Lymphatic System and Immune Flashcards
(23 cards)
Organization of Lymphatic System
Lymphocytes
Lymphatic Vessels
Lymph
Lymphoid Organs
Lymphocytes
Lymph cells that perform specific immune functions
Defend against both environmental hazards such as pathogens
And protect against internal threats such as cancer
Classified as a specific defense or the immune response
Lymphatic Vessels
Begins in peripheral tissues
Ends at a connection to the venous system
Lymph
Fluid that flows through lymphatic vessels
Similar to plasma but fewer suspended proteins
Lymphoid Organs
Connected to the lymph vessels
Lymph nodes, spleen and thymus
Functions of Lymphatic System
Production, maintenance, and distribution of lymphocytes
Lymphocytes respond to the presence of pathogens, abnormal body cells, foreign proteins
Carry fluid and solutes from tissues to blood
Distribution of hormones, nutrients and waste to general circulation
Lymphatic Vessels
Lymphatic capillaries
Lymphatic vessels
Thoracic duct
Right Lymphatic duct
Lymphatic capillaries
Present in almost every tissue and organ in the body.
Lacteals in the small intestine
Act as a one-way valve
Lymphatic vessels
Similar to veins including valves to prevent backflow
Thoracic duct
Lymph from parts of body inferior to the diaphragm and left side superior to the diaphragm
Lymphocytes
T Cells ~ 80% of lymphocytes Various “jobs” within immunity (killer, helper, suppressor) B Cells Produce antibodies NK Cells Immunological surveillance
Lymphocytes (origin and circulation)
Constantly circulating through blood, lymph and tissues
Survive for long time periods (4-20+)
Stem cells produced in red bone marrow
Differentiate into B, T, and NK Cells
As B and T Cells differentiate and mature they gain the ability to respond to the presence of a specific antigen
As NK Cells differentiate and mature they gain the ability to recognize abnormal cells
T-Cells migrate to the thymus for division and maturation
All end up in the blood-stream and peripheral tissues
Retain their ability to divide
Lymphoid Nodules
Loose connective tissue and lymphocytes
Size can increase or decrease
Often have areas of actively dividing lymphocytes
Often found in areas open to the external environment
Mucosa-associated lymphoid tissue (MALT) line digestive system
Aggregated lymphoid tissue (Peyer patches) line the intestines
Appendix
Tonsils
Pharyngeal, Palatine, Lingual
Guard entrance to digestive and respiratory tracts
Lymphoid Organs
Lymph Nodes
Thymus
Spleen
Lymph Nodes
Afferent vessels deliver lymph to the nodes
Efferent vessels deliver lymph away from the nodes
Filters lymph and detects and removes antigens
Stimulates immune response
Thymus
Gland behind the sternum above the heart
Site of T cell production and maturation
Spleen
Largest lymph organ (b/t stomach and left kidney)
Filters a large amount of blood detecting and removing antigens
stimulates the immune response
Chemical Mediator(Cytokines)
Interleukins
Increase T Cell sensitivity, stimulate B Cell Activity, enhance non-specific defenses, moderate the immune response
Interferons
Tumor Necrosis Factors
Inhibit tumor growth and kill sensitive cells
Phagocyte-Activating Chemicals
Colony-Stimulating Factors
Stimulate lymphocyte and RBC production
Miscellaneous Cytokines
Aid other aspects of the immune system and enhance blood cell production
Allergies, Asthma, Autoimmune Diseases Oh My
Allergy and Autoimmune Diseases are an inappropriate immune response to non-pathogen or self
Allergies have increased in prevalence across all age, sex and racial groups in the US and other “developed” countries
What is causing allergies etc… and their increase in prevalence? Novel stimuli? Genetics? Pollution? Cleanliness?
“Diseases of the Advantaged”
Allergies, asthma, ulcerative colitis and Crohn’s disease have all risen in frequency in developed nations (only in developed nations)
Asthma alone increased 75% from 1980 to 1994 (again, only in developed countries)
More siblings = less asthma & allergy risk
Pet in home when young = less asthma & allergy
The Hygiene Hypothesis
Dr. Erika von Mutius compared East and West Germany in 1989
Normal stimulation of the immune system during infancy and early childhood is essential for normal immune response
Without it, the immune system over reacts to harmless entities
Additional Evidence
High malaria rates = low autoimmune disorders
High tuberculosis exposure = lower asthma and hay fever rates
Previous exposure to hepatitis, Toxoplasma or H. pylori = lower asthma and hay fever rates
Schistosomiasis infection = less skin allergies
Additional Evidence
Asthma wheezing reduced when “cold” present
Higher endotoxin levels = less asthma and allergy
Vaginal births = less food allergies
De-worming = more digestive tract chronic diseases
Crohn’s disease and Trichuris suis
