases blood flow. Increased blod flow can help push neutrophils out of the larger veins and into circulation where they can get into tissues and find more pathogens to fight off.
Monocytes become _________.
Macrophages
What does a monocyte look like?
Has a large kidney bean shaped nucleus
Are monocytes actively phagocytic in the blood?
No
Are monocytes actively phagocytic in the body tissues?
Yes, when they become macrophages.
Function of Dendritic Cells
phagocytosis
Lymphocytes
found in blood & lymphatic system and are important for immunity
Name 3 Types of Lymphocytes
- Natural Killer (NK) Cells
- T Cells
- B Cells
leukocytosis
an increase in the number of WBCs due to infection
leukopenia
a decrease in the number of WBCs
(Can be caused by chemo, radiation, salmonlella infection, ricketts.)
Differential Blood Count
Blood is smeared onto a plate a viewed under a microscope. 100 WBCs are then counted and the ratio of the different types of WBCs are determined and compared against the normal ratios for a healthy person.
List the Leukocytes from Most Abundant to Least Abundatnt
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Macrophages are derived from ______.
Monocytes
What is the function of the Lymphatic System
collects lymph (fluid that has leaked from blood and cells into the tissues) and returns it to the heart while simultaneously scanning it for any pathogens
Lymph Nodes
structres within the lymphatic system that have high numbers of WBCs to scan lymph for pathogens
List 7 Important Parts of the Lymphatic System
- Lymphatic Vessles
- Lymph Nodes
- Tonsils
- Spleen
- Thymus
- Peyer’s Patches
- Bone Marrow
Where are Peyer’s Patches Found?
small intestine
chemotaxis
movement of a cell in response to chemical signals in the environment
List the 3 Main Steps of Phagocytosis
- Bacteria attaches to receptors on the phagocyte.
- The phagocytes morphs around the bacteria to ingest it.
- The bacteria is degraded
Opsonization
Antibodies attach to antigens on a pathogen - marking it for destruction. The other end of the antibody can then bind to receptors on the phagocytes for the phagocyte to take in and destroy the pathogen.
vasodilation
expansion of the diameter of blood vessles
(allows for increased blood flow)
3 Main Steps for Inflammatory Response
- Tissue Damage
- Local Vasodilation for Increased Blood Flow
(symptoms: redness, swelling, pain, warm to touch) - Phagocytes Migrate to the Damaged Tissue to Attack Pathogens
Margination
phagocytes stick to the endothelium
endothelium
inner lining of the blood vessels
Diapedesis
phagocytes squeeze between endothelial cells into the tissues
pus
collection of dead cells from an infection
Endotoxins
toxins found in the cell walls of Gram-Negative bacteria which is released when the bacteria is destroyed
(specifically, Lipid A found in the LPS)
Are endotoxins pyrogenic?
yes
Lipid A
an endotoxin
LPS contains which endotoxin?
Lipid A
LPS
Lipopolysaccharide
IL-1
Interleukin-1
(a pyrogen)
Explain How a Fever is Induced
When a macrophage ingests a Gram-Negative bacteria, endotoxin (Lipid A) is released from the cell wall of the bacteria.
In response to the endotoxin, the macrophage releases Interleukin-1 (IL-1) which travels to the hypothalamus of the brain and causes the hypothalamus to produce prostaglandins.
Prostaglandins then reset the body’s thermostat to a higher temp and produce a fever.
Does a fever indicate the seriousness of an infection?
No
What temperature would start to be considered a dangerous fever (even for an adult)?
103 and higher
Why does one often feel cold when they have a fever?
Blood vessels near the skin (peripheral blood vessels) constrict so the body will not lose so much heat and the internal temperature can rise.
Why does one tend to get sweat once their fever breaks?
When the body is ready to return back to normal temperature, the peripheral blood vessels will vaso dilate so the excess heat can be lost and body temp can return to normal more quickly.
How to antipyretic drugs work?
antipyretic drugs inhibit the production of prostaglandins which would normally increase the body’s temperature
Most common antipyretic drug?
Aspirin
transferrins
proteins which decrease the amount of free iron in the blood so that pathogenic microbes cannot use it for nutrition and growth
List 4 Benefits of a Fever
- IL-1 insreases the number of T-cells produced to fight the infection
- High temps inhibit some microbes
- Fever promotes the production of interferron proteins
- Fever promotes the production of transferrins which decreases the amount of free iron in the blood so that microbes cannot use it for growth
Interferons
antiviral proteins which interfere with viral multiplication by shutting down the protein synthesis in other cells so that they cannot be infected and reproduce the virus if infected
AMP
Antimicrobial Peptides
Complement
proteins produced by the liver which combat pathogens when activated
3 Ways Complement Can Combat Pathogens
- Participate in the Inflammatory Response by attracting Phagocytes and Triggering the Release of Histamine
- Cause Microbes to Lyse
- Act as Opsonin
What Cell Releases Histamine?
Mast Cells
2 Important Functions of Histamine
- causes vasodilation
- causes increased permeability of the blood vessels so that WBC can get to the damaged tissues more easily
How can Complement cause a cell to lyse?
the activated complement can wedge itself into the membrane of a pathogen and essentially create a tube/hole from which the insides of the pathogen can leak out from
What happens when Complement is activated?
when complement is activated, it splits into fragments and those fragments can cause other complements to also split in a chain reaction
How do Antimicrobial Peptides (AMP) Function?
they wedge themselves into the membranes of pathogens (i.e. bacteria, viruses, fungi) which disrupts the structure enough to destroy the pathogen
