Body Defenses: Nonspecific and Immune System

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Questions and Answers

Which of the following is NOT a characteristic of the nonspecific (innate) defense system?

It responds immediately to foreign substances.

It adapts to specific pathogens over time. (correct)

It includes chemical and cellular defenses like inflammation and phagocytes.

It involves external body membranes like skin and mucous membranes.

What is the primary function of the acidic skin secretions (acid mantle) in the nonspecific defense system?

To provide a physical barrier against foreign substances.

To increase the permeability of the skin to foreign substances.

To inhibit the growth of harmful bacteria. (correct)

To promote the growth of beneficial bacteria.

Which of the following is NOT a mechanism by which the mucous membranes contribute to the nonspecific defense system?

Providing a physical barrier.

Producing antibodies to neutralize specific pathogens. (correct)

Secreting lysozyme to kill bacteria.

Trapping bacteria with mucus.

What is the role of opsonization in phagocytosis?

Opsonization coats the foreign substance, making it easier for phagocytes to adhere. Signup and view all the answers

Which of the following is a characteristic of wandering macrophages?

They can move freely throughout the body. Signup and view all the answers

Which of the following statements accurately describes the process of respiratory burst?

A process where phagocytes release toxic chemicals that kill the foreign substance. Signup and view all the answers

What is the primary difference between nonspecific (innate) and specific (adaptive) defense systems?

The nonspecific system is always active, while the specific system requires prior exposure to a pathogen. Signup and view all the answers

Which of the following is NOT considered a component of the nonspecific (innate) defense system?

Antibodies. Signup and view all the answers

What is the primary role of opsonization in the immune response?

Coating foreign substances to enhance adhesion Signup and view all the answers

Which statement accurately describes Natural Killer (NK) cells?

They lyse cancer cells and virus-infected cells before the immune system is activated. Signup and view all the answers

What is the main function of inflammation in the body?

To prevent the spread of damaging agents and promote healing. Signup and view all the answers

What is the immediate effect of increased permeability of capillaries during an inflammatory response?

More fluid entering interstitial spaces causing swelling Signup and view all the answers

How does the inflammatory response contribute to pain sensation?

Due to pressure from excess interstitial fluid on nearby nerves Signup and view all the answers

Which role do inflammatory chemicals play during an injury?

They induce vasodilation and increase capillary permeability. Signup and view all the answers

What is a notable characteristic of NK cells in comparison to phagocytes?

They release perforins and target cell membranes. Signup and view all the answers

What is the significance of clotting proteins in the context of inflammation?

They create a mesh to isolate the injury and limit harmful spread. Signup and view all the answers

Study Notes

Defense Systems

Nonspecific (innate) defense system: Immediate response to protect the body from foreign substances; always ready.
Specific (adaptive) defense system (Immune System): Targets foreign substances with delayed response; key cells include macrophages and lymphocytes.

Nonspecific Defense System

Surface Membrane Barriers

Skin: Epidermis with keratin acts as a physical barrier; resistant to weak acids/bases and bacterial enzymes/toxins.
Acid mantle: Acidic skin secretions inhibit bacterial growth.
Mucous membranes: Provide physical barriers and chemical secretions to trap pathogens.
- Stomach: HCL and protein-digesting enzymes aid in pathogen destruction.
- Vagina: Acidic secretions protect against infections.
- Saliva and Lacrimal fluid: Contain lysozyme, an antibacterial enzyme.
- Mucus: Traps bacteria in respiratory and digestive pathways.

Nonspecific Cellular and Chemical Defenses

Species Resistance: Certain species have innate immunity against specific pathogens.
Phagocytes: Main types include macrophages (derived from monocytes).
- Can be wandering or fixed in tissues.
- Function through phagocytosis and respiratory bursts.
- Require adhesion to foreign substances; opsonization enhances adhesion by coating microbes with proteins.
Natural Killer (NK) Cells: Patrol blood and lymph for threats.
- Lyse and kill cancer cells and virus-infected cells before full immune activation.
- Not phagocytic; attack through membrane disruption and release of perforins.

Inflammation

Triggered by tissue injury, infections, or damage from various sources.
Purpose:
- Prevents and limits the spread of damaging agents.
- Disposes of cellular debris and pathogens.
- Initiates repair processes.
Inflammatory chemicals released by damaged cells lead to:
- Vasodilation: Increased blood flow to the area causes heat and redness.
- Increased capillary permeability: Permits fluid entry into interstitial spaces; leads to edema and pain from pressure on nerves.
Importance of Inflammation:
- Dilutes harmful substances.
- Brings oxygen and nutrients essential for repair.
- Facilitates entry of clotting proteins to isolate and protect the injury site.

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Description

This quiz covers the nonspecific and specific defense systems of the body, including external body membranes, chemical and cellular defenses, and the immune system.