Immunology

Question 1

What is innate immunity?

Answer 1

The defenses that are present at birth. Does not involve specific recognition of a microbe and lacks a memory response. Memory provides a more rapid and stronger immune reaction to microbes that invade at a later date.

Question 2

What are the first line defenses?

Answer 2

Skin and mucous membranes

Question 3

What are the second line defenses?

Answer 3

Natural killer cells, phagocytes, inflammation, fever, antimicrobial substances.

Question 4

What is adaptive immunity?

Answer 4

It is based on a specific response to a specific microbe once it has breached the innate mechanisms of defense. It is slower than innate mechanisms and characterized by its specificity and memory.

Question 5

What are physical factors of innate immunity?

Answer 5

Barriers that prevent entry or remove microbes from the body’s surface.

Question 6

What are chemical factors of innate immunity?

Answer 6

Substances made by the body that inhibit or destroy microbial growth.

Question 7

What makes up intact skin?

Answer 7

Epidermis and dermis

Question 8

What is the epidermis?

Answer 8

The outer thinner component that is in direct contact with the external environment. Outer most layer contains a protective protein called keratin.

Question 9

What are mucous membranes?

Answer 9

Consists of an epithelial layer and an underlying connective tissue layer. Lines the entire gastrointestinal, respiratory and genitourinary tracts. Secretes mucous (thick glycoprotein produced by goblet cells).

Question 10

What are some examples of physical factors of first line defense?

Answer 10

Epiglottis covers the larynx during swallowing, urethra is cleansed by the flow of urine, peristalsis, defecation and vomiting expel microbes.

Question 11

What is the lacrimal apparatus?

Answer 11

A group of structures that manufactures and drains away tears. Helps to keep microorganisms from settling on the surface of the eye.

Question 12

How does saliva provide a defense against microorganisms?

Answer 12

Helps to dilute the numbers of microorganisms and washes them from the surface of the teeth.

Question 13

How do sebaceous glands provide a chemical defense against microorganisms?

Answer 13

Secretes sebum. One component of sebum is unsaturated fatty acids, which inhibits the growth of certain pathogenic bacteria and fungi. The low pH of skin (between 3 and 5) is caused in part by the secretion of fatty acids and lactic acids.

Question 14

How does perspiration defend against microorganisms?

Answer 14

Contains the enzyme lysozyme that targets and breaks the cell wall of gram positive bacteria.

Question 15

How does saliva protect the body from microorganisms?

Answer 15

Contains lysozye, urea and uric acids (contributes to the control of microbial growth). Has a pH of 6.55-6.85 which inhibits some microbes and contains immunoglobulin A (antibody).

Question 16

How does gastric juice protect the body from microorganisms?

Answer 16

the low pH (1.2-3) is sufficient to destroy bacteria and most bacterial toxins. Also contains hydrochloric acid, enzymes and mucus.

Question 17

How do vaginal secretions protect the body from microorganisms?

Answer 17

Glycogen produced by vaginal epithelial cells is catabolized into lactic acid. The resulting pH of 3-5 inhibits the growth of many microbes.

Question 18

What are macrophages?

Answer 18

Phagocytes that come from monocytes that are capable of leaving circulation and enter into tissues.

Question 19

How can a macrophage respond to a pathogen?

Answer 19

Engulf the pathogen and destroy it with lysosomal enzymes, bind to or remove a pathogen from the interstitial fluid, destroy target by releasing toxic chemicals such as tumor necrosis factor, nitric oxide or hydrogen peroxide.

Question 20

What are free macrophages?

Answer 20

Macrophages that can wander throughout the tissue spaces in search of cellular debris of foreign invaders.

Question 21

What are fixed macrophages?

Answer 21

Also called histiocytes. Permanent residents of specific tissues and organs. Microglia are macrophages in the CNS, kupffer cells are in the liver and langerhans cells are in the skin

Question 22

What are neutrophils?

Answer 22

The most abundant white blood cell. Usually the first to come to a site of infection. Become phagocytic on encountering infectious material in the tissues.

Question 23

What are eosiniphils?

Answer 23

A white blood cell that is important in defending the body against parasitic infections. Discharges cytoplasmic granules over destructive content found in body.

Question 24

What are the mechanisms of phagocytosis?

Answer 24

Cytoplasmic extensions bind to the particle and then pull it inside, enclosed within a membrane-lined vacuole called a phagosome. The phagosome fuses with lysosome to form a phagolysosome.

Question 25

How can adherence be made more probably and efficient?

Answer 25

Complement proteins or antibodies can coat foreign particles making them easier for phagocytes to adhere to. This process is called opsonization.

Question 26

What is a respiratory burst?

Answer 26

An event that liberates large amounts of free radicals such as nitric oxide and superoxide, which have powerful cell-killing abilities.

Question 27

What are natural killer cells?

Answer 27

Cells that are responsible for recognizing and destroying abnormal cells when they appear in peripheral tissues.

Question 28

What is immunological surveillance?

Answer 28

The constant monitoring of normal tissue by NK cells.

Question 29

How do NK cells activate?

Answer 29

NK cells recognize unusual components in call plasma membranes. This activates the NK cell which adheres to the target cell. The golgi appartus moves until it is pointed directly at the abnormal cell. Performins are released at the cell surface by exocytosis and diffuse across the gap between the NK cell and target cell. The performins interact with one another and create a network of pores in the membrane. These pores are large enough to move intracellular materials through it and the target cell disintegrates.

Question 30

What is immunological escape?

Answer 30

The process of avoiding detection or neutralizing the NK cells.

Question 31

What are interferons?

Answer 31

Small proteins released by the activated lymphocytes, macrophages and tissue cells infected with a virus. When the protein comes in contact with a normal cell, the interferon binds to surface receptors and triggers the production of antiviral proteins.

Question 32

What are the three types of interferons?

Answer 32

Alpha interferons (produced by several types of leukocytes and attracts NK cells), beta interferons (secreted by gibrocytes. Slows inflammation in a damaged area) and gamma interferons (secreted by T cells and NK cells. Stimulates macrophage activity).

Question 33

What are cytokines?

Answer 33

Chemical messengers release by tissue cells to coordinate local activities. Ex) Cytokines.