Unit 4 Immunity and Disease

The body can be invaded by...

• mutagens

• bryophytes

• tracheophytes

• pathogens

Harmful microorganisms that cause diseases which can be spread are called?

• Infectious

• chronic

• malignant

• proactive

Tags

NGSS.MS-LS2-4

The skin, tears, and stomach acid are part of the body's first line of defense against infection. How do scientists classify these defenses?

• as specific defenses, because they respond to specific physical or chemical properties of pathogens

• as weak defenses, because they stop only a small percentage of pathogens that threaten the body

• as nonspecific defenses, because they bar or stop infections without discriminating pathogens from other agents

• as barrier defenses, because they act like a wall to stop pathogens from invading

Many people are allergic to substances in the environment, such as ragweed pollen, as well as foods, such as peanuts. Which of these statements BEST describes an allergic reaction to one of these substances?

• The substance is similar or identical to human antigens, and so it triggers an immune system response

• The substance invades the body and causes damage to tissues, which triggers an immune system response

• The substance does not directly harm tissues and is not a pathogen, but nevertheless triggers an inflammatory response

• The substance invades the body and triggers a response from the respiratory system or digestive system, but not the immune system

The specific defenses of the immune system include a variety of cells that circulate in the blood and that make up organs such as the spleen and thymus. How are the cells of the immune system able to differentiate pathogens from the cells of the body?

• The cells of pathogens are much smaller than human cells

• Pathogens move through the body, while human body cells are stationary

• Pathogens contain foreign molecules, or antigens, on their outer surface

• Pathogens release foreign molecules, or antigens, when cells of the immune system approach them