Lymphatic System Flashcards
What are the two main functions of the Lymphatic system?
- Transport (materials which are too large to be carried by the capillaries)
- Facilitate the immune response
- The lymphatic system begins as a blind ended ___ ___ in tissues spaces between cells
- ____ ____ drains into these structures forming _____
- Lymphatic capillaries merge to form larger vessels, called ____ ____, which transport lymph into and out of the _____ _____.
- Lymphatic Capillaries
- Interstitial Fluid — Lymph
- Lymphatic Vessles — Lymphatic Nodes
How does the lymphatic capillary mini-valve let interstitial fluid into the capillary?
- The endothelium of the capillary has mini-valves which overlap, they are forced open due to fluid pressure out of the capillary
- Interstitial fluid drains into the capillary, turning into lymph
- increasing fluid pressure in the lymphatic capillary forces the overlapping endothelium valves to close, meaning lymph cannot escape.
How permeable are the capillary mini-valves?
Highly permeable, they let all substances in.
What are anchoring filaments?
- Filaments which are attached to the endothelium of lymphatic capillaries, anchoring and providing rigidity to the cell
- They are needed as the overlapping valve structure of the endothelial capillary cell means it is not very rigid
What are properties of Lymphatic (collecting) vessels?
- Lymphatic Valves (to help build pressure to move lymph up the body)
- Large lumen (to accomodate the valves)
- Thin walls (they have the three tunics though, Tunica Intima, Tunica Media, Tunica Externa)
What are the main functions of lymph nodes?
- Destruction - foreign substances and cell debris
- Activates Immune response
What are the names of the defence cells within the lymph nodes?
- Macrophages - helps with destruction
- Lymphocytes - helps with activating immune response
How many lymph nodes does lymph travel through before reaching the heart?
Approximately 8-10
On average how many lymph nodes does a human have?
About 100
How much lymph is returned to the blood in a day?
3 Litres
what regions of the body does the Right Lymphatic Duct drain?
Head, right arm, and right thoracic region
What region of the body does the left lymphatic (or thoracic) duct drain?
Rest of the body
How does lymph get into the blood supply?
Through the subclavian veins which form together to form the superior vena cava
What is the passage of fluid from the arteries?
- Arteries (blood)
- Arterioles (blood)
- Blood capillaries (blood)
- Interstitial spaces (interstitial fluid)
- Lymphatic capillaries (lymph)
- lymphatic vessels (lymph)
- lymphatic trunk (lymph)
- lymphatic duct (lymph)
- subclavian veins (blood)
- Superior vena cava (blood)
- Heart (blood)
What are the primary lymphatic organs and tissues?
- Thymus
- Red Bone Marrow
What are the secondary lymphatic organs and tissues?
- Tonsils
- Spleen
- Peyers Patches
- Appendix
What are the two defense systems of the body?
- Innate (nonspecific) defense mechanisms
- Adaptive (specific) defense mechanisms
What is the first line of defense?
- Innate nonspecific
- Skin
- Mucous membranes
- Secretions of skin and mucous membranes
What is the second line of defense?
- Innate nonspecific defense
- Phagocytic cells
- Natural killer cells
- Antimicrobial proteins
- Inflammatory response
What is the third line of defense?
- Adaptive specific defense
- Lymphocytes
- Macrophages and other antigen-presenting cells
- Antibodies
What is an antigen?
Any substance capable of provoking an immune response
What are self-antigens?
Specific surface cell proteins
Antigens are essentially self-identifiers, all cells have them so our body can recognise they are friendly cells
Where do the defence cells in the lymph nodes (Macrophages, Lymphocytes) originate from?
Haemocytoblasts/Haematopoetic Stem Cells in the Red Bone Marrow
What are the function and properties of Macrophages?
- Arise from monocytes (in the red bone marrow)
- Widely distributed in lymphoid organs
- Take part in:
- Phagocytosis (engulfing)
- Antigen-presenting
Immature Lymphocytes are produced_________
B Cells become immunocompetent in the _________
T Cells become immunocompetent in the _________
- Red Bone Marrow
- Red Bone Marrow
- Thymus
Where do T and B Cells go once they become mature?
They circulate in the blood and lymph, seeking out pathogens
How and where do T and B cells become mature?
Once they become immunocompetent they go to the lymph nodes, where they mature and develop MEMORY
Why do mature lymphocytes (T and B cells) circulate in the blood and lymph?
To detect and destroy pathogens before they reach the lymph node
What are Antibodies?
Soluble proteins secreted by a specific type of B cell known as a PLASMA CELL
What are antibodies also known as?
Immunoglobins
Antibodies are capable of binding to a specific ______
Antigen
Which cell produces antibodies?
Plasma Cells (which are formed from B cells)
What is the role of Helper T Cells?
- Detect antigen-presenting macrophage cells
- Activate B cells to turn into plasma cells
- Activate Cytotoxic T cells
Which lymphocyte functions in the antibody-mediated immune response?
B-cells
Which lymphocyte functions in the cell-mediated immune response?
T-cells
What do Cytotoxic T cells do?
- they kill pathogens or antigen-infected cells
- Does this by releasing a cytokin called PERFORIN
What type of response are memory lymphocyte cells responsible for?
Secondary response
What are regulatory T cells and why are they necessary?
- They release cytokins which decrease the immune and inflammatory response
- They are necessary as the immune response is a positive feedback system
What are the two types of acquired immunity?
- Naturally Acquired
- Artifically Acquired
What are the two types of Naturally Acquired Immunity?
- Active - via infection - come into contact with pathogen and body forms antibodies - LONG LIVED IMMUNITY
- Antibodies are passed over from mother to fetus via placenta, or infant in breast milk - SHORT LIVED IMMUNITY
What are the two types of Artificially Acquired Immunity?
- Active - Vaccine - person given dead or attenuated pathogens, body forms antibodies - LONG LIVED IMMUNITY
- Passive - injection of immune serum (antibodies from someone who has developed immunity given to someone else) - SHORT LIVED IMMUNITY
