Lymphatic System Flashcards
(41 cards)
What is the lymphatic system?
- Series of vessels that carry excess tissue fluid to blood vessels near the heart, where the fluid enters the bloodstream
- It is scattered throughout the body of the animal
Blood and lymph are carried into what?
Blood is carried in blood vessels, lymph is carried in lymphatic vessels
Lymph contains what?
Mostly lymphocytes, nutrients, hormones (+ substances that entered the tissue fluid that were carried in the plasma)
How are blood capillaries?
They are very porous; there is enough blood pressure in the blood capillaries for fluid to leave them
What will happen to the fluid?
Fluid will be drawn back; fluids naturally flow from the interstitial spaces into the blood vessels (osmotic pressure)
What is the problem with osmotic pressure?
Osmotic pressure from the venous side is not as strong as the blood pressure from the arterial side
What will lymph capillaries do to fix the problem of inequal osmotic pressure?
By taking up the excess fluid. The lymphatic system will bring back that fluid into the bloodstream through the thoracic duct (large lymph vessel)
What is capillary hydrostatic pressure?
Blood pressure on the capillary vessels
What is blood colloidal osmotic pressure?
Water pressure caused by the concentration of solutes in the blood
Body movements propel the lymph towards the heart with the help of what?
Valves that force a one-way movement of lymph in the vessels (no muscle cells to contract and to push lymph)
Where will the lymph empty?
In the superior vena cava before it enters the heart
What is the first function of the lymphatic system?
- Removal of excess tissue fluid: fluid enters interstitial space containing nutrients, cells will pick up some of it, the rest should go into the lymphatic capillaries (if not, edema)
What is the second function of the lymphatic system?
- Waste material transport: the interstitial fluid that enters the lymphatic capillaries will contain some of the waste from tissue cells
What is the third function of the lymphatic system?
- Filtration of lymph: microorganisms, cellular debris and non-self molecules will enter the lymphatic system and be filtrated in the lymph nodes
What is the fourth function of the lymphatic system?
- Lymph can pick up and transport into the blood circulation larger proteins (including enzymes) that can’t directly enter the bloodstream
What are the roles of lymph nodes?
- Lymph from a specific area will always pass through the same lymph node
- Lymph enters the lymph node from the afferent vessels and leave the node from the efferent vessels
- Lymph node is divided into a cortex and a medulla
What is the structure of a lymph node?
- Outer surface is called capsule
- Cortex is where lymphocytes reside
- Germinal centers: Stacked lymphocytes (also called lymph nodules)
- Medulla is the skeleton of the lymph node and contains macrophages (phagocytosis)
What is the spleen?
- Spongelike organ that can store blood (soak-squeeze)
- Largest lymphoid organ in the body, not essential for life
What are the functions of the spleen?
- Blood storage in the red pulp
- Clean up non-self materials by macrophages
- Removal of dead/defective red blood cells by macrophages
- Lymphocytes cloning in the white pulp during immune response
What will trabeculae do?
Squeeze out blood from the spleen because of smooth muscles
Who have a more muscular trabeculae between carnivores and ruminants?
Carnivores
In the spleen, where do lymphocytes reside?
In the white pulp, and they will multiply during an immune response
What does red pulp contain?
Blood and macrophages
What is the Thymus?
Lymphoid organ situated in the neck of vertebrates that produces T lymphocytes
