Chapter 20 (Lecture) Flashcards
what parts of the lymphatic system makes it easy to collect fluid
loose endothelial valves
- run alongside deeper arteries and veins
- an elaborate network of drainage vessels that collect the excess protein-containing interstitial fluid and return it to the bloodstream
lymph vessels
which lymphatic ducts empty into the subclavian veins
thoracic and R. lymphatic ducts
general functions of the lymphatic system
- fluid balance (3L a day returned to circulation)
- fat absorption (lacteals located in villi of intestines)
- defense (immune function)
- returns lymph from the right half of the thorax, the right half of the head and the right arm
- enters the right subclavian vein
right lymphatic duct
- cisterna chyli in thorax is the beginning of this duct
- drains the legs, abdomen, left half of the thorax, left arm, and left half of the head (all but the right upper limb and right side of head and thorax)
- empties into left subclavian vn
thoracic duct
- formed by the coalescence of capillaries, contain valves to facilitate “one way” movement of lymph back into general circulation
- have the same 3 layered structure as vein, but much thinner
lymph vessels
- interspersed throughout tissues
- have loose endothelial conditions, so they are very permeable
- collects tissue fluid (lymph) not captured by the venous end of the capillaries (~3L a day) and returns it to venous circulation
lymph capillaries
- round or bean shaped, range in size from 1-25mm in diameter
- have a fibrous outer capsule, with fibrous trabeculae dividing up the inside into compartments
- acts as a collection point for several afferent lymph vessels
- usually only one or two efferent lymph vessels will exit
lymph nodes
the outer cortex of the lymph nodes are filled primarily with
B cell lymphocytes
the deeper medulla of the lymph nodes contain
both T and B cell lymphocytes
large clusters of lymph nodes are found close to the surface in which regions of the body
- cervical
- axillary
- cubital
- inguinal
what types of cells are found in lymph nodes
- lymphocytes
- macrophages
- reticular cells
- located in the extreme LUQ of the abdominal cavity
- filters, cleanses, and destroys foreign substances in the blood
- destroys worn out RBCS
- stores iron for later use in making hemoglobin
- acts as a blood reservoir and stores platelets
spleen
what happens to a foreign cell when it invades a node
lymphocytes undergo rapid proliferation at the germinal centers to deal with them
white pulp of the spleen is mainly
- lymphocytes
- where immune functions take place
red pulp of the spleen is mainly
- venous sinuses and capillaries
- where worn-out blood cells and bloodborne pathogens are destroyed
- all splenic tissue that isn’t white pulp
- contains splenic cords and splenic sinuses
- located in the superior mediastinum, inferior to thyroid
- increases in size until puberty then decrease until unnoticeable in adults
- aids in developing immune system / where T cells become immunocompetent
thymus
the thymus houses what type of cells
T cell lymphocytes
prevents pathogens from invading the thymus gland and prematurely stimulating T-cell lymphocytes
the thymus-blood barrier
what effect will the removal of the thymus have on an infant
it will cause them to die because they never develop immunity
- clear water
- interstitial fluid that enters lymphatic vessels (flows one-way to the heart)
lymph
- weave between the tissue cells and blood capillaries in the loose connective tissues of the body
- absent from bones (including bone marrow) and teeth
lymphatic capillaries
what happens when fluid prssure in the interstitial space is greter than the pressure in the lymphatic capillary
the minivalve flaps gape open, allowing fluid to enter the lymphatic capilary
what happens when the pressure is greater inside the lymphatic capillary
it forces the endothelial minivalve flaps shut, preventing lymph from leaking back out as the pressure moves it along the vessel
transports fat from the small intestine to the bloodstream
lacteals
fatty lymph that drains from the fingerlike villi of the intestinal mucosa
chyle
lymphatic trunks
- lumbar trunks
- bronchomediastinal trunks
- subclavian trunks
- jugular trunks
- intestinal trunk
pathway of lymph from lymphatic capillaries
- lymphatic capillaries
- collecting lymphatic vessels
- lymphatic trunks
- lymphatic ducts
fibroblast-like cells that produce the reticular fiber stroma, which is the network that supports the other cell types in lymphoid organs and tissues
reticular cells
play a crucial role in body protection and the immune response by phagocytizing foreign substances and by helping to activate T cells
macrophages
spiny-looking cells that capture antigens and bring them back to the lymph nodes
dendritic cells
daughter cells produced by B cells that secrete antibodies into the blood
plasma cells
the main warriers of the immune system
lymphocytes
how does the thymus differ from secondary lymphoid oragans
- has no follicles b/c it lacks b cells
- does not directly fight antigens (maturation site for T lymphocyte precursors)
- stroma consists of epithelial cells rather than reticular fibers
most thymic cells are
lymphocytes
- lighter-staining medullary areas that contain fewer lymphocytes that consist of concentric whorls of keratinized epithelial cells
- involved in the development of regulatory T cells (prevents autoimmune response)
thymic corpuscles
- a set of distributed lymphoid tissues strategically located in mucous membranes througout the body
- occurs in the mucosa of the respiratory and genitourinary organs as well as the rest of the digestive tract
- help protect us from the never-ending onlaught of pathogens that seek to enter out bodies
- tonsils, peyer’s patches, and appendix
mucosa-associated lymphoid tissues (MALT)
- form a ring of lymphoid tissue around the entrance to the pharynx (throat), where they appear as swellings of the mucosa
- named according to their location
tonsils
the exterior surface of the tonsil is covered by …, which invaginates into the tonsilar crypts
stratified squamous epithelium
- located on either side at the posterior end of the oral cavity
- largest tonsils and the ones most often infected and removed
palatine tonsils
a collective term for the lumpy collection for a lumpy collection of lymphoid follicles at the base of the tongue
lingual tonsil
the posterior wall of the nasopharynx; referred to as the adenoid
pharyngeal tonsil
surround the term openings of the auditory lobes into the pharynx
tubal tonsils
- clusters of lymphoid follicles, structurally similar to the tonsils
- located in the wall of the distal portion of the smal intestine
Peyer’s patches / aggregated lymphoid nodules
- a tubular offshoot of of the first part of the large intestine and contains a high concentration of lymphoid follicles
- in an ideal position to prevent bacteria (present in large numbers in the intestines from breaching the intestinal wall and to generate many “memory” lymphocytes for long term immunity
appendix
- largest lymphoid organ
- site for lymphocyte proliferation and immune surveillance, cleanses and reuses blood and blood cells
- stores platelets and monocytes
spleen
regions of reticular connective tissue, that separate the blood-filled splenic sinusoids
splenic cords
arrangement of lymphatic vessels
a one-way system of vessels beginning with blind-ended lymphatic capillaries
tumors that block the lymphatics or lymphatics are removed during cancer surgery may result in what condition
lymphedema
which vessel transports fluid back into the blood that leaks from the vascular system
lymphatics
which part of the lymphatic system is most closely associated with capillary beds
lymphatic capillaries
what is the lymphatic system’s role in relation to the cardiovascular system
it maintains blood volume and hence, pressure
function of lymphatic collecting vessels
collect lymph fluid draining from lymphatic capillaries
lymphatic organ that cleanses the lymph
lymph node
drains the lymph from the entire left side of the body and also the right abdomen and leg
thoracic duct
red lines under the skin that are sensitive to touch
lymphangitis
- has same 3 tunics as veins
- second smallest lymph vessels
- helps maintain blood pressure
lymphatic collecting vessels
smallest lymphatic vessel that collects excess tissue fluid
lymphatic capillary
functions of lymphatic vessels
- return of leaked proteins to blood
- transportation of absorbed fat from the intestines to blood
- return of tissue fluid to bloodstream
- a type of loose collective tissue called reticular CT
- dominates all lymphoid organs except thymus
lymphoid tissue
largest vessels; carry lymph fluid to subclavian veins
lymphatic ducts
what is the function of the endothelial minivalves in lymphatic capillaries
increases permeability
once collected, lymph is ultimately transported into
venous circulation
what is the origin of lymph fluid
lymph is excess tissue fluid formed from plasma that has leaked from capillaries
lymph traveling from the left arm would enter the venous circulation via the
thoracic duct
lymph vessels transport
- excess tissue fluid
- lymphocytes
- leaked plasma proteins
- dietary fats
lymph flows from lymphatic ducts directly into which of the following
veins
which lymphoid cells produce antibodies
plasma cells
true or false:
lymph arrives at the lymph nodes via afferent lymphatic vessels
true
true or false:
there are more efferent lymphatic vessels leaving a lymph node than there are afferent vessels entering a lymph node
false
which vessel serves as the source of the spleen’s blood supply from the aorta
celiac trunk
the splenic artery brunches from the celiac trunk
functions of the spleen
- remove and recycle old erythrocytes and platelets
- store iron from hemoglobin
- house B and T lymphocytes
which anatomical areas is/are protected by the tubal tonsils
the passage from the pharynx to the middle ear
The tubal tonsils surround the passages (auditory tubes) from the pharynx to the middle ear. They are used to equalize pressure behind the tympanic membrane.
referred to as the adenoids if enlarged
pharyngeal tonsils
lymph leaves a lymph node via
efferent lymph vessels
lymphatic vessels are … permeable than blood capillaries
lymphatic capillaries
fats absorbed from the small intestine are transported to the bloodstream via
lacteals
which vessel delivers lymph into the junction of the internal jugular vein and the subclavian
thoracic duct
3 large clusters of superficial lymph nodes
- cervical
- inguinal
- axillary
places where the collecting lymphatic vessels coverge to form trunks
remove and destroy microorganisms and other debris that enter the lymph from the loose connective tissues, preventing them from being delivered to the blood and spreading to other parts of the body
macrophages
functions of lymph nodes
- cleansing the lymph
- immune system activation
many antigens are brought to lymph nodes from their point of entry into the body by …. cells, which use these antigens to activate T cells in the lymph node
dendritic cells
surrounds each node with a dense fibrous capsule and extend inward to divide the node into a number of compartments
trabeculae
internal framework of a lymph node that consists of reticular fibers that physically supports its ever-changing population of lymphocytes
stroma (of lymph node)
- cointains densely packed follicles, many with germinal centers heavy w/ dividing B cells
- deeper part primarily houses T cells in transit, which circulate continuously between the blood, lymph nodes, and lymph
- dendritic cells abundant
cortex of the lymph node
- consists of medullary cords, thin inward extensions from the cortical lymphoid tissue
- B and T lymphocytes found here
medulla of the lymph node
steps to lymph node circulation
- enters the convex side of a lymph node through a number of afferent lymphatic vessels
- moves through subscapular sinus, into a number of smaller sinuses that cut through the corex and enter the medulla (and meanders thru medullary sinuses)
- finally exits node at its hilum via efferent lymphatic vessels
cisterna chyli
- located in the region between the last thoracic and second lumbar vertebrae
- thoracic duct begins here
- where B and T cells mature
- red bone marrow and thymus
primary lymphoid organs
where do B and T cells originate
red bone marrow
where do B cells mature
red bone marrow
where do T cells mature
thymus
- where mature lymphocytes first encounter their antigens and are activated
- include lymph nodes, spleen, and collections of mucosa-associated lymphoid tissue (MALT) that form the tonsils, Peyer’s patches, and appendix
secondary lymphoid organs
dominates all of the lymphoid organs except the thymus
reticular connective tissue
- a loose arrangement of lymphoid cells and some reticular fibers
- found in virtually every body organ
- larger cllections appear in lamina propria of mucous membranes
diffuse lymphoid tissue
- solid spherical bodies consisting of tightly packed lymphoid cells and reticular fibers
- lighter staining germinal centers where proliferating B cells dominate
- follicles form part of larger lymphoid organs (lymph nodes), isolated aggregations occur intestinal wall as Peyer’s patches and appendix
lymphoid follicles (lymphoid nodules)
- inflammation of the tonsils, typically due to bacterial infection
- tonsils become red, swollen, and sore
tonsilitis
- enlargement of the spleen
- may be due to accumulaion of infectious microorganisms typically caused by septicemia, mononucleosis, malaria, or leukemia
splenomegaly
- first node that receives lymph drainage from a body area suspected of being cancerous
- gives best indication of whether metastasis throughout the lymphatic vessls has occurred
sentinel node
- typically a tropical disease in which the lymphatics (particularly those of the lower limbs and scrotum become clogged with parasitic roundworms (filariasis)
- swelling reaches enormous proportions
elephantiasis
- a malignancy of lymphoid tissue
- swollen, nonpainful lymph nodes, fatigue, fever, night sweats
- giant malignantly transformed B cells (Reed-Sternberg cells)
hodgkin’s lymphoma
any disease of the lymph nodes
lymphadenopathy
diagnostic procedure in which the lymphatic vessels are injected with radiopaque dye and then visualized with X rays
lymphangiography
any neoplasm of the lymphoid tumor, whether benign or malignant
lymphoma
- all cancers of lymphoid tissues
- involves uncontrolled multiplication and metastasis of undifferentiated lymphocytes, with swelling of the lymph nodes, spleen, and Peyer’s patchs
- rapidly progressing, typically affects young people
non-Hodgkin’s lymphoma
