Chapter 22: The Lymphatic System Flashcards
What does the lymphatic system do and what 3 parts does it consist of?
Returns fluids that have leaked from the blood vascular system back into the blood.
3 parts:
1. Network of lymphatic vessels
2. Lymph
3. Lymph nodes
Lymphatic vessels
A network of drainage vessels that collect the excess interstitial fluid and return it to the bloodstream
Lymph
Fluid contained in lymphatic vessels
Lymph nodes
Checkpoints along the lymph vessels that cleanse lymph as it passes through
What do lymphoid organs and tissues do?
Provide the structural basis on the immune system (using phagocytic cells and lymphocytes to defend the body against disease)
Lymphatic capillaries
Weave between tissue cells and blood capillaries in connective tissue of the body.
What 2 structural modifications make lymphatic capillaries so permeable?
- The capillary walls are not tight, they have overlapping mini valves to allow things in.
- Collagen filaments to anchor the surrounding cells
What causes the minivalves of lymphatic capillaries to open and close?
Open:
And the pressure of interstitial fluid is greater than the pressure in the lymphatic capillary.
Close:
When pressure is greater in the lymphatic capillary it forces the valves shut to prevent backflow of fluid
Pathway of lymph flow
Smallest
1. Lymphatic capillaries
2. Collecting lymphatic vessels
3. Lymphatic trunks
4. Lymphatic ducts
Biggest
How are lymphatic vessels and blood vessels similar
Lymphatic vessels have the same methods as versus return:
- using skeletal muscle to push it
- pressure changes during breathing
- valves to prevent back flow
What direction does lymph always flow?
Towards the heart
Innate immunity
Includes all defence mechanisms that you are naturally given.
Ex. Skin, mucus, phagocytes, fever…etc
Adaptive immunity
Immunity that you gain from experiencing foreign molecules that you’re not used to. (you adapt to it)
Ex. B and T lymphocytes
Where do lymphocytes arise from? What are the 2 types?
Arise from red bone marrow
Become:
1. T lymphocytes
2. B lymphocytes
What do T lymphocytes do? Where do they mature?
Manage immune responses and can directly destroy infected cells.
Mature in the Thymus (T for thymus)
What do B lymphocytes do? Where do they mature?
Protect the body by producing plasma cells that secrete antibodies
Mature in Bone marrow (B for bone)
What do B lymphocytes give rise to?
- Plasma cells - produce antibodies to destroy foreign antigens.
- Memory B cells - remember foreign invaders so a rapid response can be made if encountered again.
What do T lymphocytes gives rise to?
- Effector T cells - secrete cytotoxic agents to destroy invaded and cancerous cells.
- Helper T cells - secrete chemical messengers to activate T and B cells .
- Regulatory T cells - help control immune response
- Memory T cells - remember foreign invaders so a rapid response can be made if encountered again.
What is the main lymphoid organ?
The lymph nodes
What are the 2 main functions of lymph nodes?
- Filtration of debris that entered the lymph
- Immune system activation to destroy foreign particles
What is the largest lymphoid organ?
Spleen
What are the two components of the spleen?
- White pulp - where immune functions take place
- Red pulp -where worn out RBC’s are destroyed
What is the function of the thymus
It is the site of maturation for lymphocyte precursors (T lymphocytes)
What is Mucosa associated lymphoid tissue?
Lymphoid tissues that are located in mucus membranes throughout the body
Includes:
- tonsils
- appendix
- peyers patches (in ileum)
Tonsils
Rings of lymphoid tissue around the pharynx.
They remove many invaders entering the pharynx in food or inhaled air.
What are the 4 types of tonsils?
- Palatine
- Lingual
- Pharyngeal
- Tubal
Where are peyers patches located?
Ileum of small intestine
What are the 3 mucosa-associated lymphoid tissues? (MALT)
- Tonsils
- Appendix
- Peyer’s patches in ileum
What type of tissue are lymphoid organs made up of?
Reticular tissue
