4.1.4- Primary Defences Against Disease

Question 1

Define what a mucous membrane is.

Answer 1

Specialised epithelial tissue that is covered in mucous.

Question 2

what is a primary defence?

Answer 2

Those that prevent pathogens from entering the body.

Question 3

What are the five main primary defences?

Answer 3

• expulsion reflexes
• the skin
• mucous membrane
• blood clotting and skin repair
• inflammation

Question 4

Primary defences are _________ _________.

Answer 4

Non specific.

Question 5

Why are primary defences non specific?

Answer 5

They will prevent the entry of any pathogen.

Question 6

What is the main primary defence in the body?

Answer 6

The skin.

Question 7

What is the outer layer of the skin called?

Answer 7

Epidermis.

Question 8

What are most of the cells in the skins epidermis?

Answer 8

Keratinocytes.

Question 9

Explain how the skin acts as a pathogen barrier.

Answer 9

Keratinisation- mitosis makes cells and they migrate out. The cytoplasm is replaced keratin and goes to the surface. These keratinised dead cells act as the barrier.

Question 10

What ion is needed for blood clotting to take place?

Answer 10

Calcium- Ca2+

Question 11

Explain how blood clots.

Answer 11

Damaged tissue released clotting factors which activates an enzyme cascade. Prothrombin is turned to thrombin enzyme (with Ca2+). Thrombin turns soluble fibrogen into insoluble fibrin and platelets plug fibrin mesh to form a clot.

Question 12

Blood clotting happens…

Answer 12

Outside of the blood vessels.

Question 13

Why does blood clotting take place out of the the blood vessels?

Answer 13

So the vessels don’t et clogged and blocked.

Question 14

Where are the three main places mucous membranes are found?

Answer 14

Lungs
Airways
Digestive system

Question 15

Explain why there are mucous membranes at the lungs, airways and digestive system.

Answer 15

They are high infection risk areas of infection fur to them having thinner exchange surfaces that are less well protected from pathogens.

Question 16

What are goblet cells?

Answer 16

They’re in epithelial tissue and they secrete mucous onto the membrane

Question 17

What is the purpose of mucous as a primary defence?

Answer 17

It traps pathogens as they try to enter the membrane.

Question 18

How does the mucous on the membrane move?

Answer 18

The clinic beat and move the band of mucous.

Question 19

How does the cilia remove pathogens. Explain how it gets rid f the mucous.

Answer 19

It beats it to the trachea and oesophagus where it is swallowed into the digestive system and the pathogens are killed by the acidity that denatures the pathogens enzymes.

Question 20

What are the three expulsion reflexes?

Answer 20

Coughing
Sneezing
Vomiting

Question 21

Explain how expulsion reflexes are triggered.

Answer 21

The irritated areas respond to irritation and the microorganism are expelled.

Question 22

Explain how inflammation is dealt with by the body.

Answer 22

Mast cells detect microorganism a and release histamine to combat infection in a range of ways. Main way is vasodilation- capillary walls are made more permeable to WBCs and SI response is initiated.

Question 23

What are the three other primary defences aside from the three main primary defences?

Answer 23

• ear canal is lined by wax to trap pathogens
• eyes protected by ab’s and enzymes in tear fluid
• mucous plug in cervix protects female reproductive system

Question 24

Define ‘inflammation’.

Answer 24

Swelling and redness of tissue caused by infection.