#14: The Immune System in Animals

The immune system is responsible for defense against __________.

pathogens

_________ immunity are immune system cells that are ready to respond to forgien invaders at all times, which provides a fast response.

Innate

_________ immunity are cells that must first be selectively activated to tailor their response to a specific pathogen, which is slightly slower.

Adaptive

In adaptive immunity, the steps are …

• activating B-cells to produce specific antibodies to target antigens

• T-cell activation to help B-cells and kill infected cells

The body’s first response to pathogens inside the body involves __________.

leukocytes

_________ are any molecules on the surface of an invader that helps to generate antibody for that invader.

Antigens

__________ are secreted proteins that bind to a specific part of a specific antigen.

Antibodies

The _______________ is the protein on the surface of B cells that binds to antigens.

B-cell receptor

Antibodies and BCRs bind to a selected region of the antigen called an _______.

epitope

_________ produce antibodies and mature in bone marrow.

B-cells

________ recognize and kill virus-infected cells, and mature in the thymus.

T-cells

To help with adaptive immunity, the _________________ explains how the immune system selects and activates specific lymphocytes

clonal selection theory

_________ cells attack the antigen and report back to the lymph nodes.

Dendritic

_________________ prepares the T cell to recognize the antigen.

Antigen presentation

T-cells are activated when their receptors recognize specific epitopes presented by _______________________________ proteins on antigen-presenting cells.

Major Histocompatibility Complex (MHC)

______ cells are helper T cells that help activate B-cells and cytotoxic T-cells

CD4⁺ T

______ cells are cytotoxic cells that kill cells which are infected with an intracellular pathogen

CD8⁺ T

Activated T and B cells produce daughter cells called _____________, which provide a secondary immune response if the same antigen enters the body again.

memory cells

_________ are an abnormal overreactive response to an antigen.

Allergies

What are the five different immune system cells?

Macrophages

Mast cells

B-cells

Helper CD4⁺ T-cells

Cytotoxic CD8⁺ T-cells

____________ cells release cytokines to recruit other immune cells to the site of infection and perform phagocytosis to kill invading cells.

Macrophage

______ cells release histamine, which increases blood flow to the wound area, causing redness, swelling, and heat.

Mast

An inflammation-causing signal released by mast cells at the site of an infection is _____.

histamine

Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of ________.

glucagon

If a patient is missing B and T cells, what would be absent from the immune response?

memory

How does the immune system of vertebrates utilize a chemical concentration gradient?

The immune system releases chemical signals called chemokines, which create a chemical gradient that leukocytes use in migrating toward the infection site.