Lymphatic System Study Guide

pathogenic

disease causing

immune system

cell pop that inhabit all organs/defends the body from agents of disease

lymphatic system

network of organs and vein like vessels

functions of the lymphatic system

fluid recovery, immunity, lipid absorption

fluid recovery

fluid continually filters from the blood capillaries to tissue space

immunity

excess filtered fluid picks up foreign cell/chem from the tissues

lipid absorption

lacteals in small intestine absorbs dietary lipids that are not absorbed by blood capillaries

edema

swelling of body tissues caused by excess fluid trapped inside them

lymphedema

a chronic condition characterized by, usually, arm or leg swelling caused by a buildup of protein-rich lymph fluid when the lymphatic system is damaged or blocked, often after cancer treatment

elephantiasis

a tropical parasitic disease caused by microscopic, thread-like worms transmitted through mosquito bites

components of the lymphatic system

lymph, lymphatic vessels, lymphatic tissues, lymphatic organs

lymph

recovered fluid, clear colorless fluid, similar to plasma but contain much less protein

lymphatic vessels

transport the lymph

lymphatic tissues

composed of aggregated of lymphocytes and macrophages that populated many organs in the body

lymphatic organs

defense cells are especially conc in these organs

separated from surrounding organs by connective tissues capsules

lymphatic capillaries

closed at one end

tethered to surrounding tissue by protein filament

endothelial cell loosely overlapped

allow bacteria/cells entrance to lymphatic capillary

create valve like flaps that open when interstitial fluid pressure is high, close when low

route of lymph flow

collecting vessels

course through many lymph nodes

6 lymphatic trunks

drain major portion of body (jugular, subclavian, bronchomediastinal, intercostal, intestinal, lumbar)

right lymphatic duct

union of right jugular, subclavian, bronchomediastinal lymphatic trunks

thoracic duct

on left side, larger/longer

begins as prominent sac in abdomen-cisterna chyli

receives lymph from below diaphragm, left arm, left side of head, neck, thorax

pathway of lymph flow from the right arm, left head and from the left leg

lymph flow at ___ and ___

low pressure, speed

each collecting ducts drain to ___

subclavian vein

valves

prevent backwards flow

moved along primarily by ___ of lymphatic vessels

rhythmic contractions

flow aided by ___

skeletal muscle pump

thoracic pump

aid flow from abdominal to thoracic cavity

rapidly flowing bloodstream

subclavian veins draws lymph to it

exercise significantly inc lymphatic return

lymphatic (lymphoid) tissue

aggregations of lymphocytes in mucous membrane/various organs

diffuse lymphatic tissue

simplest form

lymphocytes are scattered

prevalent in body passages open to exterior (respiratory, digestive, urinary, reproductive tracts)

lymphatic nodules (follicles)

dense mass of lymphocytes/macrophages that congregate in response to pathogens

lymph nodes: tonsils, appendix

payer patches

dense clusters in the ileum

primary lymphatic organs

red bone marrow and thymus

site where T and B cells become immunocompetent

able to recognize/respond to antigens

secondary lymphatic organs

lymph nodes, tonsils, spleen

immunocompetent cells populate these tissues

red bone marrow involved in

hemopoiesis-blood formation

immunity

thymus

very large in fetus

after age 14 begins involution(shrinkage)

elderly mostly composed of fatty/fibrous tissue

member of both endocrine/lymphatic system

contains developing T-lymphocytes

secrete hormones that regulate T-cells developement (thymopoientin/ thymosins)

capsules gives off trabeculae, divide parenchyma to cortex and medulla

label a lymph node

lymph nodes

organs that filter lymph and acts as T and B cell activation

mostly numerous lymphatics organs (450 in adults)

enclose with fibrous capsule with trabeculae that divide interior to compartments

stroma of reticular fibers/reticular cells

fewer efferent vessels, slow flow through nodes

reticular cells/macrophages phagocytize foreign matter

lymphocytes respond to antigens

common sites for metastatic cancer

tonsils

covered by epithelium

pathogens get into deep pits (crypts), encounters lymphocytes

there are 5

palatine tonsils

pair at the posterior margin of oral cavity

most common infected

tonsillitis-inflammation of tonsils

tonsillectomy- removal of tonsils

lingual tonsils

pair at the root of tongue

pharyngeal tonsil (adenoids)

single tonsil on back wall of nasopharynx

spleen

inferior to diaphragm, dorsal to stomach

highly vascular-vulnerable to trauma

ruptured spleen requires splenectomy

spleen diagram

red pulp

sinuses filled with erythrocytes

white pulp

rich in lymphocytes, macrophages

functions of spleen

blood production in fetus

blood reservoir

RBC disposal

immune reactions- filters blood/quickly to detect antigens

first line of defense

external barriers: skin, mucous membranes

second line of defense

non specific defense

leukocytes/macrophages, antimicrobial proteins, immune surveillance, inflammation, fever

effective against broad range of pathogens

third line of defense

immune system

defeat pathogen and leaves the body with memory so it can defeat it faster in the future

nonspecific defenses

broadly effective, no prior exposure

external barriers

inflammation,fever

specific defenses

results from prior exposure

protects against 1 particular pathogen

immune system

external barriers

skin, mucous membrane, subepithelial areolar tissue

skin

dry/poor nutrient

toughness of keratin

defensins-peptides attack microbes

lactic acid- component of sweat

mucous membrane

stickiness of mucus

lysozyme-enzyme destroy bacterial cell wall

subepithelial areolar tissue

tissue gel is a viscous barrier of hyaluronic acid

hyaluronidase- enzyme used by pathogen to circumvent hyaluronic acid defenses

phagocyte

WBC that engulf/absorb waste material in the blood stream/tissue

5 types of leukocytes

neutrophils, eosinophils, basophils, monocytes,lymphocytes

neutrophils

wander in tissue/phagocytize bacteria

create killing zone

degranulation- lysosome discharge to tissue fluid, trigger respiratory burst

create O2-, H2O2

eosinophils

found in mucous membrane

phagocytize antigen-antibody complexes, allergens, inflammatory chem

block excess inflammation, limit action of histamine

antiparasitic effects- aggregate/release enzymes to parasites

basophils and mast cells

aid mobility/action of WBC by release of histamine,heparin,leukotrienes

histamine (vasodilator)

inc blood flow to infected tissue

heparin (anticoagulant)

prevent immobilization of phagocytes

leukotrienes

activate/attract other leukocytes

lymphocytes %

contains 80% T-cells, 15% B-cells, 5% NK cells

T/B cells are part of ___ immune response

specific

natural killer (NK) are ___ specific

non

monocytes

move from blood to connective tissue/transform to macrophages

macrophages

phagocytic cells

wandering macrophages

actively seek pathogens

widely distributed in loose connective tissue

fixed macrophages

only phagocytize pathogens that come to them

microglia-central nervous system

alveolar macrophages(dust cells)-lungs

hepatic macrophages- liver

interferons

polypeptides secreted by cells invaded by viruses

antiviral effect

don’t benefit the cell that secrete them

interferons diffuse to neighboring cell/stimulate them to produce antiviral proteins

activate NK cells/macrophages, destroy infected host cells

anticancer effect

activated NK cells can destroy cancer cells

4 method of pathogen destruction

inflammation, immune clearance, phagocytosis, cytolysis

3 routes of complement activation

classical, alternative, lectin pathways

Membrane Attack Complex

creating holes in target cell

electrolytes leak out, water flow in rapidly →cell rupture

complement protein form ring in plasma membrane of target cell causing cytolysis

immune surveillance

phenomenon in which natural killer cells continually patrol the body on the lookout for pathogens/disease host cell

fever

promotes interferon activity

accelerate metabolic rate/tissue repair

inhibit pathogen reproduction

fever over 104F can be dangerous

antipyretics

fever reducing medications inhibit PGE2

stage of fever

onset (body temp rise), stadium(body temp oscillate), defervescence (body temp returns to normal)

Reye syndrome

serious disorder in children younger than 15 following an acute viral infection such as chickenpox/influenza

swelling of brain neurons, fatty infiltration of liver/other viscera, pressure of swelling brain

can be triggered by aspirin

inflammation

defensive response to tissue injury

limit spread of pathogens, destroys them, removes debris, initiates tissue repair

-itis suffix

cardinal sign of inflammation

redness(erythema)-caused by hyperemia (inc blood flow)

swelling (edema)- cause by inc capillary permeability/filtration

heat-caused by hyperemia

pain (-algia)- caused by inflammatory chem secreted by damaged cell, pressure on nerves

cytokines

class of chems that regulates inflammation/immunity

secreted mainly by leukocytes

alter physiology/behavior of receiving cell

act at short range, neighboring cells (paracrines) or same cell that secrete them (autocrines)

includes: interferons, interleukins, tumor necrosis factor, chemotactic factors ,etc

3 major process of inflammation

mobilization of body defenses, containment/destruction of pathogens, tissue cleanup/repain

what happens in the first phase of inflammation – mobilization of defenses

most immediate req for dealing with tissue injury to get the defensive leukocytes to the site quickly

hyperemia

inc blood flow

local vasodilation due to vasoactive chems

margination

leukocytes adhere to blood vessel wall

diapedesis/emigration

leukocytes crawl through gaps in endothelia cells/enter tissue fluid

endothelia cells separate causing ___

inc capillary permeability

fibrinogen

filters into tissue fluid gets activated to form fibrin

clot

forms sticky mesh that walls off microbes

heparin

prevents clotting at injury site

edema

contributes to tissue cleanup

swelling compresses veins/reduces venous drainage

force open valves of lymphatic capillaries, promoting lymphatic drainage

lymphatics collect/remove bacteria, dead cells, proteins, tissue debris better than blood capillaries

specificity

immunity directed against a particular pathogen

memory

reexposed to the same pathogen, body reacts so quickly that there is no noticeable illness

humoral immunity

antibody mediated

cellular immunity

cell mediated