BIOL 320 1st EditionLecture 11Outline of Last Lecture I. Regulation of MAPII. Extrinsic Factors Affecting BPIII. Homeostatic Imbalances for BP- Hypotension- HypertensionIV. Circulatory Shock- Definition- Result- TypesV. Vascular Disorders- Atherosclerosis- ArteriosclerosisVI. Developmental Aspects- Formed from?- Fetal Shunts- Umbilical Veins & Arteries- Vessel Formation- AgingI. Lymphatic Systema. Functionsb. Lymph Fluid Formation?c. VolumeII. Lymphatic Vesselsa. Lymph Capillariesb. Endothelial Liningc. Collectsd. Collecting VesselsIII. Lymphatic Drainagea. Pathwayb. TransportIV. Lymphatic Collecting Vesselsa. Characteristicsb. Transportc. Acquire Nutrients?V. Lymph Transport (REVIEW)VI. Lymphoid Cellsa. Macrophagesb. Lymphocytesi. Functionsii. TypesVII. Lymphoid Tissuesa. Lymph Nodesi. Regional Concentrationsii. Functioniii. Primary Cell Typeiv. CharacteristicsOutline of Current Lecture VII. Specific Lymphoid TissuesVIII. Lymphatic PathologyIX. Developmental Aspects of Lymphatic SystemI. Immune Systema. Functionsb. Innate Defensesc. Adaptive DefensesII. Surface BarriersCurrent LectureSpecific Lymphoid Tissues- Peyer's Patches:o Location: ilium (part of small intestine)o Function: destroy pathogen that has managed to breech intestinal wall- Spleen:o Location: next to stomacho Function: RBC destruction/recycling; platelets storage and release; home for numerous lymphocytes; Fe stored for recycling RBCs- Thymus:o Location: inferior to larynx by/near lungso Function: produces hormones that mature T-lymphocytes; largest in kids & shrinks/atrophies with age- Tonsils (Waldeyer's Ring):o Location: palatine, adenoid, & lingualo Function: filter throat area- MALT: mucosa associated lymphatic tissue; Peyer's patches, tonsils, appendix, nodules in bronchiole wallLymphatic Pathology- Edema: swelling; atypical accumulation of fluid- Elephantiasis:o Cause: results from filariae parasite invading lymph nodes from extremitieso Result: lymph vessels blocked/dismantled; swelling of lower extremities- Lymphoma: cancer of lymphatic systemo Hodgkin's Characteristic: giant B cells (Reed-Steinburg) Symptoms: swollen, non-painful lymph nodes; fatigue; persistent fever; night sweat Treatment: radiation Cure rate: high If you have had mono, more susceptibleo Non-Hodgkin's: all other cancers of lymphoid tissues; metastasis of undifferentiated lymphocyte Symptoms: swollen nodes, spleen, Peyer’s patches High-grade:- Target: young people- Treatment: 50% remission with chemo Low-grade:- Target: elderly- Treatment: not really respondingDevelopmental Aspects of Lymphatic System- 5th week: beginnings of lymphatic system- Origin (not thymus): mesoderm- Thymus origin: endoderm (out-pocketing/growth of pharynx)- At Birth: poorly developed (except spleen and tonsils)Immune System- Functions:1. Defensive system protect body from invasion2. Repel pathogens3. Immediately respond to exposure-- Innate Defenses = born with; always present…don't develop with exposure to environment; "non-specific" defenseso A) Surface Barriers – 1st line of defense Skin: stratified squamous epithelial; keratinized; resists weak acids/bases, bacterial enzymes & toxins Mucous membrane: "wet"; line all body cavities open to exterior; similar to protective function of skin Cilia: trap inhaled particles in nostrils & upper respiratory tract Secretions: sweat, mucous, sebum, acids, saliva Specific Barriers:o 1) Skin: pH 3-5; inhospitable to microbes; sebum contains anti-microbe toxinso 2) Stomach: pH 2; acid neutralizes bacteria & protein-digesting enzymes secretedo 3) Vagina: low pH; acids produced by normal bacterial flora;WHY yeast infections?- pH becomes more neutral (antibiotics) & yeast thrive- Normal male secretionso 4) Tears: enzymes with anti-microbial propertieso 5) Saliva: anti-bacterial/microbial enzymeso 6) GI Tract & Respiratory Tract: foreign particles trapped on/by cilia will be washed to GI tract by mucous where it will be broken downo B) Internal Defenses – 2nd line of defenseo Foreign particles that get past surface barriers now face the internal defenses (PHAGOCYTES), such as: 1) Macrophages = monocytes that have left the bloodstream- Fixed (kept in specific area…ex: Kupffer cells in liver, microglia in brain…)- Free (wander about body looking for problems…ex: skin, alveoli…) 2) Neutrophils = most abundant WBC; become phagocytic when encounter pathogen; release "defensins" which pierce pathogen membrane (BUT kill selves in process…unlike macrophages) 3) Eosinophils = weakly phagocytic; important against parasites (discharge contents of granules over "prey") 4) Mast cells = (most known for role in allergies); phagocytize bacteria readilyo In order for phagocytosis to occur: adherence must occur (somehow must "stick" to them…to outside matrix)o Events of Phagocytosis 1) Phagocyte adheres to pathogens or debris 2) Phagocyte forms pseudopods that eventually engulf the particles forming a phagosome 3) Lysosome fuses with phagocytic vesicle, forming a phgolysosome 4) Lysosomal enzymes digest the particles, leaving a residual body 5) Exocytosis of the vesicle removes indigestible and residual materialo Terms of Phagocytosis: Opsonization = "makes tasty"; coated with compliment protein and antibody…making it easier for phagocytes to grab and eat…coating foreign particles with mix of antibody & complement protein; makes "handles" for phagocytes to grab Adherence: doesn't always work- Ex: pneumococcus…difficult to grab carbohydrate capsule presento Natural Killer Cells (NKCs) = "police"o Function: induce apoptosis in tumor and virus-infected cells o Cell type: large granular lymphocytes, NOT phagocytic (attack cell membrane & release "perforins")o Mechanism of Action: 1) Non-specific: kill self (virus infected) & other cells = much less picky than lymphocytes 2) Does NOT require activation of adaptive immune system 3) Enhances inflammation (via chemicals)- 4) Release perforins (lyse offending cells)o Inflammatory Response Trigger: any kind of tissue damage (trauma, excessive temperatures, chemical burns, infection…); damaged tissue release chemicals --> inflammation Four cardinal signs: heat, redness, swelling, pain, impairment of function Benefits:- 1) Prevents spread of damaging agents- 2) Enhances tissue repair- 3) Dispose of