LO6- Lymphatic System Flashcards
What are the 2 fluid compartments of the body and what is contained in them?
Intracellular- 2/3 of body fluids and includes all fluid inside cells
Extracellular- 1/3 of body fluids and includes all fluid outside cells–> divided into interstitial fluid and plasma
How much extracellular fluid is made of interstitial fluid?
80%
What is interstitial fluid?
Fluid between cells, lymph within lymphatic vessels, serous fluid between serous membranes, synovial fluid in joints, cerebrospinal fluid around and within CNS
What direction is the lymphatic system?
One-way collection system
What is the function of the lymphatic system?
Maintenance of fluid balance in body (collects excess interstitial fluid and returns it to Cardiovascular system)
Nutrient transport- transports lipids and lipid soluble vitamins from digestive tract to blood
Defends against infection
Where does lymph tissue fluid originate from?
From blood plasma. Composed of water and dissolved substances that leave the blood capillaries (but no large plasma proteins)
What is the composition of lymph?
Similar to blood plasma and includes nutrients, gases, and hormones but NO large plasma proteins because too large to pass thru capillary walls
What is the lymphatic pathway starting at lymphatic capillaries?
Lymphatic capillaries–> tiny tubes merge to form larger lymphatic vessels–> lymphatic vessels lead to lymph nodes–> lymphatic vessels from lymph nodes lead to larger vessels called collecting ducts–> collecting ducts unite with veins in the thorax
Are lymphatic capillaries larger or smaller than blood capillaries? How about permeability?
Lymphatic capillaries are larger and more permeable than blood capillaries
What are features of lymphatic vessels?
Similar to veins in that they contain valves and permit one-way movement of lymph towards lymph nodes
What do lymph nodes do?
Filter lymph by collecting bacteria and particles
Also contain immune cells–> Lymphocytes (B cells and T cells) and macrophages (destroy bacteria and other pathogens)
What do collecting ducts do?
Collect lymph and return it to blood stream where lymph becomes plasma again and empties into subclavian veins
What is the thoracic duct?
The largest lymphatic vessel and drains lymph from about 3/4 of body
What is the right lymphatic duct?
Drains lymph from upper right 1/4 of body (right arm and right side of head, neck, and upper torso above diaphragm)
What are the three lymphatic organs?
Thymus gland, tonsils and adenoids, and spleen
Where is the thymus gland and what does it do?
In the mediastinum between the sternum and aortic arch. It plays important role in immunity and is site of T lymphocyte maturation. Also secretes thymosins (hormones that influence T cell development)
What happens to the thymus gland in adulthood?
It is replaced by fat. Thymus gland only active from birth to puberty
Where are the tonsils and what do they do?
Around openings of mouth and throat and function as immunoprotection
What are the three types of masses of lymphoid tissue called the tonsils?
Palatine tonsils- “the tonsils”
Pharyngeal tonsils- aka the adenoids
Lingual tonsils
Where is the spleen and what does it do?
It is the largest lymphoid organ in body. It is in upper left quadrant protected by the ribs. Function to clean up bacteria and old blood cells and acts as a blood reservoir
What is nonspecific immunity?
AKA innate immunity. This is present at birth and does not require prior exposure to an antigen/pathogen. It is a generalized response against all pathogens and foreign substances
What are mechanical barriers of nonspecific immunity?
Skin and mucous membranes
What are chemical barriers of nonspecific immunity?
Tears with lysozyme- they wash eyes and kill bacteria
Mucous- traps and kills bacteria
Stomach acid
What is phagocytosis?
Digestion of pathogens and foreign agents by neutrophils and macrophages
