Micro host parasite 1

Question 2

Portals of entry for microorganisms

Answer 2

Skin, mucous membranes, placenta, parenteral route (pretty much the same as portals of exit); ear, conjunctivae of eye, nose, mouth, broken skin, insect bite, urethra, vagina, penis, anus

Question 3

Why should you not exfoliate?

Answer 3

You cause a little bit of damage and increase chances of bacteria accessing lower layers of skin and

Question 4

Access through Skin

Answer 4

usually through broken skin, hair follicles, sweat glands; some can penetrate the skin

Question 5

Protective mechanisms of skin

Answer 5

Sweat (enzymes, salt); barrier (tight); sloughs of dead skin cells; sebaceous glands (antibacterials, oils, lower pH); multiple layers (dead - few nutrients); dehydrated

Question 6

Why are mucous membranes a portal of entry?

Answer 6

Living cells, thin layer, moist, warm; bacteria can exist there unless they can’t bind

Question 7

Defensive mechanisms in mucous membranes

Answer 7

Mucous traps bacteria; Cilia move mucous; normal microflora; pH (of stomach); barrier (junctions); projectile vomiting; cells slough off; peristalsis

Question 8

placenta

Answer 8

Usually microbes cannot cross placenta (cannot diffuse); only some (lysteria, some viruses) manage across and can cause abortion, birth defects

Question 9

parenteral route

Answer 9

bypassing normal portals of entry; direct entry to tissues via nail, thorn, needles, cuts, bites

Question 10

Opportunistic pathogens

Answer 10

ready and waiting to jump at the chance of infecting; ex. ones that infect immediately after taking antibiotics when normal microflora are gone

Question 11

Manifestations of infectious disease

Answer 11

Signs, symptoms, syndrome

Question 12

Symptoms

Answer 12

Subjective characteristics of disease

Question 13

Signs

Answer 13

Objective manifestations - something shows up

Question 14

Syndrome

Answer 14

Collection of symptoms and signs

Question 15

Asymptomatic or subclinical

Answer 15

No signs or symptoms - spread more easily

Question 16

Etiology

Answer 16

Study of the cause of a disease; must satisfy Koch’s postulates (but there are exceptions)

Question 17

Exceptions to Koch’s postulates

Answer 17

Inability to culture organism; Disease caused by a combination of pathogens and/or physical, genetic, or environmental cofactors (e.g., liver cancer, meningitis, pneumonia); Some pathogens are ignored (don’t know they are there); Ethics and Koch’s third postulate (can’t infect a human)

Question 18

Solution to exceptions of koch’s postulates

Answer 18

Use epidemiology; ex. we can’t inject HIV to prove it causes AIDS, but if HIV is found in every cause of the disease it makes a good case

Question 19

Explain at a molecular level why we many not be able to fulfill Koch’s third postulate by using a different host animal

Answer 19

Could react differently because there are no receptors in the host so there is no binding

Question 20

How could just binding to a cell cause disease?

Answer 20

Receptor mediated Endocytosis and get inside the cell; if it doesn’t enter, it may secrete toxins which enter cells

Question 21

Adhesins

Answer 21

proteins on fimbrae that bind to complementary receptors on host cell

Question 22

Gaining access after attachment

Answer 22

Enzymes: some break intercellular junctions (ex. collagenase); coagulase forms clot and bacteria are protected and break free later (quorum sensing)

Question 23

Botulism and tetanus

Answer 23

Botulism inhibits muscles by completely relaxing them; tetanus inhibits muscles by completely contracting them

Question 24

Toxemia

Answer 24

toxins enter the blood stream and cause a reaction elsewhere

Question 25

Exoenzyme vs. toxin

Answer 25

Both are secreted and toxins are often enzymes, but toxins cause reactions elsewhere

Question 26

Endotoxin effects

Answer 26

Released when gram -ve bacteria die; it stimulates the release of chemicals that cause fever, inflammation, diarrhea, hemorrhaging, shock, and blood coagulation

Question 27

Can endotoxin be a problem outside of infectious disease?

Answer 27

Can be separate to the infection itself; can be totally independent of bacteria (ie leftover from earlier)