Lymphatic System Flashcards
what is the function of the lymphatic system?
- drain excess interstitial fluid
- trasport dietary lipids
- carry out immune responses
how does the lymphatic system drain excess interstitial fluid
- returns fluid to the bloodstream
- maintains blood volume
how does the lymphatic system transport dietary lipids?
- lipids are absorbed in the GI tract
- return lipids to the bloodstream
How does the lymphatic system carry out immune responses?
produces and directs lymphocytes
what is required for transport in the lymphatic system?
- lymphatic capillaries
- lymphatic vessels
- lymphatic trunks
- lymphatic ducts
15% of fluid goes into these lymphatic vessels and return to the blood stream
Lymphatic capillaries
** Greater permeability than blood capillaries
- Larger in diameter
- Closed at one end
- Cells that make up the wall overlap (allow fluid in, but not out)
- Attached by anchoring filaments to surrounding tissues
slide 6 and 7
not location of lymphatic capillaries location to blood capillaries
- let fluid in but not out - lymph capillaries
what part of the small intestine villi are part of the lymphatic system?
lacteals are part of the lymphatic system
lymphatic vessels
- Lymphatic capillaries unite to form vessels
- Lymphatic vessels resemble small veins
- Along the vessels are lymph nodes
how do lymphatic vessels resemble small veins?
Thinner walls, more valves
lymphatic trunks
as lymph vessels exit nodes, they join with other lymph vessels to form trunks
- all lymph from the lower extremities drain into the lumbar trunks
what are the 9 lymphatic trunks?
- Lumbar (2)
- Intestinal (1)
- Bronchomediatinal (2)
- Subclavian (2)
- Jugular (2)
what drains into the lumbar trunks?
**lower limbs
- pelvis
- kidneys
- adrenal glands
- abdominal wall
what drains into the intestinal trunk?
- stomach
- intestines
- spleen
- pancreas
- liver
what drains into the bronchomediastinal trunks?
- thoracic wall
- lungs
- heart
what drains into the subclavian trunks?
**upper limbs
What drains into the jugular trunks?
head and neck
what are the lymphatic ducts?
- thoracic duct
- right lymphatic duct
all lymphatic trunks drain into these 2 ducts
majority of all lymph drains into what duct?
thoracic duct
slide 13 diagram
Thoracic duct?
15-18” long
- Receives additional lymph from lt. jugular, lt. subclavian, and lt. bronchomediastinal trunks
** Drains into venous blood at the junction of Left Internal Jugular and Subclavian Veins (brachiocephalic vein)**
where does the thoracic duct start?
**starts anterior to L2 in a structure called the Cisterna Chyli (junction of right and lefts lumbar and intestinal trunks)
Right lymphatic duct
0.5” long
- Receives lymph from Right Jugular, Right Subclavian, and Right Bronchomediastinal trunks
- Drains into venous blood at the junction of the Right Internal Jugular and Subclavian Veins
**Slide 18 diagram **
KNOW HOW TO LABEL IT
where does the thoracic duct pass through?
the aortic hiatus
Formation of lymph
- More fluid is filtered by blood capillaries than reabsorbed
- Excess filtered fluid (3 L/day) drains into lymphatic vessels and becomes lymph
- Also serves to return any proteins that may have been lost from the blood capillaries (lymphatic capillaries more permeable)
return of lymph is aided by what?
- skeletal muscle pump
- respiratory pump
- valves
- no assistance from the heart
lymph takes how long to go around the body and back into the blood stream?
hours
immune response (lymphatic)
- specific lymphatic organs and issues involved
what are the two groups of lymphatics in immune response?
- primary lymphatic organs
- secondary lymphatic organs
what are primary lymphatic organs?
Stem cells divide and become competent - Capable of mounting an immune response
what are the 2 primary lymphatic organs?
Red bone marrow
- B Lymphocytes (mature in the bones) and pre-T lymphocytes (migrate to thymus to become competent)
Thymus
- T lymphocytes become immunocompetent
what bones are capable of producing red bone marrow?
- skull
- proximal ends of humerus and femur
- medial ends of clavicle
- ribs
- sternum
- vertebrae
- scapula
what is the thymus?
- Mediastinum between the sternum and aorta
- Most active in neonates and pre-adolescents
- Has both endocrine and lymphatic functions
what is secondary lymphatic tissue?
sites where most immune response occurs
- lymph nodes
- spleen
- lymphatic nodules or follicles
how many lymph nodes are present in the human body?
about 600
where are large groups of lymph nodes present?
mammary, axilla and groin areas
how do lymph nodes act as filters?
- Macrophages trap and destroy foreign bodies
- Lymphocytes destroy others by immune response
- Lymph passes through many filters before returning to the blood
where are clusters of lymph nodes present?
- cervical
- axillary
- thoracic
- abdominal
- pelvic
- inguinal
spleen
- Largest single mass of lymphatic tissue
Initiates an immune response by B cells and T cells - Removes abnormal blood cells - Phagocytosis
- Store iron from recycled RBC’s
- Storage of platelets (1/3 of body supply)
- Produces blood cells in a fetus
slide 30 understand where the spleen is
- lateral to the stomach
what are the lymphatic nodules?
- MALT
- Peyer’s patches (ileum)
- Tonsils
what is MALT and where is it located?
- mucosa associated lymphatic tissue
- mucous membranes of GI, urinary, reproductive tracts, and respiratory airways
where are the tonsil nodules?
- Pharyngeal tonsil or adenoid (nasopharynx)
- Palatine tonsils (side of the oral cavity)
- Lingual tonsils (base of tongue)
what are the two kinds of immunity?
innate - non-specific
adaptive - specific
what is innate immunity?
1st Line of defense – Intact skin and mucous membranes
2nd Line of defense
- Natural Killer Cells
- Phagocytes
- Inflammation
- Fever
What are natural killer cells?
- 5% to 10% of lymphocytes
- Red bone marrow, spleen, lymph nodes
- Kill infected cells, tumour cells, viruses, or abnormal cells
- Do not need prior exposure or activation
what are phagocytes?
- neurophils
- macrophages
- ingest microbes or cellular debris
what is pus?
- Collection of dead cells and fluid
- Result of most inflammatory reactions
what is inflammation?
Non-specific response to tissue damage
- Pain
- Redness
- Immobility
- Heat
- Swelling
Redness, and swelling are from increased blood flow to the area, bringing in phagocytes and other things to help with tissue repair
What are the 3 steps of the inflammatory response?
- Vasodilation and increased blood flow and increased permeability of capillaries
- Emigration of phagocytes from the blood to the interstitial fluid
- Tissue repair
fever
- Abnormally high body temperature
- Result of infection or inflammation
- Inhibits the growth of some microbes
- Speeds up body reactions that aid in repair
what is adaptive immunity
- Body’s ability to defend against specific bacteria, viruses, toxins…
- Anything foreign that is recognized is called an ANTIGEN
- Involves B and T Lymphocytes
- Vaccinations!! Antigens are pretreated to trigger an immune response but not cause significant illness
B lymphocytes
- Produced in bone marrow
- Produce antibodies in response to specific antigens
- Also produce memory cells to remember that specific antigen
What produces antibodies?
B Lymphocytes produce antiBodies
T Lymphocytes
- Precursor cells are produced in bone marrow
- Mature in Thymus
- produce memory T cells
types of T lymphocytes
- Helper T cell (CD4 T cell)
- Cytotoxic T cell (CD8 T cell)
Cytotoxic T cell (CD8 T cell)
- Act the same way was the natural killer cells but have an antigen activation meaning it needs a specific antigen to attack
- Kill infected cells, tumour cells, viruses, or abnormal cells
