Ch. 24-26 Flashcards
(87 cards)
What are the four parts of the lymphatic system?
- Lymph=a fluid similar to plasma, does not have plasma proteins
- lymphatic vessels=network that carries lymph away from peripheral tissues to the venous system
- lymphoid tissue & organs=found throughout the body
- lymphocytes, phagocytes and other immune system cells
What are the four lymphatic and immune functions?
- drain excess interstitial fluid=3L needs to be reabsorbed, not for exchange, just collected; uses WBC to “clean”, returns to blood
- Lymph=interstitial fluid as soon as it enters lymphatic system
- transport dietary lipids
- carryout immune responses=immune system contained in lymphatic system
What are the lymphatic capillaries?
for collection only; closed at one end, contain valves, one way flow into capillary & back to the heart; have large diameters & thinner walls than blood capillaries; located b/t cells, run with capillaries
What are the structures within lymphatic capillaries?
Endothelial cells= important in maintaining one way flow into capillaries
anchoring filaments=used to keep lymphatic caps open, prevents collapse
lacteals=specialized caps in small intestine to carry lipids from diet (chyle=liquid white fat from lacteals)
Describe lymphatic flow:
blood caps (blood)->interstitial space (IF)->lymphatic caps (lymph)->lymphatic vessels->lymphatic ducts->subclavian veins (blood)
What are the primary organs and tissue where lymphatic stem cells divide and develop?
Red bone marrow=hemocytoblasts produce B cells & pre-T cells
thymus gland=matures (educates) T cells
What are the secondary organs & tissue, where the immune response occurs (battlefield)?
Lymph nodes=lymph flows from one node to the next
spleen
lymphatic nodules
Describe lymph nodes:
There are about 600 located along lymph vessels; concentrated in breast, axillary, & groin
What are the parts of the lymph node and what do they contain?
capsule=outer covering
outer cortex=contains mostly B cells and macrophages
inner cortex=contains mostly T cells
medulla=B cells, antibodies from plasma cells and macrophages
Describe lymph node flow:
afferent lymphatic vessel (into node)->subscapular sinus->trabecular sinus->medullary sinus->efferent lymphatic vessel (out of node)
Designed to pass lymph by different WBC
How does metastasis work?
secondary tumor sites can be predicted according to the direction of lymph flow from the primary tumor site
What and where is the spleen?
largest single mass of lymphatic tissue, located on the left side b/t stomach and left kidney
What are the parts of the spleen?
Capsule=outer covering, contains hilus (splenic arteries, veins, and efferent lymph vessels)
Parenchyma=center of spleen, white pulp (tissue, lymphocytes, macrophages located around artery) and red pulp (blood filled venous sinuses, contains RBCs, leukocytes and plasma cells)
What are the spleen’s three functions?
- remove worn out RBCs
- store platelets (1/3 of body)
- produce blood cells when fetus
Describe the flow through the spleen:
blood enters white pulp where it is phaged (rid of blood born pathogens)->into red pulp->into splenic veins->liver
What and where is the thymus gland?
Sits on top of heart, covered by capsule, larger in kids than adults
What are the parts of the thymus gland?
cortex=pre T cells (immature cells) collect here from red bone marrow, this is where they mature
medulla=contains more mature T cells
epithelial cells=helps educate T cells by positive selection, only 20% make it (then leave to collect in spleen, lymph nodes and lymphatic tissue)
What and where are lymphatic nodules?
spread throughout the body; egg-shaped masses of lymphatic tissue not covered by a capsule
Describe the lymphatic nodules in the oral cavity:
tonsils: (1) pharyngeal=posterior wall of nasopharnyx, (2) palatine=back side of oral cavity and (2) lingual=back base of tongue
What is MALT?
Mucosa-Associated Lymphatic Tissue, spread throughout connective tissue of GI tract, urinary and reproductive systems
What is the appendix?
mass of fused lymphoid nodules
What is the innate defense of nonspecific resistance?
present at birth, offers immediate protection against a variety of pathogens, functions the same way regardless of the type of invader
What are the human body’s physical and chemical barriers that discourage pathogens from penetrating the body (first line of defense)?
Skin=physical barrier
mucous membranes=trap many microbes & foreign substances
lacrimal apparatus=provides tears to wash away irritants to the eyes
saliva=reduces growth of microbes in the mouth
urine flow=cleanses urethra
gastric juice=strong acidity destroys many pathogens
As part of the second line of defense, what do internal antimicrobial proteins do?
found in the blood and interstitial fluid, discourages growth of microbes