innate immunity part 1

What are the two first-line defenses?

• skin

• mucous membranes

• this are always on

Skin

• provides physical protection

• the outer layer of cells embedded with keratin

Mucous membranes

• physical barrier

• goblet produces mucous

What are the antimicrobial factors in saliva?

• lysozyme

• peroxidase

• lactoferrin

Peroxidase

produces toxic oxygen radical

Lactoferrin

a glycoprotein that binds iron

Why would microbes not survive in stomach?

stomach is very acidic - has low pH

why are normal microbiota protective?

they take up space so that pathogens don’t attach

take away nutrients

produce antimicrobial factors

peristalsis - swallowing back food

shedding cells - cells attach will be carried away

how are your lungs protected?

Mucociliary escalator - mucus that is being produced in combination with cilia

What are macrophages?

• they are phagocytic cells that can engulf particles and microbial cells that make it down to the lungs

What happens if microbes get pass the first line of defences?

our innate system has sensors that can detect foreign cells

What are PRRs? How do they recognize invaders?

they are able to recognize patterns that are present on foreign cells and damage cells

they recognize MAMPS-microbe and DAMPS -damage

What is a Microbe-Associated Molecular pattern (MAMP)?

present in microbe but not eukaryotes

ex: LPS, lipoprotein, flagellan

What happens when the cell does detect damage to host cells?

Effectors kick in

what are effectors?

• fever

Where does hematopoiesis start?

in the bone marrow

What two ways can hematopoietic stem cell differientiate ?

Myeloid line

lymphoid line

What are the end products of myeloid line?

red blood cells

platelets

mast cells

eosinophils

basophil

neutrophil

monocyte

macrophage

dendrite cells

which white blood cell is the most common in blood?

neutrophils

which white blood cells are phagocytes?

neutrophils

monocytes

macrophages

which cells are involved in allergic reactions?

eosinophils

basophils

which are located in tissues?

dendrites

macrophages

How do cells communicate like PRR?

they produce cytokines which are soluble chemicals and induce changes in gene expression

What are examples of cytokines and what do they do?

• Interleukin 1 which induces fever

• TNF promotes inflammation

Explain neutrophils - how is it important in phagocytes

• circulate in the blood

• they are the first phagocytes that are recruited to infection site

• part of the inflammatory response

Explain macrophages - how is it important in macrophages

• reside in the tissue

• start out as monocyte

• have different levels

Explain the process of phagocytosis

1. first phagocytes have to chemotaxis which means they have to leave the blood stream and move towards the infection site

2. Next they have to recognize and attach to damage cells

3. after that they are engulf which means they are enclosed

4. then it is now a phagosome and fuses with lysosomes which now is called phagolysosome

5. digestive enzyme then are realeased and destruction occurs

6. the waste is then excreted from the cell through exocytosis.

What is one way that phagocytes can attach easily?

opsonins like C3b and antibodies coat pathogens to enhance recognition and binding by phagocytes.

how can pathogens avoid phagocytosis?

produce C3a and C5a that chew up molecules used for chemotaxis

produce capsule

no fusion with lysosomes so no phagolysosome

When do phagocytosis work? when do esinophils work?

P- work on small cells

E - work on large cells because they have granules that contain toxic products and enzymes