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Transcript of Lymphatic System
Nonspecific Defenses Scenario Every spring, Paula C. knows what’s coming. The flowers bloom. The wind blows. And she sniffles. Itching sneezing, rubbing watery eyes with a tissue... What is wrong with her? Ironically, Paula’s agony stems from her immune system’s admirable capability to fight off pathogens. Allergies are a hyperreactive response to dust and pollen. Sensing these foreign substances, antibodies kick into gear, replicating like crazy. The well-meaning
molecules bind to certain proteins and release a flood of chemicals, such as histamines, that lead to allergy symptoms. Have you seen Cash Cab before? So yeah...here are the official rules Two teams (Team A and B)
Random Question (5pt for each)
Take turns to answer Basic Information Close system and closely associated with the cardiovascular system
Carry clear fluid called lymph
One way system have valves to prevent backward flow Question! (Team A)
What do we call the fluid in lymphatic vessels? Question! (Team B)
What kind of system is lymphatic system? (Open/Close) A: Lymph A: Close system Four Main Functions Take up excess tissue fluid
Digested fats are absorbed and then transported from the villi in the small intestine to the bloodstream via the lymph vessels.
Return plasma proteins to the bloodstream
Help defend the body against disease, cancer, and debris Lymphatic Organs Spleen
Red Bone marrow
Peyer's Patches Spleen
located in the upper left region
5x3x2" (fist size)
Thin, so infection or physical activity may cause it to burst Red bone marrow
have stem cells that are capable of producing blood cells. Thymus Gland (child>adult)
produce thymic hormones thymosin that stimulates the maturation of lymphocytes in other lymphatic organs
Immune T lymphocytes or T-cells migrate from the bone marrow through the bloodstream to the thymus, where they mature. (only 5% leave thymus) Peyer's Patches
located in the intestinal wall and appendix
Peyer's Patches interact with antigens found in the intestine to produce antibodies Question! (Team A)
Name 1 funtion of the lymphatic system. Question! (Team B)
Where are your tonsils located? A:
Takes up excess tissue fluid
Receive lipoproteins at the interval villi and transport them to the bloodstream
Help defend the body against diseasee, cancer, and debris A: Immune Response What is lymphatic System? The immune response is how your body recognizes and defends itself against bacteria, viruses, and substances that appear foreign and harmful to the body. Remember the ELISA test? Question! (Bonus +20pt)
How does an ELISA test work? The ELISA test is similar to part of our body's immune responses. (specific defenses) Specific Defenses NonSpecific Defenses Question! (Bonus +5pt)
Give an example of immune response (hint: pollen season is here!) Question! (Bonus +10) Nonspecific defenses are directed against foreign substances
The first line of defense is the barrier against entry into the body
If the foreign agent succeeds in passing the barrier and entering the body, a second line of defense come into play. Basics Nonspecific Defenses & Specific Defenses Basics Opposite to nonspecific defenses, the specific defenses are programmed to be selective
Memory - once the system has been exposed, your body will remember that agent and launch a quicker attack if it enters again
When nonspecific defenses have failed to prevent an infection, specific defenses come into play.
Specific defenses respond to antigens. Anatomical Barriers Chemical Factors
Fatty acids in sweets help to inhibit the growth of bacteria
Lysozyme and phospholipase (found in tears, saliva and nasal secretions) breakdown the cell wall of bacteria and destabilize bacteria mambranes
Anatomical Barriers Biological Factors
The flora of the skin and the gastrointestinal tract prevents the colonization of pathogenic bacteria as it secrets toxic substances or by competing with the pathogenic bacteria for nutrients or attachment on the cell surfaces
Is a major humeral non-specific defense mechanism.
Once this is activated it can lead to increased vascular permeability, recruitment of phagocytic cells, and lysis and opsonization of bacteria
Tissue macrophages and newly recruited monocytes function in phagocytosis and intracellular killing of microorganisms
Capable of extracellular killing of infected or altered self-target cells
Contribute to tissue repair and act as antigen-presenting cells Natural Killer
These cells can nonspecifically kill virus infected and tumor cells
Very important in nonspecific immunity to viral infections and tumor surveillance
Part of the inflamatory response is the recruitment of polymorphonuclear eosinophiles and macrophages to the site of the infection.
These cells are the main line of defense in the non-specic immune system. Questions (Nonspecific Defenses) Team A!
Give an example of human's first line defense. Team B!
What are natural killer cells? Team A!
briefly describe the action of the complement system against a bacterium. Team B!
Give an example of biological first line defense. Team A!
Give an example of chemical first line defenses. Team B!
What are macrophages? Mechanical Factors:
Example: Skin- it acts as the first line of defense against invading organisms
The epithelial surfaces create a physical barrier that is impermeable to most infectious agents.
Tears and saliva help to prevent infection in the eyes and mouth
Mucus in the respiratory and gastrointestinal tract help to protect the lungs and digestive system from infection Anatomical Barriers Once infectious agents have penetrated tissues, another non-specific defense mechanism comes into play: acute inflammation. Secretory molecules play an important role in inflammation, which is characterized by edema and the recruitment of phagocytes cells. cytoplasmic extension from macrophages bacteria Because we do not ordinarily become immune to our own normal cell, it is said that the immune system is able to distinguish "self" from "nonself."
lymphocytes are capable of recognizing an antigen because they have antigen receptors (specific; receptor and antigen fit together like lock and key)
Immunity is primarily the result of the action of the B lymphocytes and the T lymphocytes. B lymphocytes (B cells)
mature in the bone marrow
give rise to plasma cells, which produce antibodies
T lymphocytes (T cells)
mature in the thymus gland
do not produce antibodies.
T cells directly attack cells that bear nonself proteins
A plasma cell is a mature B cell that mass-produces antibodies against SPECIFIC antigen Clonal selection theory It states that the antigen selects which lymphocytes will undergo clonal expansion and produce more lymphocytes bearing the same type of antigen receptor.
Some of the clone become memory cells
So if the same antigen enters the system again, memory cells quickly divide and give rise to more lymphocytes capable of quickly producing antibodies.
a process of programmed cell death (PCD) B cells cytotoxic T cells Antibody-mediated immunity HLA - human leukocyte-associated antigens Questions! (specific defenses) Team A!
Give one characteristic of B cells. Team B!
Give one characteristic of T cells. Team A!
What does apoptosis mean? Team B!
What is the function of memory cells? Video questions! Team A!
What are those Y-shape thingy? Team B!
What type of immunity is this? Last Question (Bonus +5) - Think and answer.
Will cytotoxic T cells attack cancer cells? YES!! Cancer cell Cell-mediated immunity