Unit 10 - Diseases and immunity

Question 1

Types of pathogens

Answer 1

• Bacteria
• Fungi
• Protoctists
• Viruses

Question 2

Transmissible diseases

Answer 2

Pathogens that can be passed from one host to another

Question 3

Methods of transmission

Answer 3

Direct contact and indirect contact

Question 4

Direct contact

Answer 4

Exchange of body fluids e.g. blood

Question 5

Indirect contact

Answer 5

Through air, water, food, contaminated surfaces or animals

Question 6

Vector

Answer 6

An organism that transmits a pathogen from an infected to non-infected person

Question 7

Pathogens in host

Answer 7

Reproduce rapidly and damage cells and organs

Question 8

Mechanical Barries from pathogens

Answer 8

Skin, nose hair

Question 9

Function of skin as a barrier

Answer 9

• Forms a waterproof barrier
• Microorganisms can’t get in unless skin is broken - stopped by blood clotting

Question 10

Function of nose hairs as a barrier

Answer 10

• Trap particles that could carry pathogens
• Ciliated cells move trapped particles with mucus in the throat

Question 11

Chemical barriers from pathogens

Answer 11

Mucus, stomach acid

Question 12

Function of mucus as a barrier

Answer 12

• Traps bacteria and other pathogens
• Is produced in lungs & inner lining of the gut

Question 13

Function of stomach acid as a barrier

Answer 13

Hydrochloric acid damaged or kills pathogens that could have been swallowed

Question 14

Second line of defense against pathogens

Answer 14

White blood cells and vaccinations

Question 15

White blood cells functions’ as barriers

Answer 15

• Phagocytes - surround and engulf pathogens and break down using enzymes
• Lymphocytes - produce antibodies, proteins that attach to antigens

Question 16

Function of vaccination as a barrier

Answer 16

Primes the immune system so it can react to a pathogen

Question 17

Controlling the spread of disease

Answer 17

• Clean water supply
• Good personal hygiene
• Hygienic food preparation
• Proper waste disposal
• Treatment of sewage

Question 18

Antigens

Answer 18

• Cause the body to produce immune response
• Often are proteins but can be fats & carbs

Question 19

Function of antibodies

Answer 19

Attach to antigens to either mark the pathogen for phagocytosis or causes the pathogen to break open and die

Question 20

Relationship with antibodies and antigens

Answer 20

• Antibody has a specific shape for the antigen
• Each antibody is for only one antigen

Question 21

Active immunity

Answer 21

• Gained from infection
• Antibodies react with antigen - first response
• Second response will be quicker

Question 22

Memory cells

Answer 22

• Remain in blood after infection
• If infected again, memory cells will respond and make many antibodies
• Antibodies can destroy pathogens before illness

Question 23

Vaccination

Answer 23

• Causes active immunity without infection
• Inject small amounts of pathogens ( dead or weakened)
• Lymphocytes respond and memory cells produced

Question 24

Passive immunity

Answer 24

• Short-term defense against a pathogen from antibodies from someone else
• Memory cells are not produced
• Protection only lasts a few weeks or months but is immediate
• Helps people with damaged immune systems

Question 25

Cholera

Answer 25

• Causes watery diarrhea
• Results in death & dehydration
• Comes from drinking water contaminated with human feces
• Comes from bacterium - Vibrio Cholera

Question 26

Effects cholera toxin

Answer 26

• Bacteria goes to small intestine and produces toxin
• Intestinal cells secrete chloride ions into men of intestine
• High concentration of chloride ions causes osmotic movement of large amounts of water into intestinal lumen
• Diarrhea formed - large lost of ions and water