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Immune system Karlie Casillas P.5 - Coggle Diagram
Immune system Karlie Casillas P.5
Major functions of the lymphatic & immune system
Lymphatic vessels:
elaborate network of drainage vessels
Offer a one way system, ensuring lymph flows toward heart
Include capillaries and larger lymphatic vessels
Lymphatic capillaries:
blind ended vessels that weave between tissue cells and blood capillaries
Lacteals: specialized lymph capillaries present in intestinal mucosa
Larger lymphatic vessels:
lymph capillaries drain into increasingly larger vessels collecting lymphatic vessels
Consists of collecting vessels trunks, and ducts
Have thinner walls, with more internal valves
Lymphatic trunks:
which are formed by union of largest collecting vessels, drain larger areas of body
Lymph is delivered from trunks into one of tow large lymphatic ducts
Right lymphatic duct drains right upper arm and right side of head and thorax
Thoracic duct drains rest of body
Lymphoid cells
: lymphocytes- cells of the adaptive immune system
2 types - T cells ( T lymphocytes)
B cells ( B lymphocytes)
T cells and B cells protect against antigens
T cells:
manage immune response, and some also attack and destroy infected cells
B cells:
produce plasma cells, which secrete antiboides
Macrophages -
phagocytize foreign substances and help activate T cells
Dendritic cells-
capture antigens and deliver them to lymph nodes
Location of lymphatic organs and their functions
Lymphoid organs are grouped into two functional categories
Primary lymphoid organs
: areas where T and B cells mature (red bone marrow and thymus)
Secondary lymphoid organs:
areas where mature lymphocytes first encounter their antigen and become activated
Nodes, spleen, MALT and diffuse lymphoid tissues
Spleen:
largest lymphoid organ, located in left side of abdominal cavity, below stomach
Mucosa associated lymphoid tissue (MALT):
lymphoid tissues in mucous membranes throughout body
Protects from pathogens trying to enter body
Tonsils:
function is to gather and remove pathogens in food or air
Appendix:
offshoot of first part of large intestine
Thymus:
bilobed lymphoid organ found in inferior neck, functions as lymphoid organ where T cells mature
Purpose and examples of First, Second, and third line of defense
First:
Physical barrier to most microorganisms
Keratin is resistant to weak acids and bases, bacterial enzymes and toxins
Mucosae provide similar mechanical barriers
Acid
: acidity of skin and some mucous secretions inhibits growth
Enzymes:
respiratory mucus
Second
: Phagocytes, natural killer cells, inflammatory response, antimicrobial proteins, fever
Phagocytes
: white blood cells that ingest and digest foreign invaders
Neutrophils
: most abundant phagocytes, but die fighting
Macrophages
: develop from monocytes and are chief phagocytic cells
Innate (natural) immune defenses
Constitutes first and second line of defesne
First line of defense:
external body membranes ( skin and mucosae)
Second line of defense:
antimicrobial proteins, phagocytes, and other cells( inhibit spread of invaders: inflammation most important mechanism)
Surface barriers:
skin and mucous membranes
Internal defenses:
phagocytes, natural killer cells, inflammation, antimicrobial proteins, fever
Adaptive (acquired) immune defense
Third line of defense:
attacks particular foreign substances ( takes longer to react than innate)
Humoral immunity
: B cells
Cellular immunity:
T cells
Eliminates almost any pathogen or abnormal cell in the body
Humoral response & cellular response
Humoral immunity:
Antibodies, produced by lymphocytes, circulate freely in body fluids
Bind temporarily to target cell, mark for destruction
Cellular immunity:
lymphocytes act against target cell
Directly- by killing infected cells
Antigens and Antibodies
Antigens:
substances that can mobilizes adaptive defenses and provoke an immune response
Targets of all adaptive immune response
Can be a complete antigen or hapten
Can be a self antigen
Antibodies
: also called immunoglobulins are proteins secreted by plasma cells
Capable of binding specifically with antigen by detected by B cells
Grouped into one of five Ig classes
Antibodies do not destroy antigens, they inactivate and tag them
Artificial vs. Naturally acquired immunity
Naturally acquired immunity
in Active humoral immunity is when it's formed in response to actual bacteria or viral infection,
Artificial acquired immunity
in active humoral immunity is when its formed in response to to vaccine of dead pathogens.
Naturally acquired immunity
in passive is when antibodies are passed from mother to fetus from the placenta
Artificial acquired immunity
in passive is an injection of exogenous antibodies
Passive vs. Active immunity
Active humoral immunity:
occurs when B cells encounter antigens and produce specific antigen bodies against them
2 types of active immunity: Naturally acquired:
formed in response to actual bacteria or viral infection
Artificially acquired
: formed in response to vaccine of dead or attenuated pathogens.
Passive humoral immunity:
occurs when ready-made antibodies are introduced into body
Naturally acquired
: antibodies delivered to fetus via placenta or to infant through milk
Artificially acquired:
injection of serum, such as glamma globulin
Cells involved in the immune system and their functions
Antigen presenting cells:
Dendritic cells, macrophages, B cells
Dendritic cells:
found in connective tissue and epidermis
Macrophages:
Widely distributed in connective tissues and lymphoid organs
B lymphocytes:
Do not activate naive T cells, present antigens to helper T cell to assist their own activation
Disorders associated with the immune system
Pus
: creamy yellow mixture of dead neutrophils, tissue cells and living dead pathogens
Hodgkin's disease
: is an acquired immunodeficiency that causes cancer of B cells
AIDS:
Human immunodeficiency virus cripples immune system by interfering with activity of helper T cells
Autoimmune disease:
results when immune system loses ability to distinguish self from foreign
Autoimmunity:
production of auto antibodies and sensitized T cells that destroy body tissues