Innate Defenses Biology Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which statement accurately describes an antigen?

An antigen is a protein that binds to pathogens to prevent infection.

An antigen is an immune cell that destroys pathogens.

An antigen is any substance that initiates an immune response. (correct)

An antigen is a type of antibody produced by B cells.

What characteristic of adaptive immunity allows the body to remember past infections?

Systemic nature

Immediate response to pathogens

Memory function (correct)

Antigen-specific response

Which type of cell is primarily responsible for the cytotoxic response in cell-mediated immunity?

Cytotoxic T cells (correct)

Helper T cells

Memory T cells

B cells

What role do helper T cells play in antibody-mediated immunity?

They activate previously inactive B cells. Signup and view all the answers

Which process allows antibodies to bind and neutralize toxins?

Neutralization Signup and view all the answers

Memory T cells function primarily to:

Enhance the speed of future immune responses. Signup and view all the answers

Major histocompatibility complex (MHC) proteins are crucial for which process?

Antigen presentation to T cells Signup and view all the answers

What is a primary function of plasma cells in the immune response?

Produce antibodies to fight antigens. Signup and view all the answers

What is the primary role of lysozymes in immune defense?

Destroy bacteria Signup and view all the answers

Which component is NOT a part of the innate immune responses?

Antibodies Signup and view all the answers

Which of the following correctly describes the process of phagocytosis?

Ingestion of foreign particles by immune cells Signup and view all the answers

What function do pyrogens serve in the immune system?

Stimulate fever response Signup and view all the answers

Which specific immune response results from the mobilization of phagocytes?

Inflammation Signup and view all the answers

What role does the complement system play in immune defense?

It enhances the inflammatory response and can directly destroy bacteria Signup and view all the answers

Which immune cell type is known for releasing interferons?

Virus-infected cells Signup and view all the answers

Which of the following statements accurately describes natural killer (NK) cells?

They can attack virus-infected and tumor cells. Signup and view all the answers

What is the primary cause of the symptoms associated with inflammation, such as redness and swelling?

Vasodilation and increased vascular permeability Signup and view all the answers

Which mechanism is NOT involved in the stages of inflammation?

Formation of scar tissue Signup and view all the answers

Study Notes

Innate Defenses (Nonspecific Defenses)

Inherited defenses attempt to stop all foreign invaders in the same way (nonspecific)
Broken down into mechanical, chemical, and other categories
Mechanical Protection:
- Epidermis
- Mucus
- Cilia/hair
- Lacrimal apparatus
- Saliva
- Urination/defecation
- Vomiting/diarrhea
Chemical Protection:
- Lysozymes (destroy bacteria) found in perspiration, lacrimal fluid, sebum, and saliva
- Gastric juice, vaginal secretions, urine, bile, and pancreatic juice alter pH
Interferons:
- Inhibit viral replication in cells
- Released from virus-infected cells and lymphocytes/macrophages
Natural Killer (NK) Cells:
- Present in spleen, lymph nodes, red bone marrow, and blood
- Attack foreign cells, virus-infected cells, and tumor cells
Phagocytosis:
- Neutrophils, macrophages (wandering and fixed)
- Steps: Leukocytosis, margination, diapedesis, chemotaxis, adherence/opsonization, ingestion (phagosome), and phagolysosome formation

Inflammation

Three stages:
- Increased vasodilation and permeability (causing warmth, redness, pain, and swelling)
- Phagocyte mobilization
- Tissue repair
Chemicals involved include histamine, kinins, prostaglandins, and leukotrienes

Fever

Caused by pyrogens (chemicals that increase body temperature)
Released from WBCs and bacteria
Promotes sequestration of iron and zinc, aiding defense, and speeds up reaction time

Complement System

Group of at least 20 plasma proteins
Some activate inflammatory response; others destroy bacteria directly

Adaptive Immunity (Specific Defense)

Three aspects:
- Antigen-specific
- Systemic
- Has memory
Two types:
- Cell-mediated immunity
- Antibody-mediated immunity

Overview of Cell-Mediated Immunity

Antigen penetrates and is broken down by an antigen presenting cell (APC)
Antigen fragments merge with MHC proteins on APC's membrane
Inactive T cells come into contact with APC, recognizing the altered MHC proteins and become active
Active T cells divide and differentiate
- Cytotoxic T cells (CD8 cells) rupture antigen cell walls/membrane and/or secrete lymphotoxin
- Memory T cells recognize antigens directly
- Suppressor T cells suppress cytotoxic T cells
- Helper T cells (CD4 cells) produce ILs (e.g., IL-2 for T cell proliferation)

Antibody-Mediated Immunity

Helper T cells activate B cells
B cell division & differentiation leads to Memory B cells and Plasma cells
Antibodies merge with antigen = antigen-antibody complex
Antibody actions: neutralization, immobilization, attraction of phagocytes, facilitating phagocytosis, stimulating inflammation, inhibiting antigen metabolism

Antibody Structure

Four polypeptide chains: two identical heavy (H) chains and two identical light (L) chains
Five classes of antibodies (immunoglobulins): IgA, IgD, IgE, IgG, and IgM with different locations and functions. IgG is the most abundant.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the body's innate defenses against foreign invaders. This quiz covers nonspecific defenses, including mechanical and chemical protections, as well as the role of interferons and natural killer cells. Discover how phagocytosis plays a crucial part in immune response.