68 Questions
1 Define ‘lymph’.
Answer: The colourless liquid that circulates through the lymphatic vessels to be returned to the blood.
3 List the functions of the lymphatic system.
Answer: The main function of the lymphatic system is to collect some of the escaped fluid from the blood capillaries and return it to the circulatory system to prevent swelling (edema). It also filters the lymph to aid in the body’s internal defence against pathogens. It also absorbs fats from intestinal tracts and returns it to bloodstream.
4 Describe the role of lymph nodes in protecting the body against foreign bodies.
Answer: Lymph nodes contain lymphoid tissue made up of macrophages, lymphocytes and plasma cells. There is also a crisscross network of fibres. When lymph enters these nodes, large particles will become trapped in the mesh and are then consumed by macrophages by phagocytosis. Lymphocytes and plasma cells will detect any pathogenic organism and produce chemicals to destroy the pathogen. (Unit 3 content)
5 Discuss the importance of valves in lymph vessels.
Answer: Valves are important in lymph vessels because there is no central pump to drive the direction of the flow of the lymph. Valves prevent the backflow of lymph when the pressure drops.
6 Doctors will check the size of lymph nodes in sick patients. Explain why this is an important part of the physical examination.
Answer: If a patient has an infection, the pathogen will be filtered out of the lymph at the lymph nodes. The presence of the pathogen activates the macrophages, lymphocytes and plasma cells to divide and increase in activity to remove the pathogen from the patient’s body. This increase in number and activity will cause the lymph nodes to swell, which can be detected by a doctor in a physical examination.
7 Compare and contrast lymph vessels and blood vessels.
Answer: Compare: Both transport fluid, lymph vessels and veins both contain valves to prevent backflow. Contrast: Lymph vessels originate as blind-ended tubes; they are slightly wider in lumen diameter than capillaries, they are more permeable than capillaries.
Fluid from the blood capillaries is filtered out into the surrounding tissues, forming ______ fluid.
interstitial
Some of the interstitial fluid is absorbed directly back into the blood capillaries, but the excess fluid enters the ______ capillaries to become lymph.
lymphatic
The lymphatic capillaries have specialized endothelial cells that allow them to take up fluid ______.
easily
Lymph is transported through a network of vessels, passing through ______ nodes where it is filtered and cleansed.
lymph
Eventually, the lymphatic vessels merge to form larger lymphatic trunks, which drain into one of two main lymphatic ducts: the thoracic duct or the right lymphatic ______.
duct
The lymphatic system helps maintain fluid balance by returning excess interstitial fluid back into the ______.
bloodstream
Lymph contains white blood cells (particularly lymphocytes) and antibodies, which play a crucial role in the body's ______ response.
immune
Lymph nodes filter and trap pathogens, foreign particles, and abnormal cells, initiating an immune response to defend against infections and ______.
diseases
The lymphatic ducts empty the lymph back into the bloodstream by connecting to the ______ veins in the upper chest.
subclavian
Lymphatic vessels in the intestines absorb dietary fats and fat-soluble vitamins from the digestive tract and transport them to the ______
bloodstream
Valves in lymphatic vessels are essential for maintaining the unidirectional flow of lymph towards the lymph nodes and back into the ______
bloodstream
Without valves, lymphatic fluid could stagnate or flow in the wrong direction, hindering the proper functioning of the ______ system
lymphatic
Blood vessels carry blood, which contains red blood cells, white blood cells, platelets, and plasma, while lymphatic vessels carry ______, a clear fluid containing white blood cells, proteins, fats, and cellular debris
lymph
Blood vessels primarily transport oxygen, nutrients, hormones, and waste products throughout the body, while lymphatic vessels primarily transport interstitial fluid, immune cells, fats, and proteins, and also play a crucial role in immune ______
defense
Blood vessels form a closed circulatory system with arteries, veins, and capillaries, while lymphatic vessels form an open-ended network that drains into lymph nodes and eventually returns lymph to the ______
bloodstream
Blood vessels have a unidirectional flow of blood from the heart to the tissues and back to the heart, whereas lymphatic vessels have a unidirectional flow of lymph towards the lymph nodes and eventually back into the ______
bloodstream
Lymphatic vessels transport immune cells, fats, cellular waste products, and proteins throughout the ______
body
Blood vessels carry red blood cells, white blood cells, platelets, and plasma, while lymphatic vessels carry a clear fluid containing white blood cells, proteins, fats, and ______ debris
cellular
Lymphatic vessels play a crucial role in immune ______
defense
What are the components found in the interstitial fluid that forms from the blood capillaries?
Water, dissolved substances, and small proteins
What is the main role of lymph nodes in the lymphatic system?
Filter and trap pathogens, foreign particles, and abnormal cells
Where does the lymphatic duct empty the lymph back into the bloodstream?
Subclavian veins in the upper chest
What is the function of valves in lymphatic vessels?
Maintaining unidirectional flow of lymph
What key role do lymphocytes and antibodies play in the body?
Immune response
Explain the process by which lymph is formed in the lymphatic system.
Excess fluid, large proteins, and cellular debris from interstitial fluid enter lymphatic capillaries
How do lymphatic vessels contribute to maintaining fluid balance in the body?
By returning excess interstitial fluid to the bloodstream
What is the main function of the thoracic duct and the right lymphatic duct in the lymphatic system?
Draining lymph into the bloodstream
Why are valves important in lymphatic vessels?
To prevent stagnation or reverse flow of lymph
Explain the role of lymphatic vessels in fat absorption from the intestines.
Lymphatic vessels absorb dietary fats and fat-soluble vitamins from the digestive tract and transport them to the bloodstream.
What is the primary function of blood vessels compared to lymphatic vessels?
Blood vessels primarily transport oxygen, nutrients, hormones, and waste products throughout the body, while lymphatic vessels primarily transport interstitial fluid, immune cells, fats, and proteins.
Describe the composition of lymph compared to blood.
Lymph contains white blood cells, proteins, fats, and cellular debris, while blood contains red blood cells, white blood cells, platelets, and plasma.
Why are valves in lymphatic vessels crucial for the lymphatic system?
Valves are essential for maintaining the unidirectional flow of lymph towards the lymph nodes and back into the bloodstream, preventing backward flow.
Differentiate between the structure of blood vessels and lymphatic vessels.
Blood vessels form a closed circulatory system with arteries, veins, and capillaries, while lymphatic vessels form an open-ended network draining into lymph nodes.
Explain the direction of flow in blood vessels and lymphatic vessels.
Blood vessels have a unidirectional flow from the heart to the tissues and back, while lymphatic vessels have a unidirectional flow towards lymph nodes and eventually back to the bloodstream.
What is the main function of lymph nodes in the lymphatic system?
Lymph nodes filter and trap pathogens, foreign particles, and abnormal cells, initiating an immune response to defend against infections.
Explain how lymphatic vessels contribute to immune defense.
Lymphatic vessels transport immune cells, fats, cellular waste products, and proteins throughout the body, playing a crucial role in immune defense.
Why do doctors check the size of lymph nodes in sick patients during physical examinations?
Checking lymph node size is important to assess immune response and potential infections or diseases affecting the lymphatic system.
Discuss the importance of lymph in maintaining fluid balance in the body.
Lymph helps maintain fluid balance by returning excess interstitial fluid back into the bloodstream.
Lymph nodes can range in length between:
1-25mm
What is the role of macrophages in lymph nodes?
Destroying larger particles such as bacteria by phagocytosis
How long does it typically take for macrophages to kill most bacteria ingested in lymph nodes?
10 to 30 minutes
How do lymph nodes respond when infections occur?
By increasing the formation of lymphocytes, causing swelling and soreness
Where are lymph nodes most numerous in the body?
Neck, armpits, groin, around the alimentary canal
What cells are found within the lymphoid tissue of lymph nodes?
Lymphocytes, macrophages, plasma cells
What surrounds each lymph node, forming a framework?
A capsule of connective tissue
Describe the composition of lymph nodes.
Bean-shaped structures ranging from 1 mm to 25 mm in length
What type of network of fibres is found between the cells of lymphoid tissue?
Criss-crossed network
Explain the process of phagocytosis by macrophages in lymph nodes.
Macrophages surround particles with projections and ingest them, destroying them with enzymes
Why does an infected finger result in swelling and tenderness in the armpit?
Due to the large number of lymph nodes in the armpit responding to the infection
How is lymph able to move through the lymph vessel?
as a result of smooth muscle, skeletal muscle and valves. The smooth muscle layer of the vessels is able to contract to push the lymph along the vessel. The skeletal muscles surrounding the vessels are also able to contract, providing additional force. As there is no central pump, there is no force driving the direction of the flow of lymph. Therefore, the larger lymph vessels have valves that close when the pressure drops, preventing the backflow of lymph.
The network of lymph vessels joins to form what?
two lymphatic ducts that empty the lymph into large veins in the upper chest.
What happens to the plasma that leaves the blood vessels and travels into the body tissues?
This plasma becomes tissue fluid and surrounds all the body's tissues. It then collects waste products, excess water, and toxins from the cells. It then gets collected by the lymphatic capillaries, where the fluid then turns into lymph, which travels to lymph nodes around the body and eventually enters the bloodstream through subclavian veins
How do the lymph vessels prevent back flow?
They have one-way valves and muscular walls that CONTRACT to force the lymph forward
what happens to the waste products and destroyed bacteria after being filtered by the lymph nodes?
they are carrie din the lymph fluid through larger lymph vessels up to the neck, where the thoracic duct empties the lymph back into the blood circulation. The bloodstream then removes the waste products from the body by sending it to the kidney or to the liver for further processing
What organs are part of the lymphatic system?
spleen, tonsils, thymus, adenoids
Why is exercise important for maintaining healthy lymphatic system function?
The lymphatic system does not have a central pump, so physical activity help stimulate lymphatic circulation. Muscle contractions during exercise help squeeze lymphatic vessels, promoting the movement of lymph fluid throughout the body. This enhances the removal of waste products and excess fluids from tissues, thereby supporting immune function and reducing the swelling of tissues.
What can go wrong with the lymphatic system?
Sometimes infections can cause the pumping to break down, leading to swelling in the arms of legs (lyphedema). Debris or harmful substances can make it past the lymph nodes, and cancer cells can spread to other parts of the body through the lymphatic system
What does much of your lymph start off as?
blood plasma that gets forced out of your capillaries, way down in capillary beds, where the leakage helps the exchange of nutrients and gases between the blood in the capillaries and tissue cells. Much of it gets left behind which gets collected by lymphatic system
How does the lymphatic system scan for pathogens and initiate an immune response?
Lymph fluid passes through lymph nodes containing B cells and T cells that can detect pathogens and initiate an immune response
What is the role of the spleen in the lymphatic system?
The spleen acts like a lymph node for the bloodstream, containing B cells and T cells to fight pathogens, and it also breaks down old red blood cells
What are the roles of the thymus and bone marrow in the lymphatic system?
The thymus produces and matures T cells while the bone marrow produces and matures B cells
How does the lymphatic system prevent swelling?
Lymphatic capillaries absorb excess fluid (interstitial fluid) from tissues and return it to the bloodstream via lymphatic vessels and ducts
Study Notes
Fluid Movement from Blood Capillaries to Lymphatic Vessels
- Fluid from blood capillaries filters out into surrounding tissues, forming interstitial fluid containing water, dissolved substances, and small proteins.
- Excess interstitial fluid, along with large proteins and cellular debris, enters lymphatic capillaries to become lymph.
- Lymphatic capillaries have specialized endothelial cells that allow them to take up fluid easily.
- Lymph is transported through a network of vessels, passing through lymph nodes where it is filtered and cleansed.
- Lymphatic vessels merge to form larger lymphatic trunks, which drain into one of two main lymphatic ducts: thoracic duct or right lymphatic duct.
- These ducts empty lymph back into the bloodstream by connecting to subclavian veins in the upper chest.
Functions of the Lymphatic System
- Fluid Balance: Lymphatic system helps maintain fluid balance by returning excess interstitial fluid back into the bloodstream.
- Immune Response: Lymph contains white blood cells (particularly lymphocytes) and antibodies, playing a crucial role in the body's immune response.
- Fat Absorption: Lymphatic vessels in the intestines absorb dietary fats and fat-soluble vitamins (such as vitamins A, D, E, and K) from the digestive tract and transport them to the bloodstream.
- Transportation: Lymphatic system transports immune cells, fats, cellular waste products, and proteins throughout the body.
Comparison and Contrast of Lymph Vessels and Blood Vessels
- Composition: Blood vessels carry blood containing red blood cells, white blood cells, platelets, and plasma, while lymphatic vessels carry lymph, a clear fluid containing white blood cells, proteins, fats, and cellular debris.
- Function: Blood vessels primarily transport oxygen, nutrients, hormones, and waste products throughout the body, while lymphatic vessels primarily transport interstitial fluid, immune cells, fats, and proteins, and also play a crucial role in immune defense.
- Structure: Blood vessels form a closed circulatory system with arteries, veins, and capillaries, while lymphatic vessels form an open-ended network that drains into lymph nodes and eventually returns lymph to the bloodstream.
- Direction of Flow: Blood vessels have a unidirectional flow of blood from the heart to the tissues and back to the heart, whereas lymphatic vessels have a unidirectional flow of lymph towards the lymph nodes and eventually back into the bloodstream.
Importance of Valves in Lymph Vessels
- Valves in lymphatic vessels are essential for maintaining the unidirectional flow of lymph towards the lymph nodes and back into the bloodstream.
- These valves prevent the backward flow of lymph, ensuring efficient transport.
Lymph Nodes
- Lymph nodes filter and trap pathogens, foreign particles, and abnormal cells, initiating an immune response to defend against infections and diseases.
- Lymph nodes are bean-shaped, ranging in length from 1 mm to 25 mm, and contain masses of lymphoid tissue.
- Within the lymphoid tissue are cells known as lymphocytes, macrophages, and plasma cells.
- Spaces between the cells of the lymphoid tissue are criss-crossed by a network of fibres.
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