Module 5 - Lymphatic Flashcards
Functions
Drain interstitial fluid
Return leaked plasma proteins to blood
Transport dietary fats – lipids and lipid-soluble vitamins from GI
Protect body invasion – nonspecific defences and specific immune responses
Components
Lymph
Lymphatic vessels
Lymphatic tissue
Lymphocytes
Red Bone Marrow
Lymph
Lymph – comes from interstitial fluid (fluid b/w cells) – components of blood plasma after pushed out of capillary vessels – taken in by lymphatic vessels and tissues
Lymphatic vessels - Function
Lymphatic vessels – transport the fluid
Lymphatic tissue
Lymphatic tissue – specialized reticular connective tissue containing lymphocytes
Lymphocytes
Lymphocytes – agranular white blood cells
B cells
T cells
Capillaries
Capillaries
In tissue spaces b/w cells
merch into lymphatic vessels – lead to lymph nodes
slightly larger than blood capillaries
Interlaced with capillaries & venules
Anchored to capillary bed by collagen fibers
endothelial cells tightly overlap – when pressure of interstitial fluid increases – cells separate slightly making valves for fluid to enter – one-way flow – new increased pressure inside with tighten the cells – sealing them off
fluid pushed out of blood capillary enters lymphatic capillaries
absorb large molecules – proteins and lipids
Lacteal
Lacteal – capillaries in small intestine – transports fats into blood
Lymph Trunk
Lymph Trunk – where lymphatic vessels unite at exit of lymph nodes – named by location
Lymph Duct
Lymph Duct – merging of vessels to form a large vessel – where lymph fluid is emptied into venous system
Thoracic (LEFT) Duct
RIGHT Lymphatic duct
Thoracic (LEFT) Duct
Thoracic (LEFT) Duct – lymph from left side of head, neck, chest, left upper extremity, and entire body below ribs – drains into subclavian vein – larger – connected to Cisterna chyli
Cisterna chyli
Cisterna chyli – dilated lymph sac – base of thoracic duct – collection point for lymph from abdominal and pelvic organs, and lower limbs – directs lymph to thoracic duct
RIGHT Lymphatic duct
RIGHT Lymphatic duct – drains lymph from upper right – drains into right subclavian vein
Formation of Lymph
Formation Lymph
Left over fluid from blood capillary exchange
Blood plasma leaks into tissues
Interstitial fluid outside of blood capillary comes into lymphatic capillaries
Structure of Lymph Node
Hilum – drainage area
Covering – fibrous capsule
Trabeculae – beams for support – divide node into sections
Medulla – plasma cells
Paracortex – T cells
Cortex – contains lymphoid follicle – B cells
Start as primary – 1st
Develop into germinal centers – 2nd
Substances trapped by nodal reticular fibers
Macrophages destroy by phagocytosis
Lymphocytes destroy by immune response
Respiratory pump
Respiratory pump – flow is maintained by pressure changes with inhalation
Flow of Lymph
Flow
From arteries and blood capillaries (blood)
Interstitial spaces (interstitial fluid)
Lymph capillaries (lymph)
Lymphatic vessels – valves and smooth muscle for one-way flow
Lymph trunks
Ducts
Subclavian veins (blood)
Lymph Nodes
Lymph nodes – encapsulated – mass of lymphatic tissue – filters
Scattered along lymphatic vessels
Hilum – drainage area
Covering – fibrous capsule
Trabeculae – beams for support – divide node into sections
Medulla – plasma cells
Paracortex – T cells
Cortex – contains lymphoid follicle – B cells
Start as primary – 1st
Develop into germinal centers – 2nd
Artery brings macrophages from bloodstream
Contain T cells, B cells, macrophages, and follicular dendritic cells
Lymph enters via afferent vessel – where filtered out damaged cells and microorganisms exits via efferent vessels
Skeletal Muscle contractions
Skeletal Muscle contractions – milking action – compresses vessels and forces lymph forward
Lymph Function
Functions:
Centers for antigen presentation – recognition ability
Lymphocyte activation, differentiation, and proliferation
Generate mature, antigen-primed B&T cells
Functions of Spleen
Storage of 1/3 of platelets
Phagocytosis of worn out blood cells
Hemopoiesis during fetal life
Filters RBCs
Immune function
Spleen Structure
Spleen – largest mass of lymphatic tissue – attached to stomach
Hilum – drainage area
Splenic artery – brings blood in – fans outs
Red Pulp
White Pulp
Red Pulp
Red pulp – filters RBCs
Splenic cords – surrounds everything – contain cells – macrophages
RBCs move into from arteriole
Want to drain to collecting veins
RBCs move into cord – macrophages look for bad cells
Venous sinuses filled with blood – around end arteries – slits for filtration
RBCs try to enter through slits
White Pulp
White pulp – Immune function
Cells arranged around branches of spleen artery
Areas
Lymphatic sheath – surrounds arterioles
T cells and macrophages attack antigens in blood
Marginal zone – takes antigens from circulation & brings lymphocytes
Macrophages destroy antigens in blood – phagocytosis
Follicle – B cells– around ends of arterioles
antibody-producing plasma cells
MALT – mucosa-associated lymphatic tissue
MALT – mucosa-associated lymphatic tissue – clusters of lymphocytes in mucous membranes of:
GI tract – Peyer’s patches in ileum of sm. Intestine
Respiratory airways
Urinary tract
Reproductive tract
MALT – Tonsils
MALT – Tonsils – multiple large aggregations
Protect against invasion
Producing lymphocytes and antibodies
Form a ring at junction of oral cavity and pharynx – Waldeyer’s Ring
1 Pharyngeal (adenoid)
2 Palatine tonsils
2 Lingual tonsils
1 Pharyngeal (adenoid)
1 Pharyngeal (adenoid)
Roof of posterior wall of nasopharynx – nasal meets throat
2 Palatine tonsils
2 Palatine tonsils – largest
Posterior region of oral cavity L & R – commonly removed
create Crypts – deep and branching tunnels – B & T cells
2 Lingual tonsils
2 Lingual tonsils – base of tongue
Innate Immunity – First Line
Innate Immunity – First Line
Nonspecific resistance – catch all – variety of responses against variety of pathogens and toxins
Physical barriers – first line defence
Chemical Barriers
Innate Immunity - Physical barriers
Physical barriers – first line defence
Skin – epidermis – barrier against microbes – periodical shedding – perspiration
Mucous membranes – line body cavities – secret mucus
Mucus – traps microbes and foreign substances
Lacrimal apparatus – cleans out eyes
Saliva – washes away microbes from teeth and mouth
Flow of urine – expels microbes
Cilia – hair-like projections – traps microbes
Innate Immunity - Chemical Barriers
Chemical Barriers
Sebum – oil glands on skin – protective film – fatty acids inhibit growth of bacteria
Lysozyme – in tears – enzyme breaks down cell walls of bacteria
Gastric juice – strong acidity – hydrochloric acid, enzymes, and mucus
Vaginal secretions – move microbes out – slightly acidic
Innate Immunity - Second line
Innate Immunity – Second Line
Internal antimicrobial proteins
Phagocytic and Natural Killer Cells
Inflammation
Fever
Internal antimicrobial proteins
Internal antimicrobial proteins – discourage microbial growth – 4 types
Interferons
Complement system
Iron-binding proteins
Antimicrobial proteins
Interferons
Interferons – proteins produced by infected lymphocytes, macrophages, and fibroblasts
Diffuse to uninfected cells and bind to surface – synthesize antiviral proteins –block viral replication
Enhance activity of phagocytes and NKs
Inhibit cell growth and suppress tumour formation
Complement System
Complement system – group of normally inactive proteins in blood plasma and membranes
Enhance immunity
Cause cytolysis/bursting of microbes
Promotes phagocytosis
Inflammation
Iron-binding proteins
Iron-binding proteins – reduce iron availability – bacteria cells can’t grow
Antimicrobial proteins
Antimicrobial proteins – broad spectrum antimicrobial activity
Kill microbes
Attract dendritic cells and mast cells
Phagocytic
Phagocytic
Phagocytic Cells – perform phagocytosis – ingestion of microbes
Neutrophils – stim by histamine
Macrophages – stim by histamine
Phagocytosis
Natural Killer Cells
Natural Killer Cells – microbes have penetrated physical barriers & by-passed blood barriers
Natural Killer Cells NKs – 5-10% of lymphocytes in blood
Lack membrane molecules that identify T & B cells
Attack cell w/ abnormal or unusual plasma membrane proteins
Apoptosis
Cytolysis
Innate Immunity - Second line - NK cells: Apoptosis
Apoptosis – release granzymes – protein-digesting enzyme – force self destruction
Innate Immunity - Second line - NK cells: Cytolysis
Cytolysis
NK cells bind to infected cell – release granules of toxic substances – Perforin
Perforin – inserts into membrane – creates perforations – allows extracellular fluid to flow in – cell burst
Innate Immunity - Second Line - Phagocytic cells: Phagocytosis
Phagocytosis
Chemotaxis – phagocytes are stim – to come
Adherence – attachment to microbe
Ingestion – plasma membrane extends and engulfs – sac surrounds microbe – phagosome
Digestion – lysosome break down cell walls – enzymes degrade
Killing
Innate Immunity - Second Line - Inflammation
Inflammation – dispose of microbes & prevent spread
Vasodilation & increase permeability
Emigration of phagocytes from blood to interstitial fluid – clear cellular debris
Tissue repair
PRISH
Pus – fluid – pocket of dead phagocytes – after engulf microbes – they die
Innate Immunity - Second Line - Inflammation: PRISH
PRISH
P – pain – release of chemicals
R – redness – more blood
I – immobility – loss of some function
S – swelling – accumulation of fluids
H – heat – blood
Innate Immunity - Second line - Fever
Fever – abnormally high body temperature
Causes by infection from bacteria & viruses
High temp intensified Interferons – inhibits growth of some microbes
Speeds up reactions to repair
Immunity
Immunity – body’s ability to defend against specific invaders
Specificity – looks for specific antigen
Memory – previously encountered antigens
Antigens
Antigens – foreign substances
Self-tolerance
Self-tolerance – immune system recognizes its own tissue
Adaptive Immunity
Adaptive Immunity
Cell-mediated immunity (CMI) Antibody-mediated (humoral) immunity (AMI)
Pathogens can provoke both types of immune responses
Cell-mediated immunity (CMI)
Cell-mediated immunity (CMI) – destruction of antigen by T cells
Intracellular pathogens – fungi, parasites, & viruses
Cancer cells & Foreign tissue transplants
Cells attacking cells
Antibody-mediated (humoral) immunity (AMI)
Antibody-mediated (humoral) immunity (AMI) – destruction by antibodies
B cells transform into plasma cells – synthesize & secrete specific proteins – antibodies
Antibody can bind and inactivate specific antigens
Works against extracellular pathogens – mostly bacteria body fluids & don’t enter cells
Binds to antigens in body (humors) fluids – blood or lymph
Cell formation
Cell formation
B cells – start and develop in red bone marrow
T cells – start in red bone marrow as pre-T cells – migrate to thymus to mature
Immunocompetence
Immunocompetence – B & T cells carry out immune responses – antigen receptors - distinctive surface proteins
Clonal selection
Clonal selection – rapid differentiation of lymphocytes in response to specific antigen
Create clone cells that recognize the same antigens
Effector cells
Memory cells
Antigens
Antigens
Chemical substances recognized by antigen receptors
Immunogenicity
Reactivity
Large complex molecules – proteins – can be:
Nucleoproteins
Lipoproteins
Glycoproteins
Polysaccharides
Antigens - Immunogenicity
Immunogenicity – ability to provoke immune response
Stim production of antibodies Stim proliferation of specific T cells
Antigen - Reactivity
Reactivity – Ability of antigen to react specifically with antibodies or cells it provokes
Antigenic determinants
Antigenic determinants – epitopes – specific portions of molecules – recognizable – trigger immune response
Antigen - Route of Entry
Routes of entry
Bloodstream – injured blood vessel – flow to spleen
Penetrate skin – enter lymphatic vessels – lodge in lymph nodes
Penetrate mucous membranes – entrapped by MALT
Major histocompatibility complex antigens (MHC)
Major histocompatibility complex antigens (MHC) – human leucocyte associated antigens
Unique to every person
Help T cells differentiate between self or foreign
Recognize self-antigens on all cells – except RBCs
Class I – all cells – built into plasma membranes
Class II – some cells – surface of antigen-presenting cells
Antibodies
Antibodies
Antigens induce plasma cells to secrete antibodies
Immunoglobulin or Gamma Globulins – globulin protein family
Specific antigen determinant triggers specific antibody
2 light chains – subtypes – K or Y
2 heavy chains – isotypes – MAGED – 5 types – markers
Fab domains – change – antigens bind here – variable – this is how we have different antibodies
Cells bind to constant portion – does not change
b/w disulfide bond – connects chains – help together by covalent and noncovalent bonds
Antibody Life Cycle
Life cycle:
Lymphoid stem cells
B-lymphocytes
Plasma cells
Antibodies
Antibody Functions
Neutralize antigens
Immobilize bacteria
Agglutinate antigens – reaction b/w antibody and antigens = clumps – identification of pathogens
Activate complement proteins
Help phagocytosis
Fetal and newborn immunity – IgG
Antibody - IgG
IgG – 2nd responses – opsonization (tasty 4 macrophages) – neutralize toxins – small molecule – 2 binding sites – 80% in serum
MAGED
IgM
IgA
IgG
IgE
IgD
Antibody - IgA
IgA – secreted in mucus, tears, saliva, colostrum – 4 binding sites – 13% in serum - secretory component
Antibody - IgM
IgM – large molecule pentamer – 1st response – 6% in serum – 10 binding sites
Antibody - IgD
IgD – B cell receptor – small molecule – 2 binding sites – 1% in serum
Antibody - IgE
IgE – allergy and antiparasitic responses – small molecule – 2 binding sites – 0.002% in serum
Antigen Processing
Antigenic proteins are broken down to fragments to associate with MHC molecules
Antigen-MHC complex is inserted into membrane – antigen presentation
T cells can only recognize antigen-MHC complex as intruder if processed and presented
Exogenous Processing – antigens in fluids outside body cells
Endogenous Processing – antigens present inside body cells – viral proteins after virus infects
Exogenous Processing
Exogenous Processing – antigens in fluids outside body cells
Bacteria, Parasitic worms, Inhaled pollen or dust, & Viruses – not yet infected body
Antigen-presenting cells APCs – process and present – dendritic cells, macrophages, & B cells – Epidermis – mucous membranes
Exogenous Processing - Steps
Steps
Ingestion – pathogen comes into cell + fuses with lysosome = phagolysosome
Digestion of antigen into peptide fragments – lysosomes breaks down with acid
Synthesis of MHC-II – Endoplasmic reticulum and ribosomes – produce MHC-II
Packaging of MHC-II – Golgi – packages protein
Fusion of vesicles – MHC-II binds with packaged to phagolysosome
Binding of peptide fragment to MHC-II – antigen binds to MHC-II molecule
Insertion of antigen-MHC-II complexes into plasma – leaves cell
After processing – cell will be presented to lymphatic tissue – T cells bind – trigger adaptive response
Endogenous Processing
Endogenous Processing – antigens present inside body cells – viral proteins after virus infects
Endogenous Processing - Steps
Steps
Digestion of antigen into peptide fragments – proteasome within cell splits antigen – go into endoplasmic
Synthesis of MHC-I molecule – Endoplasmic reticulum and ribosomes produce MHC-I
Binding of peptide fragments to MHC-I molecules – binds to antigen and moves out of endoplasmic
Packaging of antigen-MHC-I molecules – Golgi packaged into vesicle
Insertion of antigen-MHC-I complexes into membrane – pushes infection out of the cell to lymphatic tissue to trigger immune response
Cell-mediated Immunity
Cell-mediated Immunity
Cell vs cell
1ST signal – T cell recognizes antigen-MHC complex
2ND signal – Antigen binds to receptors on inactive T cells after processed and presented by antigen-MHC complex – Co-stimulation
Activation of T cells by specific antigen
Clonal selection – rapid proliferation and differentiation – army of same cells
Cell-mediated Immunity - Co-stimulation
Co-stimulation – prevents immune response from accidently occurring – self tolerance – prevents autoimmune disease – Key and gear shift ex.
Cytokines – interleukin-1 and -2
Pairs of plasma membrane molecules on surface of T cell and a second on surface of antigen presenting cell (APC)
Cell-mediated Immunity - Helper T cells
Helper T cells (T4) = CD4 protein
Key – APCs with MHC-II
Gear – Interleukin-2 – trigger proliferation of T cells
Result – clonal selection of other helper T cells, cytotoxic T cells, and B cells
Cell-mediated Immunity - Cytotoxic T cells
Cytotoxic T cells (T8) = CD8 protein – kill target cell w/o self damage – immunological surveillance
Key – APCs with MHC-I
Gear – Interleukin-2 – Trigger proliferation of T cells
Result – clonal selection
Cell-mediated Immunity - Memory T cells
Memory T cells – recognize original invading antigen – enables quick reaction if repeated
Antibody-mediated Immunity
Antibody-mediated Immunity
Humoral immunity
Produces antibodies to neutralize antigens
Protects against pathogens freely circulating the body
B Cells Detect on receptors
Activation – Differentiate into plasma B cells – produce antibodies
Bind to antigens all around
Antibodies neutralize – dissolve (lyse) or engulfed (phagocytosed) – antigen is broken down into peptide fragments with MHC-II self-antigen and moved to surface of B cell
Helper T cells see APC-MHC-II and co-stim B cell proliferation
Virus gets blocked by antibodies – can’t enter cell
Immunologic Memory
Immunologic Memory
Ability of immune system to remember previous encounters with antigens
Faster and more robust response at re-exposure
Memory cells produced during primary response
Immunologic Memory - Primary
Primary immune response
New antigen – slow onset
Lower antibody production
Development of memory cells
Immunologic Memory - Secondary
Secondary immune response
Re-exposed
Memory cells rapidly available
Higher antibody production
Naturally-acquired Immunity
Naturally-acquired – body did it
Passive – antibodies from mom to baby
Active – Antigens enter body naturally – body forms antibodies
Artificially-acquired Immunity
Artificially-acquired – doctor did it
Passive – pre-formed antibodies are introduced
Active – vaccines – little bit of virus is entering – body creates antibodies and memory cells
