Immune System

Question 1

The body’s defenses can be sorted into two general categories. What are they?

Answer 1

1. Non-specific
2. Specific

Question 2

_________________ defense prevent, deny, or limit the entry and proliferation of pathogens

Answer 2

Nonspecific

Question 3

What expamples of nonspecific defenses were discussed in class?

Answer 3

Physical barriers, phagocytes, immunological surveillance, interferons, the complement system, the inflammatory response, fever

Question 4

What two cell types mediate specific defenses or the acquired immunse system?

Answer 4

T cells

B cells

Question 5

T-cells confer ______-mediated immunity; B-cells confer __________-mediated immunity

Answer 5

Cell-mediated

Antigen-mediates

Question 6

The immune response:

Antigens activate both T and B cells, but the activation of __ cells generally occurs first. These cells attack the antigen and stimulate the activation of __ cells, which once activated can produce _________________

Answer 6

T cells

B cells

Antibodies

Question 7

What cells activate T cells?

Answer 7

Antigen-presenting cells (APCs)

Question 8

How do T cells recognize antigens? In other words, what steps occur to activate them?

Answer 8

An antigen-presenting cell, a macrophage, engulfs an antigen and presents part of it on its cell for T cells to recognize, activating the T cells

Question 9

What type of T cell seeks out and destroys abnormal and infected cells?

Answer 9

Cytotoxic T cells

Question 10

__________________ T cells differentiate into cytotoxic T cells the second time an antigen appears

Answer 10

Memory T cells

Question 11

______________ T cells secrete suppression factors or inhibitory cytokines that turn off other immune system cells once an infection has been brought under control

Answer 11

Suppressor T cells

Question 12

_______ cells launch a chemical attack on antigens by producing appropriate, specific antibodies

Answer 12

B cells

Question 13

How are B cells sensitized and then activated?

Answer 13

Sensitization: When an antigen appears, the B cell engulfs it via endocytosis and presents the antigens on the surface of the B cell

Activation: A previously activated helper T cell binds to B cell; the T cell releases chemicals that stimulate B cell proliferation and antibody production; some of these daughter mature into plasma cells

Question 14

What are plasma cells?

Answer 14

Plasma cells are differentiated effector B cells that produce and secrete large numvers of antibodies

Question 15

Where are B cells activated?

Answer 15

Lymph nodes

Question 16

Like its T cell counterpart, ______________ B cells do not respond to a threat of first exposure; they only do so after the second exposure

Answer 16

Memory B cells

Question 17

Antibodies are composed of two parallel polypeptide chain pairs: one pair of _____ chains and one pair of _____ chains

Answer 17

Heavy

Light

Question 18

Two variable sites on the top of the antibody form the ____________ binding sites

Answer 18

Antigen

Question 19

When antibody molecules bind to their corresponding antigen molecules, an __________________-______________ ______________ forms

Answer 19

Antigen-antibody complex

Question 20

_________________ ________________ refers to the site on an antigen to which an antibody binds, forming an antigen-antibody complex

Answer 20

Antigenic determinant

Question 21

The formation of an antigen-antibody complex can lead to neutralization (antibody covers the active portion of pathogen), ______________________ (antibody cross-links cells forming a “clump”), or _______________ (antibody cross-links form an insoluble antigen-antibody complex

Answer 21

Agglutination

Precipitation