7- Lymphatic and immune system Flashcards
3 functions of the lymphatic system
- drains excess interstitial fluid
- transports dietary lipids (and lipid-soluble vitamins)
- carries out immune response
4 components of the lymphatic system
1- Lymph
2- Lymphatic vessels
3- Lymphatic organs and tissue
4- Red bone marrow: The site of lymphocyte production.
where do lymphatic capillaries exist?
in the tissue spaces between cells.
What connects lymph capillaries to lymph nodes?
lymph vessels
joined lymph vessels (out of lymph nodes) are called
lymphatic trunks
2 main channels between lymph trunks and where lymph drains into venous blood?
the thoracic duct and the right lymphatic duct
structure of lymphatic capillaries:
- slightly larger in diameter than blood capillaries
- closed at one end
- overlapping endothelial cells work as one-way valves
- Attach endothelial cells to surrounding tissue and keep tubes from collapsing under outside pressure.
- Are attached to anchoring filaments (which contain elastic fibres).
what are lacteals?
specialised lymphatic capillaries in the villus of the small intestine that function to absorb and transport digested fats from the small intestine into the blood.
which is the main collecting duct of the lymphatic system and to where does it receive/drain lymph?
the thoracic duct
receives lymph from head, upper left side of body and entire body below ribs
drains Lymph into venous blood via the left subclavian vein
the right lymphatic duct receives and drains lymph from/to where?
Receives lymph from the upper right side of the body.
Drains lymph into venous blood via the right subclavian vein.
B cells and T cells mature where (respectively)?
B cells continue to mature in the red bone marrow.
Pre-T cells migrate from the red bone marrow and mature in the thymus.
where id the thymus gland located?
between the sternum and the aorta
describe the structure of the thymus
The thymus is divided into two oval-shaped lobes, which are sectioned off by a capsule and trabeculae. Each lobe has a cortex and a medulla.
What is involution?
progressive atrophy of the thymus following puberty
functions of the cortex and medulla of the thymus?
Cortex: Responsible for proliferation and maturation of immature T cells (pre-T cells) which have migrated from the red bone marrow.
Medulla: Responsible for the release of mature and immunocompetent T cells into blood to migrate to lymph nodes and other lymph organs.
how does the spleen contribute to the lymphatic system?
by filtering blood
3 structure in the spleen?
The Hilum: A location on the surface of the spleen that acts as a point of attachment for the gastrosplenic ligament, and the point of insertion for the splenic artery and splenic vein.
Stroma: Connective tissue cells of the spleen that consists of capsule, trabeculae, fibres and fibroblasts.
Parenchyma: Consists of lymphatic follicles and cells that surround the arteries (‘white pulp’) and vascular network (‘red pulp’).
what is white and red pulp?
White pulp: A lymphatic tissue (lymphocytes and macrophages) that exists around branches of splenic arteries.
Red pulp: Consists of venous sinuses filled with blood and splenic tissue (splenic cords).
function of white pulp?
White pulp: A lymphatic tissue responsible for the performance of B cells, T cells and macrophages, which are involved in immune functions similar to lymph node process.
function of red pulp?
Red pulp: Consists of venous sinuses filled with blood and splenic tissue and responsible for the removal of ruptured/worn out RBCs and the storage of platelets.
