Internal organs

Blood

Cerebrospinal fluid

Skin

Oral Cavity

Gastrointestinal Tract

Respiratory Tract

Urogenital Tract

Sebaceous (oil) glands

&

Apocrine (sweat) glands--pH 4-6

1. Weather

2. Age

3. Personal hygiene

Gram + bacteria:

1. Staphylococcus

2. Streptococcus

3. Propionibacterium

4. Bacillus

5. Candida - yeast found in mouth

Propionibacterium acnes can cause ACNE

Gram +

Anaerobic RODS

by lysozymes

&

Continual rinsing of conjunctiva (eye surface)

Staphylococcus epidermidis

Some Gram - rods

Aerotolerant anaerobes:

1. Streptococcus

2. Lactobacillus

3. some Yeast

Anaerobes:

1. Prevotella

2. Fusobacterium

BACTEREMIA.

--when organisms enter the bloodstream.

--quickly cleared by immune system.

(PHEW.)

Bacteria can be trapped in defective valve.

-can form vegetations (bacterial cells, glycocalyx, fibrin)

-(Subacute Bacterial Endocarditis)

When the microflora of dental plaques make acids that decalcify tooth enamel.

-causing tooth decay & cavities.

Nasopharynx

Oral cavity

Throat

1. Staphylococcus aureus

2. Streptococcus pneumonia

3. Streptococcus pyogenes

4. Corynebacterium diphtheriae

Sinus

&

Ear infections

Sinus infections 

&

Bronchitis

Sinus infections

&

Strep throat

What makes up the Lower respiratory tract?

Trachea

&

Lungs

Acid-tolerant bacteria such as:

Helicobacter pylori (peptic ulcers)

1. Duodenum

2. Jejunum

3. Ileum

Few bacteria due to stomach acids

pancreatic secretions

Bile

Gram + cocci & bacilli

Enterococcus

&

Lactobacillus

Microbiota reflects large intestine

Large # of Bacteroides & facultative aerobes like E. coli

Large intestine is a fermentation vessel.

->300 species of mostly anaerobic bacteria

-10^11 bacterial cells/gram of intestinal contents.

Bacteria ferment ingested food into products we can absorb.

About how much percentage is our caloric intake this way?

1. E.coli

2. Bacteroides (bacteroidetes)

3. Clostridium (Firmicutes)

4. Enterococcus

1. Vitamin B-12

2. Riboflavin

3. Thiamine

What supplies bacteria? 

Which bacteria?

Probiotics supply:

Lactobacillus & Bifidobacterium

What is the growth rate of bacteria in the lumen of the intestinal tract?

What are the types of facultative anaerobes associated with Urethra?

*Many of these are opportunistic pathogens that can cause UTI.

1. Escherichia

2. Klebsiella

3. Proteus

4. Neisseria (Gram - cocci)

Lactobacillus acidophilus

*acidic secretions prevent pathogens

*probiotic treatment.

makes vitamins

digests food

prevents colonization by pathogens

Bacteroides:

cause abscess or gangrene

Clostridium difficile:

causes Enterocolitis

-either germ-free or all microbial species are known

-poorly developed immune systems

-low cardiac output

-thin intestinal walls

-very susceptible to infection by pathogens

Innate/ nonadaptive immunity:

.physical barriers to infection

.nonspecific reaction destroy invading cells

-reaction to specific antigens (foreign proteins, sugars, chemicals)

-body reacts to antigens when exposed (retains memory of those antigens, faster response 2nd time)

1. Neutrophils & Monocytes

2. Basophils & Eosinphils

3. Lymphocytes

Engulf & destroy microbes

Monocytes = macrophages & dendritic cells (phagocytic)

1.  T cells - regulate specific immune response

2. B cells - produce antibodies to bind antigens

1. Skin 

2. Mucous

3. Cilia

4. Toll-like receptor proteins on tissues

Skin has keratin, oil, cells that are phagocytic.

Dead skin cells, washing, removes attached cells.

Mucous lines respiratory & digestive tract.

-trap and destroy pathogens

-mucous layers slough off

What do Toll-like receptor proteins on tissues do?

Give some examples.

recognize pathogens and collect them and bring them to phagocytes.

Ex. Gut - M cells

Skin - Langerhans cells

1. Acidic pH: stomach, skin, vagina

2. Lysozyme: tears, skin --Destroys peptidoglycan

3. Defensins - peptides that disrupt pathogens/ effective against Gram +, -, fungi, & enveloped viruses.

Peptides (small proteins) that disrupt pathogens.

Effective against Gram +, G -, fungi, and enveloped viruses.

-Redness, swelling, pain, heat

- Fluids containing WBC's leak into wound

-Clot forms to localize pathogen

-Septic shock

During Fever:

- some products of pathogens (endotoxin) are pyrogenic (fever inducing)

-cause Hypothalamus to reset body temp.

-Endogenous pyrogens are produced by leukocytes

-increases phagocytosis & antibody production

-slows bacterial growth

-high temp damages host tissue

1. infection releases microbes to tissue

2. resident macrophage engulf bacteria

3. macrophage release vasoactive factors & cytokines - causing capillaries to dilate

4. fluids containing WBC's leak into wound

5. macrophage squeeze between capillary cells (Extravasation)

6. damaged tissue secretes Bradykinin

7. Mast cells release histamine

8. histamine makes vessels open further

9. Prostaglandin stimulates nerve cells.

Chronic Inflammation: 

some pathogens (Mycobacterium) resist host defenses by?

body walls of site in granuloma (fibrotic lesion around bacteria.)

Ex. of Autoimmune Response:

(destruction of host tissue when immune sys. responds to body cells as if they were foreign)

1. Lupus erythematosus

2. Rheumatoid arthritis

3. Crohn's disease

- produce lysozyme & antimicrobial peptides to kill bacteria.

- kill with "oxidative burst" (increase in oxygen consumption during phagocytosis results in production of reactive oxygen species such as superoxide ions.)

Interferons : 

(2 types)

Interfere with viral replication

- produced by infected host cells

-species specific (mouse interferon will not work with humans.)

-virus nonspecific (human interferon helps protect against influenza & cold virus)

Type 1 Interferon:

what does it do? how?

-antiviral

-Bind to uninfected cells & make them resistant to viral infection

(1 type cleaves viral RNA, another prevents translation of RNA)

Type 2 Interferon:

does what?

Stimulates immune cells

-nearby immune cells become for sensitive (act more rapidly)

-activates macrophage, natural killer cells, T cells.

What do healthy cells make, but cancerous cells stop making called?

antibodies bind viral proteins on infected cell surface so NKC's can notice and kill the cell.

-secretes perforin protein into target cells

(perforin creates membrane pores to lyse cell)

-series of 20 proteins in blood serum

-several are proteases which sequentially cleave each other

-activation of complement cascade results in pores in target microbial membranes (membrane attach complex-MAC)

-Cell content leak out, and dies.

Age

Stress

Diet

General health and lifestyle

Prior or concurrent disease

Genetic conditions