38 Questions
What is the primary function of valves in lymphatic vessels?
To prevent backflow of lymph within the lymphatic drainage system
What is the mechanism by which skeletal muscle pump assists with lymph return?
Contraction of skeletal muscles in the limbs
What is the consequence of respiratory pump on lymph flow?
It creates a pressure gradient that assists in the flow of lymph
What is the function of lymph nodes in the lymphatic pathway?
To filter out foreign materials from the lymph
How many lymph nodes are approximately found in the human body?
600-700
What type of cells are activated in lymph nodes to respond to foreign antigens?
Lymphocytes
What is the location of lymph nodules?
In the loose connective tissue beneath wet epithelial membranes
What are the two types of immunoprotective cell lines hosted in lymph nodes?
T lymphocytes and B lymphocytes
What is the primary function of the lymphatic system in relation to fats and fat-soluble vitamins?
Absorbing fats and fat-soluble vitamins from the digestive system and transporting them to the venous circulation
What is the characteristic of lymphatic capillaries that allows fluid to enter?
Thin endothelial walls
What is the main difference between lymph vessels and veins?
Lymph vessels do not have a pump, whereas veins do
What is the function of the skeletal muscle pump in the lymphatic system?
To compress lymph vessels and promote lymph flow
What is the function of the respiratory pump in the lymphatic system?
To expand and compress lymph vessels, promoting lymph flow
What is the name of the lymphatic duct that drains the right half of the body superior to the diaphragm?
Right lymphatic duct
What is the main function of lymph nodules?
To contribute to the defense against microorganisms and foreign materials
What is the main difference between a lymph node and a lymph nodule?
Size and location along a lymphatic vessel
What are the tonsils?
Lymph nodules in the pharynx
What is the result of a tonsillectomy?
Removal of the lymph nodules in the pharynx
What is the purpose of redundant structures in the human body?
To provide backup functions in case of loss or impairment
What is the typical first symptom of Hodgkin's disease?
Swollen but painless lymph node
What is required for the diagnosis of Hodgkin's disease?
Biopsy of the lymph node
What is the treatment of Hodgkin's disease?
Chemotherapy and radiation
What is the primary function of the lymphatic system?
To return tissue fluid to the blood to maintain blood volume
Which of the following organs is responsible for T-lymphocyte maturation?
Thymus
What is the term for the fluid transported by the lymphatic vessels?
Lymph
Which of the following is a function of lymph nodes?
To monitor the composition of lymph
What would happen if the lymphatic system did not return tissue fluid to the blood?
Blood volume and pressure would decrease
Which of the following organs is responsible for filtering blood plasma?
Kidney
What is the primary function of the spleen?
To monitor the composition of blood components
What is the term for the process by which tissue fluid returns to the blood in capillaries?
Osmosis
What is the location of the thymus in the thorax?
superior mediastinum
What is the primary function of the thymus?
processing and maturation of T lymphocytes
What is the function of the spleen in the fetus?
production of red blood cells
What is the shape of the spleen?
fist-shaped
What is the function of fixed macrophages in the spleen?
phagocytosis of pathogens
What is the location of the spleen in the abdomen?
upper far left part
What is the function of thymosin produced by the thymus?
stimulation of maturation of T lymphocytes
Why is the spleen protected from physical trauma?
it is located in the rib cage
Study Notes
The Lymphatic System
- The lymphatic system is a 1-way system that returns lymph fluid to the cardiovascular system for elimination of toxic byproducts by end organs.
- It consists of fluid (lymph), vessels, and organs that contain lymphoid tissue (e.g., lymph nodes, spleen, and thymus).
Functions of the Lymphatic System
- Returns tissue fluid to the blood to maintain blood volume.
- Absorbs fats and fat-soluble vitamins from the digestive system and transports them to the venous circulation.
- Defends the body against pathogens and other foreign material.
Lymph Vessels
- Lymphatic capillaries are blind-ended tubes with thin endothelial walls.
- They are arranged in an overlapping pattern, allowing fluid to enter the capillary.
- Lymph capillaries unite to form larger lymph vessels, similar in structure to veins.
- There is no pump for lymph, but it is kept moving by mechanisms that promote venous return.
- The smooth muscle layer of larger lymph vessels constricts, and one-way valves prevent backflow of lymph.
Mechanisms of Lymph Flow
- Valves in lymphatic vessels prevent backflow.
- Skeletal muscle pump: contraction of skeletal muscles in the limbs assists with lymph return from the limbs.
- Respiratory pump: contraction of the diaphragm and intercostal muscles in the thoracic cavity assists with lymph return to the systemic circulation.
Lymph Nodes
- Small, encapsulated bean-shaped structures that filter lymph before it rejoins the blood stream.
- Widely distributed throughout the lymphatic pathway, with approximately 600-700 in the average human body.
- Located in the neck, axillae, groin, thoracic mediastinum, and mesenteries of the GI tract.
- Host 2 types of immunoprotective cell lines, T lymphocytes and B lymphocytes.
Lymph Nodules
- Small, localized collections of lymphoid tissue, usually located in loose connective tissue beneath wet epithelial membranes.
- Form in regions of frequent exposure to microorganisms or foreign materials and contribute to defense against them.
- Examples include tonsils (pharynx) and Peyer's patches (small intestine).
Thymus
- A bilobed lymphoid organ located in the superior mediastinum of the thorax.
- Processes and matures T lymphocytes.
- Shrinks with increasing age, but remains active in adults.
- Produces thymosin, a hormone that helps stimulate maturation of T lymphocytes in other lymphatic organs.
Spleen
- An organ located in the upper far left part of the abdomen, to the left of the stomach.
- Functions affect the blood that flows through it, rather than lymph.
- Functions after birth:
- Contains plasma cells that produce antibodies to foreign antigens.
- Contains fixed macrophages (RE cells) that phagocytize pathogens or other foreign material in the blood.
- Phagocytizes old red blood cells and forms bilirubin, which is sent to the liver for excretion in bile.
This quiz covers the lymphatic system, its functions, and how it interacts with the cardiovascular system to eliminate toxic byproducts from the body.
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