Human Body Defense Mechanisms Quiz

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Questions and Answers

Which of the following best describes nonspecific defenses of the body?

They are tailored to attack specific pathogens.

They provide general protection against a wide range of infections. (correct)

They are only active after the first line of defense has been breached.

They rely exclusively on antibodies to neutralize threats.

What is the primary function of the skin as part of the first line of defense?

To enhance the immune response through inflammation.

To produce antibodies for specific pathogens.

To serve as a barrier preventing pathogen entry. (correct)

To recruit white blood cells to the site of infection.

What is the role of phagocytes in the body's defense mechanisms?

To produce toxins that kill infected cells.

To release histamines that initiate inflammation.

To identify and mark pathogens for destruction.

To engulf and digest foreign invaders. (correct)

How do natural killer cells contribute to the body's defense?

By directly targeting and destroying infected or cancerous cells. Signup and view all the answers

What is a key feature of the inflammatory response in wound healing?

It involves the recruitment of immune cells to the affected area. Signup and view all the answers

Which purpose does inflammation serve during an injury?

To destroy or wall off the injury Signup and view all the answers

What are the three basic events of the acute inflammatory response?

Chemical, vascular, and cellular events Signup and view all the answers

Which of the following is NOT a characteristic of the acute inflammatory response?

Decreased temperature at the site Signup and view all the answers

Which of the following is NOT considered a first line of defense mechanism against infection?

Natural Killer cells Signup and view all the answers

What is the role of phagocytes during inflammation?

To engulf and digest pathogens Signup and view all the answers

Which chemical is primarily involved in promoting blood vessel dilation during inflammation?

Histamine Signup and view all the answers

What is the primary function of phagocytes in the immune response?

To engulf and destroy pathogens Signup and view all the answers

Natural Killer (NK) cells primarily target which of the following?

Viruses and tumor cells Signup and view all the answers

What is the final outcome of the inflammatory response?

Repair and regeneration of tissue Signup and view all the answers

What is the inflammation of the appendix called?

Appendicitis Signup and view all the answers

Which component of the immune system is responsible for mediating the complement cascade?

Proteins in the blood Signup and view all the answers

What phase follows the inflammatory phase in wound healing?

Proliferative phase Signup and view all the answers

What triggers the inflammatory response in the body?

Release of histamines and cytokines Signup and view all the answers

What is a primary role of interferons in the immune response?

To inhibit viral replication Signup and view all the answers

How does a fever function as a second line of defense?

By creating an unfavorable environment for pathogens Signup and view all the answers

Which type of white blood cell is primarily involved in the innate immune response and can differentiate into macrophages?

Neutrophils Signup and view all the answers

Study Notes

The Inflammatory Process

Inflammation is a body defense mechanism that occurs in response to injury.
The inflammatory response is basically the same regardless of the type of injury.
The inflammatory process is designed to: Destroy, Dilute, or Wall Off injury
Inflammation is closely intertwined with the repair process and helps to heal the tissue.
The inflammatory process can be divided into three basic events: Chemical events, vascular events, and cellular events.

Inflammatory Chemicals

Histamine: Released by Mast cells, causes vasodilation (increased blood flow) and increases capillary permeability.
Kinins: Plasma proteins, similar action to histamine, also attract leukocytes (white blood cells).
Prostaglandins: Derived from lipids, promote vasodilation, and increase capillary permeability.
Complement: A plasma protein system that can attract leukocytes, promote inflammation, and directly destroy bacteria.

Tissue Healing

Tissue repair is a complex process that aims to replace damaged tissue with either regenerated cells, scar tissue, or both.
The inflammatory process helps set the stage for tissue repair.
The three key phases of wound healing are:
- Inflammation Phase: Blood clots, and white blood cells (primarily neutrophils) start to clean the area.
- Proliferation Phase: Fibroblasts produce collagen to fill the gap and new blood vessels grow.
- Maturation Phase: Collagen fibers re-organize, and the wound continues to strengthen.

First Line of Defense: Surface Membrane Barriers

The first line of defense is the physical barriers of our body and include the skin, mucous membranes, cilia, stomach acid, and normal microbiota.
These barriers prevent microorganisms from entering the body.
The normal microbiota can also prevent pathogens from colonizing the surfaces by competing for nutrients and space.

Second Line of Defense: Specific and Non-Specific Defenses

The second line of defense is a non-specific defense mechanism that uses a number of components that attack pathogens.
Specific cells, chemicals, and processes comprise this defense.
Phagocytes are white blood cells that engulf and destroy pathogens.
- Neutrophils are the most abundant white blood cell, and are usually the first responders to an infection.
- Macrophages are larger phagocytes that arrive a bit slower, but can engulf more pathogens.
Natural Killer (NK) Cells are cytotoxic lymphocytes that kill virus-infected cells and cancer cells.
Interferons are proteins produced by virus-infected cells that warn other cells of the infection and help them prepare to defend themselves.
The Complement System is composed of plasma proteins that act in a cascade to help attract leukocytes, promote inflammation, and destroy bacteria.
A fever is another non-specific defense mechanism that raises the body temperature, making it harder for pathogens to survive.

Wound Healing and the Acute Inflammatory Response (AIR)

The AIR is triggered when a wound occurs.
During the AIR, blood vessels dilate and become more permeable, so there is a rapid flow of blood to the area.
This inflammatory response delivers white blood cells and other key immune cells critical for healing.
Inflammation is needed for successful tissue repair, but it must be carefully controlled.
If inflammation is not controlled, it can lead to damage.

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Description

Test your knowledge on the nonspecific defenses of the body, including the roles of skin, phagocytes, and natural killer cells. This quiz covers key features of the inflammatory response and the body's mechanisms to combat infection. Perfect for biology students interested in immunology.