31.3 Immune Responses

Sponge # 2

• What are some of the ways pathogens enter the body?

• Explain what happens when you get a mosquito bite.

31.2 Immune System

• SKIN!!!!!!!– Cuts and wounds are entry points

• Eyes• Nose• Ears • Mouth• Excretory Organs (lungs)

31.3 Immune Responses

• Your body responds to pathogens in several different ways– Your skin may swell and itch– Your immune system attacks the pathogens that

entered your skin

31.3 Immune Responses

KEY CONCEPTThe immune system has many responses to pathogens and foreign cells.

31.3 Immune Responses

• Nonspecific responses are the same for every pathogen.• In inflammation, blood vessels become leaky.

– white blood cells movetoward infection anddamaged tissue

– characterized by swelling, redness, and pain

capillary wallextracellular space

white blood cell

31.3 Immune Responses

• In fever, body temperature increases.

– High fevers can cause seizure, brain damage, and even death.

– Low fevers stimulate white blood cells to mature.

31.3 Immune Responses

– Antigens are surface proteins on pathogens.- Each pathogen has a different antigen.- Help the immune system identify a foreign cell or

virus

virus

antigens

31.3 Immune Responses

• memory cells- specialized T and B cells that provide acquired immunity because they “remember” an antigen that has previously invaded your body– Next time they come across the same pathogen they

destroy it before you get sick

B cellT cell

31.3 Immune Responses

The immune system rejects foreign tissues.

• Tissue rejection occurs in organ or tissue transplants.• Tissue rejection is the result of an immune response.

– immune system detects protein markers on the donor tissue

– makes antibodies against the donor’s tissue