immunology lecture 3

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Questions and Answers

Why is lysozyme more effective against Gram-positive bacteria?

It disrupts the DNA of the bacteria.

The peptidoglycan is more accessible in Gram-positive bacteria. (correct)

It targets the lipid bilayer of the cell membrane.

It is less effective against Gram-negative bacteria.

What is the role of defensins in the immune response?

They neutralize toxins produced by bacteria.

They enhance the recruitment of leukocytes.

They disrupt the cell membranes of microbes. (correct)

They act as antibodies against pathogens.

Which term describes the collection of microorganisms that normally inhabit our body?

Pathogen

Microbiota (correct)

Parasites

Symbionts

Which of the following is NOT classified as an innate immune cell?

T lymphocytes Signup and view all the answers

What is the primary function of granulocytes in the immune system?

They directly destroy pathogens. Signup and view all the answers

What mechanism do antimicrobial peptides like defensins utilize to combat microbes?

By causing membrane disruption. Signup and view all the answers

Which cells are considered myeloid antigen-presenting cells (APCs)?

Monocytes, Macrophages, and Dendritic Cells Signup and view all the answers

Which immune response relies on both innate and adaptive immunity?

Leukocyte activities Signup and view all the answers

What distinguishes innate immunity from adaptive immunity?

Innate immunity is present at birth and non-specific. Signup and view all the answers

Which of the following correctly describes the first line of defense in the immune system?

It consists of physical and chemical barriers. Signup and view all the answers

What is a key characteristic of adaptive immunity?

It requires previous exposure to pathogens to be effective. Signup and view all the answers

Which component of the innate immune system helps digest the cell walls of bacteria?

Lysozyme Signup and view all the answers

Which statement about the second line of defense in the immune system is true?

It involves innate immune responses that are non-specific. Signup and view all the answers

What is one major difference between humoral and cell-mediated immunity?

Humoral immunity involves B cell-mediated responses. Signup and view all the answers

Which type of immunity is activated without prior exposure to pathogens?

Innate immunity Signup and view all the answers

What role do epithelial surfaces play in the immune system?

They serve as a barrier to prevent pathogen entry. Signup and view all the answers

Study Notes

Immune System

Innate immunity: immediate, non-specific defense present at birth; no memory
Adaptive immunity: developed after birth, specific to pathogens, has memory
Humoral immunity: B cell-mediated via Igs
Cell-mediated immunity: T cell-mediated
Protection against pathogens: relies on physical barriers, chemical barriers, and sensor cells
Physical barriers: epithelial surfaces
Chemical barriers: antimicrobial peptides, commensals
Sensor cells: detect pathogens, initiate immune response
Microbiota (or commensals): the collection of microorganisms naturally inhabiting the body
Antimicrobial peptides: defensins, cathelicidin, histatin
Lysozyme: digests cell walls of Gram-positive and Gram-negative bacteria
Defensins: amphipathic peptides that disrupt microbial cell membranes
Leukocytes (White Blood Cells): important in both innate and adaptive immune responses
Innate immune cells: Granulocytes, Agranulocytes, Dendritic Cells
- Granulocytes: neutrophils, eosinophils, basophils, mast cells
- Agranulocytes: monocytes, macrophages, NK cells
- Myeloid antigen-presenting cells (APCs): monocytes, macrophages, dendritic cells
- Innate lymphocytes: NK cells, ILCs
Phagocytes: macrophages, granulocytes, dendritic cells; engulf and destroy pathogens

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Description

Explore the complexities of the immune system, including innate and adaptive immunity. This quiz covers the roles of B cells, T cells, physical and chemical barriers, and how the body protects against pathogens. Test your knowledge on important components like microbiota and antimicrobial peptides.