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Lymphatic System - Marieb
Terms in this set (54)
What are three functions of the lymphatic system?
1. fluid recovery
3. lipid absorption
What is the function of lymphatic vessels?
To pick up and return excess tissue fluid (and leaked proteins) to the cardiovascular system
What is lymph?
a colorless fluid containing white blood cells, that bathes the tissues and drains through the lymphatic system into the bloodstream.
collected from tissues by capillary beds.
How is lymph circulated throughout the body?
The lymph flows from the interstitial fluid through lymphatic vessels up to either the thoracic duct or right lymph duct, which terminate in the subclavian veins, where lymph is mixed into the blood. Have one-way valves that prevent backflow.
What are the functions of lymph nodes?
act as filters, contain many leukocytes
What are three regions where there is a large concentration of lymph nodes?
Axilla, groin, neck
What are the clinical symptoms of lymph nodes when there is an infection?
Describe the function of the spleen
Stores platelets, matures B lymphocytes, brings blood into contact with lymphocytes and macrophages, removes worn out RBCs
function of thymus
site of T cell maturation
Name the body's first, second, and third line of defense.
1st and 2nd lines of defense are innate or nonspecific immune systems
3rd line of defense is adaptive, specific immune system
What are nonspecific defense mechanisms?
2. Chemical action
What are natural killer cells?
Large granular lymphocytes, target cells that lack "self" MHC1 cell-surface receptors. Induce apoptosis in cancer cells and virus infected cells. Secrete potent chemicals that enhance the inflammatory response.
Describe the inflammatory response
Inflammation occurs in 3 main stages: vasodilation or increased permeability of blood vessels, the emigration of phagocytes, and the tissue repair phase.
How is fever an immune response?
Fever may allow interferons to work optimally, and it inhibits some microbial growth, increases the mobility of leukocytes, and increases the phagocytic activity of leukocytes. Happens when immunity response is overwhelmed.
What is a specific immune response
defense response against a specific foreign or abnormal cell
What is an antigen?
a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.
What are the two types of lymphocytes and how does each function?
T cells, B cells, and natural killer cells.
T cells - developed in the thymus gland. Cells are distinguished by the specialized T-cell receptor molecule that is located on the surface of the cell. This molecule is important in immunity because it recognizes antigens and is able to bind to them.
B cells - mature in the bone marrow of humans. Cells distinguished from other lymphocytes by a protein on their surface known as the B-cell receptor. This protein is specialized to recognize and attach to specific antigens.
Natural killer - are known to be cytotoxic. This means that they have the ability to kill other cells. These cells are an important part of the immune system because they are able to recognize virally infected cells, as well as some types of tumor cells, and kill them before they cause a great amount of harm.
What are the two subgroups of B lymphocytes?
memory cells, plasma cells
What is B lymphocyte sensitization?
The B-Lymphocyte internalizes the antigen and presents it in a different form on its surface.
T helper cells recognize this and bind to the B cell releasing cytokines.
This sensitizes or primes the B cell and it undergoes clonal selection, which means it reproduces asexually by mitosis. Most of the family of clones become plasma cells.
These cells, after an initial lag, produce highly specific antibodies at a rate of as many as 2000 molecules per second for four to five days.
The other B cells become long-lived memory cells.
Describe a primary immune response
The Primary Immune Response - when a pathogen enters the body it takes time to produce cloned plasma B cells which secrete antibodies complementary to the pathogens antigen. The antibody level in the blood will rise, however the delay can result in the person suffering from the disease. Once the pathogen has been eliminated the blood antibody level falls. Specific Memory B cells will remain
Describe a secondary immune response
The Secondary Immune Response - If the same pathogen (with same antigens) reinvades the body, the specific memory B cells will be activated, clone rapidly to produce more antibodies faster.
naturally acquired active immunity
develops after exposure to antigens in environment
naturally acquired passive immunity
Transplacental or via colostrum
artifically acquired active immunity
artificially acquired passive immunity
antibodies gathered from a human or other animal and are injected into an individual. Ex.) antiserum for a snakebite.
What are antibodies?
Substances created in the body to attack specific foreign substances called antigens.
located on B cell membranes where they act as antigen receptors
When bound to B cell membrane, serves as antigen receptor; first Ig class released to plasma by plasma cells during primary response; potent agglutinating agent; fixes complement.
Main antibody of both primary and secondary responses; crosses placenta and provides passive immunity to fetus; fixes complement. memory cells. small and cross the placenta.
Bathes and protects mucosal surfaces from attachment of pathogens.
Binds to mast cells and basophils, and triggers release of histamine and other chemicals that mediate inflammation and certain allergic responses.
B-lymphocytes are active in antibody-mediated immunity and T lymphocytes are active in ___________ immunity.
Killer T cells
Lymphocytes that use enzymes to destroy the cell membranes of bacteria and other foreign invaders.
Helper T cells
One type of T lymphocyte that activates B cells and other T lymphocytes
Suppressor T cells
a lymphocyte that can suppress antibody production by other lymphoid cells.
What do macrophages do?
phagocytize foreign substances and help activate T cells
Why do our bodies reject tissue or organs from someone else?
Cell mediated- or adaptive immunity.
class I or class II MHC antigens, which are the main T cell targets involved in rejection of a transplanted tissue or organ
exaggerated (hypersensitive) responses to antigens called allergens
A disorder in which the ability of an immune system to protect against pathogens is defective or absent.
Autoimmune diseases occur when
Antibodies develop and begin to destroy the body's own cells
A chronic and infectious disease in which the body's immune system is damaged, making a person vulnerable to a number of serious, sometimes fatal, infections and cancers.
Explain the "immunological balancing act" during pregnancy
General enhancement of innate immunity and suppression of adaptive immunity. Antibody mediated response is enhanced, and the communication between the two is dis regulated.
this allows a state in which the host mother will not attack the fetus during pregnancy.
What class of antibodies pass through the placenta and what are the results of this transfer?
Results in passive immunity against pathogens, epigenetic inheritance of immunologic memory, immunological imprinting, suppression of IgE responsiveness and suppression of tumor development
How long does the passive immunity in the newborn last after birth?
3-4 months after birth, antibodies gone by 9 months. Start to make own IGg by 6 months.
Role of amniotic fluid in immunity
The cytokines and prostaglandins in the amniotic fluid might impact the development of the immune system of the fetus.
Amniotic fluid plays a role in defense of the fetal and uterine structures against infection, signaling the uterus that the fetus has sustained an infection, initiating parturition, and/or modulating the maternal immune response to prevent rejection of the fetus.
What are some organisms that commonly transfer across the placenta?
Listeria, Treponema pallidum, HIV-1, parvovirus B19, rubella, toxoplasmosis, cytomegalovirus.
What are some of the immunological benefits of human milk?
IgA cross into breastmilk and are protective for intestinal organisms particularly.
The more pathogens the parent was exposed to, the more protection she passes on to their infant.
All classes are found, but IgA is predominant. IgG are consistent for at least the first 180 days.
IgA and M are highest in colostrum.
Long term benefits include decreased: asthma, food allergies, GI and respiratory infections, necrotizing enterocolitis, diabetes mellitus.
What classes of immunoglobulins are found in colostrum and human milk?
How does a mother's antigenic exposure relate to the immunological properties of her milk?
The more pathogens the parent was exposed to, the more protection she passes on to their infant.
Ideally, why should immunization of women occur at least 3 months before conception?
To reduce the risk of infection and adverse fetal effects. Risks associated with immunization during pregnancy include fetal viremia, teratogenesis, interference with development of the infant's response to immunizations during childhood, and maternal side effects that might compromise uteroplacental function.
What are the two major reasons newborns are more vulnerable to infection?
Altered host defense mechanisms, particularly in the preterm infant.
a lack of experience and exposure to many common organisms, resulting in delayed or diminished adaptive immune responses to foreign antigens.
What might elevated levels of IgM in the newborn suggest?
Infection in utero
Describe the changes that occur in a newborns normal colonization by organisms in the days after birth.
Newborns are normally colonized with organisms in parental genital tract. Also parental skin flora and other organisms in the environment.
Gut is initially sterile but within hours begins colonization. Diet significantly influences the pattern of bacterial flora.
Oligosaccharides in breastmilk help prevent colonization with pathogenic organisms by competing for mucosal bacterial receptors.
Also creates an acid environment in which lactobacillus and bifidobacterium thrive, preventing growth of acid-sensitive organisms.
one-way circulation towards the heart. contain frequent one-way valves.
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