week 4 Flashcards
signs and symptoms of strep throat:
-begins quickly
-pain with swallowing
-fever
-red and swollen tonsils, sometimes with white patches or streaks of pus
-tiny red spots on roof of mouth
-swollen lymph nodes (anterior neck)
symptoms to rule out strep throat:
-cough
-runny nose
-hoarseness
-conjuntivitis (viral)
what is the centor score?
the probability that the pharyngitis is strep
criteria:
-age (3-14 most common)
-exudate or swelling
-tender/swollen anterior cervical lymph nodes
-temp
-cough
what bacteria causes group A strep?
streptococcal pyogenes
gram + bacteria
what are the characteristics of a scarlet fever rash?
-“sandpaper rash”
-small, numerous papular elevations
-blanches with pressure
-starts on trunk and extends outwards
what is the treatment for BACTERIAL strep?
-penicillin (x10 day course)
possible etiologies of a persistent strep?
GERD
abscess
malignancy
tonsillitis
allergies
appearance of simple squamous:
-oval nuclei parallel to the basal lamina
-flattened, single layer of cells
lining blood vessel or lymph vessel: endothelium
lining a body cavity: mesothelium
appearance of simple cuboidal:
-square cells
-single layer
-round nuclei
-little cytoplasm distributed evenly around nucleus
appearance of simple columnar:
rectangular cells
single layer
usually oval nuclei (not always)
usually nuclei are towards the basal lamina (not always)
may have migrating immune cells
appearance of stratified squamous:
multiple layers
top layer flattened
bottom layer can be cuboidal or columnar in shape
surface modifications
-non-keratinized (usually; means nuclei in the top layer)
-keratinized
-parakeratinized
keratin vs. parakeratin
keratin does not have nuclei in the top layer; parakeratin looks like a keratin layer but nuclei ARE present
where are stratified columnar and cuboidal cells found?
mainly in the ducts of larger glands
what type of epithelium is respiratory epithelium?
pseudo-stratified columnar
cilia
goblet cells present
what are stereocilia?
long microvili that clump together (paintbrush)
made of actin, therefore are NOT true cilia
what are the features of transitional epithelium?
balloon or umbrella cells (larger cells) on the surface
type of pseudo-stratified epithelium because all cells touch the basal lamina but not all cells reach surface (picture says otherwise…)
commonly seen in uroepithelium
-these cells can stretch
-important with the expanding bladder w/ urine
what are discoidal vesicles?
-part of the transitional epithelium
-not actually vesicles-membrane infoldings that are cut to look like vesicles
-artifact (artificial structure that is present from when the slide was cut/prepared?)
-allow for the expansion of the epithelium when the bladder fills with urine
contrast the appearance of microvili on a TEM and a LM?
TEM: appear fingerlike, can distinguish them, can see linear features inside (microfilaments)
LM: cannot visualize them as separate structures, appear as a dense line
what are microvili composed of?
microfilament core (actin)
what are cilia composed of?
core of protein tubulin in a 9+2 arrangement (motor proteins move the cilia)
basal bodies (base of the microtubule arrangement) are composed of 9 triplets of microtubules
what are the permanent type of cell-cell junctions?
-zona occuldens (tight junctions)
-zona adherens (belt desmosome)
-macula adherens (spot desmosomes)
-zonula communicantes (gap junction)
transcellular vs paracellular
transcellular: movement through the cytoplasm
(transporters, channels)
paracellular: in between two cells, prevents movement through cells
(tight junctions, zona occuldens; made of protein strands, the more protein strands, the tighter the junction)
what proteins are involved in zonula occuldens (tight junctions)?
Claudin and Occuldin
Claudin is the protein which confers the barrier properties.
what proteins are involved in the structure of the zonula adherans?
-interacts with the microfilaments of the terminal web (belt around the cell)
-receptors on either cell are cadherins (desmocollins, desmogleins)
what are junctional complexes?
symmetrical structures consisting of 3 components:
-zonula occuldens (tight junction)
-zonula adherans (belt desmosome)
-macula adherans (spot desmosome)
what proteins compose a gap junction (zonula communicantes)?
x6 connexins form a connexon with a gap in the middle
the connexon of one cell lines up with the connexon of another cell so that the holes line up
a gap junction consists of numerous connexons
allows for cell communication (e.g. electrical signal shared between cardiac cells)
what are the 2 layers of the basal lamina?
lamina rara (laminin, entactin, perlecan)
lamina densa (type IV collagen)
what are the 2 possibilities for having a basement membrane?
AKA a basal lamina that is thick enough to visualize with LM
1) cells have a basal lamina and a reticular lamina (reticular fibers made of collagen III)
2) cells have a fused basal lamina (cells pointing away from each other, each have a lamina rara with their lamina densas fused together)
describe the function and structure of hemidesmosomes:
function: adhere epithelial cells to the basal lamina
interact intracellularly with intermediate fibers
interact extracellularly with the matrix of the basal lamina
receptors: integrins
disruption: causes the epithelium to pull away (e.g. blisters)
what is the function of focal contacts?
adhere the cell to the proteins of the extracellular matrix
integrins=receptors of the ECM
ultimately connect the cell to the actin cystoskeleton
list the types of basal cell: matrix receptors?
-integrins: heterodimers (alpha and beta subunits)
-intergral membrane proteoglycans (e.g. syndecan)
-glyoproteins (e.g. CD44)
how are glands formed? how are the two kinds different from each other?
ORIGIN: epithelial, formed by the invagination of the surface epithelium
EXOCRINE: retain a connection to the surface, forming a duct
ENDOCRINE: lose the connection and secrete into the blood supply, endocrine
what type of glandular cell is a goblet cell?
exocrine (duct)
secretes mucus
found in the respiratory tract, secretes mucus that is moved by cilia
contrast the cellular appearances of mucous cells and serous cells:
mucous cells
-flattened nuclei
-cells appear washed out (mucous lost during processing)
-secrete mucous
serous cells
-rounded nuclei
-stains well
-secrete proteins
what are the 3 types of exocrine secretion?
merocrine
-exocytosis
-e.g. pancreas
apocrine
-piece of cell pinches off
-e.g. milk secretions
holocrine
-whole cell becomes the secretion
-e.g. sebaceous glands
name the 3 types of tonsils with location, cell type, distinguishing characteristics
PALATINE
-oropharynx
-paired
-stratified squamous with several crypts (also s. squamous)
PHARYNGEAL
-in the nasopharynx
-single
-pseudo-stratified columnar with cilia and goblet cells (AKA respiratory epi)
-no crypts but small folds
-adenoid (can become inflamed and hypertrophied)
LINGUAL
-base of the tongue
-numerous
-single crypt
-stratified squamous
what do the following factors cause?
histamine
bradykinin
prostaglandins
nitric oxide
-arteriolar dilation
-hyperemia (redness)
-slowing/stasis of the blood
-fluid extravasation into tissues (swelling)
what responses are the following factors responsible for?
complement C5a (anaphylotoxin/chemotaxin?)
leukotriene B4
chemokines
bacterial products
neutrophil activation
rolling and adhesion
emigration to tissue
chemotaxis
what responses are the following factors responsible for?
serotonin
histamine
C3a, C5a
bradykinin
leukotrienes
endothelial activation
adhesion molecules and increased permeability
plasma proteins “leak” into tissues
what are the 3 components of acute inflammatory exudates?
- neutrophils migrating in response to chemotaxin signals (complement component C5a and LTB4)
- spaces in the tissue that indicate fluid accumulation (edema)
- several other plasma proteins are found in the tissue space - evidenced by fibrin threads (from plasma fibrinogen)
what are the 5 cardinal signs of inflammation?
-rubor (redness, hyperemia, vasodilation)
-tumor (swelling)
-calor (heat, due to hyperemia (vasodilation)
-dolor (pain due to bradykinin and PGE2)
-functio laesa (loss of function due to combined effects)
what suffix indicates inflammation?
-itis
exceptions: pleurisy (inflammation of the pleura) and cellulitis (infection that causes inflammation)
what bacteria cause purulent inflammation?
pyogenic bacteria
staphylococci
strep pyogenes
e. coli
Neisseria spp. (N. meningitidis, N. gonorrhea)
what stage of inflammation is characterized by pus formation?
acute suppurative inflammation
clinical examples of purulent inflammation:
-lobar PNA
-bronchopneumonia
-acute appendicitis
-acute suppurative tonsillitis
contrast suppurative acute inflammation vs fibrinous acute inflammation:
SUPPURATIVE - high # of neutrophils, more cells than fibrin and fluid
FIBRINOUS - more fibrin compared to cells and tissue fluid
where is fibrinous inflammation most common?
in serous tissues such as the pericardium and the pleura
how does acute pericarditis occur?
inflammation causes a fibrin coat to form on top of the visceral layer of the serous pericardium
when is acute serous inflammation usually seen (what injuries and tissue types)?
burn injuries and in serous membrane lined cavities (e.g. pleural effusion)
what is a granuloma?
inflammation found in many diseases
characterized by the presence of giant cells
form when the immune system attempts to wall off substances that it perceives as foreign but is unable to eliminate them
giant cells = macrophages fused together to form a multi nucleated cell
what are the 2 types of giant cells?
Langhan’s giant cells
-immunological cause
-e.g. infectious organisms such as bacteria and fungi
Foreign Body giant cells
-non immunological cause
e.g. glass, splinters, silica, asbestos etc.
compare and contrast the appearance of Langhan’s and Foreign Body giant cells:
although both are comprised of several macrophages fused together, the nuclei arrangement differ.
Langhan’s - nuclei form a horseshoe shape and somewhat resemble one next to the other
FB cells - the nuclei are distributed randomly, no horseshoe shape
how can streptococcus be characterized?
gram (+) bacteria
cocci arranged in chains (or pairs)
non-motile
catalase negative (distinguishes from staph)
non-spore forming
most are facultative anaerobes (some obligate)
what 3 methods are used to classify each species within the streptococcal genus?
- hemolytic patterns
- Lancefield groupings
- biochemical/physiological properties on other tests
what streptococcal species are capable of alpha hemolysis?
S mutans
S mitis
S pneumoniae
what streptococcal species are capable of beta hemolysis?
S agalactiae
S pyogenes
what streptococcal species are associated with gamma hemolysis?
nonenterococcus (S bovis)
enterococcus (E faecium, E faecalis)
what is the hemolytic patterns test used for?
distinguishes strep bacteria based on how well they can lyse RBCs in a blood agar
alpha: partial
beta: full
gamma: none
how is the serologic properties test used to distinguish strep?
-divide into groups based on the antibodies that recognize surface antigens (Lancefield groups)
-based on antigenic differences in cell wall carbs (group A - V), cell wall pili associated protein, and polysaccharide capsule group B (GBS)
how is the bacitracin sensitivity test used?
-divides B hemolysis groups into groups A and B
-bacitracin is an Abx that interferes with peptidoglycan synthesis
group A - inhibited (S agalactiae)
group B - not inhibited (S pyogenes)
B-BRAS
how is the optochin test used?
-distinguishes S pneumoniae from other alpha hemolytics
-optochin inhibits its growth
“overpass: OVRPS”
viridians - resistant
pneumoniae - sensitive
explain how the bile sensitivity test is used?
-another test that distinguishes S pneumoniae from other alpha hemolytics
-S pneumoniae is bile soluble
-viridians are bile insoluble
explain how the camp test is used:
-to distinguish S agalactiae from other B hemolytics
-releases CAMP factor
-not fully B hemolytic on its own but the CAMP factor helps enlarge its zone of hemolysis
-forms a characteristic arrow shape
S agalactiae colonization site:
vagina
S gallolyticus colonization site:
gut
S pneumoniae colonization site:
upper respiratory tract
S pyogenes colonization site:
throat, skin
Viridians group streptococci colonization site:
oral cavity
what are the 6 steps of a viral infection?
- attachment
- penetration
- uncoating
- replication
- assembly
- release
where do DNA viruses replicate?
in the host nucleus, using the host’s machinery
exception: pox viruses
where do RNA viruses replicate?
in the host’s cytoplasm, using its own machinery and the host’s ribosomes
exception: influenza virus which replicates in the nucleus
what is the most common cause of viral pharyngitis?
adenovirus
what is the most common cause of bacterial pharyngitis?
group A strep - S pyogenes
what is the most common cause of fungal pharyngitis?
candida albicans
term for “pain with swallowing”
odynophagia
describe the process for CD4 activation:
- TCR binds to the antigen peptide presented by the MHC II molecule
- co-receptor CD4 binds directly to MHC II
- co-stimulator B7 (DC) binds to CD28 (CD4)
- TCR and co-receptors move to the center of the TCR base to form a ring “immune synapse”
- tyrosine kinase (Lyc) of CD4 co-receptor phosphorylates CD3 and zeta
- activates transcription factors NF-kB and NFAT
- increases IL-2 and IL-2Ra expression
- autocrine stimulation
- cell proliferation
in what x2 ways can helper T cells help CD8 cells during weak immune responses:
-directly secrete IL-2 that acts directly on the CD8 cells
-indirectly by activating more DCs to increase the expression of co-stimulator B7, therefore resulting in more DCs interacting with CD8s
in what ways is CD8 activation different from CD4 activation?
- cross presentation - CD8 T cells can also be activated by the presentation of extracellular antigens by dendritic cells on MHC I (instead of MHC II)
- CD8 may require help from CD4s if the immune response is weak and there isn’t sufficient IL-2 being produced
what are the 3 major subsets CD4 cells and what kinds of pathogens do they respond to?
Th1 - intracellular pathogens
Th2 - helminths, injury
Th17 - extracellular pathogens
what cytokines differentiate a CD4 cell into Th1?
IL-12 and TFN gamma
what ligand does a Th1 cell express on its surface once it makes physical contact with the macrophage?
CD40
what cytokine does Th1 release once it binds to the CD40 receptor on macrophage?
IFN gamma
what cytokines do Th2 cells respond to?
IL-4 and IL-13
what cytokines do Th2 cells secrete in response to IL-13 and IL-4?
IL-4, IL-5, IL-13
what cytokines induce the differentiation/proliferation of Th17 cells?
IL-1, IL-6, IL-23, TGF-beta