Lymphatic system Flashcards
How does the lymphatic system travel?
Milking motion from skeletal muscle
Always going towards heart
Located in interstitial spaces
Returns to veins close to the heart
What is the process of the lymphatic system?
Lymph from lymph capillaries (intermingled with normal capillaries) carried to LYMPH NODE (filtration and WBC maturation), then carried to SUBCLAVIAN veins near heart
What are the two lymphatic ducts and where do they drain from?
Right lymphatic duct (right arm, thorax, head)
Thoracic duct (everywhere else)
What is the purpose of lymph?
Returns fluid from interstitial fluid to blood
Water, blood cells, protein
What is the purpose of lymph nodes?
Filters lymph before returning to blood
Biological filter- Phagocytosis destroys particles
Mechanical filter- stops particles from moving through body
What are the different structures of a lymph node?
Afferent vessels (in) Efferent vessels (out)- fewer, lymph moves slowly
What is the purpose of the tonsils?
Two modes on side of throat that get rid of bacteria and foreign substances going in the mouth
What is the thymus and what is its purpose?
Produces hormones
Prepares T cells (adaptive immune system)
What is the spleen and what is its purpose?
Stores platelets, filters blood
Active immune response through humor all and cell mediated pathways
Rich in B and T Lymphocytes
What is the role of the intestines and appendix in the lymphatic system?
Peyers patches in intestines remove bacteria
Appendix removes bacteria
What is innate immunity?
Innate immunity- FIRST and SECOND LINE OF DEFENCE
-genetic mechanisms or mechanisms present at birth before being exposed to any conditions
Protects against NON SPECIFIC INVADERS
Responds immediately
NO MEMORY
What is the first line of defence?
SKIN- physical barrier
MUCOUS MEMBRANES- traps microorganisms (along GI tract)
NASAL HAIRS- filter
SECRETIONS OF SKIN- sebum, mucous, acids
GI TRACT- HCL to kill bacteria
TEARS AND SALIVA- clean and lubricate
What is the second line of defence?
PHAGOCYTIC CELLS that engulf invaders
- neutrophils
- macrophages
- some are fixed in organs, others float free in body
INFLAMMATION- inhibit iron, zinc- needed by bacteria. Releases histamine a that dilate blood Vessels, making them leaky, allowing easy access at invader
COMPLEMENT MECHANISM- plasma proteins that cause enemy cell to burst- circulate inactive through blood
NATURAL KILLER CELL MECHANISM- group of lymphocytes that kill types of cancer cells and virus infected cells
INTERFERONS- inhibit spread of viral infection
What is an antigen?
Anything that can induce an immune reaction
Bacteria, virus, fungi, allergens
What is the ADAPTIVE defence system?
THIRD LINE OF DEFENCE
Develops after born in response to specific antigens that enter body
More aggressive and slow than innate
Has memory
What is included in the third line of defence?
Lymphocytes
- T cells - mature in thymus
- B cells- mature in bone marrow
How do B cells work?
Produce ANTIBODIES that attack PATHOGENS
called antibody mediated immunity or HUMORAL IMMUNITY
antibodies circulate freely in plasma
How does HUMORAL IMMUNITY work?
B lymphocytes with specific receptors recognize and bind to antigens
Binding to antigen activates lymphocyte to undergo CLONAL SELECTION AND MULTIPLICATION
//Basically when antigen enters body, lymphocytes can select the specific antibody it needs (CLONAL SELECTION THEORY)
Large number of clones produced to make antibodies (primary humoral response)
B cells secrete produced antibodies, circulating in blood for 4-5 days
B cells become MEMORY B cells- ready to respond to same threat
How do T cells work?
Attack pathogens (virus, cancer. Infections) directly
Referred to as CELL MEDIATED IMMUNITY
T cell will activate macrophages to destroy pathogens
2 types of T-cells
-helper T cells- recruit other cells to fight invaders, activate chemical reactions in pathogen by binding to it
Cytotoxic T cells- kill infected cells by inserting toxic chemicals
What are allergies? What is happening when we have them?
Hypersensitivity to harmless antigen
Antibodies travel to cells that release histamine S and other inflammatory substances, causing an allergic reaction
What is the structure of antibodies?
4 amino acid chains, linked by disulphide bonds
2 identical amino acid chains are linked to form a HEAVY CHAIN (400 amino acids) - these determine type of ig (immunoglobulin- antibody)
2 identical amino acids form LIGHT CHAIN (220 amino acids)- antigen binding sites
What are the 5 different types of antibodies?
IgM 5%- protects blood stream
IgG 75%- cross placenta barrier, protect blood and tissues
IgA 15%- mucous membranes, saliva, tears, protects GI tract
IgE- allergies
IgD- activation of B cells
What are the different types of adaptive immunity?
Natural immunity
-natural passive: body gets antibody naturally (from mother to fetus)
-natural active: body gets infection then makes long term defence system
ARTIFICIAL IMMUNITY
-artificial active: body gets antigen from vaccine- long term antigen
-artificial passive: administered after exposure to antigen (ie, anti venom. Short lived, 2-3 weeks)
What are REGULATORY T CELLS?
- Release chemicals to suppress activity of T and B cells one invasion is conquered
- stop autoimmune diseases
What are the main functions of the lymphatic system?
Body defence and disease resistance
Transporting/draining interstitial fluid
Transports fats from GI tract
