Written response Lymphatic and Immune System

What makes up the lymphatic system? What are the functions of lymphatic vessels and lymphoid organs and tissues?

-lymphatic vessels, lymph, lymph nodes,

lymphatic vessels return fluid to blood cells and lymphatic organs/tissues act in immune system

What type of tissue is lymphoid tissue, and how does it function?

Reticular connective tissue (provides anatomical basis for body’s defense also “home” of the white blood cells)

Where are lymph nodes located and what is their function?

They are in Cervical, Axillary, and Inguinal regions

Acts as filters to remove and destroy microorganisms and other debris for the lymph before it is transported back to the bloodstream

1.      For any ONE of these lymphoid organs and tissues, summarize the: major functions; presence of capsule, cortex, and medulla; presence of lymphoid follicles; type of stroma; other special features: (a) Lymph nodes; (b) Spleen; (c) Tonsils (MALT); (d) Peyer’s patches (MALT; (e)Appendix (MALT); (f) Thymus

Appendix

prevent pathogens from penetrating mucous membrane site for lymphocyte activation and proliferation, no capsule/medulla, presence of lymphoid follicles, reticular connective tissue, diffuse lymphatic tissue addition to follicles

What structures act as the first line of defense to keep invaders out of the body? Provide examples how chemicals act in this line of defense

First line of defense: Surface barriers, skin and mucous membranes represent a physical barrier to most microorganisms and their enzymes and toxins

Chemicals include acid to inhibit bacterial growth, enzymes (lysozyme) to destroy microorganisms, mucin to create sticky traps, defensins as antimicrobial peptides, and other specialized regional secretions

What acts as the body’s second line of defense? What 5 components are in this second line?

-        Phagocytes: adhere to a pathogen before it can engulf it. Neutrophils and Macrophages: destroy pathogens by engulfing them, acidifying the phagolysosome and digesting the contents with lysosomal enzymes

-        Natural killer cells: able to lyse and kill cancer cells and virally infected cells before the adaptive immune system has been activated, and secrete chemicals that enhance the inflammatory response

-        Inflammation: any time the body tissues are injured by physical trauma, intense heat, irritating chemicals, or infection by viruses, fungi, or bacteria

-        Antimicrobial proteins: enhance the innate defenses by attacking microorganisms directly or by hindering their ability to reproduce

Fever: systemic response to microorganisms

What are the benefits of the inflammatory response?  What occurs during inflammation?

-prevent further damage

-WBCs eat pathogens/debris

-Alert adaptive immune system

-RBCs to set up repair

-heat, redness, pain, and swelling occur during inflammation

What is the purpose of the adaptive immune response?  What are its characteristics?

-recognize and destroy specific antigens (flu virus)

-provide antibodies in body humor

-memorize exposure to same antigen for defense attack

What is an antigen?  Compare and contrast complete and incomplete antigens.

-substances that trigger the body’s adaptive defenses

-complete: have immunogenicity (stimulate proliferation of specific lymphocytes and antibodies) and react with activated lymphocytes and antibodies

-incomplete (Haptens): not capable of stimulating immune response. But if they interact with proteins of the body, they can be recognized as potentially harmful.

Describe the difference in function of plasma cells and of memory B cells that form once B cells are activated

-Plasma cells (majority): release antibodies (slower, less) during primary response

-Memory cells (minority): release more antibodies (faster, more) during secondary response.

Summarize the differences in active and passive humoral immunity, in terms of how they are acquired and how long the protection lasts.

-Active: we make the antibodies, naturally contact with pathogen, artificial vaccine

-Passive: we’re given preformed antibodies (temporary), naturally: breastfeeding, artificial: injection of antibodies

Describe the regions of an antibody.  What are the five classes of antibodies, and how do they differ?

-4 looping peptide chains: Two heavy (H) chains and two light (L) chains (each with constant and variable parts)

-M: complement

-A: body humor

-D: B cell antigen receptor

-G: most common in both responses

-E: inflammation, allergies