Ch. 24-26 Flashcards
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
What is the complement system?
The complement system is made up of about 25 proteins that work together to assist, or “complement,” the action of antibodies in destroying bacteria. cause blood vessels to become dilated and then leaky, contribute to the redness, warmth, swelling, pain, and loss of function that characterize an inflammatory response.
What do interferons and tranferrins do?
interferons=prevent viruses from replicating
transferrins=iron binding proteins, reduces iron needed for bacterial growth
What are Natural Killer Cells?
5-10% of lymphocytes, attack cells that display abnormal plasma membrane proteins, T-lymphocytes; are non-specific
Phagocytes are specialized cells that ingest microbes and other cellular debris (neutrophils, macrophages). How do they work?
Chemotaxis=chemically stimulated movement of phagocytes
Adherence=attachment of phagocyte to microbe
Ingestion=process of engulfing the microbe
Digestion=uses digestive enzymes & strong oxidates (H2O2)
Killing=digestion & oxidation kills microbe
What is inflammation and the reason for it?
Defensive response to tissue damage; it’s an attempt to dispose of microbes, toxins, & foreign material at the site of injury to prevent the spread to other tissues and to prepare site for repair. ex: pathogens, abrasions, chemical irritation, cell disturbance, or extreme temperature
Describe the inflammation process:
Injured cells release prostaglandins, proteins, potassium ions; Changes interstitial environment & stimulates mast cells; Mast cells release histamine & heparin
Increased blood flow - raises local temperature, causes area to swell, redden, and become painful; blood clot forms - isolates it; complements break down bacteria & attract phagocytes; activated neutrophils attack debris & bacteria
phagocytes & foreign proteins activate body’s specific defense system, macrophages clean up pathogens & cell debris, fibroblasts form scar tissue
What are the products of inflammation?
Necrosis=local tissue destruction
pus=mixture of debris & necrotic tissue
abscess=pus accumulated in an enclosed space
What is a fever and how does it work?
abnormal high body temperature that occurs because of hypothalamic thermostat reset; it intensifies effects of interferons, inhibits some microbe growth, & speeds up reactions that aid in attack & repair. (pyrogens=any material that causes the hypothalamus to raise body temp; pathogens, toxins, antibody complexes
Describe how immunity is an adaptive defense with specific resistance:
Immunity is the ability to mount a specific resistance against specific antigens.
Specific=signals out foreign substances for destruction, also recognizes self
memory=remembers antigens & kills it faster on next encounter
systemic=affects the whole body; not restricted to the area of infection
What are antigens and three common pathways they enter lymphatic tissue?
anything perceived as foreign due to surface proteins
- enter bloodstream, trapped as they flow through spleen
- penetrate skin, enter lymphatic vessels & lodged in lymph nodes
- penetrate mucous membranes & become entrapped by MALT