Lymphatic System Flashcards
Three primary functions of lymphatic system
- draining excess interstitial fluid and returns lost plasma proteins to the bloodstream
-Transporting dietary products
-Carrying out immune responses
More permeable than the blood capillaries
Lymphatic capillaries
What are the lipid-soluble vitamins from diet that are absorbed by the GI Tract that enter the lymphatic capillaries and become part of the lymph
Vitamins A,D,E,K
Immune responses that are carried out by the T cells and B cells (agranulocytes produced by lymphatic organs and tissues) with macrophages’ help
Cell-mediated and antibody-mediated immune responses
Clear, pale-yellow fluid present in lymphatic tissues and transported by lymphatic vessels.
Lymph
The lymph draining from the small intestines, which means juice and is creamy white because it contains lipids
Chyle
Three types o lymphatic vessels
Lymphatic capillaries and larger lymphatic vessels, lymph trunks, and lymphatic ducts
Tiny vessels found in the interstitial spaces, slightly larger in diameter than blood capillaries
Lymphatic capillaries
Specialized lymphatic capillaries in the small intestines that carry dietary lipids into lymphatic vessels and eventually into the blood
Lacteals
When lymphatic capillaries merge, it forms ____ similar to veins, but with thinner walls and more valves
larger lymphatic vessels
Form as lymphatic vessels exit lymph nodes
Lymphatic trunks
Drain lymph from the lower limbs, the wall and viscera of pelvis, kidneys, and adrenal glands, and the abdominal walls
Lumbar trunks
Drain lymph from the stomach, intestines, pancreas, spleen, and part of liver
Intestinal trunks
Drain lymph from thoracic wall, lung and heart
Bronchomediastinal trunk
Drain lymph from upper limbs
Subclavian trunks
Drain lymph from the head and neck
Jugular trunk
Lymph from lymphatic trunks drains into two main channels collectively known as ___
Lymphatic ducts
Receives lymph from the left side of the head, neck, chest, left upper limb, and entire body inferior to ribs
Thoracic (left lymphatic) duct
A dilation from where thoracic duct arises
Cisterna chyli
Collects lymph from the right and left lumbar trunks and from the intestinal trunks
Cisterna chyli
Accepts lymph from the left jugular, subclavian, and bronchomediastinal trunks and drains lymph into venous blood at the junction of the left internal jugular and left subclavian veins
Thoracic duct
Collects lymph from the upper right side of the body. Accepts lymph from the right jugular, subclavian, and bronchomediastinal trunks and drains lymph into venous blood at the junction of the right internal jugular and right subclavian veins
Right lymphatic duct
True of false. More fluid filters out of blood capillaries than the amount that returns to them by reabsorption
true
The pump accomplished by the milking action of skeletal muscle contractions compressing the lymphatic vessels, and forcing lymph toward the junction of jugular and subclavian veins
Skeletal muscle pump
Pump that is associated with breathing. Lymph flows from an area of high pressure to low pressure
Respiratory pump
Lymph flows from the abdominal region towards thoracic region
inhalation (breathing in)
Lymph flows from the thoracic region towards the abdominal region
exhalation (breathing out)
Primary lymphatic organs
Red bone marrow and thymus gland
Secondary lymphatic organs
Lymph nodes, spleen, and lymphatic nodules (follicles)
Serves as the sites where stem cells divide and become immunocompetent capable of mounting an immune response
Primary lymphatic organs
Give rise tp mature, immunocompetent B cells and pre-T cells in RBM, which migrate to and become immunocompetent in thymus gland
Pluripotent stem cells
A bilobed organ found in the mediastinum between the sternum and aorta
Thymus gland
Extensions of the capsules that divides the two lobes of thymus glands, penetrate inward and divide each lobe into lobules
Trabeculae (little beans)
Comprised large numbers of T cells and dispersed dendritic cells. The immature T cells from RBM transferred into the cortex multiply and start to mature
Outer cortex of thymus gland
structurally similar to neurons’ dendrites with their long, branched projections, support the
pre-T-cells’ maturation process
dendritic cells
have several long processes that
surround and serve as a framework for about 50 T cells; they help “educate” the pre-T cells
in a positive selection process
Epithelial cells
True or false. Only about 3% of
developing T cells survive in the cortex and enter the inner medulla. The remaining T cells
die via apoptosis (programmed cell death).
False - 2%
Help remove cellular debris in thymus
Thymic macrophages
is consists of widely distributed, more
mature T cells, epithelial cells, dendritic cells, and macrophages.
Inner medulla of thymus gland
Some of the epithelial cells
become arranged into concentric layers of flat cells that degenerate and become filled with
keratohyalin granules and keratin. These clusters are called _______________
thymic (Hassall’s) corpuscles
thought to serve as T cell death sites in the medulla of thymus gland
thymic (Hassall’s) corpuscles
Serve as site for most immune responses
Secondary lymphatic organs and tissues
The capsule, trabeculae, reticular
fibers, and fibroblasts constitute the ____ (supporting connective tissue) of a lymph node
stroma
in the lymph nodes, it contains egg-shaped masses of B cells called lymphatic
nodules (follicles).
Outer cortex of superficial cortex
Lymph node’s _____ consists of outer and inner potion
Superficial cortex
Consists chiefly of B cells
primary lymphatic nodules
forms in response to an antigenic challenge and are sites of
plasma cell and memory B cell formation
secondary lymphatic nodule
part of lymph nodes, it does not contain lymphatic
nodules, but it consists mainly of T cells and dendritic cells that enter a lymph node from
other tissues
inner cortex of superficial cortex
bean-shaped found along lymphatic vessels. They are distributed
throughout the body, both superficially and deep, and usually occur in groups. The large group of them is present near the mammary glands and in the axillae and groin
lymph nodes
contains B cells, antibody producing plasma cells that have migrated out of the cortex into the medulla, and
macrophages
deep parenchymal medulla of lymph node
Penetrate the node’s convex surface at some points and contain valves that open toward the node’s center, directing the lymph inward
Afferent lymphatic vessels
Series of irregular channels that contain branching reticular fibers, lymphocytes, and macrophages
Sinus
Positioned under the capsule
Subcapsular sinus
Extend through the cortex parallel to trabeculae
Trabecular sinus
Extend through the medulla
Medullary sinus
Broader and fewer in number than the afferent vessels
Efferent lymphatic vessels
They contain valves that open away from the lymph node’s center to
convey lymph, antibodies secreted by plasma cells, and activated T cells out of the node
Efferent lymphatic vessels
The efferent lymphatic vessels arise from one side of the lymph node at a slight depression called _____ where blood vessels also enter and leave the lymph node
Hilum
Serves as a type of filter
Lymph node
is an oval-shaped, largest single mass of lymphatic tissue in the body, measuring about 12 cm (5 inches) in length. It is located in the left hypochondriac region between the stomach
and diaphragm
spleen
The organs surrounding the spleen make indentations in its visceral
surface–the ____ impression (stomach), the ____ impression (left kidney), and the ____ impression (left flexure of the colon)
Gastric - renal - colic
Contains mostly lymphocytes and macrophages arranged around branches of splenic artery called central arteries, whereas T and B cells carry out immune functions and spleen macrophages destroy blood-born pathogens by phagocytosis
Spleen’s white pump
consists of blood-filled venous sinuses and cords of splenic tissue called splenic cords. These functions include removing ruptured, worn-out, or defective blood
cells and platelets by macrophages; storing platelets, up to 1/3 of the body’s supply; and producing blood cells (hemopoiesis) during fetal life.
Spleen’s red pump
Egg-shaped masses of lymphatic tissue that are encolsed by a capsule and are also called mucosa-associated lymphatic tissue (MALT), and includes Peyer’s patches, appendix, and tonsils
Lymphatic nodules (follicles)
Situated in the ileum of small intestines
Peyer’s patches
Thin tube about four inches long found at the small and large intestines’ junction
appendix
from a ring at the oral cavity and oropharynx junction at the nasal cavity and nasopharynx junction
tonsils
positioned between nasopharynx posterior wall
single pharyngeal tonsil or adenoid
lie on the oral cavity posterior region
2 palatine tonsils
found at the base of the tongue
paired lingual tonsil
What are the first line fo defenses
skin and mucous membranes
it is in the blood and interstitial fluid prevent microbial growth. It includes interferons, complement, iron-binding proteins, and antimicrobial proteins
antimicrobial substances
produced by lymphocytes, macrophages, and fibroblasts
infected with viruses. IFNS released by virus-infected cells diffuse to uninfected neighboring
cells to induce the synthesis of antiviral proteins that interfere with viral replication
interferons
secreted by helper and cytotoxic T cells and natural killer cells strongly stimulates phagocytosis by neutrophils and macrophages, activates NK cells and enhances both cell-mediated and antibody-mediated immune responses
gamma interferon
produced by infected cells to prevent viral multiplication in uninfected cells. These are also produced by antigen-stimulated macrophages to stimulate T cell growth.
-activates natural killer cells, suppress cell growth, and inhibit some tumors’ formation
alpha and beta interferon
consists of group of ordinarily inactive proteins in blood plasma and plasma membranes. It causes microbes’ cytolysis (bursting), promote phagocytosis, and contribute tp inflammation
complement system
suppress the growth of certain bacteria by reducing the amount of available iron.
iron-binding proteins
Iron-binding proteins include ____ in the blood and tissues, _____ in milk saliva and mucus, ______ in liver, spleen and RBM, and _____ in re blood cells
transferrin - lactoferrin - ferritin - hemoglobin
Antimicrobial substances that are short peptides with a broad spectrum of antimicrobial activity.
Antimicrobial proteins
Antimicrobial proteins include ____ produced by sweat glands, ____ and ____ by neutrophils, macrophage, and epithelia, and _____ by platelets
dermicidin - defensins - cathelicidins - thrombocidins
cells destroy infected target cells by releasing granules that contain perforin and granzymes that initiate cellular destruction by freeing the microorganisms
Natural killer cells
Inserts into the target cell’s plasma membrane and creates channels in the membrane so extracellular fluid flows into target cell and the cell burst (cytolysis)
perforin
protein-digesting enzymes, induce the target cell to undergo apoptosis
granzymes
present in the spleen, lymph nodes and RBM. Lack the membrane molecules to identify B and T cells but they can kill different infected body cells and ecrtain tumor cells
NK cells
Ingest foreign particulate matter. its 2 major types are neutrophils and macrophages
phagocytes
Phase of phagocytosis that refers to chemically stimulated momevment of the phagocytes to the site of damage
chemotaxis
Phase of phagocytosis which is the attchemnt of phagocyte to the microbe or other foreign material
adherence
Phase of phagocytosis that occurs when the plasma membrane of the phagocyte extend projection (pseudopods) that engolfs the microbe which results to phagosome
ingestion
Phase of phagocytosis that ensues when the phagosome enters tthe cytoplasm and unites with a lyysosome to form a larger structure (phagolysosome)
digestion
Phagocyte form lethal oxidants and hydrogen peroxide in a process called ____
oxidative burst
Phase of phagocytosis that results from lysozymes chemical attack, digestive enzymes, and oxidants within a phagolysosome
killing
Confines and destroys microbes and initiates tissue repair
inflammation
manifestations of inflammation
redness, pain, swelling, heat
3 stages of inflammation
-vasodilation and increased permeability of blood vessels
-emigration of phagocytes from blood into interstitial fluid
-tissue repair
released by mast cells and basophils and platelets. Neutrophils and macrophages also stimulate its release which produces vasodilation
histamine
polypeptides formed in blood from inactive precursors (kininogens)
kinins
lipids, especially pf the E series, are released by damaged cells that intensify the effcts of histamine and kinins. May also stimulate emigration of phagocytes through capillary walls
prostaglandins
produced by basophils and mast cells and function in adherence of phagocytes and as chemotactic agents
leukotrienes
Its components stimulate histamine release, attract neutrophils by chemotaxis and some components can destroy bacteria
complement system
Body’s ability to defend itself against specific invading agents which is made compatible by T cells and B cells that are immunocompetent
specific resistance or immunity
molecules capable of recognizing specific antigens
antigen receptors
T cells exit the thymus as ____ or ____ cells
CD4 or CD8
In cell-mediated immunity, ____ proliferate into cytotoxic T cells that directly attack the invading antigen
CD8 T cells
Most ____ become helper T cells that aid both cell-mediated and antibody-mediated immune responses
CD4 T cells
foreogn susbtances that provoke immune responses
antigens
antigens ability to provoke an immune response by stimulating the production of antibodies, proliferation of T cells, or both
Immunogenicity
Antigens ability t react specifically with the antibodies or cells it provoke
reactivity
antigens that have both immunogenicity and reactivity
complete antigens
Large antigen has small parts that can trigger the immune responses. These are called
epitopes
They only respond to antigens made up proteins
T cells
Respond to antigens amde up pf proteins, lipids, carbohydrates, and nucleic acids
B cells
Has reactivity but lacks immunogenicity
hapten
The diversity of antigen receptors in both B cells and T cells results from shuffling and rearranging a few hundred versions of several small gene segments
genetic recombination
normal antigens
self-antigens
self-antigens located in the plasma membranes of the body cells
major histocompatibility complex (MHC) antigens
transmembrane proteins are also called ___ because they are first identified on white blood cells
human leukocyte antigen (HCA)
type of MHC antigen that are built into all body cells’ plasma membranes except RBC
Class I MHC
type of MHC antigen that appear on the surface of the antigen-presenting cells (special class of cells: dendritic cells, macrophage, and B cells)
Class II MHC
pathway of antigen processing whereas foreign antigens present in fluids outside the body cells such as bacteria
processing of exogenous antigen
What process and present exogenous process
Antigen-presenting cells
steps of processing of exogenous antigen
a) ingestion of antigen through phagocytosis or endocytosis
b) digestion of antigen into peptide fragments w/in phagosome or endosome that contains protein-digesting enzymes
c) synthesis of MHC-II by APC at endoplasmic reticulum
d) packaging of MHC-II into vesicle
e) fusion of vesicles (containing antigen peptide fragments and MHC-II)
f) binding of antigen peptide fragments into MHC-II
g) insertion of antigen-MHC-II into plasma membrane through exocytosis
foreign antigens that are synthesized inside the body cells
processing of endogenous antigens
steps of processing endogenous antigens
a) digestion of antigen into peptide fragments by protein-digesting enzymes within infected cell
b) synthesis of MHC-I molcules at endoplasmic reticulum
c) binding of antigen peptide fragments into MHC-I in the infected cell
d) packaging of antigen-MHC-I into vesicles
e) insertion of antigen-MHC-I complex into plasma membrane via exocytosis
Small protein hormones that stimulate or inhibit many normal cell function
cytokines
cytokines produced by monocytes and macrophage that promotes the proliferation of helper T cells and acts i the hypothalamus to cause fever
interleukin-1
secreted by helper T cells costimulates the proliferation of helper t cells, cytotoxic T cells, B cells, and NK cells
interleukin-2
produced by activated helper t cell is a costimulator for B cells, vauses the plsma cells to secrete Ig E antibodies
interleukin-4
produced by specific activated CD4 T cells serves as costimulator for B cells and causes plasma cells to secrete IgA antibodies
interleukin-5
cytokine produced mainly by macrophage that stimulates the accumulation of neutrophils and macrophages at the inflammation site and stimulates killing of microbes
tumor necrosis factor
secreted by T-cells and macrophage that is necessary for turning off immune responses
transforming growth factor - beta
effective against intracellular pathogens and foreign tissue transplant. T cells are the ones involved in this immunity
cell-mediated immunity
true or false. activation, proliferation, and differentiation of T Cells must occur in cell-mediated immune response
true
antigen receptors on the T-cell receptors’ surface called ____ should recognize and bind to specific foreign antigen fragments presented in the antigen – MHC complex.
T-cell receptors (TCRs)
_____ by a TCR with CD4 or CD8 proteins
is the first signal in activating a T cell and, simultaneously, receives a second signal, a process known as _____
antigen recognition - costimulation
Two signals causing T cell activation
antigen recognition and costimulation
a population of identical cells, called a ____, which can recognize the same specific antigen.
clone
Activation, proliferation, and differentiation of T cells occur in
______.
secondary lymphatic organs and tissues
T cell differentation give rise to
helper t cells, cytotoxic t cells, and memory t cells
type of t cell differentation that cooperate with b cells to intensify antibody production by plasma cells
Helper T cell
Type of T cell differentiation that kill host target cells by releasing granzymes, perforin, granulysin, and lymphotoxin
Cytotoxic T cell
destroys target cell DNA
lymphotoxin
prevents macrophage migration from site of infection
macrophage migration inhibition reflex
remain in lymphatic tissue and recognize original invading antigens, even years after
memory T cells
Soldiers that march forth to do battle woth foreign invaders in cell-mediated immune responses. They deliver a lethal hit that kills the target cells
Cytotoxic T cells
In recognizing infected target cells (have microbial antigens displayed on
their surface) using receptors on their surfaces and then binding them, the cytotoxic T cells release ____ (protein-digesting enzymes) that trigger apoptosis.
granzymes
The second mechanism is cytotoxic T cells’ binding with infected body cells and releasing two proteins from their granules:
perforin and granulysin
enters the channels created by perforin and destroys the microbes by creating holes in their plasma membrane
granulysin
immune responses carried out by cytotoxic T cells, macrophages, and natural killer cells. When a normal cell transforms into a cancerous cell, it often displays different cell surface components called tumor antigens.
Immunological surveillance
When a normal cell transforms into a cancerous cell, it often displays different cell surface components called
tumor antigens
works mainly against antigens present in body fluids and extracellular pathogens (viruses, bacteria, and fungi outside the cells). This type of immunity primarily involves B cells.
Antibody-mediated immunity
Although B cells can respond to an unprocessed antigen present in lymph and interstitial fluid, their response is much more intense when they process the antigen
true
some of the activated B cells enlarge, divide, and differentiate into a clone of
antibody-secreting
plasma cells
some activated B cells do not differentiate into plasma cells but
remain as ____. These are ready to respond more rapidly and forcefully should similar antigen reappear in the future.
memory cells
Antibodies belong to a group of glycoproteins called ____; thus, they are also
known as immunoglobulins (Ig).
globulins
How many polypeptide chains does antibodies contain
4; 2 heavy and 2 light chains
How many amino acids does heavy chain consists
450
How many amino acids does light chain consists
220
How many disulfide bond is there for linking two heavy chains
2
How many disulfide bond is there for holding each light chain to a heavy chain
1
region of antibody that displays considerable flexibility which can make it assume a T shape or Y shape and can bind to two epitopes
hinge portion
region of antibody that is formed beyonf the hinge by the parts of the 2 heavy chains
stem region
region of antibody that are the tips of H and L chains that constitutes the antigen-binding site
variable regions
region of antibody that is responsible for the type of antigen-antibody reaction that occurs
constant region
class of antibody that is the most abundant. About 80% in the blood, lymph, and intestines and is a monomer
IgG
The only class of antibodies that cross the placenta from mother to fetus, giving significant immune protection for fetus
IgG
class of antibody found mainly in sweat, tears, saliva, and GIT secretions and smaller quantities are present in blood and lymph (10-15%) and occurs as monomers pr dimmers
IgA
class of antibody which its levels decrease during stress, lowering resistance to infection and it provides localized protection on mucous membranes against bacteria and viruses
IgA
class of antibody that is 5-10% found in lymph and occurs as pentamers. The first antibody class to be secreted by plasma cells. It activates complement and causes agglutination and lysis of microbes and act as monomer
IgM
class of antibody that serve as antigen receptor and examples are anti-A and anti-B antibodies which bind to A and B antigens during incompatible transfusion
IgM
class of antibody found on B cells surfaces as antigen receptors and occurs as monomers. 0.2%
IgD
class of antibody that is only 0.1% and located on mast cells and basophils, involved in allergic and hypersensitivity reactions against parasitic worms
IgE
actions of antibodies
neutralizing antigen, immobilizing bacteria, agglutinating and precipitating antigen, activating complement, and enhancing phagocytosis
acts as a flag that attracts phagocytes once antigens bound to antibody’s variable region
stem region
composed of over 30 proteins produced by the liver and
circulating in blood plasma and within tissues throughout the body.
complement system
are designated by an uppercase letter C, numbered C1 through C9, based on their
order of discovery. The C1 to C9 complement proteins are inactive and only become
activated when split by enzymes into active fragments, which are indicated by lowercase
letters a and b (for example, C3 — C3a and C3b).
complement proteins
Other complement proteins are
referred to as
factors B, D, and P (properdin)
pathway of complement activation which starts when antibodies bind to antigens that activates C1
Classical pathway
pathway of complement activation which does not involve antibodies and is initiated by an interaction between lipid-carbohydrate and complement protein factors B,D,P which activates C3
alternative pathway
pathway of complement activation whereas the macrophages that digest microbes release chemicals that cause liver to produce proteins called lectins and activate C3
lectin pathway
promotes attachment of phagocyte to a microbe
opsonization
C3b also
initiates a series of reactions that bring about cytolysis. C3b splits C5. Next, the C5b
fragment binds to C6 and C7, which attach to an invading microbe’s plasma membrane.
true
Then C8 and several C9 molecules join the other complement proteins and form a _____ that becomes inserted into the plasma membrane which creates channels in the plasma membrane that result in cytolysis, the microbial cell’s bursting due to the inflow of extracellular fluid through the channels.
cylinder-shaped membrane attack complex
bind to mast cells and cause them to release histamine that
increases blood vessel permeability during inflammation. C5a also attracts phagocytes to
the site of inflammation (chemotaxis)
C3a and C5a
This ability is due to the presence of long-lasting antibodies and
very long-lived lymphocytes that arise during proliferation and differentiation of antigen-stimulated B cells and T cells. Immune responses, whether cell-mediated or antibody-mediated, are much quicker and more intense after a second or subsequent exposure to an antigen than after the first exposure.
immunological memory
Measure of immunological memory
antibody titer (the amount of antibody in serum)
immunologic response that occurs after initial contact with antigen. No antibodies present for several days. Slow rise of IgM and IgG followed by decline of antibody titer
primary response
immunologic response that occurs with a subsequent encounter with a similar antigen which invloves memory cells. Antibody titer is far greater than primary response
secondary response
consists mainly of IgG antibodies. During a secondary response, the antibodies produced have an even higher affinity for the antigen than those produced during a primary response. Thus they are more successful in disposing of it
secondary response
Trait of T cells that is its ability to recognize tgeir own major histocompatibility complex (MHC) proteins.
Self-recognition
In the thymus, the pre-T cells develop the capability for self-recognition via
positive selection
The T cells with this capability survive. However, the immature T cells that fail to
interact with thymic epithelial cells cannot recognize self-MHC proteins. These cells undergo apoptosis (self-destruction) and become permanently lost.
true
Refers to the T cell’s lack of reactivity to peptide fragments from its own proteins. It occurs by weeding-out, a process called negative selection
Self-tolerance
Self-reactive T cells undergo apoptosis and die
deletion
Self-reactive T cells remain alive but are unresponsive to antigenic stimulation
anergy
In self-tolerance, T cells with receptors that recognize self-peptide fragments or self-antigens are eliminated or inactivated. The T cells selected to survive do not respond to self-antigens.
true
