Exam 3 Flashcards
What is the cessation of bleeding?
Hemostasis
Excessive blood loss could result in diminished blood volume & pressure in an ever-decreasing cycle until
Death
What is the immediate but temporary constriction of a blood vessel ?
Vascular Spasm
In vascular spas, what does smooth muscle in vessel walls do?
Contract
In vascular spasm, what can it do to the vessel that can stop completely & half flow of blood ?
Can close the vessel.
The vascular spasm is initiated by what stimulation?
NS stimulation in response to blood vessel damage.
Chemicals released by cells of the damaged vessels.
Chemical released by platelets.
What is the accumulation of platelets that
can seal small breaks in blood vessels?
Platelet Plug.
(important step in clot formation)
What can close small tears in smaller vessels & capillaries?
Platelet plug
In platelet Plug formation, When a blood vessel is damaged, collagen is exposed and a protein, what is released from endothelial cells?
Von Willebrand factor
(vWF) binds exposed collagen
What has surface receptors on their membrane that ALSO binds vWF ?
Platelets
In platelet plug formation, 2. after platelets adhere to collagen, they become…?
Activated
In platelet plug formation, what do they release in the 2nd step.
Release ADP, thromboxanes, & other chemicals via exocytosis
- ADP & thromboxane bind receptors on surface of other platelets, activating them
- These platelets are now activated… & release additional
chemicals => creates a cascade=> more platelets
In platelet plug formation, 3. After platelets are activated, they change shape & express fibrinogen receptors that can bind what?
Bind fibrinogen, a plasma protein
Fibrinogen forms a bridge between fibrinogen receptors of different platelets which creates ?
Creates platelet plug.
Activated platelets also release phospholipids (platelet factor III) and coagulation
factor V, which are imp. in clot formation
Vascular spasms & platelets plugs can only close small tears/ cuts in
Vessel walls
What happens in case of a severe damage in blood vessel walls?
coagulation results in formation
of a blood clot- a network of fibrin, a threadlike protein fiber that traps blood cells, fluid, & platelets at the injury site.
In coagulation, blood cot formation occurs through activation of
Clotting factors, proteins that are normally in the plasma in their inactive state.
Activation is the result of many
chemical reactions.
In Coagulation, Some reaction require additional molecules such as Ca2+ and
platelet surface molecules
How are clotting factor activated?
Extrinsic pathway and Intrinsic pathway.
begins with chemicals outside the blood
Normally triggered by trauma
Extrinsic pathway
begins with chemical inside the blood
Triggered by internal damage to vessel wall
Intrinsic pathway
2 pathways converge to form common pathway—> forms a
a fibrin clot
Common pathway starts with activation of
Factor X
formed through combination of
activated Factor X, Factor V,
platelet phospholipids, &
Ca2+ on surface of platelets
Prothrombinase
Prothrombinase converts plasma protein
prothrombin to the enzyme …
Thrombin
Thrombin converts plasma protein fibrinogen to insoluble protein …
Fibrin
forms the fibrous network of the
blood clot
Fibrin
is required for formation of many factors like diet, gut microbes
Vitamin K
What can reduce Vitamin k?
Antibiotics can kill intestinal bacteria also
Reduce #s of clotting factors formed
- Increase bleeding
is a lipid soluble vitamin
Vitamin K
Req’s bile for absorption from
large intestine.
* Obstruction of bile flow can decrease Vit K absorption
What does blood contain to prevent uncontrolled formation of clots throughout the circulatory system?
Anticoagulants
Clotting factors must exceed a threshold in a localized region to
form clot
What happens after forming clot retraction occurs?
Platelets contain actin & myosin, which operate similarly to how they contract in muscle
- Extensions of platelets that bound fibrinogen (information of clot) contract, therefore retracting the clot
- Serum, plasma without much of the fibrinogen & clotting factors, is squeezed out of clot
Clot retraction
Clot retraction pulls edges of damaged vessels closer together
- Fibroblasts move in & new connective tissue forms
- Epithelial cells in region divide & repair damaged area
Process of dissolving clot
Fibrinolysis
Fibrin broken down by enzyme..?
Plasmin
is a mechanism of action for some substances (ex. tPA) used to treat abnormal clot formation
Plasmin Activiation
Excessive blood loss can cause chock or death
TRUE
is the transfer of blood from one
person to another
Transfusion
is the introduction of a fluid other than
blood
Infusion
Can be used to increase volume of blood. Often sufficient to prevent shock… RBC
production will follow
Infusions
3 main function of lymphatic systems?
Fluid balance, lipid absorption, and defense.
lymphatic capillaries collect fluid that has previously left circulation
Fluid balance
from digestive tract
lipid absorbption
microorganisms/foreign bodies are
filtered from lymph & blood
Defense
Clear fluid in lymphatic vessels is called
Contains water & solutes (ions, nutrients, gases,
proteins, hormones, enzymes, waste products)
* Ultimately passes back into circulation
Lymph
lymphatic vessels located in lining
of digestive tract that absorb lipids
Lacteals
Lymph with absorbed fats, traveling in
lacteals, is called
CHyle
- Recall that fluid moves out
of capillaries into
interstitial spaces - Not all fluid returns via
circulatory system - Some enters into
lymphatic capillaries - Fluid now called
lymph
lymph
Lymphatic vessels
originate in most bodily
tissues as small, dead-
end
Lymphatic capillaries
More permeable than blood capillaires
Lymphatic capillaries
Allows fluid to enter capillary
but prohibits it from passing
back into interstitial spaces
Lymphatic capillaries
Lymphatic capillaries join to form
larger
lymphatic vessels
Inner layer- endothelium surrounded
by elastic membrane
- Middle layer- smooth muscle cells & elastic fibers
- Outer layer- thin layer of fibrous
connective tissue
Lymphatic Vessels
drain lymph from head & neck
Jugular trunks
Lymphatic vessels converge to form larger
vessels called
Lymphatic trunks
drain lymph from upper limbs, superficial thoracic wall, & mammary glands
Subclavian trunks
drain lymph from thoracic organs & deep thoracic wall
bronchomedoastinal trunks
drains lymph from some abdominal organs (intestines, stomach,
pancreas, spleen, liver)
Intestinal Trunk
drain lymph from lower limbs, pelvic & abdominal walls, ovaries/
testes, kidneys, adrenal glands
Lumbar Trunks
Lymphatic trunks drain into large veins in the thorax or to larger vessels called
lymphatic
ducts which drain into large veins
Largest lymphatic vessel (~38-45 cm) is the
Thoracic duct
- Lymphatic Capillaries
—> - Lymphatic Vessels —>
- Lymphatic Trunks —>
- Lymphatic ducts
—> - Large veins
FLOW OF LYMPH
filters lymph
lymph nodes
Round/Oval/Bean shaped bodies located
along Lymphatic vessels
lymph nodes
Lymph moves through vessels via 3 mechanisms
Contraction of lymph vessels, contraction of skeletal muscles, and thoracic pressure changes
Valves create “chambers” and smooth muscle contractions move lymph from one to
the next
* Smooth muscle cells include some pacemaker cells, which spontaneously
depolarize
Contraction of lymph vessels
compresses lymphatic vessels and moves lymph
contraction of skeletal muscles
During inspiration, pressure in thoracic cavity decreases & lymphatic vessels expand
* Lymph flows into them
* During expiration, pressure in thoracic cavity increases & lymphatic vessels compress
* Lymph moves
Thoracic pressure changes
Lymphatic tissue cell types
Lymphocytes (most)
* B cells & T cells
* Macrophages
* Dendritic Cells (ex. Langerhans cells in skin)
* Reticular cells (type of fibroblast that
produces reticular fibers- provide structural
& functional support)
Lymphatic tissue & organs are organized into:
Primary lymphatic organs
* Secondary lymphatic tissue & organs
Locations
where lymphocytes become
immunocompetent— able to launch an
immune response
* Red bone marrow
* Thymus
* Red bone marrow is location where
lymphocytes originate
* Pre-B cells become
immunocompetent in red bone
marrow
* Pre-T cells become
immunocompetent in thymus
Primary lymphatic organs
Locations where lymphocytes
interact with each other, other
immune cells, foreign bodies/
microorganisms to produce an
immune response
* Include:
* Lymphatic nodules, incl. tonsils
* Lymph nodes
* Spleen
* Diffuse lymphatic tissue
Secondary lymphatic tissues and organs
Lymphatic organs & tissues contain very fine collagen fibers called
reticular fibers
Form a network that filters foreign substances from bodily fluids
reticular fibers
Lymphatic organs are differentiated from lymphatic tissue by the presence
of a connective tissue capsule
* Organs are encapsulated
* Tissues are non-encapsulated
* Often associated with mucous membranes that line: digestive,
respiratory, urinary, reproductive tracts
* Referred to as Mucosa-associated lymphatic tissue (MALT)
* Well-positioned to intercept microorganisms as they enter body
Secondary lymphatic tissue and organs.
MALT (Mucosa-
Associated Lymphatic
Tissue) can be further
broken down into
NALT- Nasopharynx
* BALT- Bronchi
* SALT- Skin
* GALT- Gut
Contains lymphocytes, macrophages, etc.
* No clear boundary
* Located: Deep to mucous membranes, around nodules, within nodes & spleen
Diffuse lymphatic tissue
Denser, loosely spherical organization of lymphatic tissue
* Located in:
* Loose connective tissue of digestive, respiratory, urinary, reproductive systems
* Lymph nodes & spleen
* Large groups of nodules are found in specific areas of body including:
* Peyer’s patches in distal small intestine
* Tonsils
Lymphatic nodules
are groups of lymphatic nodules & diffuse
lymphatic tissue located deep to mucous
membranes within pharynx
* Protect against harmful materials entering nose
& mouth
tonsils
3 types of tonsils
Palatine Tonsils*- oval masses located bilaterally at junction of mouth & pharynx
Pharyngeal Tonsil- collection of nodules near junction of nasal cavity & pharynx
* When enlarged, commonly called adenoids
* Can interfere with breathing
Lingual Tonsils- collection of nodules on posterior surface of tongue
small roundish structures located along lymphatic located along lymphatic vessels
Lymph nodes
what filters lymph?
Lymph nodes
what removes foreign materials & microorganisms?
Lymph nodes
Lymphocytes accumulate
& carry out functions& carry out functions
true
.
throughout body:
** Cervical & head (~70) filter from head & neck
** Axillary (~30) filter from upper limbs & superficial thorax
** Thoracic (~100) filter from thoracic wall & organs
** Abdominopelvic (~230) filter from abdomen& pelvis
** Inguinal & Popliteal (~20) filter from lower limbs &
superficial pelvis
** Categorized as superficial or deep
** Superficial lymph nodes are in the hypodermis.
** Deep lymph nodes are everywhere else
** Most are located near/on blood vessels
Lymph nodes
What forms a network throughout the node?
Reticular fibers that extend from capsule & trabeculae.
In some regions, cells are packed between reticular fibers form ?
lymphatic tissue
in other areas, fibers bridge open spaces are
lymphatic sinuses
What contains diffuse lymphatic tissue, sinuses, trabeculae & lymphatic nodules
outer cortex
what contains medullary cords & medullary sinsuses
Medulla
carry lymph to the node
Afferent lymphatic vessels
carry lymph away from the node
efferent lymphatic vessels
Macrophages line lymphatic sinuses remove ?
microorganisms. Also, stimulate lymphocytes to undergo cell division.
proliferate in cortical
lymphatic nodules, called
germinal centers. New lymphocytes are released into lymph, travel through bloodstream &/or lymphatic tissues
stores & filters blood, increase in size with infectious disease.
Increased # of immune cells
Spleen
Functions of spleen
Macrophages phagocytize old/damaged RBCs
-Destroying defective RBCs
** Detecting & responding to foreign bodies in blood
** Immune response initiated by specialized lymphocytes
** Acting as a blood reservoir
** During exercise, splenic volume can decrease by 40-50%
** Allows more RBCs to be present in circulation & increase O2 delivery to muscles.
In spleen, outer capsule is dense irregular connective tissue and
smooth muscle
In spleen, connective tissue fibers form
trabeculae that travel inward, forming compartments
In spleen, compartment contain
white pulp- diffuse lymphatic
tissue & lymphatic nodules
** Surrounding arteries in spleen
red pulp - fibrous lymphatic tissue & venous sinuses, containing macrophages & RBCs
-surrounding veins in spleen
supplies spleen
splenic artery -
Branches enter Hilum & travel to trabeculae
** Arterial branches extend into white pulp
** Arterioles enter lymphatic nodules & form capillaries
** Blood in capillaries flows into red pulp containing
splenic cords (network of fibers) & venous sinuses
(enlarged capillaries)
** Venous sinuses connect to trabecular veins,ultimately forming Splenic Vein
** Most blood flows through the spleen rapidly (sec’s)
Spleen often ruptured, can result in severe bleeding, shock, death
treated by suturing/use of blood clotting agents/ mesh wrapping.
splenectomy is possible
Bilobed gland located in superior mediastinum
Thymus
In thymus, Each lobe surrounded by thin connective tissue
Capsule
In thymus, trabeculae travel into thymus from capsule, dividing it into
Lobules
Site for maturation of T cells and secretes hormone Thymosin
Thymus
Processes performed by lymphatic system.
- lymphatic capillaries & vessles remove excess fluid form tissues, forming lymph
- Lymph nodes filter lymph: they are sites where lymphocytes respond to infections
- Lacteals in small intestine absorbs lipids, forming chyle
- Lymph & Chyle pass through
thoracic duct or lymphatic trunks before entering blood. - Spleen Filters blood & is a site where lymphocytes respond to infections
6.Lymphocytes (pre-B and pre-T cells) originate from stem cells in bone marrow.
- Pre-B cells become mature B
cells in red bone marrow & are release into blood.
- pre T cells enter blood & migrate thymus. - Pre-t cells increase in # & become mature T cells in the thymus, then release into blood.
- B cells and T cells from blood enter & populate all lymphatic tissues
- can remain in tissues or pass through & return to blood to respond to infections.
- responsible for much immunity.
What is the ability to resist damage from foreign substances? (Microorganisms, harmful chemicals, internal threats)
Immunity
“nonspecific resistance”, response is the same each time the body encounters “threat”
Innate immunity. They are present in all multicellular organisms
“specific immunity”, subsequent encounters with a foreign substance are recognized and responded to quicker, because of previous encounter.
Adaptive Immunity, unique to vertebrates.
What are characteristics of adaptive immunity but not innate immunity?
Specificity & memory
Ability of adaptive immunity to recognize a particular substance.
Specificity
- Innate immunity responds generally against bacteria
- Adaptive immunity distinguishes among different kinds of bacteria
TRUE
The ability of adaptive immunity to “remember” previous encounters with a particular substance
Memory, response is faster, stronger, longer-lasting
Innate immunity overview
Includes defenses present at birth, & genetically
determined
* Immune response is standardized- no specificity
* Ex) Each time a bacterial cell is introduced into the body, cells of innate immunity phagocytize it
— same speed & efficiency each time
Adaptive immunity
Includes body defenses that are acquired throughout a person’s lifetime
* Depends upon previous exposure
* Response is faster & stronger during subsequent exposures
* Immune system “remembers” foreign body from first encounter
* Ex) First encounter: bacteria damage tissues & produce disease symptoms
* Body may take days to destroy them
* Second exposure- bacteria destroyed by adaptive immune
mechanisms before symptoms develop
* Person is said to be immune
Main components of innate immunity are?
- Physical barriers
* Prevent entrance of microbes & physically remove them - Chemical mediators
* Act against microbes or active further mechanisms to
destroy them - Cells involved in phagocytosis & production of chemicals
Innate immunity- physical barriers
First line of defense- prevent entry.
include: skin, mucous membrane
same structures remove substances from body
Ex) tears, saliva, urine wash substance away
Innate immunity - chemical mediators
Some chemical mediators are on cell surfaces, where they
kill microbes/prevent their entrance into cell
* Ex) lysozymes
* Other chemical mediators promote inflammation/attract
WBCs/stimulate phagocytosis
* Ex) histamine
* Some chemicals bind to receptors on other cells’ surfaces and stimulate a response (ex. Stimulate cell proliferation &differentiation)
Innate immunity- cells- neutrophils
Neutrophils: ~126 billion leave blood & pass through walls of
digestive tract/day
* 1st to respond
* enter infected tissue
* release chemical signals- increase inflammatory response &/or
kill microorganisms
* Phagocytize microorganisms
* Usually die after 1 phagocytic event & are eliminated in feces or in pus
Innate immunity - cells- macrophages
Macrophages: large phagocytic cells
* derived from monocytes
* When monocytes leave blood, they enlarge ~5x (increase
lysosomes & mitochondria)
* Phagocytic- ingest more & larger particles than neutrophils
* Present in many areas- dermis, hypodermis, mucous
membranes, serous membranes, sinuses of lymphatic system
* Go by different names in specific areas (Ex. Microglia in NS, dust cells in lungs, Kupffer cells in liver)
Innate immunity- cells - other cells
Basophils & Mast Cells- can be activated by innate
immunity or adaptive immunity
* Release chemicals that produce inflammatory
responses
* Eosinophils- secrete enzymes that kill some parasites
* Natural Killer Cells- lymphocytes- general response
to tumor & virus-infected cells (not part of adaptive
immunity)
Inflammation
can be local or systemic
Local- confined to specific area (redness, swelling)
Systemic- occurs in many parts of body simultaneously
Includes:
* Red bone marrow produces & releases more neutrophils- increased
phagocytosis
* Fever induced by release of chemicals called pyrogens
* Body temp increases- promotes phagocytosis & inhibits growth of
some microorganisms
* In severe cases, increased vascular permeability causes severe decrease in blood volume— > shock, death are possible
Adaptive immunity is the ability of lymphocytes to recognize, respond to & “remember” a substance. Substance is called an?
Antigen
(Adaptive immunity) 2 major types of lymphocytes
Bcells & Tcells.
Adaptive immunity can be divided into:
- Antibody-mediated immunity
* Involves proteins, called antibodies, in body fluids such as plasma, lymph,
interstitial fluids
* B cells give rise to cells that produce antibodies - Cell-mediated immunity
* Involves actions of different types of T cells (Ex. Cytotoxic T cells, Helper T cells,
regulatory T cells)
(Adaptive immunity) - Antigens can be
Foreign Antigens- introduced from outside the body
* Ex) parts of microorganisms/viruses, pollen, animal dander or droppings, food or drugs
* May trigger allergic reactions
* Self Antigens- molecules produced by body that stimulate an adaptive immune
response
* May be beneficial
* Ex) tumor antigens
* May be harmful
* Ex) autoimmune diseases result from unwanted destruction of own tissue
* Rheumatoid arthritis - joint tissue is destroyed
(Adaptive immunity) - antigen recognition
Antigens are large molecules
* Only a small portion of the antigen is recognized by a lymphocyte
* Portion on antigen is an epitope (aka antigenic determinant)
* Each antigen has many epitopes
* Different lymphocytes may respond each
* Lymphocytes have antigen receptors
* Highly specific to an individual epitope on an individual antigen
* Lock & Key
(Adaptive immunity) - antigen recognition by t cells
Antigen receptors are different for B cells vs T cells
* T cells: Receptors are made of 2 polypeptide chains with:
* a constant region
* a variable region- can bind antigen
* Different variable regions of receptors allow for specificity!
(Adaptive immunity) antigen recognition by B cells
B cells: Antigen receptors are essentially antibodies
on the surface of B cells
* made of 4 polypeptide chains with:
* 2 identical variable regions- can bind antigen
A major role of immune cells
is to “ID” cells in the body:
1. Must distinguish between “self” & foreign antigens
2. Must detect if “self-cells” have been compromised
(infected or mutated)
MHC Molecules
Method of recognition by lymphocytes often involves
interaction with Major histocompatibility complex
(MHC) molecules
MHC molecules:
* Have glycoprotein structure
* Found on plasma membranes of most body cells
* Have a variable region that can bind antigens found
within the cell
* Display these antigens outside the cell plasma
membrane
* Antigens may be produced in the cell - or - processed in the cell
* “Endogenous” if produced in the cell
* “Exogenous” if obtained from outside
the cell (via phagocytosis)
2 Classes of MHC Molecules:
- MHC class I molecules
display endogenous
antigens- those produced in
the cell - MHC class II molecules
display exogenous
antigens- those obtained
from outside the cell
MHC class I molecules
display endogenous
antigens (antigens produced in the cell)
* Ex) When viruses infect cells, they “hijack” the
cell’s reproductive equipment to produce viral
proteins
* Viral proteins can be broken down in the cell
* Protein fragments combined with MHC
Class I molecules (Rough ER), processed
by Golgi & transported to plasma
membrane
* Complex bound by receptors on T
cells
* Binding activates T cells —> destroy
cell!!
* Stops viral replication!
MHC CLASS I MOLECULES, CONT
Process is called “MHC-restricted”— requires both the antigen &
the cell’s own MHC molecule
* Self protein fragments may sometimes (inadvertently) be used to
form MHC-complexes
* Usually don’t trigger immune response because of previous
inactivation of lymphocytes that would recognize self proteins
* refining of lymphocyte populations happens largely during
embryonic development
MHC CLASS II MOLECULES
MHC class II molecules are found on “antigen-presenting
cells”
* These cells display exogenous antigens (antigens
produced outside the cell) that were previously
phagocytized & broken down
* Ex’s of antigen-presenting cells include B cells,
macrophages, monocytes, dendritic cells (ex.
Langerhan’s cells in skin)
- MHC CLASS II MOLECULES, CONT
Antigen-presenting cells endocytose foreign bodies, which are broken down (forming antigens) in vesicles
* Vesicles from Golgi containing MHC Class II molecules combine with vesicles containing antigens
* MHC Class II molecule combines with antigen & are transported to plasma membrane
* Complex is displayed & bound by antigen receptors on T cells
* Process is also MHC-restricted
* However— cell NOT destroyed…
MHC CLASS II MOLECULES, CONT.
- Instead, this is a trigger to fight
the foreign body - The specific lymphocyte that
can recognize the antigen is
stimulated to divide - Production of antibodies
triggered - Antibodies will bind
foreign antigens &
destruction of foreign
bodies with those antigens
will follow
Lymphocytes are derived from stem cells in
red bone marrow.
some become pre T-cells –> go to thymus
divide and mature into T cells.
some become pre B cells, stay in red bone marrow. mature into B cells
B cells & T cells are members of group of clones
Identical to others in the same group.
- each clone response to the same specific antigen.
positive selection for B cells and T cells capable of an immune response.
negative selection against clones that respond to “self” antigens.
After formation, B cells and T cells circulate in blood & ?
lymphatic tissue.
Before exposure to antigen, # of clones to that antigen is low.
antigens come into contact with lymphocytes & activate them.
Activation process caries based on lymphocyte type and antigen type
2 general principle of activation:
1. lymphocytes must be able to recognize the antigen
2. After recognition, lymphocytes proliferate & destroy antigen
Lymphocyte proliferation beings with recognition of an
Antigen.
Recall that if the antigen originated OUTSIDE the cell, it is an exogenous antigen & is presented by a MHC
Class __II_ molecule
lymphocyte proliferation:
- MHC molecule recognition- 1st trigger
* For MHC Class II molecules, Helper T cells
are usually the first to recognize the
antigen
* (Not pictured) For MHC Class I molecules,
Cytotoxic T cells are usually the first to
recognize the antigen
* 2nd trigger- May require costimulation
* additional events needed to stimulate
proliferation of lymphocytes
* Ex.) chemical release
* Ex.) binding between lymphocyte &
presenting cell
Lymphocyte proliferation:
- For MHC Class II molecules— the Helper T
cell begins to divide
* Daughter cells can: - Be stimulated by same antigen to
further divide— more proliferation! - Find & stimulate B cells or Cytotoxic
T cells
* B cells & Cytotoxic T cells then
proliferate: responsible for immune
response that destroys antigen (more
to come…) - Become Memory Helper T cells-
long lived!
* become active in future encounters
with same antigen
Adaptive immunity can be divide into
- antibody mediated immunity
- involves B cells that give rise to cells that produce soluble antibodies that destroy antigen-producing agents - cell mediated immunity
-involves actions of different types of T cells
detail of antibody Mediated
After Helper T cell is activated, 1
option is that it finds & stimulates a
B cell
* B cell must bind the same antigen
* B cell divides, daughter cells divide,
etc.
1. Produces many generations of B
cells that recognize the same
antigen
2. Many become plasma cells— cells
that directly make soluble
antibodies
3. Some become Memory B cells—
long lived!
* May become active in future
encounters with the same antigen
are proteins produced in response to an antigen
antibodies.
Prevalent in plasma
Recall that plasma proteins included globulin proteins.
often types of gamma globulin proteins, knwon as “immunoglobulins”
Antibodies
All have Y shaped structure made of 4
polypeptide chains
antibodies.
Have variable region- ends of
heavy & light chains
* Combines with epitope of antigen
* Specificity
* Have constant region-
responsible for action of antibody
(ex. Attachment to specific WBCs)
* Nearly identical in all antibodies
of a particular class
effects of antibodies
Direct- disables antigen
Indirect- initiates events that
lead to antigen destruction.
Effects of antibodies can: Direct
Direct:
(a) Bind epitope, which
interferes with antigen
functioning
(b) Bind epitope on 2 different
antigens- preventing
antigen functioning
Effects of antibodies “indirect”
(c) Binds antigen through variable region; constant
region activates a cascade of proteins called
compliment cascade
* Stimulates inflammatory response: attracts
WBCs, increase vascular permeability, kills
foreign body
d) Binds antigen through variable region; attaches
to Mast cells or Basophils via constant region:
* stimulates cells to release chemicals (ex.
Histamine) that initiate inflammation
(e) Act as opsonins— connect to antigen via
variable region; connects to macrophage via
constant region & triggers phagocytosis
Antibody production
is different between 1st
exposure & subsequent exposures to an antigen
Antibody production
First exposure initiates primary response
* Subsequent exposures initiate secondary
response aka memory response
Antibody production- primary response
The first exposure of a B cell to an antigen (for which it is specific)
initiates the Primary response, including:
* Cell division & differentiation
* Antibody production
* Receptors on surface of B cells are antibodies
* Have same variable region as antibodies later produced by the B
cell
* Primary response takes 3-14 days to produce sufficient antibodies to
disable antigen
* Disease symptoms usually develop
Adaptive immunity: cell mediated immunity
Antibodies cannot cross plasma membrane
* Cell mediated immunity (other branch of Adaptive Immunity) is effective
against cytoplasmic microorganisms (Ex. Viruses, parasites, cytoplasmic
bacteria)
Cytotoxic T cells:
* Become activated when exposed to their specific antigen
* Antigen is presented by MHC Class I molecules, which helps ID
abnormal or infected cells
* Activation leads to proliferation…
Antibody production” secondary response”
a Secondary response, including:
* Memory B cells rapidly divide to produce plasma cells
* Produce LOTS of antibodies
* Secondary response:
* Is much quicker: hours-days to start producing antibodies
* Produces more antibodies
* Antigen is usually rapidly destroyed
* Symptoms do not develop; person is “immune”
* Produces more Memory B cells to the antigen
* Memory B cells are the basis of adaptive immunity
* Plasma cells die after destruction of antigen & circulating antibodies are degraded
* BUT some Memory B cells live for years to a lifetime!
Adaptive immunity, cell mediated immunity
Cytotoxic T cells proliferate and…
1. Produce more Cytotoxic T cells
2. Produce Memory T cells (long lived; serve similar purpose as Memory B
cells)
3. Release chemicals such as cytokines that activate immune functions (ex.
recruit macrophages for phagocytosis)
4. Cause lysis of target cell via chemical signaling:
* Perforin is protein that is released by cytotoxic T cells and forms a channel
in the plasma membrane of the target cell…
* Water enters…
* Lysis!
Acquiring adaptive immunity
Not present at birth, must be acquired
* 4 types, depending on how immunity is acquired:
* Active immunity- individual is exposed to antigen & individual’s
immune system responds
* Passive immunity- another person or animal develops immunity,
which is transferred to another individual
* Either of the above can also be:
* Natural- occurs through everyday living; not intentional
* Artificial- deliberate introduction of antigen or antibody
* Aka immunization
Adaptive immunity “Active natural”
Exposure to an antigen (Ex. Microorganism) can
cause immune system to mount an adaptive
immune response
* First exposure: individual is usually symptomatic
Adaptive immunity “ active artificial”
Antigen is deliberately introduced (vaccine), via injection
* Process is called immunization or vaccination
* Vaccine may include:
* Part of a microorganism
* Dead microorganism
* Live altered microorganism
* Stimulates immune system to mount an adaptive immune response
* BUT does not cause disease symptoms
Adaptive immunity “passive natural”
Antibodies are transferred from mother to child through placenta or breast milk
* Mother’s lifelong active immunity (natural or artificial) has produced
antibodies
* Some can be transferred to baby, though only last through first few months
post-birth
* Baby’s immune system must take over
Adaptive immunity “ passive artificial”
Begins with vaccinating an animal (sometimes can be human)
* Antibodies & sometimes cells are removed from animal & injected into human
* Injection called an antiserum
* Contains blood serum (plasma minus clotting factors)
* Provides immediate, but temporary, protection for individual receiving injection
* Ex) rabies, hepatitis, measles, bacterial toxins such as botulism, snake & spider
venom
Adaptive immunity “longevity”
Longevity of immunity varies:
* Active: can last weeks (ex. common cold)- lifetime (ex.
Polio)
* Individual makes their own memory cells
* Preferred for longevity of immunity
* Passive: not long-lasting
* Person does not make their own memory cells
* Preferred when immediate protection is desired
STRUCTURES OF RESPIRATORY SYSTEM
External nose- creates chamber for air inspiration
Nasal cavity- chamber for cleaning, warming and humidifying air
Pharynx- common passage for food and air
Larynx- airway, rigid structure keeps passage open
Trachea- common tube to lungs
Bronchi- directs air to each lung
lungs- network of air tubes sacs (alveoli) and capillaries - sites of gas exchange between air & blood
Functions of respiratory system
Breathing aka pulmonary ventilation- movement of air into and out of the lungs.
Gas exchange- diffusion of gases across membranes.
Pulmonary gas exchange- movement of gases between atmospheric air in lungs & the blood.
Tissue gas exchange- movement of gases between blood & body cells
Respiratory tract can be divided into two different ways: upper & lower respiratory tracts
Upper respiratory tract - nose to larynx
Lower respiratory tract- trachea through alveoli in lungs
functionally:
conducting zone- strictly performs pulmonary ventilation. includes nose to smallest air tubes in lungs.
Respiratory zone- responsible for pulmonary gas exchange.
Exclusively in lungs- includes alveoli and specialized air tubes
