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162 Cards in this Set
- Front
- Back
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Why is the spleen fragile |
It is mostly blood cells |
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Organization of the lymphatic system |
lots of lymph nodes where appendicular meets axial so infections don't travel to the heart |
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Where does a majority of infection enter the body |
Eyes and mouth |
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What does the lymphatic system do |
Protects us against disease caused by pathogens and microscopic organisms (viruses, bacteria, fungi, parasites that each attack in a specific way) |
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Lymphatic system cells respond to what |
Environmental pathogens, toxins, abnormal body cells (cancer) |
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What is lymphatic drainage |
Water continuously moves out of capillaries and back into the bloodstream (85% - 20.4 L/day) and via the lymphatic system (15% - 3.6 L/day) |
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What happens to the lymphatic system when you're dehydrated |
The lymph number drops so the lymphatic system doesn't work as well |
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What does lymphatic drainage ensure |
Constant plasma and interstitial fluid communication |
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What does lymphatic drainage accelerate |
Dissolution of gases through tissues |
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What does lymphatic drainage transport |
Insoluble lipids and tissue proteins that can't cross capillary walls |
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What does lymphatic drainage flush out of the lymphatic system |
Flushes bacterial toxins and chemicals to immune system tissues |
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4 parts of the lymphatic system |
Lymph lymphatic vessels (lymphatics) lymphoid tissue/organs lymphocytes, phagocytes and other immune stem cells |
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What is lymph |
A fluid similar to plasma with no plasma proteins |
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What are lymphatic vessels |
Network that carries lymph from peripheral tissues to the venous system |
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Function of lymphatic system |
Produce, maintain, and distribute lymphocytes |
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What percentage of circulating leukocytes are lymphocytes and where are most lymphocytes |
20-30% of circulating leukocytes, most are stored instead of circulating |
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3 types of lymphocytes (specific or nonspecific) |
Thymus dependent (T cells, specific) Bone marrow derived (B cells, specific) Natural killer (NK cells, non-specific) |
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What is the circulation of fluids in lymphatic system and what does it transport |
Circulate from blood plasma of the body to lymph and then back to the venous system in a one way track It transports hormones, nutrients, and waste products |
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What are lacteals and what do they do |
Special lymphatic capillaries in the small intestine that transport lipids from the digestive tract |
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What is lymphedema |
Blockage of lymphatic drainage from a limb that causes swelling and interferes with immune system function |
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What vessels does the lymphatic system begin with |
Smallest vessels (lymphatic capillaries or terminal capillaries) |
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Where are lymphatic vessels found |
Everywhere in the body except in the bone marrow and the central nervous system |
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How do lymphatic capillaries differ from blood capillaries |
-They start as pockets rather than tubes -Have larger diameters to transport larger molecules -Thinner walls (fluid moves by skeletal muscle compression) -Flat or irregular in section -Endothelial cells are loosely bound together with overlap |
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What feature of lymphatic capillaries acts as a one way valve |
Overlap. It allows fluids, solutes, viruses and bacteria to enter but prevents return to intercellular space |
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What vessels to lymphatic vessels travel by |
Veins |
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2 divisions of lymphatics |
Superficial lymphatics Deep lymphatics |
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Where are superficial lymphatics found |
In the skin, mucus membranes, and serous membranes lining body cavities |
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What are deep lymphatics |
Larger vessels that superficial that accompany deep arteries and veins |
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The lymphatics (superficial and deep) join to form what |
Large lymphatic trunks that empty into 2 major collecting vessels |
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The 2 major collecting vessels |
Right lymphatic duct (ride side from the diaphragm up) Thoracic duct (every other part of the body |
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Right lymphatic duct collects lymph from where and empties where |
Collects lymph from right jugular trunk, right subclavian trunk, right beonchiomediastinal trunk Empties into right subclavian vein |
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Where does the thoracic duct collect lymph from and where does it empty |
Collects from everything inferior to the diaphragm and everything superior to the diaphragm on the left side Empties into subclavian vein |
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What are cisterna chyli |
A sac like chamber at the base of the thoracic duct |
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Where are lymphocytes produced and stored |
In lymphoid tissues (tonsils), lymphoid organs (spleen, thymus), red bone marrow |
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What do lymphocytes do |
Detect problems and travel to site of injury or infection |
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Where do lymphocytes move |
From blood to interstitial fluid (lymph) through capillaries and returns to venous blood through lymphatic vessels |
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What are lymphoid tissues |
Connective tissues the are dominated by lymphocytes |
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Lymphoid nodules |
Areolar tissue with densely packed lymphocytes (about 1 mm in diameter) |
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What does the germinal center contain |
Dividing lymphocytes |
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Where are lymphoid nodules |
- lymph nodes - spleen - respiratory tract (tonsils) - in wall of pharynx (left and right Palatine tonsils, pharangeal tonsils (adenoid), 2 lingual tonsils) - along digestive and urinary tracts |
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Mucosa-associated lymphoid tissues (MALT) |
Lymphoid tissues associated with the digestive system |
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Peyers patches |
Aggregated lymphoid nodules that are clustered deep to the small intestinal epithelial lining the help keep e coli in place in the large intestine |
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What is the appendix and where is it located |
A mass of fused lymphoid nodules located near the junction of the small and large intestine |
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What are the lymphoid organs and how are they separated from surrounding tissues |
Lymph nodes, thymus, spleen Separated by fibrous connective tissue capsule (keeps what is in in and what is out out) |
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Lymphoid function early warning system |
- Like the bat signal for T lymphocytes - Antigen presentation occurs - First step in the immune response - extracted antigens are presented to lymphocytes or attached to dendritic cells to stimulate lymphocyted |
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What are antigens and what does antigen presentation ensure |
- Antigens are proteins made up of 20 random amino acids and are the bodies unique ID marker - ensures that it is the right cell at the right time and this happens while the cell is digesting the pathogen |
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Lymphoid tissues and lymph nodes do what |
They are distributed to monitor peripheral infection and the stimulate macrophage and lymphocytes in the nodes |
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What protein displays antigen fragments during antigen presentation |
Class II MHC proteins |
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Can lymphocytes self activate |
No Phagocytes have to digest the pathogen, antigen presentation happens, this signals t lymphocytes to bind to the antigen (lock and key fit), if the key fits then it signals the correct t lymphocyte |
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Lymph node functions |
Filter Macrophages Protect against pathogens in digestive/respiratory systems |
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How do lymph nodes act as filters |
They purify the lymph before its return to venous circulation and to the heart, removing 99% of antigens |
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What do macrophages do |
Engulf debris and pathogens |
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How do lymph nodes protect against pathogens in the respiratory/digestive systems |
The lymph nodes of the gut, trachea, lungs, and thoracic duct helps to keep stuff isolated to one area of the body instead of it getting to vital organs in the trunk |
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Lymph glands |
Large lymph nodes at groin and base of the neck that swell in response to inflammation due to dividing cells in the body |
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Size of lymph nodes |
1-25 mm in diameter |
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Hilum |
A shallow indentation where blood vessels and nerves reach lymph nodes |
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Trabeculae |
Bundles of collagen fibers extending from the capsule into the interior of the lymph node to help direct lymph flow to efferent vessels |
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2 types of lymphatic vessels and what they do |
Afferent - carry lymph from peripheral tissues to lymph nodes (dirty lymph) Efferent - leave lymph node at the hilum and carry lymph to venous circulation (clean lymph) |
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The thymus location, when it starts to deteriorate, and division |
Located in mediastinum Deteriorates after puberty, diminishing the effectiveness of the immune system since no new t lymphocytes with be made Has 2 distinct lobes (butterfly shape) |
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How are the lobes of the thymus divided |
Septa divides lobes into smaller lobules which contain a dense outer cortex and a pale central medulla |
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What do reticular epithelial cells (REC's) do |
Surround lymphocytes in the cortex Maintain the blood thymus barrier Secrete thymus hormones (thymosins) |
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What do thymosins stimulate |
Stem cell divisions and t cell differentiation (the ability to fight a specific antigen, gives a t cell its specific antigen ID) |
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What is the medulla formed from |
REC's form concentric layers called Hassell's corpuscles |
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What does the medulla not have |
A blood thymus barrier so t cells can enter or leave the bloodstream |
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Where do lymphocytes divide |
In the cortex, then t cells migrate into the medulla |
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Where do mature t cells go |
They leave the thymus by medullary blood vessels |
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3 functions of the spleen |
- removal of abnormal blood cells and other blood components by phagocytosis - storage of iron recycled from red blood cell - initiation of immune responses by B and T cells in response to antigens in circulating blood |
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Structure of the spleen |
-Inside the fibrous capsule • Red pulp - contains many red blood cells plus fixed and free macrophages • White pulp - resembles lymphoid nodules |
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Why is the spleen fragile |
It is mostly blood cells |
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Splenectomy |
The removal of the spleen due to damage and bleeding since there is not a way to repair the spleen, this makes you more susceptible to bacterial infection |
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What is lymphopoiesis and what does it involve |
Lymphocytes production that involves peripheral lymphoid tissues, bone marrow, and thymus |
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How are lymphoid stem cells made |
In the bone marrow hemocytoblasts divide into two type of lymphoid stem cells |
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What is produced in the bone marrow and where does it go |
In the bone marrow, B and NK cells are produced and B cells go to lymph nodes, spleen, and other tissues while NK cells migrate through the body In the thymus, the cells start at the bone marrow but go to the thymus to form t cells in an environment isolated by the blood thymus barrier via thymic hormones (differentiate by thymosin) |
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What do body defenses do and what are the categories |
provide resistance to fight infection, illness, and disease Nonspecific and specific defenses |
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What type of cells are nonspecific defense and how does it work |
NK cells It always works in the same way against any type of invading agent and operate with specific defenses to provide resistance to infection and disease It always happens first |
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What type of cells are specific defenses and what do they fight |
B and T cells They only fight 1 type of antigens |
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List non specific resistance |
Physical barriers Phagocytic cells Immunological surveillance Interferons Complement Inflammation Fever |
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Physical barriers (non specific resistance) |
Keep hazardous materials outside of the body Include the outer layer of skin, hair, epithelial layers of internal passageways, secretions that flush away materials (sweat glands, mucus, urine), and secretions that kill/inhibit microorganisms (enzymes, antibodies, stomach acid) |
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What do phagocytic cells do |
Attack and remove dangerous microorganisms (before lymphocytes are acitvated) |
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What type of phagocytic cell is the first line of cellular defense |
Neutrophils |
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What are the two types of phagocytic cells |
Microphages (eosinophil, neutrophil) Macrophages (derived from monocytes) |
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What is immunological surveillance |
It constantly monitors normal tissues with NK cells and can see when cells have foreign antigens on their surface (indicating a problem) and they attack the cells (body cells w/ viral infection, cancer cells, or bacteria Respond more rapidly than B or T cells, it is immediate |
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What are interferons |
Chemical communicators Cytokines are proteins released by activated lymphocytes, macrophages, and tissue cells infected virally that coordinate local activities They come into contact with a normal cell and trigger the production of antiviral proteins to block replication in the cell |
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Neutrophils (police who drives a Porsche, microphage) |
Are abundant (50-70%), mobile, fast, 1st at injury site, engulfs bacteria, most numerous, life span of 30 minutes to 10 hours, form pus |
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Eosinophils (microphage) |
Slower, not so numerous (1-5%), target pathogens coated with antibodies, reduces inflammation, good against parasites, wxocytosis of toxic compounds |
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How do microphages get to infections |
Leave the bloodstream and enter peripheral tissues to fight infections |
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Macrophages (police that drives a garbage truck) |
Large phagocytic cells derived from monocytrs that are distributed through the body |
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Once macrophages are activated, what is the response to the pathogen |
They engulf pathogen and destroy it with lysosomal enzymes, bind to the pathogen so other cells can destroy it, or destroy the pathogen by releasing toxic chemicals into interstitial fluid |
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2 types of macrophages |
Free - mobile and travel throughout the body through the tissues and blood Fixed (histiocytes) - stay in specific tissues or organs (dermis and bone marrow) |
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Special histiocytes and where they are found |
Microglia - in CNS Kupffer cells - found in liver sinusoids Langerhans cells - found in skin |
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What functional characteristics do macropgages and microphages share |
Emigration - move through capillary walls (ameboid movement) Positive chemotaxis - are attracted/repelled by chemicals in surrounding fluids Adhesion - phagocytosis begins when phagocyte attaches to target (surrounds it with a vesicle and digests it with lysosomes or peroxisomes) |
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NK cell activation |
NK cells identify and attach to abnormal cells, the golgi apparatus in the NK cell forms perforin, vesicles release the perforin and it loses the abnormal cell membrane |
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Complement proteins |
Plasma contains 11 proteins Form the complement system (cascade reacrion) and complement action of antibodies |
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2 pathways to activate complement system |
Classical and alternate pathway |
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The classical pathway |
The fast method C1 binds to antibody molecule attached to the antigen (bacterium, could take weeks to happen) Bound protein acts as an enzyme (catalyzes chain reaction) |
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Alternate pathway |
Slow method When you are exposed to the antigen, factor P, B, and D interact in the plasma Doesn't require antibodies |
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What do both the classical and alternate complement pathways end with |
The conversion of inactive complement protein (C3) to active form (C3B) |
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Effects of complement activation |
- Stimulation of inflammation - Attraction of phagocytes - enhancement of phagocytosis by opsonization (coat with complement proteins) - Destruction of target cell membranes (5 complement proteins join to form membrane attack complex or MAC) |
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Is inflammation widespread or localized and what is it triggered by |
Localized response triggered by any stimulus that kills cells and injures tissues |
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Cardinal signs/symptoms of inflammation |
• Swelling (tumor) - due to histamine increasing capillary for water to get through and vasodilstion bringing more blood to the area • Redness (rubor) - due to more blood flow • Heat (calor) - blood is warm • Pain (dolar) - due to swelling |
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3 effects of inflammation |
Temporary repair and barrier against pathogens Retards spread of pathogens into surrounding areas Mobilization of local and systemic defenses and facilitation of repairs (regeneration) |
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What do injured cells release |
Prostaglandins (affect metabolic rate), proteins, potassium ions |
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Injured cells releasing chemicals results in what |
The interstitial environment changes and stimulates mast cells to release histamine and heparin |
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What happens when mast cells release histamine and heparin |
There is increased blood flow causing area to swell, redden, and become painful. It also raises local temperature then a blood clot forms around the damaged area isolating it |
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What are the effects of raising local temperature |
Increase enzymatic reactions Increase phagocytosis activity Denature foreign proteins or viral enzymes |
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After blood clot forms, what do complements do |
They break down bacteria and attract phagocytes. Then activated neutrophils attack debris and bacteria, phagocytes and foreign proteins activate body's specific defense, macrophages clean up cell debris and pathogens, and fibroblasts form scar tissue |
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Products of inflammation |
Necrosis- local tissue destruction in area of injury Pus - mixture of debris and necrotic tissue and dead neutrophils Abscess - pus accumulated in an enclosed space |
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What is a fever |
A maintained body temperature above 37 °C or 99 °F |
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What does a high body temperature do |
- Increases body metabolism, each 1 °C increases rate by 10% - Accelerates defenses - Inhibits some viruses and bacteria ( both proteins which can be denatured by high temperature) |
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What are pyrogens |
Any material that causes the hypothalamus to raise body temperature (circulating pathogens, toxins, or antigen-antibody complexes |
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What is interleukin 1 (IL 1) |
A pyrogen released by active macrophages and is a cytokine |
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What does specific resistance respond to and what is another name for it |
Immunity and it responds to specific antigens with coordinated action of T cells |
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What do T cells provide and defend against |
Provide cell mediated immunity and defends against abnormal cells and pathogens inside cells |
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What do B cells provide and defend against |
Provide antibody-mediated immunity and defend against antigens and pathogens in body fluids |
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Difference between innate and acquired immunity |
Innate is present at birth and acquired requires exposure to Ag after birth |
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Two types of acquired immunity and the difference |
- active (your own immune system doing something): antibodies develop after exposure to antigen and result of immune response - passive (someone else): antibodies are transferred from another source |
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Types of active acquired immunity |
• Naturally acquired- through environmental exposure to pathogens • Induced - stimulate under controlled conditions through vaccines containing pathogens |
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What do vaccines contain |
Dead, inactive, or Ag from pathogen |
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Typed of passive acquired immunity |
- naturally acquired: antibodies acquired from the mother (placenta or breastmilk) - induced: by injection of antibodies (like rabies shot) |
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4 properties of immunity |
Specificity Versatility Memory Tolerance |
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Specificity property of immunity |
Each B or T cell responds only to a specific antigen (responds to the molecular structure of Ag) and ignores all others (lock and key fit) |
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Versatility property of immunity |
Body produces many types of T lymphocytes (trillions of B and T cells) which differentiate to different receptor combinations. Each fights a different type of Ag and an active lymphocytes clones itself to fight specific antigen until there is enough Ab |
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Memory property of immunity |
Some memory cells (inactive lymphocytes) stay in circulation and provide immunity against new exposures. The response will be faster, stronger, and longer lasting |
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Tolerance property of immunity |
The immune system ignores normal antigens and any B or T cell that attacks seld are destroyed during development |
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2 divisions of the immune response |
Cell mediated immunity (T cells) and antibody mediated immunity (B cells) |
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Immune response steps |
- Ag triggers B and T cells - T cells are activated first after phagocytosis - T cells attack Ag and stimulate B cells - B cells mature to plasma cells and make Ab's - Ab's bind and attack Ag |
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B cells - percentage and what do they differentiate into |
10-15% of circulating lymphocytes that differentiate into plasma cells |
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What do plasma cells do (formed from B cells)and what type of immunity |
Produce and secrete antibodies which bind to antigens Humoral immunity |
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Nk cells function and percentage |
5-10% of circulating lymphocytes that ate responsible for immunological surveillance and attack foreign cells, virus infected cells, and cancer cells |
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T cell types and percentage |
80% of circulating lymphocytes Cytotoxic T cells: attack cells infected by viruses and produce cell mediated immunity Helper T cells: stimulate function of T and B cells Suppressor T cells: inhibit function of T and B cells Memory T cells: made from cytotoxic and helper T cells |
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T cells only recognize antigens bound where |
To glycoproteins in cell membranes |
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Antigen presenting cells (APC's) are responsible for what |
Activating T cells against foreign cells and proteins |
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2 types of APC's |
Phagocytic APC: free and fixed macrophages (including kupffer cells of liver and microglia of CNS Pinocytic APC: langerhans cells in skin and dendritic cells in lymph nodes and spleen |
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What do Cytotoxic T cells do |
Seek out and immediately destroy target cells (quick/large numbers) If it binds to Ag displaying cell, it destroys it by releasing perforin to destroy antigenic cell membrane, secrete poisonous lymphotoxin to destroy target cells Activate apoptosis that causes the cell to die |
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The slow response takes how long and involves what |
Can take up to 2 days from the time of first exposure to an antigen for Cytotoxic T cells to reach effective levels Involves memory Tc cells which produce Cytotoxic T cells and stay in circulation to provide fast response if same antigen appears again |
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How long do Suppressor t cells take and what do they do |
Takes a few weeks They secrete suppression factors, inhibit response of T and B cells after initial immune response, and limit immune reaction to a single stimulus |
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What do Helper T cells do and how are they formed |
An activated CD4 cell divides into active T cells which secrete cytokine and memory T cells that remain in reserve They stimulate the function of T and B cells |
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AIDS reduced what cell population |
T cells |
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4 functions of cytokines |
- Stimulate T cells divisions (produce memory T cells and accelerate cytotoxic T cell maturation) - Attract and stimulate macrophages - Attract and stimulate NK cells - Promote activation of B cells |
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What do B cells do |
They are responsible for antibody mediated immunity (humoral) and attack antigens by producing specific antibodies |
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What is B cell sensitization |
First corresponding antigens in interstitial interstitial fluids bind to B cell receptors. The B cell is preparing for activation so it takes the antigen into the B cell where it is processed then it returns to the surface bound by a Class II MHC protein |
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Why are Helper T cells important |
A sensitized B cell is prepared for activation but it needs a Helper T cell activated by thr same antigen. Helper T cells bind to the MHC complex and secrete cytokines that promote B cell activation/division |
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What does an activated B cell divide into |
Plasma cells that synthesize and secrete antibodies into interstitial fluid Memory B cells that are like memory T cells and remain in reserve to respond to the next infection |
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7 functions of Ag-Ab complexes |
- Neutralization of antigen binding sites - Precipitation and agglutination: formation of the immune complex - Activation of complement - Attraction of phagocytes - Opsonization: increasing phagocyte efficiency - Stimulation of inflammation - Prevention of bacterial and viral adhesion |
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Primary and secondary responses happen in what kind of immunity |
Cell mediated and antibody mediated |
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What is the primary response and how does it work |
When there is a first exposure to produce the initial response and it can take up to 2 weeks for the peak response to develop. After this it declines rapidly. During this responsebantigens activate B cells, plasma cell differentiate, and the antibody titer slowly rises |
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What is a secondary response and how does it work |
Triggered by a subsequent exposure and it more prolonged/extensive and the memory cells are already primed. This activates memory B cells at lower antigen concentrations than the original and they secrete antibodies in massive quantities |
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What happens during bacterial infection responses |
- Neutrophils and NK cells begin killing the bacteria - Cytokines draw phagocyted to the area - Antigen presentation activates Helper T cells and Cytotoxic T cells - B cells activate and differentiate - Plasma cells increase antibody levels |
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Difference between bacterial and viral infection response |
During viral, Cytotoxic T cells and NK cells are activated by contact either virus infected cells |
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When can a fetus produce an immune response/immunological competence |
After exposure to an antigen at about 3-4 months |
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What happens with autoimmune disorders |
It is a malfunction of system that recognizes and ignored "normal" antigens so activated B cells make auto antibodies against body cells |
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What causes immunodeficiency diseases |
- problems with embryological development of lymphoid tissues (can result in severe combined immunodeficiency disease SCID) - viral infections like HIV (can lead to AIDS) - immunosuppressive drugs or radiation treatments (can lead to complete immunological failure) |
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What are allergies and allergens |
Allergies are inappropriate or excessive responses to antigens. Allergens are antigens that trigger allergic reactions |
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What is a Type 1 allergy |
Aka immediate hypersensitivity and it is a rapid and severe response to the presence of an antigen (most common, environmental allergies) |
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What does Type 1 allergy sensitization and second exposure do |
Sensitization leads to production of large quantities of large antibodies distributed throughout the body Second exposure leads to massive inflammation of affected tissues |
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What does the severity of an allergic reaction depend on |
The individuals sensitivity and the locations involved. Allergens in the bloodstream can cause anaphylaxis |
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What does anaphylaxis do |
It affects cells throughout the body by changing capillary permeability producing swelling (hives) on the skin and it makes the smooth muscles of the respiratory system contract so it is hard to breathe |
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What can cause anaphalactic shock (circulatory collapse) |
Peripheral vasodilation |
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What do antihistamine drugs do |
Block histamine released by MAST cells and can relieve mild symptoms of immediate hypersensitivity |
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What do glucocorticoids do |
They are secreted to limit immune response and if there is long term secretion (chronic stress) then it inhibitd the immune response and lowers the resistance to disease |
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Functions of glucocorticoids |
- depression of the inflammatory response - reduction in abundance and activity of phagocytes - inhibition of interleukin secretion |
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Effects of aging on immune response |
- thymic hormone production I'd greatly reduced - T cells become less responsive to antigens - fewer T cells reduces responsiveness of B cells - immune surveillance against tumor cells declines |
