Chapter 21 Lymphatic and Immune Systems

1. Chapter 21Lymphatic and Immune Systems • Maintains fluid balance • Protect body from infection and disease

2. Lymphatic Vessels Within Capillary Network • Lymphatic capillaries weave through blood capillaries.

3. 2 Major Functions of Lymphatic System • 1.) Fluid recovery • absorbs plasma proteins and fluid from tissues and returns it to the bloodstream • interference with lymphatic drainage leads to severe edema • lipid absorption • Lacteals in small intestine absorb dietary lipids • 2.) Immunity • fluids from all capillary beds are filtered • immune cells stand ready to respond to foreign cells

4. Lymphatic Obstruction Elephantiasis- mosquito-borne infection effect the skin to cause it to thicken. Also, the scrotum of men and breasts of women are similarly effected.

5. Lymph and Lymphatic Tissue • Lymph • clear, colorless fluid, similar to plasma • Lymph is like blood in the vascular system • This fluid flows within lymphatic vessels • Lymphatic tissue is specialized connective tissue that contains lymphocytes

6. Route of Lymph Flow • Lymphatic vessels are vein-like, have valves and go along the course with arteries and veins • Lymphatic vessels permits interstitial fluid to flow in and out • The flow- Lymphatic capillaries to: • Lymphatic vessels to: • Lymph nodes. • So lymphatic vessels, unlike blood circulation, don’t have arteries but start with capillaries.

7. Valve in a Lymphatic Vessel • Why valves?

8. Lymphatic Drainage

9. Lymphatic Drainage of Mammary and Axillary Regions • Drainage of Right side of the body: • Right lymphatic duct to: • Right subclavian

10. Drainage of Thorax • Drainage of the Left side of the body: • Cisterna Chyli (sis-turn-a ki-lay) to Thoracic Duct to Left Subclavian vein.

11. 4 Mechanisms of Lymph Flow • 1.) Moved along by rhythmic contractions of lymphatic vessels and Cisterna Chyli (“Heart for the lymph”) • 2.) Flow aided by skeletal muscle pump • 3.) Thoracic pump aids flow from abdominal to thoracic cavity • Valves prevent backward flow • 4.) Rapidly flowing bloodstream in subclavian veins, draws lymph into it • Exercise significantly increases lymphatic return

12. Lymphatic Cells • T lymphocytes • Mature in Thymus • B lymphocytes • Mature in Bone marrow • Secondary lymphatic organs- sites where the B and T cells carry out the immune response • Lymph nodes • Spleen

13. Lymphatic Organs • At well defined anatomical sites. • Lymph nodes • cervical, axillary and inguinal regions close to surface • thoracic, abdominal and pelvic groups deep in cavities • Tonsils • guard entrance to pharynx • Spleen • inferior to diaphragm on the left • Thymus • behind sternum

14. Thymus Gland • Thymus gland is located posterior to the sternal angle • Thymus gland produces T cells • The thymus may not become atrophied as we age

15. Lymph Node • Lymph Nodes- approximately 600 bean shaped nodes in the body • Lymph nodes - only organs that filter lymph • reticular tissue cells (like a network of cotton fibers), macrophages phagocytize foreign matter • lymphocytes respond to antigens • lymphatic nodules-germinal centers for B cell activation

16. Lymph Node

17. Lymphadenopathy • Collective term for all lymph node diseases • Lymphadenitis • swollen, painful node responding to foreign antigen • Lymph nodes are common sites for metastatic cancer • swollen, firm and usually painless

18. Swollen Lymph nodes • Lymph nodes filter lymph • Foreign substance are trapped • Macrophages destroy by using phagocytosis • Examination of swollen glands: • Neck- sweep from clavicle on SCM to ear • Axilla- place hand at apex, lower arm • Groin- palpate just below pubic bone by femoral artery

19. CANCER Firm, hard Non-movable No fever Not painful Diagnosis- neoplasm INFECTION Soft Movable Fever Painful Diagnosis- swollen lymph nodes Differential Diagnosis of Nodes

20. “Don’t Yank Me!” • Tonsils- aggregation of lymphatic tissue at the ring of the throat • The tonsils, are strategically positioned to participate in immune response against foreign substances that are inhaled or ingested. • Research shows that tonsillectomy is related to respiratory problems • Appendix- Lymphoid tissue that assists in ______ _________

21. Spleen • Largest mass of lymphatic tissue, 5 inch long • 3 Functions- • Immune function: assists red bone marrow and liver • Clears blood from RBCs and WBCs • Blood storage, platelets are stored • The spleen- “Mean, bloody and clean”

22. Resistance to Disease • Resistance- your body’s ability to ward off disease • Two Types: • 1.) Nonspecific • General defense such as skin, mucous membranes, acidity of the stomach • 2.) Specific (also called Immunity) • Specific defense, produces specific cells (lymphocytes) that combat particular bugs • results from prior exposure, protects against only a particular pathogen • immune system • Susceptibility- the body’s lack of resistance

23. Nonspecific Resistance to Disease- External • Immediate protection against a wide range of pathogens, general not a specific response • External resistance to disease- passive defense (Barrier- like castle walls, moat- flow) • Barrier: the skin • toughness of keratin • dry and nutrient-poor • defensins: peptides, from neutrophils attack microbes • lactic acid (acid mantle) is a component of perspiration barrier • Barrier: gastrointestinal barrier • Leaky gut syndrome is a break in this barrier • Flow: mucous • stickiness of mucus • lysozyme: enzyme destroys bacterial cell wall • Flow: cilia, tears, saliva, urine, defecation, vomit, diarrhea, sebum, perspiration, gastric juice, vaginal secretions

24. Natural Killer Cells and Phagocytes • Natural killer cells are lymphocytes that kill microbes and tumor cells • It can mess with the membrane of the bug causing cytolysis or it can bind to the cell and never get off it’s back • Phagocytes- ingest microbes by 5 processes: • Chemotaxis- chemical from infection attract phagocytes • Adherence- jumps on the bugs back • Ingestion- pseudopods “hug” the bug • Digestion- from enzymes and lethal oxidants, • Killing • Two major phagocytes are: Neutrophils, Macrophages

25. Inflammation • Defense response from cell damage due to bugs, physical trauma or chemical agents such as diet • suffix -itis denotes inflammation of specific organs • Cardinal signs • paincaused by inflammatory chemicals (bradykinin, prostaglandins) secreted by damaged cells, pressure on nerves • heatcaused by hyperemia • redness(erythema) caused by hyperemia ( blood flow) • swelling(edema) caused by  capillary permeability and filtration • “Pa, He Read Swell” • Diet loaded with refined foods, hydrogenated oils, dairy products can cause subclinical inflammation and disease

26. Tissue Repair • Facilitated by hyperemia that provides materials needed and heat that increases metabolism • Fibrin clot may provide a scaffold for repair • Painis your normal friend, it tells you to attend! • it limits use of body part allowing for repair

27. Fever • Elevation of core temperature • Most common cause is infection • Defense mechanism: Up to a point fever is beneficial • promotes interferon activity and phagocytosis • accelerating metabolic rate and tissue repair • inhibiting pathogen reproduction • How high is too high? Coma and death occurs at 111F- 115F, practically 104-5 degrees is the limit

28. Specific Immunity • Immunity is the bodies ability to defend against specific invaders such as viruses, toxins, bacteria • This system is Antigen (Ags) based- substances that are recognized as foreign and provoke an immune response • Immunology- study of the immune response • Immune system principal components- Thymus, Red Bone Marrow

29. Antigens (Bad Guys) • Antigen means Antibody Generator- these guys stimulate antibodies production, like pollen to an allergic person, usually made of protein • Two important characteristics: • 1.) Immunogenicity- the ability to provoke an antibody reaction • 2.) Reactivity- the ability to react with the antibody it provoked

30. Of Bs and Ts • The cells that develop immunocompetence, the ability to carry out an immune response are B and T cells. • Both start mostly in the bone marrow, Bs mature in the bone marrow but Ts leave home and go to the thymus to mature • Both cells acquire antigen receptors that can detect antigens.

31. T Cell Doing What It Does Best…

32. …Destruction of Cancer Cell

33. Immunological Memory • A hallmark of the immune response is memory, this memory is for the antigen that triggered the response in the past • Long lasting antibodies “embody” this memory • When you recover from an infection without taking antibiotic drugs, if at a later time you are infected again by the same bug the response will be swift, so swift that you may not know you were infected • Vaccination work on the theory that man can induce immunological memory this is called: artificial active immunity

34. Vacinations- Pros and Cons • Pro- Small Pox • Con- Black Death that swept through Europe in the 14th century killing more than 25 million people, a third of the European population • Con- Polio vaccine • http://www.hrsa.gov/vaccinecompensation/table.htm

35. Antibody Classes • Immuno globulins- glycoprotein antibodies • IgA: Stress decreases, less protection for mucous membrAnes against bacteria and viruses • Exercise raises levels of Ig A • IgD: Minor antibody • IgE: Protects against parasites, involved in allErgy • IgG: The Great antibody, most abundant and protests against bacteria and viruses • IgM: Antibody in blood plasMa (creates ABO blood type) • In acute infection- IgM, Chronic infection- IgG

36. Hypersensitivity (Allergy) • Excessive immune reaction against antigens that most people can tolerate called allergens • Hypersensitivity- Acute (most common) • anaphylaxis: IgE (allErgy) mediated, mucus hypersecretion, congestion; hives, watery eyes, runny nose • Asthma (most common chronic illness in children) • inhaled allergens, bronchiole constriction • Anaphylactic shock: bronchiolar constriction, dyspnea, vasodilation, shock, death; treatment- epinephrine

37. Immunodeficiency Diseases • Severe Combined Immunodeficiency Disease • hereditary lack of T and B cells • vulnerability to opportunistic infection

38. Immunodeficiency Diseases • AIDS • HIV structure • invades helper T cells, macrophages and dendritic cells by “tricking” them to internalize viruses by receptor mediated endocytosis • reverse transcriptase (retrovirus), uses viral RNA as template to synthesize DNA, new DNA inserted into host cell DNA, may be dormant for months to years

39. HIV Structure Comparing cells to bacteria to viruses- If a typical cells was about 2 feet a bacteria would be a speck, if a bacteria was 2 feet the virus would be a speck.

40. AIDS • Signs and symptoms • early symptoms: flulike chills and fever • progresses to night sweats, fatigue, headache, extreme weight loss, lymphadenitis • normal T cell count is 600 to 1,200 of blood but in AIDS it is < 200 • thrush: white patches on mucous membranes may appear • Kaposi sarcoma: cancer originates in endothelial cells of blood vessels causes purple lesions in skin

41. HIV Transmission • Through blood, semen, vaginal secretions, breast milk, or across the placenta • Most common means of transmission • sexual intercourse (vaginal, anal, oral) • contaminated blood products • contaminated needles • Not transmitted by casual contact • Undamaged latex condom is an effective barrier to HIV especially with the spermicide nonoxynol-9