How does lymph enter and exit a lymph node?
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Lymph enters through several afferent lymphatic vessels and exits through one to two efferent lymphatic vessels at the hilum.
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How does lymph enter and exit a lymph node?
Lymph enters through several afferent lymphatic vessels and exits through one to two efferent lymphatic vessels at the hilum.
What are the sinuses in the lymph node and their function?
Sinuses are spaces that support the flow of lymph, beginning at the sub-capsular sinus and branching into trabecular sinuses in the cortex and medullary sinuses in the medulla.
Where are tonsils located?
Tonsils are located in the pharyngeal region at the top of the throat.
What are the secondary lymphatic organs?
The spleen, lymph nodes, tonsils, and lymphatic nodules.
How are lymph nodes distributed in the body?
Lymph nodes are widely distributed in the body and usually occur in clusters or chains.
How does lymph enter the lymph nodes?
Lymph follows afferent lymphatic vessels to get into the subcapsular sinus of lymph nodes.
Where do the lymphatic ducts empty their lymph?
Into venous circulation at the junction of the internal jugular and subclavian veins on each side of the body.
Why is an alternative drainage route required for tissue fluid?
To prevent excess fluid from accumulating in tissues, as not all tissue fluid re-enters the blood capillaries.
Which organs are part of the lymphatic system?
The thymus, spleen, lymph nodes, tonsils, and lymphatic nodules.
What are the main structural components of a lymph node when cut at a sagittal plane?
An outer cortex and an inner medulla.
What is the function of the ring of lymphoid tissue formed by the tonsils?
To collect and remove pathogens entering the body from inhaled air via the nasal cavity and swallowed food via the oral cavity.
What is the function of lymphocytes in lymphatic nodules?
To kill pathogens that travel along the digestive tract and generate a diverse range of memory lymphocytes from sampling different antigens.
How does the lymphatic system work with the cardiovascular system?
It forms a circulatory unit that returns fluid leaked from blood vessels back to the blood and drains excess fluid and proteins away from tissues.
What cells predominantly occupy the superficial layer of the lymph node's cortex?
B-cells and macrophages.
What are lacteals and where are they located?
Lacteals are specialized lymphatic vessels present in the intestines, where food absorption takes place.
What are the primary lymphatic organs and their functions?
Red bone marrow and thymus are primary lymphatic organs where maturation of lymphocytes takes place.
What is the primary function of lymph nodes?
Filtering out foreign substances and killing pathogens such as bacteria and viruses in the lymph.
What is the role of the reticular meshwork in lymph nodes?
It supports the structure of the lymph node and enhances the filtering effect by causing lymph to flow slowly.
Where can lymphatic nodules be found besides specialized lymphoid organs?
In the connective tissue of easily infected mucous membranes.
What are the two main lymphatic ducts in the body?
The right lymphatic duct and the thoracic duct.
Where does the thoracic duct arise from?
It arises as an enlarged sac called the cisterna chyli, situated at the first and second lumbar level.
What structural feature do the spleen, lymph nodes, and thymus share?
They all have a dense, fibrous capsule around them, providing physical support and forming paths for blood vessels, efferent lymphatic vessels, and nerves.
What are the four groups of tonsils?
Pharyngeal tonsil (or adenoid), tubal tonsils, palatine tonsils, and lingual tonsils.
What are Peyer's patches?
Aggregates of lymphoid nodules found in the ileum of the small intestine.
What is the function of the right lymphatic duct?
It drains lymph from the right upper part of the body (one-fourth of lymph drainage).
What happens to the lymph inside lacteals when it is rich in lipid?
It turns milky, hence lacteals are also known as white and milky veins.
What are the main functions of the lymphatic system?
The lymphatic system aids in circulation, body defense, and digestion.
What role do lymphocytes and macrophages play in the lymph nodes?
They monitor the contents of the lymph and clear harmful micro-organisms like pathogens or tumour cells.
Where do B-lymphocytes and T-lymphocytes mature?
B-lymphocytes mature in the bone marrow, while T-lymphocytes mature in the thymus.
What role do lymph nodes play in the lymphatic system?
Lymph nodes filter and cleanse pathogens from the lymph.
How does lymph leave the lymph nodes?
Lymph flows into efferent lymphatic vessels to leave the lymph node after coursing through the medullary sinuses.
What are lacteals and what is their function?
Lacteals are lymphatic vessels involved in the absorption of fat from digested food in the small intestine.
What is the normal size range of lymph nodes?
About 1 mm to 2 cm in length.
What cells are predominant in the deep cortex (paracortex) of the lymph node?
T-cells.
What happens to lymph after it enters the subcapsular sinus of lymph nodes?
It flows into trabecular sinuses close to the trabeculae and then into the medullary sinuses or diffuses through lymphatic nodules before reaching the medullary sinuses.
Which tonsils are the largest and most often infected in childhood?
The palatine tonsils.
What is the function of the thoracic duct?
It drains lymph from the right lower part and the whole left side of the body (the remaining three-fourths of lymph drainage).
What is lymph and how is it formed?
Lymph is the interstitial fluid inside lymphatic vessels. It is formed when plasma passes through the capillary wall and enters the surrounding tissue, forming tissue fluid.
What are the two types of lymph nodes based on their location?
Superficial and deep lymph nodes.
What might be required if tonsils are repeatedly infected?
Surgical removal (tonsillectomy).
What is the function of lacteals?
Lacteals are important for the absorption and transportation of lipids or chylomicrons in the body.
