Human Anatomy Defense Mechanisms

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Questions and Answers

What primarily defines the immune system?

A network of cells, tissues, and organs providing protection (correct)

A group of organs that dispose of waste materials

A system that only reacts to pathogens after infection

Components that aid in digestion

What is the role of the reticulo-endothelial system (RES)?

To transport nutrients to tissues

To allow immune cells to bind and move outside the blood (correct)

To digest nutrients in the bloodstream

To filter blood of pathogens only

Which lymphoid organ is NOT classified as a primary lymphoid organ?

Both A and B

Spleen (correct)

Bone marrow

Thymus

Where do B cells mature in the immune system?

Bone marrow Signup and view all the answers

What is the main purpose of the lymphatic system in immunity?

To transport immune cells and initiate immune responses Signup and view all the answers

Which type of immunity results from the actions of circulating cells in the body?

Both innate and adaptive immunity Signup and view all the answers

How do extracellular fluids (ECF) support the immune system?

By enabling immune cells to move and operate Signup and view all the answers

Which of the following correctly identifies the key players in the immune system?

Phagocytes and lymphocytes Signup and view all the answers

What is the primary role of basophils in the immune system?

Production of histamine Signup and view all the answers

How do mast cells differ from basophils in terms of location?

Mast cells are tissue resident. Signup and view all the answers

Which of the following best describes monocytes?

A granulocyte with clear cytoplasm. Signup and view all the answers

What is a key function of tissue macrophages?

Engulfing and digesting dead cells. Signup and view all the answers

In which phase of the immune response do macrophages play a critical role?

Innate immunity Signup and view all the answers

What is the lifespan of circulating monocytes before they migrate into tissues?

8 hours Signup and view all the answers

What characteristic is typical of granulocytes like basophils?

Presence of large cytoplasmic granules Signup and view all the answers

What happens to monocytes once they migrate into tissues?

They differentiate into macrophages or dendritic cells. Signup and view all the answers

What role do mucous secretions play in the first line of host defense?

They trap and eliminate microbes. Signup and view all the answers

Which of the following components of saliva contributes to its antimicrobial properties?

Lysozyme and Phospholipase A. Signup and view all the answers

How does the acidic pH of the vagina contribute to host defense?

It inhibits the growth of microbes. Signup and view all the answers

What mechanism does the intestinal flushing action utilize to eliminate microbes?

It prevents microbes from colonizing. Signup and view all the answers

What is the role of normal flora in non-sterile body sites?

They provide antimicrobial substances and compete for resources. Signup and view all the answers

Which of the following factors contributes to the defense mechanism in the mouth and intestinal tract?

Flushing action and lysozyme. Signup and view all the answers

What is one primary function of tears in ocular defense?

They mechanically blink to trap microbes. Signup and view all the answers

Which of the following accurately describes the role of bile salts?

They inhibit and prevent certain microbes in the intestinal tract. Signup and view all the answers

What is one of the primary functions of the complement system?

To lyse bacteria and some viruses Signup and view all the answers

Which white blood cell is considered the principal phagocytic cell of innate immunity?

Neutrophil Signup and view all the answers

What do lactoferrin and transferrin primarily do in the immune response?

Compete with bacteria for iron Signup and view all the answers

What is the main target of neutrophils during an inflammatory immune response?

Bacterial pathogens Signup and view all the answers

Which component is responsible for breaking down bacterial cell walls?

Lysozyme Signup and view all the answers

What is the role of eosinophils in the immune system?

Responding to parasitic infections Signup and view all the answers

What is an effect of cytokines in the immune response?

Signal various immune responses Signup and view all the answers

What is the percentage of neutrophils in blood leukocytes?

40-75% Signup and view all the answers

What is the primary site for the development of T cells in the immune system?

Thymus gland Signup and view all the answers

Which component is NOT considered a part of the anatomical barriers in the immune system?

Natural killer cells Signup and view all the answers

What factor of the skin helps to inhibit microbes by creating a low pH?

Anti-microbial fatty acid Signup and view all the answers

What is the function of ciliated epithelium in the respiratory tract?

Propel mucus away from the tract Signup and view all the answers

Which of the following is a non-specific cellular component of the immune system?

Neutrophils Signup and view all the answers

The spleen is involved in which aspect of the immune system?

Encounter of mature lymphocytes with pathogens Signup and view all the answers

Which type of immune response is characterized as 'specific'?

Acquired Signup and view all the answers

Which of these is considered a humoral component of the innate immune system?

Complement Signup and view all the answers

Study Notes

First Line of Defense: Anatomical and Physical Barriers

Mucous secretion traps and eliminates microbes; surfactants in the lungs act as opsonins.
Eyes protect through blinking, tearing to flush and wash the surface, and Lysozyme which breaks down bacteria.
Skin serves as a physical barrier with squamous epithelium, antimicrobial fatty acids, low pH, and keratin.
Intestinal epithelium aids in peristalsis and mucociliary actions to expel microbes.

Chemical and Biological Defense Mechanisms

Saliva contains lysozyme and phospholipase A, inhibiting bacterial cell membranes.
Gastric juice’s low pH (HCl) kills or inhibits microbial growth.
Urine’s acidity cleanses the urinary tract; vaginal flora inhibits pathogen growth through acidity.
Normal flora in non-sterile body sites compete for resources, promoting an unfavorable environment for pathogens.

Immunology: Overview

Study of the immune system’s components and functions, providing non-specific and specific protection against pathogens, toxins, and tumor cells.
Integrated systems include the reticuloendothelial system (RES), extracellular fluids system (ECF), blood vascular system, and lymphatic system.

Lymphoid Organs and Cell Types

Primary lymphoid organs: Bone marrow (B cells mature) and thymus (T cells mature).
Secondary lymphoid organs: Spleen and lymph nodes, where adaptive immune responses occur.
Stem cells in bone marrow are precursors to all immune cells.

Components of the Immune System

Divided into innate (non-specific) and acquired (specific) immunity.
Innate immune system includes anatomical barriers, humoral components, and cellular components like leukocytes.
Humoral components consist of complement proteins, cytokines, and antimicrobial substances like lysozyme.

Cellular Components of the Immune System

Neutrophils (40-75% of leukocytes), principal phagocytes, respond rapidly to bacterial infections.
Eosinophils are specialized for parasitic infections and modulating allergic responses; less abundant than neutrophils.
Basophils, with large granules, produce histamines and recruit other immune cells to sites of infection.
Monocytes become macrophages and dendritic cells, crucial for phagocytosis and presenting antigens to lymphocytes.

Immune Response Mechanisms

Phagocytosis is a critical process where white blood cells like neutrophils and macrophages engulf and digest foreign bodies.
Neutrophils are early responders to inflammation, primarily targeting bacteria.
Macrophages, derived from monocytes, play a crucial role in cleaning up dead cells and debris post-infection.

Important Cells in the Immune System

Natural killer (NK) cells target virally-infected or tumor cells.
Dendritic cells act as antigen-presenting cells, stimulating T-cell response.
B cells produce antibodies, enhancing the adaptive immune response against specific pathogens.

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Description

Explore the various anatomical and physiological defenses the human body employs to eliminate microbes. This quiz covers mucous secretion, ciliated epithelium, and the role of tears and other mechanisms in maintaining health.