Mod 2: Histology Flashcards
Innate immunity: passive vs active
Adaptive immunity: passive vs active
INNATE
Passive: mom ANTIBODIES move across placenta (IgG to fetus)/in breast milk (IgA to infant)
Active: ANTIBODIES for neutralization, opsonization, precipitation of toxin or pathogen (antidotes)
ADAPTIVE
Passive: immunization WITH BACTERIAL/VIRAL EPITOPES
Active: real-life exposure TO PATHOGEN
Differences b/w innate and adaptive immunity
Innate: both active and passive – Ab introduced to person
Adaptive: both active and passive – exposure to actual pathogen
Innate: no memory cells produced
Adaptive: memory cells produced
Initial vs repeat exposure timeline
More efficient and specific antibody molec during repeat exposure
Initial:
1. Innate immune sys EARLY inflammation (0-4 hrs)
2. Innate immune sys LATE inflammation (4-5 days)
3. Adaptive immune sys (14 days)
4. Pathogen removal/tissue repair
Repeat
- Innate immune sys EARLY inflammation (0-4 hrs)
- Innate immune sys LATE inflammation (2-3 days) SHORTER
- Adaptive immune sys (5-7 days)
- Pathogen removal/tissue repair
MHC I vs MHC II
MHC I: on all nucleated cells of body
MHC II: on phago WBC that have been activated (engulfed a pathogen)
Where are MHC I molec synthesized?
RER TGN (trans golgi network) membrane embedded in plasma membrane **MHC I always produced by our cells**
PRR
What cells are they located on?
Toll receptors -- recognize PAMPs located on: neutrophils periph tissue macrophages periph tissue NK
PAMPs
surface molec with repeated/identical protein (glycoprotein) subunits on pathogens
Proinflammatory cytokines
histamine (basophils, mast cells) – vasodilation, inc cell permeability
prostaglandin (damaged cells) – smooth muscle in blood vessel wall contracts, vasodilation, inc cell permeability
Bonds that hold light chains to heavy chains
heavy chains to heavy chains
disulfide
Structure of heavy and light chains of Ab
Heavy and light chains both have variable and constant region
2 heavy and 2 light chains per antibody
variable region is where antigen epitope binds
Functions of antibodies – initial binding
Neutralization: Ab covers biologically active part of microbe/toxin
Agglutination: Ab cross-links cells – forms clump
Precipitation: Ab cross-links circulating particles to form an insoluble complex
enhance recognition and diminish disease-causing properties
Antibody functions – after binding
Complement fixation: Fc region of antibody binds complement proteins, complement is activated
Opsonization: Fc region of antibody binds to receptors of phago cells, triggering phagocytosis
Activation of NK cells: Fc region of antibody binds to NK cell, triggering release of cytotoxic chemicals
facilitate removal of pathogen
Functions of immune-lymphatic sys
Transport medium (moves WBC and immunesignalling molec b/w blood, periph tissues, immune sys organs)
Circulation of digested/absorbed lipids (from GI tract to heart)
Recognition, degradation, and removal of antigens
MBL vs classic pathway
MBL: day 1, does not require Ab
classic: day 5-7, REQUIRES Ab
Where are complement proteins produced?
liver (they are soluble plasma proteins)
What are the pro-inflammatory cytokines?
C3a
C5a
What opsonizes the pathogen?
C3b
When do monocytes become macrophages?
when exit bloodstream and enter periph tissue
Unique resident pop of macrophages
Langerhan’s: skin/epidermis
Kupfer: liver
Microglia: brain/SC
Cells involved in innate vs adaptive response
Innate:
- -neutrophils
- -monocytes/ macrophages/ dendritic cells
Adaptive:
- -B cells
- -T cells
PAMP – PRR interactions result in…
inflammatory cytokines released
increased numbers of phago cells
number of pathogens dec
CD4+
CD8+
CD4+ on helper T cell
CD8+ on cytotoxic (killer) T cell
NK cells as a “tweaker”
intermediate in specificity
bridge b/w innate and adaptive immune responses
Describe flow of lymph fluid
unidirectional away from periph tissue toward lymph node toward heart returned to blood at brachiocephalic vv
Describe structure of lymphatic vessels
thin walls of smooth muscle (1-2 layers)
valves
Most lymph fluid drains to…
thoracic duct (drains into left subclavian v/ brachiocephalic v)
Right arm and head lymph fluid drains to…
right lymphatic duct
drains to right subclavian v/ brachiocephalic v
Higher number of lymph nodes in…
Cervical Axillary Breasts Abdominal Inguinal regions (at major intersections in body where there are aa and vv/ areas where there is direct access to outside world)
Size of lymph nodes
1-25 mm in diameter
Hilum of lymph node
entry/exit point of lymph node
entry for arterial blood
exit for venous blood
exit for filtered lymph fluid (EFFERENT lymphatic vessels)
Afferent vs efferent lymphatic vessels
Afferent: to
Efferent: away (efferent becomes afferent as passes to next node)
Structure of lymph node
covered by thin, fibrous capsule
subcapsular space (filled with lymph fluid)
collagen fibers from capsule invaginate to form trabeculi in stroma of node
lymph fluid moves through trabecular sinuses toward central region (which is filled with lymph fluid)
medullary sinus
Residents of subcapsular sinus
follicular dendritic cells (these are the best macrophages/APCs)
- -pathogen debris or APC presents to follicular dendrites
- -pathogen material attaches to follicular dendritic cells –> activate WBC for specific response
Functions of respiratory sys
Main site of gas exchange --conduct, warm, moisten air --exchange air from environment with CO2 produced by cells of the body Acid-base balance of body Phonation (larynx) Pulmonary defense (thick lamina propria with immune cells) Metabolism Olfactioin
Components of conducting portion of resp sys
- -nasal cavity
- -nasopharynx
- -larynx
- -trachea
- -primary bronchi
- -terminal bronchioles
Features of conducting portion of resp sys
Passages that deliver air to lung
No alveoli
Warm, moisten, and filter air b/f reaches resp portion
Components of resp portion of resp sys
Resp bronchioles
Alveolar ducts
Alveolar sacs
Alveoli (primary site of gas exchange)
Upper resp sys structures
Sphenoidal sinus
Frontal sinus
Nasal cavity
Pharynx
Lower resp tract contents
Larynx
Trachea
Bronchi
Lungs
Amount of mucous removed by beating cilia per minute
10 mm per minute
Purpose of lysozymes, IgA in secretions from Bowman’s glands
prevent pathogens from gaining intracranial entry
Functions of the larynx
Close trachea during swallowing (epiglottis is in the larynx)
Produce sound – true vocal cords
Ventricle
Ventricular folds
Ventricle: elongated space that separates TRUE vocal cords and FALSE vocal cords (ventricular folds)
Ventricular folds: FALSE vocal cords
Vestibule of larynx
area above the vocal cords
Functions of trachea
conduit for air
remains open
Cell types at bronchioalveolar duct junction
clara cells
cuboidal cells
ACE
Angiotensin converting enzymes (ACE, CD143)
transmembrane ectopeptidase
angiotensin I –> II
Inactivates kinins
Important for regulation of vascular tone and BP
What kind of immunity is occurs in lymph nodes?
Adaptive immunity
–specific cells become activated and mobilized against single pathogen
Residents of subcapsular sinus
follicular dendritic cells
(pathogen debris or APC present to follicular dendritic cells)
(pathogen material attaches to follicular dendritic cells –> activate WBC for specific immune sys)
Bacterial infection pathway in lymph node
Activate APC
Activates Th2
Th activates B cell –> plasma cell produces Ab
Viral infection pathway in lymph node
Th1 activates cytotoxic (killer) T cells
Killer T cell leaves lymph node –> goes through venous blood to site of infection
Release perforin at cells with MHC I displaying viral epitope
What is the difference b/w action of plasma cells of bacterial infection and cytotoxic T cells of viral infection?
Plasma cells do not leave the node, only Ab produced by plasma cell leave the node
Cytotoxic T cells leave the node
HEV
high endothelila venules – where gas and nutrient exchange occurs in lymph node
Some of the fluid in the lymph node is absorbed directly back into the blood stream – why is this important?
Less fluid moving through the lymph node allows for SLOWER flow through node – so WBC can better examine pathogen debris
Afferent and efferent lymph vessel valves
both afferent and efferent lymph vessels have valves – except in the head and neck
Cells in: subcapsular sinus paracortex lymphatic nodules medullary cords
subcapsular sinus: dendritic cells
paracortex: Th cells
lymphatic nodules: B cells
medullary cords: macrophages, Th and killer T cells, plasma cells
Cells in parts of the lymphatic nodule
Primary follicle
Germinal center of secondary follicle
Plasma cells move to…?
Primary: resting B cells
Germinal center of secondary follicle: activated/dividing B cells
Plasma cells move to medullary cords
CD4+ vs CD8+ cells
CD4+: Th1 and Th2
CD8+: cytotoxic killer T cells
Primary lymphoid organ
Primary: give rise to or help mature lymphocytes (red bone marrow and thymus)
Structures formed from lateral plate/splanchnic mesoderm in 3 week old embryo
Pericardial sac (fibrous CT)
Cardiac muscle (contractile, conducting, neuroendocrine)
Fibrous skeleton (fibrous CT)
–AV valves, semi lunar valves, tendinous cords
Blood vessels of heart
Blood cells to circulate
In what week are there rudimentary organs of every sys?
week 8
RBC begin development where? What time? Features?
Then start production in embryo…where? time? features?
Day 21: RBC with NUCLEUS produced in extraembryonic meso covering yolk sac
Week 5: RBC WITHOUT nucleus produced in embryo in splanchnic meso near organs
Vasculogenesis vs angiogenesis
Vasculo: formation of NEW blood vessels
Angio: formation of new blood vessels FROM EXISTING blood vessels
BOTH REQUIRE VEGF
Receptors for vasculogenesis
Flk-1: vasculogenesis –> hemangioblasts (clusters of MSCs)
Flt-1: vasculogenesis –> capillary tube formation
Locations of blood cell development during embryonic/fetal life
yolk sac
liver/spleen
bone marrow
Due to the embryology of the development of the heart and diaphragm…
heart attached to skeletal muscle of diaphragm via fibrous connection
Mesothelium
single layer of simple squamous epithelium with underlying aerolar CT found in one of the closed ventral body cavities (thoracic, abdominopelvic)
Purkinje fibers are what kind of cell
modified cardiac m cells