Immunology Chapter 16 Study Guide

Questions and Answers

What is the role of the skin and mucous membranes in innate immunity?

The skin is the body's largest organ consisting of the dermis, epidermis, and keratin. Mucous membranes consist of epithelium and inhibit entrance by trapping microbes.

Physical factors include skin and mucous membranes. Provide five examples.

Dermis, epidermis, keratin, saliva, urine.

What is the role of normal microbiota in innate immunity?

Normal microbiota compete with pathogens or alter the environment.

What is the difference between microbial antagonism and commensalism?

Microbial antagonism involves beneficial microbes competing against pathogens, while commensalism refers to a relationship where one organism benefits and the other is neither helped nor harmed. Signup and view all the answers

What are leukocytes and what roles do granulocytes and monocytes play?

Leukocytes are white blood cells. Granulocytes are active in initial infection stages, and monocytes mature into macrophages for phagocytosis. Signup and view all the answers

What is the main function of the blood circulatory system?

To deliver oxygen and nutrients to tissues and carry away waste products. Signup and view all the answers

How do the structures and functions of monocytes and neutrophils compare?

Monocytes are precursors to macrophages, while neutrophils are highly phagocytic cells active in the initial stages of infection. Signup and view all the answers

What does white blood cell count indicate?

It is a calculation of the percentage of each kind of white cell in a sample of 100 white blood cells. Signup and view all the answers

What does the lymphatic system consist of?

The lymphatic system consists of lymph, lymphatic vessels, lymphoid tissue, red bone marrow, lymphocytes (T and B cells), lymph nodes, and tonsils. Signup and view all the answers

What are lymph nodes and their functions?

Lymph nodes are bean-shaped filters that cleanse lymph and serve as sites for T and B cell activation. Signup and view all the answers

List the six different types of white blood cells and a function for each.

<ol> <li>Neutrophils - phagocytosis; 2. Basophils - production of histamine; 3. Eosinophils - production of toxic proteins; 4. Monocytes - phagocytosis; 5. Dendritic cells - immune response initiation; 6. Lymphocytes - destroy target cells.</li> </ol> Signup and view all the answers

Define phagocyte and phagocytosis.

Phagocyte is a cell capable of engulfing harmful particles; phagocytosis is the ingestion of particles by eukaryotic cells. Signup and view all the answers

What are the stages of phagocytosis?

Adherence and ingestion. Signup and view all the answers

Identify six mechanisms microbes use to avoid destruction by phagocytosis.

<ol> <li>Inhibit adherence; 2. Kill phagocytes; 3. Lyse phagocytes; 4. Escape phagosome; 5. Prevent phagosome-lysosome fusion; 6. Survive in phagolysosome.</li> </ol> Signup and view all the answers

What do fixed and wandering macrophages do?

Fixed macrophages reside in specific tissues, while wandering macrophages roam and gather at infection sites. Signup and view all the answers

List the stages of inflammation.

<ol> <li>Redness; 2. Swelling; 3. Heat; 4. Pain; 5. Loss of function.</li> </ol> Signup and view all the answers

Study Notes

Skin and Mucous Membranes in Immunity

Skin is the largest organ and consists of the dermis and epidermis with keratin.
Mucous membranes, made of epithelium, help trap microbes and inhibit their entry.

Physical vs. Chemical Factors

Physical factors include skin and mucous membranes, such as:
- Dermis (inner skin)
- Epidermis (outer skin)
- Keratin (protective protein)
- Mucus membranes (found in saliva, vagina, gastrointestinal tract, earwax, vomit, diarrhea, urine, tears)
Chemical factors include:
- Fungistatic fatty acids in sebum
- Low skin pH (3-5)
- Lysozyme present in tears, saliva, perspiration, and urine
- Low gastric juice pH (1.2-3.0)
- Low pH (3-5) of vaginal secretions

Normal Microbiota and Innate Immunity

Normal microbiota compete with pathogens and modify the environment to favor beneficial microorganisms.

Microbial Antagonism vs. Commensalism

Microbial antagonism involves beneficial microbes competing against pathogens, while commensalism is where one organism benefits without significantly affecting the other.

Leukocyte Classification

Leukocytes are white blood cells categorized into:
- Granulocytes: visible stained granules, active during infection and allergic reactions.
- Monocytes: precursors to macrophages, involved in phagocytosis.

Lymphatic vs. Blood Circulatory Systems

Blood circulatory system delivers oxygen and nutrients, removes waste.
Lymphatic system transports hazardous materials (toxins, pathogens) and is separate from blood circulation.

Monocytes vs. Neutrophils

Monocytes mature into macrophages and activate during lymph node swelling.
Neutrophils are highly phagocytic, motile cells active at infection onset, destroying foreign microorganisms.

White Blood Cell Count

A calculation of the percentage of each type of white blood cell in a sample of 100 cells.

Lymphatic System Components

Comprises lymph, lymphatic vessels, lymphoid tissues, red bone marrow, lymphocytes (T and B cells), lymph nodes, and tonsils.

Types of White Blood Cells

Granulocytes (with granules in cytoplasm):
- Neutrophils: phagocytosis.
- Basophils: produce histamine.
- Eosinophils: produce toxic proteins against parasites and some phagocytosis.
Agranulocytes (without granules):
- Monocytes: phagocytosis, precursors to macrophages.
- Dendritic cells: initiate immune response and phagocytosis.
- Lymphocytes: target cell destruction via cytolysis and apoptosis (T and B cells).

Phagocytes and Phagocytosis

Phagocyte: a cell that can engulf harmful particles.
Phagocytosis: the ingestion of particles by eukaryotic cells.

Phagocytosis Process

Involves stages of adherence to the pathogen and ingestion into the cell.

Mechanisms to Avoid Phagocytosis

Inhibit adherence (e.g., M protein, capsules).
Kill phagocytes (e.g., leukocidins).
Lyse phagocytes (e.g., membrane attack complex).
Escape phagosome.
Prevent phagosome-lysosome fusion.
Survive in phagolysosome.

Fixed vs. Wandering Macrophages

Fixed macrophages reside in specific tissues (e.g., liver, lungs, spleen).
Wandering macrophages move throughout tissues to sites of infection or inflammation.

Stages of Inflammation

Stages include redness, swelling, heat, pain, and potential loss of function.
Associated with tissue damage, vascular changes (vasodilation, increased permeability), and phagocyte migration.

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Description

This study guide focuses on the role of the skin and mucous membranes in innate immunity, along with differentiating physical and chemical factors. It includes key definitions and examples essential for understanding the body's natural defense mechanisms.