Week 6 - The Lymphatic System Flashcards
Give an overview of the lymphatic system
Comprosed of several structures and organs:
1. Lymphatic tissue
2. Bone marrow
3. Lymph
4. Lymphatic vessels
Protects us against disease
Lymphoid cells respond to: Environmental pathogens, toxins, Abnormal body cells such as cancers.
What are some pathogens that cause disease?
Viruses (Bacteriophage, Simian Virus, Epstein Barr Virus)
Bacteria ( E.coli, S. aureus)
Parasites (Schistosome)
Fungi (Candidiasis)
What are the 4 parts of the lymphatic system?
Lymph (fluid) - Similar to plasma w out plasma proteins
Lymphatic Vessels (lymphatics) - Carry lymph from peripheral tissues to venous system.
Lymphoid tissues and lymphoid organs
Lymphoid cells (Lymphocytes, phagocytes)
List the main functions of the lymphatic system
- To produce, maintain, and distribute lymphocytes.
- Return of fluid and solutes from peripheral tissues to blood
- Distribution of hormones, nutrients and waste products from tissue of origin to circulation.
Describe how production and distribution of lymphocytes occurs.
Prod: Occurs in - Lymphoid tissues (e.g tonsils)
Lymphoid organs (e.g spleen)
Red bone marrow
Dist: Travels through lymphatic vessels and capillaries - Detects problems, travels into site of injury or infection.
Describe Lymphatic vessels and capillaries
Lymphatic vessels begin as lymphatic capillaries, which are closed on one end.
Lymphatic capillaries are located between cells of many tissues
Lymphatic capillaries merge to form lymphatic vessels, which have thin wallls and many valves.
Whats the difference between lymphatic vessels and blood capillaries??
Lymph start as blind pockets rather than tubes, have larger diameters, thinner walls and flat or irregular in section.
what are Lymph trunks and ducts?
From the lymph vessels, lymph passes through lymph nodes and then into lymph trunks. - Lymph trunks include the lumbar, intestinal, bronchomediastinal, subclavian and jugular trunks.
Lymph truks then merge to form either the thoracic duct or the right lymphatic duct.
What are some Circulating Lymphocytes?
T Cells: thymus dependent
B cells: bone marrow-derived
NK cells: natural killer cells - also bone marrow derived.
What are the primary and secondary lymphatic organs and tissues?
Primary: Red bone marrow
Thymus
Secondary: Lymph nodes
Spleen
Lymphoid Nodules
Whats the difference between lymph organs and lymphoid nodules?
Lymph organs (lymph nodes, thymus, spleen) are separated from surrounding tissues by a fibrous capsule
Lymphoid nodules = bundle of lymphoid tissue without fibrous capsule. e.g tonsils, appendix, digestive system.
Describe Lymph node circulation in relation to afferent lymphatics
Flows though lymph node in a network of sinuses:
- from subscapular space: contains macrophages and dendritic cells
- through outer cortex: contains B cells w germinl centers
- through deep cortex: dominated by T cells
- Through the core (medulla): contains B cells and plasma cells, organized into medullary cords
- Finally, into hilum and efferent lymphatics.
what is the function of the lymph node?
A filter: purifies lymph before return to venous circulation
Removes: Debris, Pathogens, 99% of antigens.
How are the lymph nodes distributed accross the body?
Lymph nodes of gut, trachea, lungs and thoracic duct - Protect against pathogens in digestive and respiratory systems.
Lymph nodes (Glands) - at groin and base of neck, swell in response to inflammation
Lymphadenopathy - chronic or excessive enlargement of lymph nodes may indicate infections, endocrine disorders, or cancer.
Non-specific vs specific immunity
Non-specific: Block or attack any potential pathogen, present from birth, no memory.
Specific: Identify, attack and develop immunity to a specific antigen. Aquired in response to antigens
