Untitled Flashcards Set

Lymph is a clear watery liquid that is formed from interstitial fluid= found between cells

• 90% of interstitial fluid diffuses back into capillaries

• 10% enters the lymphatic vessels

when interstitial fluid enters a lymphatic vessel it is renamed “lymph

• Lymph vessels have “dead ends”= lymph capillaries

• Lymph capillaries are lined with overlapping epithelial cells

• Capillaries open into large lymph vessels 

Lymph moves through the vessel because it is pushed by pressure from surrounding skeletal muscles

• Lymph vessels carry lymph to lymph nodes

• Lymph nodes= capsule of connective tissue

• Trabecule= structure

• Germinal centers are areas of rapid mitosis where immune cells are quickly produced to fight off invaders found in lymph 

• Enters=afferent=slows down

• Exits=efferent=slows down 

Large ducts in the chest= Right lymphatic duct and Thoracic duct

Other lymphoid organs= spleen & thymus= protect the body from infection, DO NOT FILTER

Lymph nodules are different structurally because they are loosely associated tissues and are not surrounded by a caple 

Spleen=upper left abdomen

• White pulp: composed of lymphatic tissues + lymph nodules for filtering blood

• Red pulp: Remove worn out RBC and is reservoir for stored blood

Thymus: endocrine & lymphatic

• T-lymphocytes release thymosin and  are formed in bone marrow and travel to thymus for thymic education

• Thymic education: recognize foreign invaders

• Lymph nodules are associated with mucous membrane because invaders became trapped 

MALTS: mucosa-associated lymphoid tissues

• Can either be scattered or bundled together

Tonlis: Protective ring to trap foreign invaders

Peyer's Patches & Appendix: Filter bacteria from food + restric bacteria to GI tract

Innate: 

• External: Skin oil + sweat decrease bacterial growth 

• External: Mucous membranes: Traps and sweeps pathogens (saliva, tears, gastric juices: contain enzymes)

• Internal: Phagocytes “eat” foreign invaders (neutrophils + macrophages)

• Internal Natural killer cells: Lyse infected or abnormal body cells based on lack of “self” receptors”

• Internal: inflammation: edema (help macrophages), pyrogenic (fever), basophils + mast cells (dilate)

• Internal: complement proteins (work with other defenses by lysing bacteria)

• Internal Interferons: warning signal secreted by virally infected cells

Cytokines: chemical signal used to help cells communicate during an immune response

If non specific defense don't stop the infection the body will create an immune specific response= antigens trigger response

• Specific responses= lymphocytes: produce antibodies to match certain antigen

Functions of acquired immunity

1. Difference between self + non self antigens

2. Recognize a specific antigen among trillions of possible substance

3. Generate a large diversity of antibodies so any possible substance can be recognized 

4. Provide memory of antigens 

Humoral

•  B cells (before)

• Respond to antigens before they infect body cells

Cell mediated

• T cells (after)

• Response that have already been infected with foreign invaders

B lymphocytes

• Recognize a foreign antigen

• Rapidly divide create cloned plasma B cells and memory B cells 

**Memory B cells: long lived and produce a swift and strong response if the same antigen is encountered 

Plasma B cells

1. Neutralize 

2. Immobilized (agglutination)

3. Activate macrophages 

**Active immunity: earned because it is developed by the creation of our won antibodies

**Passive immunity: borrowed because the immunity of other individual is already created

• Natural: contraction of flu virus (active)

• Artificial: Administration of flu vaccine (active)

• Natural: Antibodies passed from mom to baby through breast milk (passive)

• Artificial: Blood serum from an individual with covid antibodies (passive)

B cells:

• Can also act as APC’s

• APC’s: engulf antigen and present policies of antigen to other immune cells

APCS= B cells, macrophages, dendritic cells

• Antigen is presented on a receptor known as MCH-2

• T cells bind to MHC-2 for stronger response 

Cell mediated response

1. APC display foreign antigen to helper T cell=activated

2. Singicing cascade to create more helper T cells & memory T cells

3. Cytokine signals active cytotoxic T cells which bind to infected cells and cause cell death

4. Regulatory T cells: release chemicals to slow the immune response after antigen is destroyed 

secondary infection= Memory T & B cells

Secondary response: Vaccines can mimic fist infection so the next they immediately recognize the antigen