Host Defense Mechanisms Overview

Play an AI-generated podcast conversation about this lesson

What is the primary function of tears?

To produce saliva and vaginal secretions

To wash away pathogens from the urinary tract

To protect the eyes (correct)

To act as a flushing mechanism

Which of the following is NOT considered a chemical barrier in the body's first line of defense?

Sebum

Blood transferrins

Gastric juices

Normal microbiota (correct)

What is the primary function of lysozymes in the body's defenses?

To bind to available iron and starve bacteria

To produce a slightly acidic environment on the skin

To act as a flushing mechanism against pathogens

To break down the cell wall of bacteria (correct)

What is the primary role of blood transferrins in the body's defenses?

To remove available iron, which bacteria need for growth Signup and view all the answers

What is the main reason the skin's pH is slightly acidic?

To produce the chemical factor of sebum, a waxy lipid Signup and view all the answers

Which of the following is considered a biological barrier in the body's first line of defense?

Normal microbiota Signup and view all the answers

What is the primary function of gastric juices in the body's defenses?

To destroy most bacteria, except for those that can tolerate acidity Signup and view all the answers

What is the main function of T cells and B cells?

Play a role in adaptive immunity Signup and view all the answers

Which type of white blood cell is a first responder in the innate immune system?

Neutrophils Signup and view all the answers

What is the first phase of phagocytosis?

Chemotaxis Signup and view all the answers

Which cell type is responsible for engulfing pathogens through phagocytosis?

Phagocytes Signup and view all the answers

What is a phagosome?

Endocytosed vesicle containing the pathogen Signup and view all the answers

Which phase of phagocytosis involves the formation of a phagolysosome?

Digestion Signup and view all the answers

What is the role of opsonization in the immune response?

To coat the surface of something Signup and view all the answers

What is the function of histamine release from mast cells?

To increase blood vessel permeability Signup and view all the answers

What happens when complement proteins bind to mast cells?

Release of histamine Signup and view all the answers

How does the membrane attack complex (MAC) affect pathogens?

It creates holes in the pathogen's cell membrane leading to bursting Signup and view all the answers

What is a strategy used by some microbes to evade the complement system?

Producing capsules to prevent complement protein binding Signup and view all the answers

Which process involves attracting phagocytes to the site of infection?

Inflammation Signup and view all the answers

What is the main outcome of the complement system's cytolysis process?

Pathogens bursting due to holes created in their cell wall Signup and view all the answers

What is the role of the first line of host defense?

To provide physical barriers to prevent pathogens from entering the body Signup and view all the answers

Which of the following is NOT a component of the first line of host defense?

Antibodies Signup and view all the answers

What is the primary function of the keratin protein in the top layer of intact skin?

To reinforce and protect the underlying layers of skin Signup and view all the answers

How does the ciliary escalator contribute to the first line of host defense?

It moves mucus and trapped pathogens towards the throat for removal Signup and view all the answers

What is the primary role of the lacrimal apparatus in the first line of host defense?

To flush away pathogens from the eye Signup and view all the answers

Which of the following statements about intact skin is TRUE?

Intact skin has a continuous layering of closely packed epithelial cells Signup and view all the answers

What is the purpose of the mucus secreted by the mucous membranes?

To trap pathogens and facilitate their removal from the body Signup and view all the answers

What are complement proteins unable to do easily?

Bind to bacterial cells Signup and view all the answers

What prevents the formation of the membrane attack complex (MAC)?

Bacterial enzymes Signup and view all the answers

How do bacteria protect themselves against complement proteins?

By inactivating complement proteins Signup and view all the answers

What do interferons (IFNs) interfere with?

Viral infections in animal cells Signup and view all the answers

What type of cells produce interferons (IFNs)?

Animal host cells Signup and view all the answers

What is the primary function of interferons (IFNs)?

To alert neighboring cells of a potential viral infection Signup and view all the answers

How do interferons (IFNs) initiate an antiviral response in uninfected cells?

By binding to cell membrane receptors Signup and view all the answers

What is the first step in the mechanism of action of interferons?

Virus enters animal host cell and multiplies Signup and view all the answers

What do interferons (IFNs) cause uninfected neighboring cells to do?

Heighten their antiviral defenses Signup and view all the answers

What is the final step in the mechanism of action of interferons?

Uninfected cell produces antiviral proteins Signup and view all the answers