Defense Against Infection

Topic 6.3: Defense Against Infectious Disease

Essential Idea: The human body has structures and processes that resist the continuous threat of invasion by pathogens.

At SHS, Topic 6.3 is taught in the following class unit(s):

Statements & Objectives:

6.3.U1 The skin and mucous membranes form a primary defense against pathogens that cause infectious disease.

Define pathogen.
State that skin and mucous membranes form the first line of defense against pathogens.
Outline the role of skin, sebaceous glands and mucous membranes in the defense against pathogens.

6.3.U2 Cuts in the skin are sealed by blood clotting.

State two benefits of blood clotting when skin is cut.

6.3.U3 Clotting factors are released from platelets.

Outline two roles of platelets in the blood clotting cascade.

6.3.U4 The cascade results in the rapid conversion of fibrinogen to fibrin by thrombrin.

Describe the blood clotting cascade, including the role of platelets, clotting factors, thrombin, fibrinogen and fibrin.

6.3.U5 Ingestion of pathogens by phagocytic white blood cells gives non-specific immunity to diseases.

State the white blood cells are the second line of defence against pathogens.
Outline the function of phagocytic white blood cells in defense against pathogens.

6.3.U6 Production of antibodies by lymphocytes in response to particular pathogens gives specific immunity.

Define “specific immune response.”
Contrast antigen and antibody.
Describe the structure and function of antibodies.
State the function of plasma cells and memory cells.

6.3.U7 Antibiotic blocks processes that occur in prokaryotic cells but not in eukaryotic cells

Define antibiotic.
Outline the mechanisms by which antibiotics kill bacteria.
Explain why antibiotics are ineffective against viruses.

6.3.U8 Viruses lack a metabolism and cannot therefore be treated with antibiotics.

Explain why antibiotics are ineffective against viruses.

6.3.U9 Some strains of bacteria have evolved with genes that confer resistance to antibiotics and some strains of bacteria have multiple resistance.

List five measures that can be taken to avoid the development of antibiotic resistance.
Explain why multiple drug antibiotic resistance is especially dangerous.
State an example of a multidrug resistant bacteria.

6.3.A1 Causes and consequences of blood clot formation in coronary arteries.

State the function of the coronary arteries.
Define coronary thrombosis.
List sources of arterial damage that increase the risk of coronary thrombosis.
List factors that are correlated with an increased risk of coronary thrombosis and heart attack.

6.3.A2 Effects of HIV on the immune system and methods of transmission.

Describe the consequences of the HIV on the immune system.
Outline the relationship between HIV and AIDS.
List ways the HIV virus is spread.

6.3.A3 Florey and Chain’s experiments to test penicillin on bacterial infections in mice.

Explain methods and results of Florey and Chain’s experiments.

6.3.NOS Risks associated with scientific research- Florey and Chain’s tests on the safety of penicillin would not be compliant with current protocol on testing.

Compare allowable research risks of the past with those of the present.

In the News:

Mucus: the body’s unsung hero
End to Aids in sight as huge study finds drugs stop HIV transmission (2019-05-02)
Releasing our inner jellyfish in the fight against infection (2018-07-09)
Protect the skin, build barriers: Old acquaintance in a new role (20174-11-08)
New antibiotic resistance genes found (2017-10-16)
Skin microbes trigger specific immune responses (2015-01-05)
Unraveling the mechanism of skin barrier formation (2017-04-14)
To stop the bleeding, the platelet have to 'die' (2016-08-09)
Understanding how the 'police' of the cell world deal with 'intruders' and the 'injured' (2016-08-30)