Defense systems

Question 1

Describe the way in which the skin provides protection

Answer 1

-it covers the whole body and provides a physical barrier thats difficult for microbes to penetrate

Question 2

Describe the way in which the stomach provides protection

Answer 2

-it contains hydrochloric acid which kills microbes that are swallowed

Question 3

Describe the way in which the nose provides protection

Answer 3

-nasal hairs act as a physical barrier against dust and larger micro organisms
-sticky muscus traps dust and microbes

Question 4

Describe the way in which the trachea and bronchi provides protection

Answer 4

-goblet cells produce further muscus which traps microbes
-ciliated cells contain cilia (protrusions) which beat rythmically to propel muscus back up the airway to the back of the throat

Question 5

Describe the way in which tears provides protection

Answer 5

-they contain enzymes known as lysozymes which destroy microbes

Question 6

Describe the second line of defense

Answer 6

process is called phagocytosis
-the phagocyte engulfs the pathogen
-the white blood cell kills the pathogen

Question 7

Is the second line of defence persific

Answer 7

no, its non persific meaning it can happen to any pathogen

Question 8

Describe the third line of defence using lymphocytes

Answer 8

-lymphocytes produce antibodies
-(white blood cell) antibodies bind to antigens on pathogen
-the pathogen is then killed

Question 9

Which of the 3 (phagocytosis, lymphocytes and lymphocyte looks like this y

Answer 9

lymphocyte

Question 10

Which of the 3 (phagocytosis, lymphocytes and lymphocyte

Answer 10

-produce antitoxins
-antitoxins bind to toxins which bacteria have produced
-toxins are neutralised

Question 11

When is the second line of defence used

Answer 11

-if pathogens do enter the human body, in the body’s immune system

Question 12

What is the most important part of the immune system

Answer 12

the white blood cells (leucocytes)

Question 13

White blood cells can be found

Answer 13

-circulating around the body in the plasma travelling through blood vessels
-static in some organs (liver)

Question 14

Name 3different actions that white blood cells can carry out

Answer 14

-Engulf and break down bacteria by phagocytosis
-Produce antibodies
-Produce antitoxins

Question 15

Match these up with the defintions
B-Lymphocyte -Engulf and break down bacteria
Phagocytes Produce antibodies
T-Lymphocyte -Produce antibodies

Answer 15

B-Lymphocyte - Produce antibodies
Phagocytes- Engulf and break down bacteria
T-Lymphocyte- produce antitoxins

Question 16

Explainn how a lymphocyte invades pathogens

Answer 16

It produces anitobodies, which bind to specific antigens on the surface of a pathogen
Different lymphocytes produce antibodies that are complementary to only one type of antigen
-this makes it a specific defence system

Question 17

How do white cells protect us against pathogens
(6marks)

Answer 17

The white blood cells protect us against pathogens because there are 3 lines of defences. the first line mainly stops pathogens from entering whereas in the second line, the phagocyte engulfs the pathogen and this is more reliable due to it being non persific
in the third line, lymphocytes produce antibodies and they then bind to antigens on path this then kills the pathogens