(7-16) Innate Immunity Flashcards
1. Differentiate innate immunity and adaptive immune response. 2. Define: Self vs. non-self, Phagocytes, Inflammation, Fever 3. Define first-line defense. 4. Define or identify: Lysozyme, Lactoferrin, Cytokines 5. List and describe the mechanical and chemical factors that are involved in preventing the invasion of microorganisms through the skin and mucous membranes. 6. Describe the role of normal flora in innate immunity. 7. Identify and describe of the roles of the following kinds of cel
Which 3 features of innate immunity constitute the body’s first line of defense?
- Epithelial cells (barrier)
- Antimicrobial substances (on skin & mucous)
- Normal flora
What happens when the body’s barriers are breached (general)?
A non-specific system of cells and circulating proteins reacts to invading microorganisms.
Is the inside of the body sterile or contaminated?
Sterile
Explain why the dermal and epidermal layers of the skin are difficult for invaders to penetrate.
- The Dermis is composed of tough fibrous connective tissue.
- The multi-layered epidermis is composed of stratified squamous epithelium. The outer layer is keratinized, which helps with water-tightness, and when the outer layer sloughs off, microbes fall of with it.
Which 3 parts of the body are lined with mucous membranes?
- Digestive tract
- Respiratory tract
- Genitourinary tract
What is the purpose of the mucous lining body tracts, and which cellular structural feature assists with this task?
Mucous helps wash microbes from surfaces. Cilia help to propel microorganisms to areas where they can be eliminated (ex stomach, or outside body).
What 3 antimicrobial substances are found on skin and in mucous?
- Lysozyme
- Lactoferrin
- Defensins
What is lysozyme, and which 2 places is it found?
~ Enzymes that degrade peptidoglycan (PTG).
~ Found in tears, saliva
What is lactoferrin, and which 3 places is it found?
~ Substance that sequesters iron (an essential nutrient)
~ found in saliva, mucous, and milk
What are defensins, and how do they work?
~ Antimicrobial peptides found in mucous
~ make holes in microbial membrane
What is Normal Flora?
Microorganisms growing on body surfaces of healthy individuals
How does normal flora protect from disease?
Normal flora protects via competitive exclusion.
~ covers binding sites so pathogens have nowhere to bind
~ competes for nutrients with pathogens
Where do cells of the immune system come from?
Thy are all derived from hematopoietic stem cells in red bone marrow.
What do erythrocytes (RBCs) do?
They carry oxygen in the blood.
What are platelets?
They are broken pieces of megakaryocytes. They assist in blood clotting.
What are white blood cells (WBCs)?
Defensive blood cells
What 4 categories are WBCs divided into?
- Granulocytes
- Mononuclear phagocytes
- Dendritic cells
- Lymphocytes
Which 3 cells are classified as Granulocytes?
- Neutrophils
- Basophils
- Eosinophils
Which 2 cells are classified as mononuclear phagocytes?
- Monocytes
2. Macrophages
Which 2 cells types are lymphocytes divided into?
- B cells
2. T cells
How do dendritic cells function in immunity?
They engulf material in tissue and bring it to cells of adaptive immunity.
What 3 characteristics make neutrophils very important in immunity?
- Most abundant leukocyte in blood
- First to respond to infection
- Highly efficient phagocytes
What is the neutrophil’s main limitation?
It will die after only a few days– once its granules are empty.
What do monocytes do?
They circulate in blood and migrate to tissue in order to differentiate into macrophages.
~ liver, spleen, lymph nodes, lungs, peritoneal cavity
How do basophils function?
They cause inflammation by releasing histamine.
~ Also active in allergic reactions
Describe the attributes of macrophages.
~ Are highly phagocytic.
~ Live for weeks-months.
~ Constantly regenerate lysosomes
What are eosinophils’ 2 functions?
- Important in expelling parasitic worms
2. Also have a role in allergic reactions
What are Toll-like Receptors?
Protein receptors on the surface of macrophages (and other phagocytes) that recognize patterns on other cells.
~ Peptidoglycan
~ Lipopolysaccharide (bacteria only)
What are the 4 cardinal signs of inflammation?
- Heat
- Pain
- Redness
- Swelling
What 3 events take place when TLRs are activated?
- Phagocytosis may be activated
- Chemokines released that attract other immune cells
- Pro-inflammatory cytokines released
Activated compliment bound to pathogens is a signal for what?
phagocytosis
How can Complement proteins destroy pathogens directly without phagocytosis?
They make holes in the pathogens membrane (membrane attack complex, MAC).
When do macrophages die?
After destroying 100 or more bacteria
What do chemokines do?
They recruit other immune cells to infection
~ More neutrophils
~ Monocytes (differentiate into more macrophages)
Name 3 events that can cause Inflammation.
- Tissue damage
- Pro-inflammatory cytokines released upon TLR activation
- Complement binding
What are the 4 basic steps of inflammation?
- Localized vasodilatation
- Increased capillary permeability
- Walling off of inflamed area
- Phagocytosis
What does pus consist of?
Dead neutrophils
What occurs during the Localized vasodilatation step of inflammation?
- Increases blood flow and reduce blood velocity
2. Brings more immune cells, complement, etc, but causes _______________ and _______________
What does the Temperature regulation center of body respond to?
fever-inducing substances called pyrogens
Fever-inducing cytokines are termed what?
Endogenous pyrogens
Microbial products that induce fever are termed what?
Exogenous pyrogens
In what 2 wys does fever inhibit the growth of pathogens?
- Elevating temperature above maximum growth temperature
2. Activating and speeding up other body defenses
