6.3

Question 1

what is a pathogen

Answer 1

disease causing organism

Question 2

state first line of defence

Answer 2

Skin (no opening), tears (enzymes destroy bacteria), mucous (trap bacteria, destroy), sweat (antimicrobial effects), sebum (seal off pore of hair follicle)

Question 3

benefits of blood clotting

Answer 3

prevents excessive bleeding, prevents pathogens from entering, platelets encourage hemostasis.

Question 4

Explain blood clotting using thrombin, fibrinogen, and fibrin

Answer 4

thrombin is an enzyme in plasma that causes clotting by converting fibrinogen into fibrin. Fibrinogen is a soluble protein. Fibrin is an insoluble protein. It forms a fibrous mesh that prevents blood flow by holding patlets

Question 5

State the blood cells in the second line of defence

Answer 5

Phagocytes and lymphocytes

Question 6

what is the lymphatic system and what are its components

Answer 6

Lymphatic system protects from illness causing invaders, maintain body fluids, help with digestion, remove cellular waste. Its components are
organs (tonsils, appendix, thymus)
Lymph nodes (specialized cells create lymphocytes)
Lymph (clear fluid in lymphatic vessels, contain lymphocytes)
Lymphatic Vessels (transport Lymph)

Question 7

what do Lymphocytes do

Answer 7

Produce antibodies to destroy pathogens by splitting up their cell wall or by making them stick together, making the job of phagocytes easier.

Question 8

what do Phagocytes do

Answer 8

engulf pathogens

Question 9

what are memory cells

Answer 9

the leftover lymphocytes are stored as memory cells. Results in immunity

Question 10

what is the third line of defense

Answer 10

Specific immunity response (response to antigens by creating cells that directly attack pathogens or by producing antibodies (proteins)

Question 11

what is coronary thrombosis and what are its causes

Answer 11

blood clot in the coronary artery and can lead to haert attack. It is caused by arteriosclerosis (when coronary arteries get thick), smoking, high cholesterol, High b.p., diabetes, obesity/lack of exercise.

Question 12

function of coronary artery

Answer 12

supply oxygen-rich blood to heart

Question 13

define antibiotic

Answer 13

medicine that inhibits growth of infection

Question 14

how can an antibiotic kill a bacteria

Answer 14

attack its cell wall synthesis or interfere with bacterial protein production

Question 15

why are antibiotics not effective against viruses

Answer 15

Viruses use host cells to replicate and antibiotics cannot kill host cells

Question 16

why is multidrug resistance dangerous

Answer 16

infections become harder to treat, longer hospital stays, higher medical cost, increased mortality. Eg of multidrug-resistant bacteria: MSRA, VRE

Question 17

Consequences of HIV on the immune system

Answer 17

HIV attacks T cell by replicating inside of it. T cells are used to fight pathogens. without T cells, our body is more prone to infections

Question 18

how is HIV transmitted

Answer 18

transmitted into by passing fluid into another person’s body. Eg; unprotected sex, sharing of injecting equipment, mother-baby during pregnancy, breastfeeding, contaminated blood transfusion.

Question 19

who is alexander Flemming

Answer 19

he found penicillin in 1928 through the use of mold

Question 20

Florey and Chain experiment

Answer 20

8 mince were injected with pathogenic bacteria in the late 1930s. the 4 which were injected with penicillin survived. The other 4 died. in 1941, they treated policemen with a bacterial infection on his face. His condition improved but the supply ran out and he died.
By WWII, there was a mass distribution of penicillin to allied troops. As a result after WWII, 646 billion units were produced per year