Immunity Flashcards
What are the organs and functions of the lymphatic system?
Organs:
- Thymus,
- Spleen,
- Lymph (Vessels, Notes, Fluid),
- Red Bone Marrow (And more!)
Functions:
- Drain excess interstitial fluid from tissue spaces and return to the blood
- Transport dietary lipids and lipid-soluble vitamins absorbed by GI tract
- Carry our immune responses against particular microbes or abnormal cells
What are the features of lymphatic vessels? What are the features of lymphatic capillaries?
-
Lymphatic vessels -
- Closed at one end
- Like veins but thinner with more valves
-
Lymphatic Capillaries
- Allow lymph fluid to flow in but not out,
- Slightly larger than blood capillaries
- Have anchoring filaments to stretch when fluid accumulates
What is chyle? Why its color is creamy-white?
Chyle is lymph with lipids that drains from the small intestines specialized capillaries called Lacteals
Lipids cause its color to be creamy-white
What are the 5 main lymph trunks and 2 main lymph channels?
Trunks:
- Lumbar
- Intestinal
- Broncomediastinal
- Subclavian
- Jugular
Channels:
- Thoracic Duct
- Right Lymphatic Duct
How is thoracic duct formed?
From which area and to which vessel does the thoracic duct drain lymph?
From which area and to which vessel does the right lymphatic duct drain lymph?
Thoracic duct
- Formed at the dilation called the Cisterna Chyli
- Receives lymph from: left side of the head, neck, and chest, the left upper extremity, and the entire body below the ribs.
- Drains lymph into venous blood at the junction of the left internal jugular and left subclavian veins
Right lymphatic duct
- Receives lymph from the upper right side of the body.
- Drains lymph into venous blood at the junction of the right internal jugular and right subclavian veins.
What are the primary lymphatic organs? What is their major function?
Primary Organs:
- Red Bone Marrow
- Thymus
Function
- Sites where stem cells divide and become immunocompetent, capable of mounting an immune response
What is the location of the thymus? What are the component cells in outer cortex and inner medulla of the thymus?
The Thymus is located in the mediastinum between the sternum and the aorta
Component Cells of the Outer Cortex and Inner Medulla:
- Large number of T Cells
- Dendritic Cells
- Epithelial Cell
- Macrophages
This is where the T Cells under go self recognition (OC) and self tolerance (IM) but only 2% survive
What are the component parts of a lymph node? What are the functions of a lymph node?
- *Stroma** - The Connective Parts
- *Parenchyma** - Outer/Inner Cortex, Deep Medulla
Function as a filter
- Macrophages destroy foreign substances by phagocytosis
- Lymphocytes destroy foreign substances by immune responses
What are the component structures and cells in the outer cortex, inner cortex, and medulla of a lymph node?
Outer Cortex -
- Groups of B cells called lymphatic nodules (follicles)
Inner Cortex -
- T Cells and Dendritic Cells
Inner Medulla -
- B cells, antibody-producing plasma cells from cortex, and macrophages
How does the lymph flows through the lymph nodes?
Afferent Lymphatic Vessel -> directs lymph inward
Subcapsular Sinus -> sinus / irregular channels
Trabecular Sinus ->
Medullary Sinus ->
Efferent Lymphatic Vessel ->
Conveys lymph antibodies, and activated T cells out of the node
Where is the location of the spleen? What are the surface features of spleen?
Located in the left hypochondriac region between the
stomach and the diaphragm
Superior surface (Ribs)
Visceral surfaces with organs, gastric (stomach), renal (left kidney), and colic (left colic flexure of large intestine)
What are the component structures of white pulp of spleen?
White pulp – lymphatic tissue consisting mostly of lymphocytes and macrophages around branches of the splenic artery called central arteries
What are the component structures and function of red pulp of the spleen?
Red Pulp - Blood filled venous sinuses, cords of splenic tissues called splenic cords (Or Billroth’s Cords)
Red blood cells, Macrophages, Lymphocytes, Plasma Cells and Granuloctes
1) Removal of RBC by macrophages (ruptured, worn out, defective)
2) Storage of platelets - up to 1/3 of body’s supply
3) Production of blood cells during fetal life
Define lymphatic nodule. What are the locations of lymphatic nodules?
Egg-shaped masses of lymphatic tissue not surrounded by a capsule (and therefore not an organ)
Scattered throughout the body in mucous membranes of GI tract, Urinary, Reproductive, and Respiratory. In these areas they are called Mucosa-Associated Lymphatic Tissue (MALT)
What are the Peyer’s patches?
Large aggregations of lymphatic nodules in the ilieum of the small intestine
What are the locations of five tonsils on the pharyngeal walls?
Waldeyer’s tonsillar ring
1 Pharyngeal Tonsil (Adenoid) posterior wall of the nasopharynx
2 Palatine tonsils at the posterior region of the oral cavity
2 Lingual tonsils located at the base of the tongue
Classify immunity.
Immunity is classifed into:
- Innate Immunity (Non-Specific)
- Adaptive Immunity (Specific Immunity - Cell Mediated, Antibody Mediated)
What are the external (first line) physical and chemical components of innate immunity?
Mechanical:
- Epidermis of the skin
- Epithelial layer of mucous membranes
- Mucus, cilia and hairs of the nose
- Urine flow
- Vaginal secretions - Acidity of vaginal secretions
- Defecation and vomiting
Chemical:
- Lacrimal apparatus - Lysozymes of tears
- Flow of saliva - Lysozymes of Saliva
- Sebum of sebaceous glands
- Perspiration
- Gastric juice of the stomach (acidic)
What are the internal (second line) components of innate immunity?
- Antimicrobial proteins
- Interferons
- Complement
- Iron-binding proteins
- Antimicrobial proteins
- Phagocytes
- Natural killer cells
- Inflammation
- Fever
What are the component cells in the third line of body defense?
Specific Immune Response from B Cells and T Cells
Define Phagocytosis. What are the five steps of phagocytosis?
Phagocytosis is a non-specific process wherein neutrophils and macrophages (from monocytes) migrate to an infected area.
- Chemotaxis - chemically stimulated movement of phagocytes to site of damage
- Adherence - Attachment to the microb
- Ingestion - pseudopods engulf the microbe
- Digestion - enters cytoplasm and merges with lysosomes which break down
- Killing - digestive enzymes quickly kill
Define inflammation. What are the four characteristic signs of inflammation?
Inflammation is a nonspecific, defensive response of the body to tissue damage that results in:
- Redness
- Pain
- Heat
- Swelling
What are the three basic stages of inflammation?
- Vasodilation and increased permeability of blood vessels
- Emigration of phagocytes from the blood into intersitial fluid
- Tissue repair
What are the events occurring in vasodilation and emigration stages of inflammation?
Vasodilation allows more blood to flow to the damaged area which helps remove toxins and debris
- Increased permeability means defensive proteins can enter injured area
- Histamine released - causes vasodilation/permeability
- Local temp rises and increases reactions (heat)
- Edema results from increased permeability (swelling)
- Pain - kinins affect nerve endings, chemical reactions
Emigration - phagocytes arrive, neutrophils destroy invading microbes, die off quickly and then monocytes arrive (when the phagocytes die, they turn into pus)
Name of the physical factors of innate immunity. What are the functions of each
- Epidermis - Forms a physical barrier
- Mucous membrane - Inhbit entrance of microbes
- Mucus - trabs microbes in respiratory and GI tracts
- Hairs Filter out microbes and dust
- Cilia w/ mucus trap and remove microbes
- Lacrimal Apparatus - tears dilute and wash away irritating substance
- Saliva - washes microbes from surfaces of teeth
- Urine - Washes microbes from urethra
- Defecation and vomiting - expel microbes from body
Name the chemical factors of innate immunity. What are the functions of first line chemical factors?
- Sebum - forms protective acidic film over skin
- Lysozome - antimicrobrial substance in perspiration, tears, saliva, nose, and tissue fluids
- Gastric juice - destroys bacteria and most toxins in stomach
- Vaginal Secretions - slight acidity discourages bacterial growth
What are the antimicrobial substances forming the second line of defense? What are the functions of each of them?
- *Interferons** - Released by infected cells to induce synthesis of antiviral proteins to slow down replication
- *Complement System** - Enhances immune reaction causes cytolysis of microbes, promotes phagocytosis, contributes to inflammation
- *Iron-Binding Proteins** - inhibit the growth of certain bacteria by reducing avail iron
- *Anti-Microbial Proteins** - kill wide range of microbs, attract dendritic and mast cells
What are the functions of natural killer cells?
Attack any body cell that displays an abnormal or unusual plasma membrane protein
Play a very important role in fighting cancer
What is adaptive immunity?
What are the 2 aspects by which adaptive immunity differs from innate immunity?
Adaptive immunity is the ability of the body to defend itself against SPECIFIC invading agents
- SPECIFIC
- MEMORY
Define antigen. Define epitope
Antigens (Ags) – antibody generators, are substances recognized as foreign that provoke immune responses.
Epitopes – Antigenic determinants, small parts of a large antigen molecule act as triggers for immune responses
Define antigen presenting cells. Give examples.
Antigen-presenting cell engulfs and destroys a foreign invader and isolates the antigens of those cells to “display” and present to helper T cells (CD4)
Examples:
Dendritic cells
Macrophages
Which cells link the innate immune system and the adaptive immune system?
To which cells antigen presenting cells present the foreign antigens?
Antigen Presenting Cells (APCs) link the innate immune system to adaptive immune system
They present the antigen to Helper T cells to activate them (Using Class II MHC)
What are the functions of activated helper T cells?
Activated helper T cells aid in both types of immune responses and activate other lymphocytes to become:
T cytotoxic cells (CD8 cells) which directly kill foreign invaders
B cells (which make antibodies that kill or helps kill foreign invaders).
What are the functions of cytotoxic T and memory T cells?
Cytotoxic T Cells - Directly attack the foreign invader
Memory T Cells - rRspond to a subsequent exposure, do not actively participate, proliferating and differentiating into more effector and memory cells
Which cells are called effector cells in adaptive immunity?
What is their fate after immune response?
Effector cells are made up of:
- Active Cytotoxic T Cells
- Active Helper T Cells
- Plasma cells
Most die after immune response
What are the functions of memory T and memory B cells?
Memory T and Memory B cells are formed after the initial encounter with an antigen and create the immunological memory which allows the body to respond much faster to the next appearance (Hours)
Define MHC molecules.
What are 2 types of MHCs? To which cells each one presents the antigen?
Major Histocompatibility Complex Molecules - the proteins that are used as cell markers to flag self from non-self
- Class I MHC - in almost all body cells, present non-self proteins to Cytotoxic T Cells
- Class II MHC - only found on APC, present to Helper T cells
Which cells form the two arms of the adaptive immune response?
ACTIVATED T Cells and B Cells form the two arms of the adaptive immune response
Which cells are involved in cell-mediated immunity?
Helper T Cells (Effector and Memory)
Activated Cytotoxic T Cells - primary - Directly attacks
Which cells are involved in antibody- mediated immunity?
Helper T Cells
Activated B Cells (Primary)
Define a clone of cells.
What happens to the effector cells and memory cells of a clone after the initial immune response?
Clone — a population of identical cells, all recognizing the same antigen as the original cell.
After the initial immune response, effector cells die and memory cells live on to respond to a subsequent exposure
What are the mechanisms by which cytotoxic T cells destroy the infected cells?
Using receptors on their surfaces, recognize and bind to infected target cells that have microbial antigens. Release granzymes, protein-digesting enyzymes, that cause apoptosis, released microbes are destroyed by phagocyte
Release perforins - insert into the plasma membrane of the target cell and creates channels in the membrane, extracellular fluid flows into the cell and cytolysis occurs. Microbes are destroyed by granulysin
Cytotoxic T Cells may also target cells by releasing toxic molcule called lymphotoxin which activates enzymes that fragment the target cells DNA.
What is the process of activation and clonal selection of B lymphocytes?
- Antigen binds to B-cell receptors (BCRs)
- Antigen is taken into B cell, broken into peptide fragments and combined with MHC-II self antigens, moved to the B cell plama membrane
- Helper T Cells recognize the antigen-MHC-II complex and deliver the costimulation needed for B cell proliferation and differentiation
- Helper T cell produces Interleukin-2 and other cytokines that function as costimulators to activate B cells
- Once Activated it undergoes Clonal Selction - the result is the formation of a clone of B cells that consists of plasma cells (to secrete antibodies) and memory B cells
What are the 5 classes of immunoglobulins?
IgG, IgA, IgM, IgD, IgE
(GAMDE - Give Adam More Dollars Eve)
What are the characteristics of IgG, IgA, and IgE?
- IgG - Most abundant, found in blood lymph and intestines, monomer, protects against bacteria and viruses by enhancing phagocytosis, neutralizing toxins and triggering complement system - only class to cross placenta
- IgA - 10-15%, Mainly in Sweat, Tears, Saliva, Mucus, Breat milk, GI - levels decrease during stress, lowering resistance, Provides localized protection of mucous membrains
- IgE - Less than .1%, located on mast cells and basophils, involved in allergic and hypersensitivity reactions, provides protection against parasitic worms
Which cells produce the Igs?
What are the ways by which the antibodies are effective in producing immunity?
Plasma cells, that are derived from B lymphocytes, produce the Antibodies (Igs)
-
Neutralizing the Antigens - block/prevent attachment
2. Immobilizing bacteria (on cilia/flagella) - Agglutinating and precipitating antigen - clump them together
- Activating complement - classical pathway
- Enhancing phagocytosis - flag that attracts phagocytes once antigens are bound (opsonization)
Define active immunity and passive immunity.
Active immunity – the body’s response to make antibody after exposure to a pathogen (antigen) - LONG TERM
Passive immunity – the body simply receives antibodies that have been preformed - SHORT TERM
Give examples of natural active immunity, artificial active immunity and natural passive immunity.
Natural Active – contracting hepatitis A and production of anti-hepatitis A antibodies
Natural passive – baby receives antibodies from its mother through the placenta and breast milk
Artificial active – a person receives a vaccine of an attenuated (changed/weakened) pathogen that stimulates the body to form an antibody
Artificial passive – injection of prepared antibody
Define complements. What are their functions? What is MAC?
Complement is a defensive system made up of over 30 proteins produced by the liver and found circulating in blood plasma and within tissues throughout the body
Functions: destroy microbes by causing phagocytosis, cytolysis, and inflamtion
A membrane attack complex (MAC) forms as a result of activation of the complement cascade (The MAC results in lysis of the cell)
Most complement proteins are C1-C9
Which cells of the immune system can target and remove cancer cells from the body?
- Cytotoxic T cells
- Macrophages
- Natural killer cells (Most effective)
