Lesson 11 - Lymphatic and Immune System Flashcards
immune system
not an organ system- but a cell population that inhabits all organs and defends the body from agents of disease
immune cells are concentrated into a true organ system called…
the lymphoid system
the lymphoid system (4)
- network of organs and vein-like vessels that recover fluid
- inspect fluid for disease agents
- activates immune response
- return fluid to the bloodstream
lymphoid (lymphatic) system
lymphatic vessels that penetrate nearly every tissue, and a collection of lymphoid tissue and organs that produce immune cells
fluid recovery (2)
- fluid continually filters from the blood capillaries into the tissue spaces
- blood capillaries reabsorb 85% and the rest enters the lymphatic system
lymphedema
swelling due to the interference in lymphatic drainage
functions of the lymphoid system (2)
- immune surveillance
- lipid absorption
functions of the lymphoid system: immune surveillance (3)
- excess filtered fluid picks up foreign cells and chemicals from tissues
- passes through lymph nodes where immune cells stand guard against foreign matter
- activated a protective immune response
functions of the lymphoid system: lipid absorption
lacteals in small intestine absorb dietary lipids that are no absorbed by blood capillaries
components of the lymphoid system (4)
- lymph
- lymphatic vessels
- lymphoid tissue
- lymphoid organs
lymph
recovered fluid from tissues; clear, colorless fluid similar to plasma but low in protein
lymphatic vessels
vessels of the lymphoid system that transport lymph
lymphoid tissue
aggregates of lymphocytes and macrophages that populate many organs of the body
lymphoid organs
organs where lymphoid cells concentrate, surrounded by connective tissue capsules
lymph chemical composition varies in different places, compare and contrast lymph from the intestines versus after lymph nodes
- lymph collected from the intestine may look milk because of high lipid content
- lymph collected after lymph nodes have high amounts of lymphocytes
what is the main supply of lymphocytes in the blood stream?
lymph collected after lymph nodes
lymphatic capillaries are also called…
terminal lymphatics
what locations are lymphatic vessels absent from? (4)
- cartilage
- cornea
- bone
- bone marrow
lymphatic capillary cells are tethered to surrounding tissue by _____ _____
anchoring filaments
what are microscopic vessels that penetrate nearly every tissue of the body? HINT: lol not blood vessels
lymphatic vessels
describe the capillary walls of lymphatic vessels
endothelial cells overlapping each other like roof shingles
lymphatic capillaries are _____ at one end
closed
what structure of lymphatic vessels keeps lymph moving in one direction?
endothelium creates valve-like flaps that open when interstitial fluid pressure is high and close when it is low
intercellular clefts
gaps between cells (lymphatic vessel cells) are large enough to allow bacteria and cells to enter lymphatic capillary
what happens to lymphatic endothelial cells when the tissue swells with fluid?
causes the overlapping edges of the endothelial cells to pry apart and brain int e fluid into the lymphatic capillary
three layers of lymphatic vessels
- tunica interna
- tunica media
- tunica externa
lymphatic vessels: tunica interna (2)
contains…
endothelium and valves
lymphatic vessels: tunica media (2)
contains…
elastic fibers and smooth muscle
lymphatic vessels: tunica externa
thin outer layer
lymphatic capillaries merge to form _____ vessels
collecting
collecting vessels converge to form _____ _____
lymphatic trunks
all lymphatic ducts converge to form these two collecting ducts
- right lymphatic duct
- thoracic duct
right lymphatic duct
receives lymph from the right arm, right side of the head and thorax
where does the right lymph duct emtpy?
the right subclavian vein
thoracic duct
receives lymph from below the diaphragm; left arm, left side of the head, neck, and thorax
the thoracic duct begins as a sac in the abdomen called the _____ _____
cisterna chyli
where does the thoracic duct empty?
the left subclavian vein
summary of the path from tissue fluid back to the bloodstream (8)
lymphatic capillaries –> collecting vessels –> 11 lymphatic trunks –> two collecting ducts –> subclavian veins –> brachiocephalic veins –> superior vena cava –> right atrium
lymph flows under forces similar to those that govern venous return except…
no pump (heart)
lymph flows at _____ pressure and _____ speed than venous blood
low, slower
stretching of lymphatic vessels stimulates…
their contraction
lymph is moved along by…(5)
- rhythmic contractions of lymphatic vessels
- squeezing of skeletal muscle
- rhythmic pulsations of nearby arteries
- the thoracic (respiratory) pump
- rapidly flowing blood in the subclavian veins draws lymph into it
cells associated with lymphoid system (6)
- neutrophils
- natural killer (NK) cells
- T cells
- B cells
- macrophages
- dendritic cells
neutrophils
antibacterial cells
natural killer (NK) cells
lymphocytes that attack and destroy infected host cells and cancerous cells
T lymphocytes (T cells) mature in what loaction?
the thymus
B lymphocytes (B cells)
activation causes proliferation and differentiation into plasma cells and produce antibodies
macrophages
large phagocytic cells that act as APCs
antigen-presenting cells (APCs)
display antigens on surface to alert other immune cells
dendritic cells
APCs found in the skin, mucous membranes, and lymphatic organs
lymphatic tissue
aggregations of lymphocytes in the connective tissues of mucous membranes and various organs
diffuse lymphoid tissue
lymphocytes are scattered
where is diffuse lymphoid tissue prevalent? (4)
in body passages open to the exterior like the respiratory, digestive, urinary, and reproductive tracts
in mucous membranes, diffuse lymphoid tissue is called….
mucosa-associated lymphoid tissue (MALT)
lymphoid nodules (follicles)
lymphocytes and macrophages gather in dense masses
aggregated lymphoid nodules (2)
- formerly Peyer patches
- large clusters of nodules in the small intestine
T/F lymphoid nodules may be temporary or permanent features of some tissues
true
primary lymphoid organs (2)
- red bone marrow
- thymus
immunocompetent
able to recognize and respond to antigens
secondary lymphoid organs (3)
- lymph nodes
- tonsils
- spleen
what are locations where immunocompetent cells migrate and populate are called…
secondary lymphoid organs
what separates lymphatic tissues from neighoboring tissues?
connective tissue capsules
red bone marrow
soft, loosely organized, highly vascular material separated from osseous tissue by endosteum of bone
red bone marrow is involved in these two things
- hematopoiesis
- immunity
blood-forming cells attached to….
reticular cells and other elements of marrow stroma
what is secreted to stimulate stem cells to produce formed elements?
colony-stimulating factors
as blood cells mature, they…
push their way through the reticular and endothelial cells to enter the sinus and flow away in the bloodstream
thymus is a member of what systems (3)
endocrine, lymphoid, and immune systems
thymus
bilobed organ located in superior mediastinum between sternum and aortic arch
the thymus houses developing ______ and _____ hormones regulating their activity
T cells, secretes
with age, the thymus exhibits a large degree of _____
involution
by age 65, people are unable to make…
new T cells
immunosenescence
destruction and remodeling of immune organ structure as well as innate and adaptive immune dysfunction with aging
fibrous capsules of the thymus give off _____ that divide the gland into several lobes
trabeculae (septa)
lobes have _____ and _____ populated by T cells
cortex, medulla
thymic _____ cells involved in T cell development
epithelial
thymic epithelial cells secrete these signaling molecules…(5)
- thymosin
- thymopoietin
- thymulin
- interleukins
- interferon
cortical epithelial cells
along with pericytes, surround capillaries to form blood-thymus barrier
lymph nodes
bean-shaped structures that cleanse lymph and are sites of lymphocyte activation
what is the most numerous lymphoid organ?
lymph nodes, about 450 in a typical young adult !
the parenchyma is divided into the _____ and _____
cortex and medulla
germinal centers
in the cortex where B cells multiply and differentiate into plasma cells
several _____ lymphatic vessels lead into the node along its convex surface
afferent
lymph leaves the node through one to three _____ lymphatic vessels that leave the _____
efferent, hilum
cervical lymph nodes are found in the
neck
axillary lymph nodes are in the
armpit
thoracic lymph nodes are found in the
thoracic cavity, especially the mediastinum
abdominal lymph nodes are found in the
posterior abdominopelvic wall
intestinal and mesenteric lymph nodes are found in the
mesenteries and near the appendix and intestine
inguinal lymph nodes are found in the
groin
popliteal lymph nodes are found…
in the back of the knee
lymphadenitis
swollen, painful lymph node responding to foreign antigen
lymphadenopathy
collective term for all lymph node diseases
metastasis
cancerous cells break free from original primary tumor, travel to other sites in the body and establish new tumors
metastasizing cells easily enter _____ vessels
lymphatic
where do metastasizing cells generally end up?
they lodge in the first lymph node they encounter
cancerous nodes are usually… (3)
swollen, firm, and painless
after infecting a node, cancer tends to spread…
to the next node downstream
treatments for breast cancer (3)
- lumpectomy
- mastectomy
- along with removal of nearby axillary nodes
tonsils
patches of lymphoid tissue located at the entrance to the pharynx
what guard against ingested or inhaled pathogens
tonsils
tonsillar crypts
deep pits covered with epithelium lined by lymphoid nodules
tonsillitis
acute inflammation of palatine tonsils
spleen
the body’s largest lymphoid organ
where is the spleen
inferior to the diaphragm and posterolateral stomach
medial hilum
passage of splenic artery and vein, and lymphatic vessels
parenchyma of the spleen exhibits two types of tissue
red pulp and white pulp
red pulp
sinuses filled with erythrocytes
white pulp
lymphocytes, macrophages surrounding small branches of splenic artery
functions of the spleen (4)
- erythrocyte graveyard
- blood cell production in fetus
- maintains army of monocytes for release when needed
- stabilizes blood volume
how does the spleen stabilize blood volume?
through plasma transfers to lymphoid system
white pulp monitors blood for….
foreign antigens
ruptured spleen requires a….
splenectomy
what is the consequences of a splenectomy?
leaves the person susceptible to future infections and premature death
