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 • 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, it bathes the cells… • 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 of Mammary and Axillary Regions

9. Lymphatic Cells (WBC’s) • Macrophages • Large WBC’S that eat invaders • Tlymphocytes • Mature in Thymus • B lymphocytes • Mature in Bone marrow • Memory cells • Specialized B & T lymphocytes that recognize a pathogen (invader) after it has been encountered and react with a quick response

10. Lymphatic Organs • Organs of the immune system • 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

11. Thymus Gland • Thymus gland is located posterior to the sternalangle (above the heart) • Thymus gland produces T cells

12. 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 (eat) foreign matter • lymphocytes respond to antigens

13. Swollen Lymph nodes • Lymph nodes filter lymph • Common site for metastatic cancer • 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

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

15. 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. • Most common reason for tonsillectomy today is apnea

16. Spleen • Largest mass of lymphatic tissue, 5 inch long • 3 Functions- • Immune function: filters blood for antibody covered invaders • Recycles old & damaged blood cells • Stores blood to prevent shock

17. 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

18. 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: the skin • toughness of keratin • dry and nutrient-poor • lactic acid (acid mantle) is a component of perspiration barrier • Barrier: gastrointestinal 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

19. Nonspecific Resistance to Disease- Internal • Natural killer cells: lymphocytes & Phagocytes • Fever • Can kill or prevent invader from reproducing • How high is too high? Coma and death occurs at 111F- 115F, practically 104-5 degrees is the limit • Inflammation • suffix -itisdenotes inflammation of specific organs • Pain, heat, redness, swelling • Increased blood flow, temp & WBC’s leaking out

20. Specific Immunity • Immunity is the bodies ability to defend against specific invaders such as viruses, toxins, bacteria • This system is Antigen based- substances that are recognized as foreign and provoke an immune response • Immunology- study of the immune response

21. Antigens (Bad Guys) • Antigen means Antibody Generator- these guys stimulate antibodies production, like pollen to an allergic person, usually made of protein • Antibodies are proteins designed by the immune system to lock onto a specific part of an invader and mark it for destruction. They are specific to a particular invader.

22. Primary & Secondary Immune Response • Primary Response • Primary response happens the first time a pathogen is encountered. It takes 5-7 days to mount a specific response (antibodies), so the illness will last 7 – 10 days. • Secondary Response • Secondary response occurs at each subsequent encounter with that pathogen. Memory cells will trigger immediate response to the antigens, so that the person may not even feel ill.

23. Active & Passive Immunity • Active Immunity • A result of actually encountering the antigen • Can happen by getting the disease or by vaccination • Vaccination exposes the body to a weakened or killed version of the disease • Passive Immunity • Receiving antibodies from another person • Mother’s milk • “blood serum” – antibodies filtered from another person’s blood

24. Hypersensitivity (Allergy) • Excessive immune reaction against antigens that most people can tolerate called allergens • Hypersensitivity- Acute (most common) • anaphylaxis: 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

25. Immunodeficiency Diseases • Severe Combined Immunodeficiency Disease • hereditary lack of T and B cells • vulnerability to opportunistic infection • One disease that has been successfully treated with genetic engineering

26. 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

27. 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

28. 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