immunity Flashcards
what are the levels of the wound healing
- homostasis and coagulation
- inflammation
- proliferative and migration
- remodeling
What is the role of the circulatory system?
TRANSPORTATION
REGULATION
PROTECTION
what kinds of transportations are exist in the body
- Respiratory (RBCs)
- Nutritive (digestive)
- Excretory (wastes)
how circulatory system regulate the body
Hormonal
• Temperature
how circulatory system protect the body
Hormonal
• Temperature
how much blood is in the human body
5 LITRES = 169.07 fluid ounces or 10.57 pints
what is the blood made of
Blood plasma: Fluid portion (55%)
Formed elements: Cellular portion (45%)
• White blood cells, platelets (<1%)
• Erythrocytes (RBCs; >99%)
what is the blood plusma made of
- Water (92%)
- Proteins (7%)
- Solutes (1%)
what is the role of the plasma in keeping the presure inside the capillaries
Plasma plays a role in maintaining plasma
colloid osmotic pressure (pressure “pulls”
fluid from interstitial space into capillaries)
how much of the blood plasma is water
92% of the plasma is water which is the fluid portion
how much of the plasma is protein
7%
which proteins are presentint in the plasma
Albumins
- Globulins
- Fibrinogen
Complement proteins
what is the role of the albumin in the plasma
Smallest and most numerous proteins; transports hormones
what is the role of the plasma protein in the body
Exert plasma colloid osmotic pressure; regulates blood volume
what is the role of the Globulins
Transport iron, hormones, lipids
what is the role of the Fibrinogen
Essential for blood clotting
what is the role of the Complement proteins
Activated by presence of pathogens
what are the other solutes in the blood plasma
Electrolytes
- Nutrients
- Gases
- Regulatory substances
- Waste products
which Electrolytes are present in the plasma
Na+, K+, Ca2+, etc.
which nutrients are present in the plasma
Amino acids, glucose, fatty acids, vitamins, minerals
which gasses are present in the plasma
O2, CO2, N2
what are the Regulatory substances in the plasma
Hormones, enzymes
what are the waste products in the plasma
Urea, creatinine, ammonia, etc
what are the main component of the circulatory system (Formed Elements)
Erythrocytes (RBCs): Transport oxygen from the lungs to the body
Leukocytes (WBCs): Immune cells; protect the body from foreign
invaders
Platelets: Cellular fragments that promote blood clotting
what is the blood cell formation process
Hematopoiesis
where Hematopoiesis happens
Hematopoiesis occurs in the bone marrow
in adults
what are the process of the Hematopoiesis
Hematopoietic stem cells (HSCs) become… …Progenitor cells, which become… • Precursor cells that give rise to… • WBCs • RBCs • Megakaryocytes (precursor cell to platelets)
what does Precursor cells need for the differentiation
Require CYTOKINES
for differentiation!
explain the RBC Formation – Erythropoiesis
- HSCs differentiate into myeloid progenitor
cells (see previous slide), which develop into
proerythroblasts - Erythroblasts and normoblasts are formed
and begin synthesizing hemoglobin - Further in its development, the cell ejects its
nucleus and becomes a reticulocyte - Further maturation occurs in the blood
(erythrocyte)
how long is the Lifespan of an RBC
120 days
why the hemoglobin is red
Each RBC contains 280m hemoglobin molecules that give blood its red colour
what is the hemogllobin made of
Hemoglobin: 4 globin proteins, each with a heme group that contains an iron core
what is the role of the heme iron
Heme iron (Fe) combines with oxygen to transport it to tissues
what is the proces of the stimulation of erythropoiesis
A decrease in blood oxygen stimulates erythropoiesis
- The kidneys sense this drop in blood oxygen and release erythropoietin (EPO)
- EPO acts within the bone marrow to stimulate maturation of reticulocytes
- Newly formed erythrocytes can now transport oxygen (attached to hemoglobin) to tissues as needed (including kidneys)
how much iorn do men need
Adult men of all ages: ~9 mg/day
how much iron wome need
Pre-menopausal adult women: ~18 mg/day
• Post-menopausal women: ~9 mg/day
what is the anemia
Anemia: Low RBC and/or hemoglobin concentration
what are the WBC Myeloid lineage:
- Eosinophils, basophils, and neutrophils
* Monocytes
which factor differentiate the WBC Myeloid lineage:
• colony-stimulating factor (CSF) to
differentiate
what Myeloid progenitors give rise to
Myeloid progenitors also give rise to
megakaryocytes, which become
platelets thanks to thrombopoietin (TPO)
what are the WBC Lymphoid lineage
:
• T lymphocytes
• B lymphocytes
• Natural killer (NK) cells
what is the most used type of the stem cell
HSCs are the most clinically used
type of stem cell in medicine!
which cancer is treated by the HSC
Used to treat certain blood cancers
like leukemia
what is the leukemia
Leukemia: Cancer of the progenitor
cells that become leukocytes
Cellular constituents of the
IMMUNE SYSTEM
what is the immune system
The immune system includes all of the cells,
tissues, and processes involved that defend
against potential pathogens
what are the two defense mechanism
innate ( non-specific ) defense machanism
adaptive ( specific ) defense mechanism
what is the first line of the defense
non specific
skin
mucouse membrane
secration of skin and mucouse membrane
what is the second line of the defense
non specific phagocytic cells natural killers anti microbial proteins the inflammatory response
what is the third line of the defense
lymphocytes
anti bodies
macrophages and other antigen presenting cells
what is the relationship between the antigen and the antibody
Antigens found on the surface
of all cells can be detected by
certain molecules (antibodies)
secreted by immune cells
Antigen recognition (or lack thereof) classifies that antigen as either being:
:
• SELF (non-foreign)
• NON-SELF (foreign
what are the blood types
Type O+ (39% of Canadians) • Type O- (7% of Canadians) – UNIVERSAL DONOR • Type A+ (36% of Canadians) • Type A- (6% of Canadians) • Type B+ (7.6% of Canadians) • Type B- (1.4% of Canadians) • Type AB+ (2.5% of Canadians) – UNIVERSAL ACCEPTOR • Type AB- (0.5% of Canadians)
what is the blood types based on
Blood types are based on antigens present on erythrocytes among different individuals
what is the type A blood
A antigen
anti-B antibody
what is the type B
B abtigen
anti-A antibody
what is the type AB
both A and B antigen
neither the antibody
what is the type O blood
neither antigen A or B
anti-A and anti-B antibody
what is the AGGLUTINATION when type A is transfered to type B
• Individuals with Type B blood carry anti-A antibodies
• Anti-A antibodies recognize A antigens on the transfused
blood and mark them as FOREIGN
• Anti-A antibody binding to antigen causes clumping of the erythrocytes (agglutination)
• Antigen-antibody complexes form and activate complement proteins in the recipient’s plasma
• Causes hemolysis of erythrocytes
what is the • Rh factor (Rh):
• Rh factor (Rh): Another antigen that is
commonly present on erythrocytes
what is the rh positive and rh negative
If Rh antigen is present (~85% of Caucasians): Rh positive
• If Rh antigen is not present: Rh negative
what is the difference between the antigen A and antigen B and antigen rh
Unlike anti-A or anti-B antibodies, anti-Rh antibodies are not normally present in Rh- individuals UNLESS they have been previously exposed to Rh antigen
is offspring genetically as same as the mother in terms of the rh antigen
Offspring are genetically different from
their mothers, so a mother may be Rh- while their fetus rh +
what is the role of the plecenta in the exposure of the fetus blood to the maternal blood
Placenta normally shields fetal blood from maternal blood (see Repro section), but exposure may occur during parturition
what is the eryththroblastosis fetalis
Next pregnancy: If the fetus is Rh+,
eryththroblastosis fetalis can result
• Hemolysis of Rh+ RBCs in the fetus
what is the anti body and what is its role
Antibodies are part of the adaptive (specific) immune system
• This system is built and trained to recognize and destroy specific antigens
what are some of the innate immune barriers and what are their responses
Skin/mucous membranes»» Physical barrier for pathogens
Digestive tract»_space;»High acidity of stomach
Inflammatory response»_space;»>Histamine release, fever
Phagocytosis»_space;»>Cells that engulf foreign material
Interferons»»> Produced by cells infected by viruses
Complement system»_space;»>Promote phagocytosis with the help
of antibodies (adaptive immunity)
what is the mechanism of the anti body
Antibodies target pathogens (bacteria, viruses, foreign RBCs), but binding alone does
not destroy them
• Antibodies serve as “flags” for immunological attack by:
1. Innate immune cells like macrophages and neutrophils
(next couple of lectures)
2. Complement proteins present in the plasma
what is the The Complement System
• Serves as a LINK between the innate and adaptive immune system!
• Liver produces complement proteins and release them into circulation (9 inactive
proteins labeled C1-C9)
what is the complement activation leads to
Complement activation leads to the
eventual destruction of the pathogen
what are the two ways of the Complement protein activation
Classical Pathway
Alternative Pathway
in both cases, activation of complement proteins involves sequential modifications to the proteins to generate proteolytic enzymes
what is the classical pathway
Involves antibody recognition followed by a cascade of complement protein modifications
Starts off with…
1. Antibody binding to antigen on membrane of bacterial cell
2. C4 binds to antibody-antigen complex; activated C1 hydrolyzes C4 into C4a and C4b (C4b becomes “fixed” in the membrane)
3. C3 is then split into C3a and C3b via a C3 convertase (C4b + C2a)
4. C3b converts C5 into C5a and C5b, which attract other immune cells to the site
5. C5-C9 are inserted into the cell mb to form a membrane attack complex (MAC
what is the mechanism of the Alternative Pathway
No antibodies required!
• Involves surface protein recognition by complement proteins
Low levels of C3 are constantly monitoring for and binding to
surface proteins
If C3 binds to LPS on a bacterial cell, it is then activated
what are the differences between alternative and the classic pathway
The production of C3 convertase is where both pathways converge • In both cases, cleavage of C3 results in C5 activation and subsequent MAC production • Classical pathway: • C3 convertase = C4b and C2a • Alternative pathway: • C3 convertase = C3b and factor B (another serum protein)
what is the final result of the complement system
Formation of MAC (resulting in hemolysis) 2. Chemotaxis: 3. Opsonization: 4. Stimulation of histamine release:
what is the chemotaxis
- Chemotaxis: Free complement
fragments attract phagocytic cells to
site of infection
what is the opsonization
- Opsonization: Complement proteins
recruit phagocytic cells to eat bacteria
free complements induce which cells to release the histamine in the body
- Stimulation of histamine release:
Free complement fragments induce
mast cells and basophils to release
histamine
what are the physical and cellular barrier of the lungs
– Respiratory secretions
– Resident macrophages
what are the Alveolar macrophages and what they do
Alveolar macrophages are phagocytic cells; they
recognize bacterial antigens and can either…
– Engulf bacteria (phagocytosis) and destroy them via
lysosomal enzymes
– Recruit other innate immune cells to the site via
chemotaxis
what are the cytokines
– IL-1β (Interleukin-1)
– TNF-α (Tumour necrosis factor)
what is the role of the CYTOKINES:
Increase vascular permeability
• Increase vasodilation
• Increase expression of endothelial adhesion proteins
what is the CHEMOKINES and what is its role
CHEMOKINES: CXCL8
– Help attract other immune cells to the site of infection
which cells released histamine and what is its role
Histamine released by mast cells and basophils further increase vasodilation and vascular permeability
which cells release the prostaglandis and what is its role
– Prostaglandins released by damaged cells to intensify the effects of histamine
which cells release the Leukotrienes and what is its role in the body
Leukotrienes released by mast cells and basophils further increase vascular
permeability
what is the role of the Complement proteins,
Complement proteins, in addition to their direct role in killing bacteria, also stimulate histamine release, attract neutrophils by chemotaxis, and promote phagocytosis
how neutrophis arrive on the scene
As the battle continues, neutrophils arrive on the scene thanks to
chemokines secreted by macrophages (chemotaxis)
do monocytes arrive after or before the neutrophils
Monocytes (macrophage and dendritic cell
precursors) arrive later
how Neutrophils and monocytes enter the tissue
Neutrophils and monocytes from the
blood enter the tissue at the site of
infection thanks to extravasation (also
called diapedesis)
what is THE INFLAMMATORY RESPONSE:
Inflammation is characterized by classic or cardinal signs
what are the responses of the inflammetory
Rubor (redness): Increased vasodilation
– Calor (heat): Increased vasodilation (fever covered in next
slide)
– Tumor (swelling): Increased vascular permeability
– Dolor (pain): Increased cytokine release stimulates pain receptors
– Functio laesa (loss of function): Tissue health is suboptimal; not in homeostasis
what does ibuprofen do
Anti-inflammatory medications such as ibuprofen (a nonsteroidal anti-inflammatory drug [NSAID]) BLOCK the formation
of prostaglandins
what is the prednison and what is its role
Prednisone, acting like cortisol, suppresses the immune
system by BLOCKING the formation of prostaglandins
AND leukotrienes
why y BLOCKING the formation of prostaglandins
AND leukotrienes is bad
Reduced vascular permeability = fewer immune cells
at the site of infection = infection persists
how fever happens
FEVER: Monocytes and macrophages, upon interaction
with bacteria, secrete cytokines that act as pyrogens
• Pyrogens affect the preoptic area of the hypothalamus,
raising body temperature
what is the worst and best senario of the fever
At worst, high fevers can lead to organ damage and spread of infection. At best, fevers are uncomfortable and temporary, and assist with recovery from infection.
what are the GRANULOCYTES
neutrophils
eosinophils
basophils
what are the AGRANULOCYTES
lymphocytes
monocytes
what is the basophils
Contains granules that stain blue with hematoxylin dye
• Has a bilobed nucleus
• Low #’s in circulation; <1% of WBCs
what is the function of the basophils
FUNCTIONS:
– Releases histamine (vasodilator)
– Releases heparin (slows down blood clotting)
which cell is similar to the basophils
• MAST CELLS: similar to basophils, but located in
tissues instead of the blood
what is the neutrophil
Neutrophils
• Contains granules that stain very slightly pink with eosin
• Has a multilobed nucleus
• Most abundant leukocyte; 54-62% of WBCs
what is the function of the neutrophils
– First responders to infections
– Phagocytose bacteria; ~5-20 bacterial cells during
their short lifespan (1-2 days)
what is the Eosinophils
- Contains granules that stain bright red with eosin
- Has a multilobed nucleus
- ~1-3% of WBCs
what is the function of the eosinophils
FUNCTIONS:
– Defend against parasites
– Also help against viral infections, allergic responses,
and certain types of bacteria
– Higher number of eosinophils correlates with
increased severity of asthma
what is the Monocytes
• Agranulocyte: no granules; 2-3x larger than an RBC
• Has a kidney-shaped nucleus
• ~3-9% of WBCs; but only stay in the blood for ~8 hrs
before differentiating
what is the Monocytes are precursors to:
– Monocytes are precursors to:
• Tissue resident macrophages
• Dendritic cells
which Tissue resident macrophages:
All tissues; spleen, lymph nodes, bone marrow
what are the microphages in the liver , brain and lungs
Kupffer cells: Liver
• Microglia: Brain
• Alveolar macrophages: Lungs
what is the function of the macrophages
Phagocytose bacteria (100 bacterial cells per lifespan) AND act as antigen-presenting cells
what is the dendritic cells
Dendritic cells: Antigen-presenting cells
what is the second function of the macrophages
“tissue clean up crew
Remove debris: Old RBCs, dead neutrophils, cells undergoing apoptosis
what is the lymphocytes
Agranulocyte: no granules; only slightly larger than
an RBC
• Has an “eccentric” nucleus
• ~25-33% of WBCs; ~5% circulating, the rest in
tissues until they encounter pathogens
what are the type of the lymphocytes
– T lymphocytes (adaptive immune system)
– B lymphocytes (adaptive immune system)
– Natural killer cells (innate immune system)
what are the function of the natural killers
Protect against viral infections
and some types of cancer
• Unlike B and T lymphocytes, natural killer cells
respond very quickly (within a few to several
hours) upon stimulation
how natural killers distroy the target cells
Destroys target cells by cell:cell contact through
granzymes
what doe the natural killer secregate
• Can release interferons (IFNs) and other cytokines to warn uninfected cells AND/OR enhance immune response mediated by other cell types
what are the B and T lymphocytes
B and T Lymphocytes
• Part of the adaptive immune system (both humoral and immune-mediated immunity)
what is the adaptive defense
• A subset of WBCs are conditioned to respond and attack
pathogens
how does adaptive defense work
• While some of their comrades remain at the site of infection, other macrophages/dendritic cells transport antigens to a lymph node
. Neutrophils release free antigen into the bloodstream,
where these molecules can eventually reach a lymph
node
what are the lymph nodes
• Lymph nodes are part of the lymphatic system (next lecture) and are home to B lymphocytes and T lymphocytes
what are the NAÏVE LYMPHOCYTES
Mature lymphocytes that have not yet encountered antigen
why lymphocytes need training
Lymphocytes must be trained and cloned to mount an immune response to a specific antigen
where doe B and T lymphocytes mature in the body
Immature B lymphocytes stay and mature in the bone marrow
• Immature T lymphocytes leave and mature in the thymus (gone in adults)
what is the Immunocompetence
Immunocompetence: Ability to carry out adaptive immune
responses
what happens to the lymphocyte beofore moving to the lymphoid organs
Gain antigen receptors on their
membranes before moving to
lymphoid organs
two major type of the T- Lymphocytes
• Two major types of mature, immunocompetent
T cells thus exit the thymus: – Helper T cells (CD4+ T cells) – Cytotoxic T cells (CD8+ T cells)
what is the difference between the mature T cells and the non-mature T cells
• Mature T cells now have antigen receptors that can respond to antigen presented by antigen presenting cells
do we have a lot of the lymphocytes when the pathogen enters the body
• Initially, when a pathogen first enters the body,
there are only a few lymphocytes that have the
correct antigen receptor to respond to that
antigen
what is the CD4+ T Lymphocytes ( the antigen-presenting cell)
(cell mediated immunity
Antigen presenting cells (macrophages, dendritic cells, etc.) are “professional” cells that can present antigen on a complex called MHC II (major histocompatibility complex)
how does the CD4+ T lymphocytes is activated
Antigen presented by MHC II molecules on antigen
presented cells will activate CD4+ T lymphocytes
(helper T cells)
where re the immunocompetent helper T cells are located
Some immunocompetent helper T cells in the
lymph node will have antigen receptors that can
recognize the “presented” antigen
how does the clonal selection is related to the cd+4 cells
ACTIVATION: Results in the clonal selection of
that helper T cell that correctly responded to the
antigen
for the proper activation what has to happen between the antigen receptor and co- receptor
For proper activation and clonal selection to occur, the antigen receptor (T cell receptor) and a co-receptor (CD4) must BOTH bind to the MHC II molecule
how do the active helper t-cells respond ? buy secreting which enzyme
Active helper T cells respond by secreting cytokines that
enhance the immune response of cytotoxic T cells and
activation of B cells
are all of the t cells able to recognize the specific antigen
Not every immunocompetent helper T cell that leaves the thymus will recognize our specific antigen
• The ones that do will become activated, will proliferate, and become “effector” versions (help!!) or “memory” versions that can easily become effectors if infection occurs again
how does MHC 1 works in other tissue’s cells
• RECAP: Antigen presenting cells (macrophages, dendritic cells, etc.) have MHC II molecules on their membrane that they can use to activate helper T cells
• ALL nucleated cells also have MHC I molecules on their membrane too
• If a tissue cell (not an APC) is infected with a virus, it can present antigen on MHC I molecules on its membrane
By presenting antigen in this way, the infected tissue cell acts
like a martyr, signaling to cytotoxic T cells that it should be
destroyed
how is the cytotoxic T cell activate
• Cytotoxic T cell activation occurs in a similar manner to
helper T cell activation
what happens if the cytotoxic T cell encounters a target cell with a foreign antigen that it can recognize on the MHC I molecule
If a mature, immunocompetent cytotoxic T cell encounters a target cell with a foreign antigen that it can recognize on the MHC I molecule, the T cell will kill it
• Similar to helper T cells, cytotoxic T cell activation requires a co-receptor to bind to MHC I → CD8
why does cytotoxic T cell require the co- receptor
• Similar to helper T cells, cytotoxic T cell activation requires a co-receptor to bind to MHC I → CD8
what is the destroying mechanism of the cytotoxic
Once activated, cytotoxic T cells release perforin to make pores in the cell membrane
• Following pore creation, granzymes(protease enzymes) are released into the cell to destroy it from the inside
• Cytotoxic T cells can also stimulate apoptosis in the affected cell
which cytotoxic leave the lymph nodes and which one stay
Unlike cytotoxic T cells that leave lymph nodes to seek out and destroy foreign antigens, B cells stay put
what happens tothe B cells when they mature and gain immunocompetence in bone marrow
When B cells mature and gain immunocompetence in bone marrow, they move to lymph nodes where they can produce certain types of antibodies
when naive B cells ungergo clonal selection
• When certain naïve B cells are exposed to a particular antigen which binds to their B cell receptor, they undergo clonal selection
what is the other name of the B cells
humoral immunity
what will activated B cell become after the proliferate
– Plasma cells (effector cells) that serve as antibody factories (short-lived)
– Memory B cells (continue to proliferate; long
lived)
how doe sthe memory B cells action during the re-exposure to the same antigen
Upon re-exposure to the same antigen, memory B
cells rapidly expand to produce more plasma cells
and memory B cells
what is the role of the helper T cell in B cell activation
• Helper T cells also aid in B cell activation, AND B
cells can reciprocate by acting like APCs (antigen
presentation via MHC II)
what is the role of the Neutralizing antigen
Antibodies block or neutralize bacterial toxins and can prevent viral attachment to body cells
what is the role of the Agglutinating antigen
Antibodies cause “clumping” of pathogens (see Immune lecture 1)
why Precipitating antigen happens
Antibodies cross-link soluble antigens into complexes that are too
large to stay in solution
what is the role of the Activating complement
Initiate the classical pathway of the complement system (see
Immune lecture 1)
what is the role of the Opsonization
Coat” the microbe for easier recognition and phagocytosis by
phagocytes
which function of the lymphocytes has a long lasting effect of antibodies
• Due to the presence of long-lasting antibodies and lymphocytes thanks to clonal selection of lymphocytes
which response of the immune system is slower and which one is faster
Primary responses mediated by the immune
system tend to be slower and less
intense than secondary responses
how do we train our immune system
Natural infection • IgG antibodies received through placental circulation or breast milk • Vaccination • Immune serum: gamma globulin (antibody) transfer
explain the passive and active naturally acquired immunity
naturally: infaction , contact with the pathogen
passive : antibodies passes from the mother to the fetus via pacenta or passes through her milk
explain passive and active artificial immunity
passive injection of an immune serum
active :vaccine dead or attenuated pathogens
how lymphocytes become self- tolerance
When lymphocytes undergo maturation, they are trained to recognize self-antigens in a process called self-tolerance
The non-reactive lymphocytes get to stay, while reactive lymphocytes are weeded out
what is the Autoimmune disorders
Autoimmune disorders: this mechanism fails, leading to the development of autoantibodies
what is the allergy
Allergies are abnormal responses by B lymphocytes or T
lymphocytes
what are the Immediate and intermediate allergic reactions
– APCs present antigen to helper T cells that eventually help
recruit eosinophils to the site
– Helper T cells also stimulate B lymphocytes, which
become plasma cells that secrete IgE antibody
how does the igE acts during the alergy
IgE binds to mast cells and basophils which release
histamine & other cytokines
what is the Delayed allergic reactions
– Cell-mediated T lymphocyte response; symptoms are
caused by the release of cytokines
– Antihistamines provide no relief
what is the Anaphylaxis
: If the antibodies/chemicals/cytokines produced
by the immune system are in large quantities, they may
reach systemic circulation and cause anaphylactic shock
how does Anaphylactic shock happens and how does the epinephrin works
Anaphylactic shock causes extreme
vasodilation, low blood pressure/volume,
and bronchoconstriction
Epinephrine injection allows for near
immediate relief of these life-threatening
symptoms
what is the mechanism of the epinephrin
• Epinephrine, acting as a hormone, travels
to adrenergic receptors on the blood
vessels, heart, and bronchioles
what is the difference between the IgG and IgM
IgG and IgM are types of antibodies; IgG is most abundant in the blood, and IgM antibodies cause issues during mismatched blood transfusions.
what is the purpose of the lymphatic system
Drain excess interstitial fluid
• Return filtered plasma proteins to the blood
• Carry out immune responses
• Transport dietary lipids
what is the interstitial fluid
Interstitial fluid (water + salts, nutrients, and
wastes) is formed from filtration out of blood
tissue capillaries
how does The Lymphatic System Draining interstitial fluid
Lymphatic capillaries within tissues have a
porous junctions within their endothelial cells,
allowing them to soak up:
• Excess interstitial fluid + proteins
• Microbes, antigens & immune cells
• Lipids
how is the Lymphatic Circulation
• Lymph fluid picked up from interstitial space is transported
to lymph nodes
• Lymph fluid containing APCs or free antigen will subsequently
activate lymphocytes in lymph node (Immune lecture 2)
• Lymph fluid will continue to lymphatic duct where it will drain
into a major vein
how does the lymphatic capillaries act like
• Lymphatic capillaries act like a “sponge”
to soak up interstitial fluid (lymph fluid)
• Series of one-way valves move the fluid
through circulation
• “Squeezed” through movement!
why feet/legs feel swollen after airline travel?
Prolonged periods of sitting can cause blood to pool in the veins
• Excess blood in lower limbs = more fluid leaking out into interstitial space
• Without movement, lymphatic circulation cannot bring fluid back up to the heart
• Harmless for short periods of time!
what are the name of the other lymphoid tissues
Tonsils: Trap and destroy pathogens that enter the throat
• Thymus: Site of maturation for T lymphocytes (before adulthood)
• Spleen: Filters blood and removes bacteria and viruses as well as worn out RBCs
• Peyer’s patches: Prevent bacteria from penetrating through the intestinal wall
• Appendix: Functions similarly to other intestinal lymphoid tissue
why all of the homeostaic processes can take place in the circulatory system
• All homeostatic processes can take place in the circulatory system because it is a CLOSED SYSTEM
what is the role of the blood clothing in the hemostasis
Sequence of responses that results in wound repair
what is the goal of the coagulation during the blooding
The goal of hemostasis is to stop the bleeding that results from a break in a blood vessel via coagulation thanks to the action of platelets
why coagulation happens concurrently with the activation of the local innate defense
This often happens concurrently with the activation of local innate defense mechanisms (resident macrophages) to protect against potential infection
does stopping of bleeding help us maintain circulatory homeostasis
Hemostasis (stopping of bleeding) helps
us maintain circulatory homeostasis
how does the platelets form
Formed from the breakdown of megakaryocytes in a process called thrombopoiesis
does platelets enter main circulation
Platelets enter main circulation
•
what is the shape of the platelets
Disc shaped, no nucleus
what is the function of the platelets
Stop blood loss from damaged blood vessels and promote coagulation
what happens to the platelets in the absent of the injery
In the absence of injury…
• Circulating platelets are inactive
• Intact endothelial cells release a type of prostaglandin and nitric oxide; both inhibit platelet aggregation
what are the steps of the blood clothing
Vascular spasm causes vasoconstriction
2. Exposed collagen fibers causes platelets to stick, forming a plug
3. Coagulation: Fibrin is formed, trapping the platelets and some
RBCs, forming a clot
4. Clot dissolves once tissue damage is repaired
how does the vascular spasm occurs
Vascular spasm occurs by…
• Damaged endothelial cells release a cytokine that signals to surrounding smooth muscle to contract
• If the smooth muscle is damaged, they will intrinsically contract as well
• Pain receptors stimulated by inflammatory cytokines cause contraction
what are the process of the Formation of a platelet plug
Platelet adhesion: VWF is now exposed and binds to platelets
• “Stuck” platelets now secrete ADP, thromboxane A (TxA2), and serotonin to recruit other platelets to the site
how does the platelet plug is strengthened
The platelet plug is strengthened by an insoluble mesh of protein called fibrin, which together with the platelet plug form a blood clot
what does the fibrin is converted from
Fibrin is converted from fibrinogen through a series of enzymatic activation of blood factors
conversion occur through which pathways
Conversion may occur through:
• Intrinsic pathway (damaged vessel wall)
• Extrinsic pathway (extravascular damage)
where doe sthe most coagulation factors are produced
Most blood coagulation factors (proteins) are
produced in the liver, and are inactive within
circulation
which factor is activated by the damage to the endothelial cells
• Damage to the endothelial cells reveals collagen, which activates Factor XII • Factor XII activates Factor XI • Factor XI activates Factor IX • Factor IX activates Factor X
what is the Extrinsic pathway:
• Damaged extravascular cells release Tissue
Factor (TF) into the bloodstream
• TF activates Factor VII
• TF-Factor VIIa activates Factor X
what is the Expedited pathway
Expedited pathway that leads to the activation of
the factor needed to produce fibrin
what is the mechanism of the common pathway
Common pathway:
• Factor X is needed to convert prothrombin into thrombin
• Prothrombin is a Vitamin k dependent glycoprotein; Vit K
deficiency = bleeding tendencies
• Thrombin converts fibrinogen to
fibrin
what happens once the tissue has repaired
Fibrinolysis
• Once tissue has repaired, Factor XIIa AND/OR tissue plasminogen activator (tPA)
convert plasminogen to plasmin in the bloodstream
• Plasmin breaks down (lyses) fibrin proteins (fibrin degradation products; FDPs)
• Clot is dissolved and blood can flow normally within this repaired blood vessel
what is the Thrombosis
Thrombosis: Inappropriate formation of blood clots which can eventually occlude a blood vessel
• Clot is now called a thrombus
what cause the thrombosis
Caused by endothelial injury, abnormal blood
flow, or hypercoagulability, Atherosclerosis, high BP, high blood glucose
how does the Heart attack, stroke, or pulmonary embolism result
If the clot forms in a coronary artery, in the brain,
the lung, or if a clot moves from a peripheral
vessel to these organs…
• Heart attack, stroke, or pulmonary
embolism can result
what are the Fibrinolytics/thrombolytics
- Heparin
- Inhibits the activity of thrombin
- Warfarin
- Inhibits activation of vitamin K (factors VII, IX, and X)
- Aspirin
- Inhibits release of TxA2
