Lymphatic and Immune
Systems
Chapter 21
Components
• Lymph
• Lymph vessels
• ___________,
nodules, lymphatic
organs, diffuse
lymphatic tissue
• ________________
Functions of Lymphatic System
Immunity
– Filters fluids from capillary
beds
– _____________________
_____________________
• Lipid absorption
– ____________ in small
intestine absorb lipids
• Fluid recovery/balance
– ______________________
________________ (2 to 4
L/day) from tissues and
returns it to CVS
Lymph and Lymphatic Capillaries
• _________________
– clear, colorless fluid, ________
__________________________
• Lymphatic capillaries
– closed at one end
– tied to tissue by ___________
____________________
– endothelial cells loosely
overlapped
• allow bacteria and cells to enter
• ____________________________
____________________________
____________________________
Lymphatic Vessels
• Large vessels composed of 3
layers
– ________________:
endothelium and valves
– tunica media:
______________
________________________
– tunica externa: thin outer
layer
Route of Lymph Flow
• Lymphatic capillaries
• Collecting vessels
• _________________: drain
major portions of body
• Collecting ducts :
– __________________ –
R arm, R side of head
and thorax; empties
into R subclavian vein
– __________________ -
larger & longer,
begins at the cisterna
chyli; gets lymph from
below diaphragm, L
arm, L side of head,
neck and thorax;
empties into L
subclavian vein
Mechanisms of Lymph Flow
• __________________________________
• Moves by contractions of vessels
– stretching of vessels stimulates contraction
– aided by skeletal muscle pump
– ______________________ aids flow from
abdominal to thoracic cavity
• ______________________________
• Rapidly flowing blood in subclavian veins,
draws lymph into it
• Exercise _________________ lymphatic
return
Lymphatic Cells
• __________________________ cells
– responsible for immune surveillance
• T lymphocytes
– _____________________________
• B lymphocytes
– activation proliferation and differentiation into
plasma cells antibodies
• __________________________ Cells
– _______________________________
– _________________ (in epidermis, mucous membranes and
lymphatic organs)
– ____________________ (also contribute to stroma of lymph
organs)
Lymphatic Tissue
• ___________________________ tissue
– mucous membranes and CT of organs
– Mucosa-Associated Lymphatic Tissue (MALT):
in passages open to exterior
• Lymphatic nodules
– dense oval masses of lymphocytes,
– __________________: at junction of small to
large intestine
Lymphatic Organs
_______________ lymphatic organs
– where T & B cells become immunocompetent
– __________________________
• _________________ lymphatic organs
– immunocompetent cells live here
– __________________________________
Lymph Node
• Lymph nodes - filter lymph
• Fewer____________vessels, slows flow through node
• ____________________ divide node into compartments
– Formed from capsule
– containing stroma (reticular CT) and parenchyma
(lymphocytes and APCs)
– divided into cortex (lymphatic nodules) and medulla
• ________________________________________________
• lymphocytes respond to antigens
__________________
• Collective term for lymph
node diseases
• _____________________
– swollen, painful node
responding to foreign
antigen
• Lymph nodes are
common sites for
metastatic cancer
– ______________________
______________________
Tonsils
• ____________________
– pair at posterior margin of oral cavity
– _____________________________
• ____________________
– pair at root of tongue
• ____________________ (adenoid)
– single tonsil on wall of pharynx
• Covered by epithelium
• Pathogens in tonsillar crypts and encounter
lymphocytes
Thymus
• Trabeculae, divide parenchyma into lobules of
cortex and medulla
• Reticular epithelial cells
– secretes hormones (______________________
_____________________________________)
• ______________________________________
• ______________________________________
• Very large in fetus;________________ after age 14
– Elderly: fatty, fibrous tissue
Spleen
• Parenchyma
– _______________: sinuses filled with erythrocytes
– white pulp: _________________________________
• Functions
– blood production in fetus
– ____________________________
– ____________________________
– ____________________________________________
Defenses Against Pathogens
• _________________________ - broadly
effective, no prior exposure
– first line of defense
• ______________________
– second line of defense
• ____________________________________________
• ____________________________________________
• ________________________ - results from
prior exposure, ____________________________
_________________________________________
– third line of defense
• ______________________________
External Barriers
• ____________________
– toughness of keratin
– __________________________
– ____________: peptides, from neutrophils attack
microbes
– lactic acid (acid mantle) - sweat
• _________________________________
– stickiness of mucus
– _______________: enzyme destroys bacterial cell walls
• Subepithelial areolar tissue
– tissue gel: ____________________________________
• hyaluronidase: enzyme used by pathogens to spread
Leukocytes and Cutaneous Defenses
• Neutrophils
• Eosinophils
• Basophils
• Monocytes
• Lymphocytes
Neutrophils
• ________________________
• Create a killing zone
– __________________________
• lysosomes discharge into tissue fluid
– respiratory burst
• _____________________________ (O2.-, H2O2, HClO)
___________________
• ____________________________________
• _____________________________
• Promote action of basophils, mast cells
• Enzymes block excess inflammation, limit
action of histamine
___________________
• Aid mobility and action of WBC’s by
release of
– _________________________________
• blood flow to infected tissue
– _________________________________
• prevents immobilization of phagocytes
__________________
• ___________________________________
• Specialized macrophages found in specific
localities
– ____________________________
• epidermis, oral mucosa, esophagus, vagina, and
lymphatic organs
– ___________________ (CNS)
– _____________________ (lungs)
– hepatic macrophages (liver)
_________________
• Circulating blood contains
– 80% T cells
– 15% B cells
– 5% NK cells
Antimicrobial Proteins
_______________________
• Secreted by cells infected by viruses
– _____________________________
– stimulate neighboring cells to produce
antiviral proteins
– _______________________________________
• destroy infected host cells
• ____________________________________________
Antimicrobial Proteins (cont.)
• __________________________ in blood
activated by pathogens
• Mechanisms of action
– enhanced inflammation
– _____________________________
• promoted by opsonization
– _____________________________
• membrane attack complex forms on target cell
– immune clearance
• Ag-Ab complexes carried to liver and spleen
Immune Surveillance
• __________________
– destroy bacteria, transplanted
cells, cells infected by viruses, and
cancer cells
• release _____________________
__________________________
___________________
• Response to tissue injury
– limits spread/destroys pathogens
– ____________________
– initiates tissue repair
• ____________________
– small proteins regulate inflammation
and immunity
• ____________________________________
factor, and chemotactic factors
Inflammation
• ______________________________
– redness (erythema)
– ______________________ capillary
permeability and filtration
– heat caused by ____________________
– _________________ inflammatory
chemicals from damaged cells, pressure on
nerves
Inflammation
• Three major processes
1. _______________________________
2. containment and destruction of pathogens
3. _______________________________
Mobilization of Defenses
• Leukocyte Deployment
– ________________
• leukocytes adhere to
blood vessel walls
– ___________________
(emigration)
• leukocytes squeeze
between endothelial cells
into tissues
Containment and Destruction of
Pathogens
• ____________________ traps pathogens
• ____________________ prevents clotting
– pathogens are surrounded by clot
• ______________________
– leukocytes are attracted to chemotactic chemicals
• ________________________________________
– phagocytosis
– respiratory burst
– cytokines recruits macrophages and neutrophils
– macrophages and T cells secrete colony-stimulating
factor to stimulate leukopoiesis
Tissue Cleanup
• Monocytes agents of cleanup arrive in 8 to
12 hours, macrophages
• ____________ venous flow, lymphatic
flow that favors removal of bacteria and
debris
• Formation of ____________
– _______________________________________
_______________________________________
_______________________________________
• Defense mechanism ___________
– promotes _______________________
– inreases metabolic rate and tissue repair
– inhibits pathogen reproduction
• ____________________________
– _________________
• resets body thermostat higher
> 105F may delirium, 111F- 115F, coma-death
• Stages of fever
– onset, stadium,
_______________
Specific Immunity
• Specificity and memory
• _______________________: cell-mediated
(T cells)
• ____________________________:
_____________ mediated (B cells)
Passive and
Active Immunity
• Active
– _________________________________ (produces
memory cells)
• produce antibodies or T cells ___________________________
____________________________________________________
– Artificial active immunity (produces memory cells)
• ____________________________________________________
• ___________________________
– ______________________________ (_________________)
• temporary, fetus acquires antibodies from mother
– ______________________________________________
• temporary, injection of immune serum (antibodies)
_________________
• Trigger an immune response
• ___________________________
– proteins, polysaccharides, glycoproteins,
glycolipids
• _________________________________
– stimulate immune responses
• Haptens
– _______________________________________
_______________________________________
_______________________________________
Life Cycle of T cells
• Specific immunity depends on lymphocytes
• _______________________________
• _______________________________
– maturing T cells to produce antigen receptors
– immunocompetent T cell has antigen receptors
• Deployment
– naïve T cells colonize lymphatic tissue and organs
B Lymphocytes (B cells)
• Sites of development
– fetal stem cells remain in bone marrow
• ________________________
– B cells should not react to self antigens
• or suffer clonal deletion
• Self-tolerant B cells form B cell clones
– ________________________
Antigen-Presenting Cells (APCs)
• B cells and
macrophages, display
antigens to T cells
Cellular Immunity
• T cells attack foreign cells and diseased
host cells; memory of Ag
• Three classes of T cells
1. _______________________________________
2. Helper T cells: __________________________
_______________________________________
3. _______________________: provide immunity
from future exposure
Attack Phase: Role of Helper T Cells
• ___________________
– _________________
_________________
– attract neutrophils,
NK cells,
macrophages
– _________________
_________________
– stimulate T and B
cell mitosis and
maturation
Attack Phase: _________________
• Only T cells directly attack enemy
cells
• Killing mechanism
– __________________________________
– interferons - decrease viral replication and
activates macrophages
– _______________________________________
Memory
• ______________________
– some T cells become long lived memory cells
• T cell recall response
– _______________________________________
_______________________________________
____________ Immunity
• ____________________
– B cell receptors bind antigen,
take in and digest antigen then
display epitopes
– TH cell divide, differentiate
plasma cells antibodies to that
antigen
• Attack
– _______________________
_______________________
_______________________
• ___________________
– some B cells differentiate
memory cells
Antibody Structure
• Protein
• _________________
• Light chain
• __________________
__________________
• Immune system
capable of as many
as 1 trillion different
antibodies
Antibody Classes
• _______________________
– Plasma, mucus, saliva, tears, milk,
intestinal secretions
• _______________________
– B cell membrane antigen receptor
• IgE: monomer
– on mast cells
– ______________________________
______________________________
______________________________
• _____________________
– 80% circulating, cross placenta to
fetus, 2 immune response,
complement fixation
• _____________________
– 10% in plasma, 1 immune response,
agglutination, complement fixation
Humoral Immunity - Attack
• ______________________
– antibodies mask pathogenic region of antigen
• ________________________
– antigen binds to IgM or IgG, antibody activates
complement; primary defense against foreign cells,
bacteria
• __________________________
– antibody has 2-10 binding sites; binds to multiple
enemy cells immobilizing them
• Precipitation
– _____________________________________________
_____________________________________________
Hypersensitivity (Allergy)
• Excessive immune reaction against antigens that most people
tolerate - allergens
• Type I Antibody mediated (________), acute reaction
– ________________: anaphylactic shock
– ________________: pollen, dust cat dander
– asthma
• Type II Antibody mediated (___________), subacute
– _______________________________
– 5-12 hours
– Graves disease, myasthenia gravis
• Type III Antibody mediated (__________), subacute
– Antibody complexes ppt, 3-8 hours
– ________________________________________________
• Type IV Cell mediated, delayed (12-72 hours)
– __________________________________________
– Poison ivy, TB test
Match
• Type 1
• Type 2
• Type 3
• Type 4
Autoimmune Diseases
• Failure of self tolerance
– cross-reactivity
– __________________________________
– changes in structure of self-antigens
• Production of ______________________
Immunodeficiency Diseases
• Severe Combined
Immunodeficiency Disease
– hereditary lack of T and B cells
– __________________________
__________________________
Immunodeficiency
Diseases
• AIDS
– HIV structure
– enters helper T cells, macrophages and
dendritic cells by receptor mediated
endocytosis
– _______________________________________
viral DNA inserted into host cell DNA, may be
dormant for months to years
AIDS
• Signs and symptoms
– early symptoms:
– Flu-like chills and fever
– Later
• night sweats, fatigue, headache,
extreme weight loss, lymphadenitis
– normal TH count is 600 to 1,200
cells/L of blood in AIDS it is < 200
cells/L
• opportunistic infections
(Toxoplasma, Pneumocystitis,
herpes simplex virus, CMV or TB)
• _______________: white patches on
mucous membranes
• ____________________: cancer
originates in endothelial cells of
blood vessels causes purple lesions
in skin
HIV Transmission
• ____________________________________
____________________________________
• Most common:
– sexual intercourse (vaginal, anal, oral)
– contaminated blood products
– contaminated needles
• ____________________________________
• Latex condom is an effective barrier to HIV
especially with spermicide nonoxynol-9
Treatment Strategies
• Prevent binding to CD4 proteins of TH cells
• Disrupt reverse transcriptase, inhibit assembly
of new viruses or their release from host cells
• Medications
– none eliminate HIV, all have serious side-effects
– Resistance develops, meds used in combination
– AZT azidothymidine
• first anti-HIV drug, inhibits reverse transcriptase
– Protease inhibitors
• inhibit enzymes HIV needs to replicate
– now more than 16 anti-HIV drugs