Lymphatic System Flashcards
What are the primary lymphoid organs
The site of maturation and origination of B and T cells
- Bone Marrow
- Lymphatic vessels and Lymph
What are the Secondary lymphoid organs
Site of T and B cell activation
Encounter antigen —> Activation —> immune response
- Spleen
- Lymph nodes
- Lymph nodules, tonsils, appendix, Peyers patches etc.
Describe Lymph
Contains Leukocytes, nutrients and waste
What is the function of the Lymph
Drain excess interstitial fluid
Transport dietary products like lipid soluble vitamins
Immune Function: transport soluble lymphocytes around the body and pathogens from affected areas to local lymph nodes
What happens in the bone marrow
Erythropoiesis and maturation of B lymphocytes including deletion and self receive B cells
Describe the Thymus
Sits directly above the heart
- maturation of T lymphocytes
- selection of T lymphocytes
- positive selection (MHC restriction)
- negative selection (Self-tolerance)
What are the two parts of the spleen
Red pulp and white pulp
Describe the characteristics of red pulp
- Removal of ruptured and worn out blood cells by macrophages
- storage of platelets 33% of total body supply
- haemopoiesis during foetal development
Describe the characteristics of white pulp (lymphatic tissue)
- Activation of B and T lymphocytes similar to lymph nodes
- Macrophages: phagocytosis of blood-borne pathogens
What is the function of the lymph nodes
Regulation of the immune system response and exposure to antigens & exposure to antigens and activation of naive B and T lymphocytes
Describe the structure of the Lymph nodes
Cortex with follicles: B cells, Macrophages, dendritic cells
- Paracortex: T cells and dendritic cells
- Medulla: nature B cells and macrophages
Describe the structure of Mucosa-Associates Lymphoid Tissue (MALT) (Lymph nodules)
No capsule
No lamina proporia (connective tissue) of mucous membranes
Describe the function of lymph nodules (MALT)
Activation of B and T cells
