Ch2pp33-35

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are the major interfaces protected by layers of epithelial cells?

Endocrine system and lymphatic system

Gastrointestinal tract, respiratory tract, and genitourinary tract (correct)

Skeletal system and muscular system

Nervous system and cardiovascular system

What do antimicrobial peptides, defensins, and cathelicidins do?

Kill bacteria and some viruses by disrupting their outer membranes (correct)

Have no effect on microbes

Attract more microbes to the body

Stimulate the growth of bacteria and viruses

Which cells form a mechanical barrier against microbes?

T cells

Epithelial cells (correct)

Platelets

Red blood cells

Where do microbes mainly come into contact with vertebrate hosts?

Interfaces between the body and the external environment Signup and view all the answers

What are the two pathways of macrophage activation called?

Classical and alternative Signup and view all the answers

What is the source of tissue-resident macrophages?

Progenitors in the yolk sac or fetal liver Signup and view all the answers

Which receptors are involved in the activation and functions of macrophages?

TLRs and NLRs Signup and view all the answers

What are the roles of tissue-resident macrophages?

Ingest and destroy microbes, clear dead tissues, produce cytokines Signup and view all the answers

What induces classical macrophage activation?

Innate immune signals such as from TLRs, and the cytokine IFN-γ Signup and view all the answers

What distinguishes alternative macrophage activation?

It occurs in the absence of strong TLR signals and is induced by the cytokines IL-4 and IL-13. Signup and view all the answers

What activates phagocytosis in macrophages?

Cell surface receptors such as mannose receptors and scavenger receptors Signup and view all the answers

What are tissue-resident macrophages derived from?

Progenitors in the yolk sac or fetal liver early during fetal development Signup and view all the answers

What is the role of intraepithelial lymphocytes in epithelia?

React against infectious agents penetrating the epithelia Signup and view all the answers

What is the primary function of neutrophils and monocytes?

Recognize and ingest microbes for intracellular killing Signup and view all the answers

What stimulates the rapid increase of neutrophils in response to certain infections?

Colony-stimulating factors (CSFs) Signup and view all the answers

Which feature enhances neutrophils' ability to kill ingested microbes?

Expression of receptors for complement activation and antibodies Signup and view all the answers

What do neutrophils initiate at sites of tissue damage?

Clearance of cell debris Signup and view all the answers

What is the primary role of monocytes in extravascular tissues during inflammatory reactions?

Differentiate into macrophages Signup and view all the answers

Study Notes

Immune Functions of Epithelia, Neutrophils, and Monocytes/Macrophages

Epithelia contain intraepithelial lymphocytes, a type of T cell, which react against infectious agents penetrating the epithelia.
Epithelia serve as physical barriers and produce antimicrobial substances to prevent infection.
Neutrophils and monocytes are two types of circulating phagocytes that are recruited to sites of infection to recognize and ingest microbes for intracellular killing.
Neutrophils are the most abundant leukocytes in the blood, numbering 4000 to 10,000 per μL and rapidly increase in response to certain infections.
Neutrophils are stimulated by colony-stimulating factors (CSFs) secreted in response to infections, making them the first and most numerous responders to infections, particularly bacterial and fungal infections.
Neutrophils express receptors for complement activation and antibodies, enhancing their ability to kill ingested microbes.
Neutrophils are also recruited to sites of tissue damage and initiate the clearance of cell debris.
Neutrophils have a short lifespan in tissues, providing early defense but not prolonged defense.
Monocytes are less abundant in the blood than neutrophils, numbering 500 to 1000 per μL, and differentiate into macrophages in extravascular tissues during inflammatory reactions.
Blood monocytes and tissue macrophages are two stages of the same cell lineage, often referred to as the mononuclear phagocyte system.
Monocytes and macrophages are involved in the clearance of cell debris and are present in most healthy organs and tissues.
Neutrophils and macrophages share features such as phagocytosis, chemotaxis, and the ability to migrate through blood vessels into tissues.

Studying That Suits You

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

Description

Test your knowledge on the components of the innate immune system, including epithelial cells, sentinel cells, circulating and recruited phagocytes, innate lymphoid cells, NK cells, and plasma proteins. Explore the properties and roles of these cells and soluble proteins in innate immune responses.