Lymphatic System (EXAM 1)

What are 3 important things to remember about 3 erythrocytes (RBC’s)?

* O2/CO2 transport
* Carry hemoglobin
* Anucleated

What are 3 important things to remember about leukocytes (WBC’s)?

* Immune protection
* Don’t carry hemoglobin
* Nucleated

List the different types of leukocytes

* Neutrophils
* Eosinophils
* Basophils
* Monocytes
* Lymphocytes (B cells & T cells)

Neutrophils

* Most abundant WBC
* Anti-bacterial & anti-fungal phagocytes

Eosinophils

* Anti-parasitic phagocytes

Basophils

* Release of histamines
* Decreased heparin during allergic reactions causes increased inflammatory response

Monocytes

* Travel and differentiate into macrophages
* Macrophages are large monocytes

B cells

* Produce antibodies to attack specific foreign invaders

T Cells

* Attack infected body and tumor cells

Describe the structure of lymph fluid (plasma) within the lymphatic circulation

Present in:

* Capillaries


* Trunks
* Ducts
* Vessels

Describe the structure of lymphoid organs and tissues

Present in

* Red bone marrow
* Thymus
* Lymph nodes
* Spleen
* Tonsils

Describe the function of lymph fluid within the lymphatic circulation

* Drain excess ISF from blood capillaries
* Return fluid to the venous circulation
* Maintain body fluids/BV

Describe the function of lymphoid organs and tissues

* Contain lymphocytes and other WBCs
* Detect the presence of foreign invaders/abnormal cells in lymph plasma or blood
* Initiate immune response

What is significant about the primary lymphoid organs and tissues?

* The site where stem cells mature and become fully capable of initiating immune response

Explain the red bone marrow and what it does

* Produces hemopoietic stem cells
* Differentiate into lymphoid stem cells

What 2 cells stay in the RBM to fully mature?

* B cells
* NK cells

Where do pre-T cells go to mature?

* Thymus

What happens in the Thymus?

* Location where pre-T cells fully mature
* Either into Tc cells or Th cells

What is the role of the secondary lymphoid organs and tissues?

* Location where lymphocytes activate immune response
* Help detect foreign invaders

What are the 3 secondary lymphoid organs?

* Lymph nodes - filter lymph
* Spleen - Filter blood
* Tonsils - Monitor resp/digest. systems for inhaled/ingested materials

Where are the tonsils located?

Within the nasopharynx

What are the 3 different tonsils?

* Pharyngeal tonsil (above/behind oral cavity)
* Palatine tonsil (Back of mouth)
* Lingual tonsil (Back of tongue)

Explain the location of the spleen

* Located in upper left abdomen
* Deep to diaphragm
* Lateral to stomach and pancreas

What does the spleen contain?

* Splenic artery and vein
* Branches from abdominal aorta
* Drains into HPV

What are the functions of the spleen?

* B, T cells, macrophages filter blood
* Remove old blood cells and platelets
* Produces, stores blood and platelets
* Clean blood exits splenic vein

What is the outer capsule and trabeculae of a lymph node made of?

* Dense IR CT

What is the lymph drainage from right breast to venous circulation?

* Lymph capillaries - Lymph vessels - mammary lymph nodes - efferent lymph vessels - bronchomediastinal trunk - R. lymph duct - R. brachiocephalic vein

Quickly describe the innate immune system

* Immune response present @ birth
* Phagocytes consume pathogens
* Neutrophils, basophils, eosinophils, macrophages
* NK cells destroy infected/damaged cells

Quickly describe the adaptive immune response

* Immune system developed over time
* Lymphocytes must recognize pathogens to illicit response
* T cells and B cells do this differently
* Produce memory cells

What are the 3 innate first line defenses?

* Physical barrier
* Chemical Barriers
* Reflexes and processes

What are the 2 main defenses used by the physical barrier?

* Skin
* Mucous membranes

What are some chemicals used in the first line defenses?

* Saliva
* Gastric juices
* Sweat and oil
* etc.

What are some reflexes and processes used in the first line of defense?

* Coughing/sneezing
* Urinating/defecating
* Vomiting

What are the 2 second line defenses of the innate immune system?

* Phagocytosis
* Cytolysis

What 3 leukocytes are active during phagocytosis?

* Neutrophils
* Monocytes
* “resident” macrophages

What is the role of neutrophils during phagocytosis?

* Released in bloodstream and travel wherever needed

What is the role of monocytes during phagocytosis?

* Released in bloodstream and travel wherever needed
* Not active cells
* Turn into “wandering” macrophages

What is the role of “resident” macrophages during phagocytosis?

* Live in specific tissues
* Guard + protect in prep for microbes

What is phagocytosis?

* Ingestion of microbe or cellular debris

What is cytolysis?

* NK cells destroy infected/damaged cells

What are the 4 steps of cytolysis?

1. Infected cells bind NK cells
2. NK cells release proteins (perfarins) to embed host cell
3. ECF flows through host cell
4. Host bursts

What are the cardinal signs of inflammation?

* Pain
* Redness
* Immobility
* Swelling
* Heat
* (PRISH)

What are the 3 stages of inflammation?

1. Vasodilation of arterioles
2. Emigration of Phagocytes to affected area
3. Tissue repair

Explain the vasodilation of arterioles during inflammation

* Increase in permeability of capillaries
* Increased BF
* due to release of histamine from WBCs/damaged cell

Explain the emigration of phagocytes during inflammation

* Neutrophils, macrophages
* move from blood to ISF
* dependent on chemotaxis

Explain how tissue is repaired during inflammation

* Blood clotting
* Scar formation
* Epithelium regenerates
* Dependent on age, blood supply, nutrition

What are the 2 different types of the adaptive immune system?

* Cell mediated
* Antibody mediated

What antigens are recognized by the cell-mediated response?

* Abnormal cell
* Infected cell
* Cancerous/damaged cells

What cells are involved in a cell-mediated response?

* APCs
* Th cells
* Tc cells
* Destroy Ags

What antigens are recognized by the antibody-mediated response?

* Viruses
* Bacteria
* etc

Where is the antibody-mediated response most active?

* Blood
* Lymph

What cells are present in the antibody-mediated response?

* APCs
* B cells
* Turn into plasmocytes
* Secrete antibodies that destroy Ags
* Macrophages
* Th cells

What are MHCs?

* Self antigens
* Embedded into membranes of all cells (except RBCs)

What are the 2 classes of MHCs?

* MHC I
* All body cells (except RBCs)
* MHC II
* APCs

Explain the presentation and recognition of exogenous Ags

* Located within blood or lymph
* Viruses, bacteria, etc
* Brought into APCs by phagocytosis
* Digested into fragments
* Bind to MHC II, then presented

Explain the presentation and recognition of endogenous Ags

* Within cells
* Digested into fragments
* Binds to MHC I, then presented

What does MHC stand for?

* Major histocompatibility complexes

After Th cells bind to MHC II, what protein strengthens their binding?

CD4

What cytokines are released after the APC binding to MHC II is complete?

* Tumor Necrosis Factor Alpha
* Interleukin-1

What cytokine is released by active Tc cells?

* Interleukin-2

After Tc cells bind to MHC I, what protein strengthens their binding?

CD8

What cytokine being released by active Th cells activates costimulation?

* Interleukin-2

What function creates pools of active and memory Tc cells?

* Clonal selection

What do active Tc cells do?

* Leave lymph organ/tissue to circulate within the body
* Attack cells with Ag

What do memory Tc cells do?

* Wait for next exposure to Ag
* Immune system is much better prepared for subsequent infection