Chapter 12 Learning Objectives

Question 1

1st Line of Defense

Answer 1

Innate (born with it), nonspecific: surface protection composed of anatomical and physiological barriers that keep microbes from penetrating sterile body compartments.

Question 2

1st Line of Defense examples

Answer 2

• Physical Barriers (skin)
• Microbiota Barrier
• Chemical barriers (enzymes in tears, lysosomes)

Question 3

2nd Line of Defense

Answer 3

Innate nonspecific: Cellular and chemical system comes immediately into play if infectious agents make it past the surface defenses

Question 4

2nd Line of Defense examples

Answer 4

• Phagocytosis (dendritic cells, macrophage, neutrophils)
• Inflammation
• Fever (pyrexia)
• Antimicrobial products

Question 5

3rd Line of Defense

Answer 5

Adaptive (develops throughout life), specific defenses: specific host defenses that must be developed uniquely for each microbe through the action of specialized white blood cells.

Question 6

3rd Line of Defense examples

Answer 6

• B cells and T cells

Question 7

Define Marker or Antigen

Answer 7

A marker (aka antigen) is a molecule that identifies self from non-self. Recognizes whether something belongs in the body or not. Found on the surface of cells, viruses, and bacteria.

Question 8

Markers importance in second and third line defenses.

Answer 8

Second-line defense: the body’s quick response to invaders. White blood cells, like macrophages, look for foreign markers and attack anything that doesn’t belong (such as bacteria and viruses). PRRs (Pattern Recognition Receptors) are important as they recognize PAMPs.

Third Line of Defense: the specific and memory-based part of the immune system. Special cells, like B cells and T cells, learn to recognize the unique markers of harmful invaders. If the same invader returns, the immune system remembers it and responds faster and stronger next time.

Question 9

Name the body systems that participate in immunity

Answer 9

Lymphatic system (primary and secondary) and circulatory system

Question 10

Three kinds of cells that function as phagocytes.

Answer 10

Dendritic cells, Macrophages, and Neutrophils

Question 11

Connect the mononuclear phagocyte system to innate immunity

Answer 11

MPS includes specialized white blood cells called monocytes and macrophages that help detect, engulf, and destroy harmful invaders like bacteria, viruses, and dead cells. These cells are found in the blood, thymus, lymph nodes, spleen, liver, and lymphoid tissues

Question 12

Cytokines

Answer 12

• cytokines are like signals that make sure the immune system knows when and where to act. regulate, stimulate, suppress, and otherwise control many aspects of cell development, inflammation, and immunity
• Produced by monocytes, macrophages, lymphocytes, fibroblasts, mast cells, platelets, and endothelial cells

Question 13

Pro-inflammatory Cytokine

Answer 13

Interleukin-1 (IL-1)

Question 14

Anti-inflammatory Cytokine

Answer 14

Interleukin-10 (IL-10)

Question 15

Four body systems that participate in the first line of defense.

Answer 15

Integumentary System (skin), Respiratory System (mucous membrane), Digestive System (mucous membrane), Urinary System

Question 16

Two examples of how the normal microbiota contributes to the first line of defense.

Answer 16

Normal microbiota serve as a first line of defense against infection and disease by competing with pathogens for resources and binding sites.

Question 17

1st step of inflammation.

Answer 17

Injury and Immediate Reactions

• following an injury, early changes occur in the vasculature (arterioles, capillaries, venules) in the vicinity of the damaged tissue

Question 18

2nd step of inflammation.

Answer 18

Vascular Reactions

• vicinity dilate (flush irritants away from area), then constrict (attempt to stem blood leaving vessels), and then dilate again (bring helpful blood components to site)
• vasodilation: increase flow of blood, facilitates influx of immune components and causes redness and warmth

Question 19

3rd step of inflammation.

Answer 19

Edema and Pus formation

• accumulation of the exudate gives rise to local swelling and hardness called edema
• pus composed of mainly wbc and debris generated by phagocytosis

Question 20

4th step of inflammation

Answer 20

Resolution and Scar Formation

• repair results in either complete resolution of tissue or in formation of scar tissue
• macrophages leave blood vessels (diapedesis)
• stem cells in area divide and repopulate the damaged site with new cells

Question 21

two types of lab testing used to assess inflammation.

Answer 21

CRP (C Reactive Protein): Most effective, follow inflammation to a T

ESR (Erythrocyte Sedimentation Rate): measures the amount of blood that drops (sedimentation)

Question 22

Mechanism of fever

Answer 22

Fever (Pyrexia) is caused by Pyrogens. Can be exogenous (from viruses, bacteria, protozoa, fungi, endotoxin-LPS, etc) or endogenous (released from monocytes, neutrophils and macrophages. Involves cytokine IL-1.

Question 23

How does fever help defend the body.

Answer 23

• Inhibits multiplication of temp. sensitive microorganisms.
• Interferes with nutrition of bacteria, reduces iron availability
• increases metabolism and stimulates immune reactions
• Speeds up hematopoiesis, phagocytosis, and specific immune reactions

Question 24

Four types of antimicrobial host-derived products

Answer 24

• interferon
• complement
• antimicrobial peptides
• restriction factors

Question 25

four functions of complement as presented in lecture.

Answer 25

- Opsonization (C3B) Complement proteins coat pathogens (such as bacteria or viruses), making it easier for phagocytic cells (like macrophages and neutrophils) to recognize, engulf, and destroy them. This process is called opsonization, and it enhances the ability of the immune system to eliminate invaders. C3B ATTRACTS PHAGOCYTES.

Question 26

four functions of complement as presented in lecture.

Answer 26

- Chemokines (C5A) small signaling proteins that direct the movement of immune cells to specific sites in the body. They are crucial for immune cell trafficking during immune responses and inflammation.

Question 27

four functions of complement as presented in lecture.

Answer 27

- Anaphylatoxin (C3A) Think anaphylactic shock, VERY serious. small molecules that are produced as part of the complement system (specifically from the activation of complement proteins C3 and C5). They have a powerful role in inflammation and immune cell recruitment. The main anaphylatoxins is C3A.

Question 28

Four functions of complement as presented in lecture.

Answer 28

- Pokes holes One of the key roles of the complement system in immune defense is to poke holes in the membranes of pathogens (like bacteria) or infected host cells. This happens through the formation of the Membrane Attack Complex (MAC). Another immune response that involves poking holes is the action of cytotoxic T cells (also called killer T cells). Natural Killer (NK) cells also participate in poking holes in infected or cancerous cells.