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Flashcards in 7/16 Deck (99)
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1

how do you calculate RBF and RPF

RBF = (PAH clearance) / (1-Hct)

RPF = (PAH clearance)

PAH clearance = [(urine PAH) x (urine flow)] / (plasma PAH)

2

how does the lecithin-sphingomyelin L/S ratio change in a developing baby

they're ~the same until about 30 weeks, then L starts increasing while sphingomyelin stays roughly the same.
This increases the L/S ratio

3

how is glucose taken into the cells

facilitated diffusion via carrier-mediated transport

the GLUT carrier proteins are stereoselective for D-glucose

4

what is ferritin

an intracellular iron-binding storage protein

useful serum marker of total body iron stores

decreased in iron-deficiency anemia
elevated in iron-overload or infection

5

what is transferrin

molecule that delivers iron to liver and bone marrow

measure of iron in blood

for every 3 transferrin molecules, 1 will be bound to Fe.

6

what is TIBC and % saturation

TIBC:
measure of transferrin molecules in the blood

% saturation:
percentage of transferrin molecules that are bound by iron (normal is 33%)

7

what happens to Iron lab values when you have low iron

Low ferritin
(storage of Fe is depleated)

high TIBC
(always opposite of Ferritin)

low serum Fe

low % saturation

high Transferrin (when there's low Ferrying, the liver will make more TF to try to increase Fe, and that's also where the high TIBC comes from)

8

where is the majority of water reabsorbed in a nephron

proximal convoluted tubule

9

what is the thin descending loop known as

concentrating segment
passively reabsorbs water.
impermeable to Na+

10

what happens in the thick ascending loop

Na/K/2Cl transporter to reabsorb some of these ions.
urine becomes less concentrated as it ascends

impermeable to water, so it stays in the tubules.

11

what happens in the early Proximal convoluted tubule

reabsorbs >60% water filtered by glomerulus, regardless of hydration status

reabsorbs all glucose and amino acids

reabsorbs most small ions and uric acid

isotonic absorpption

12

what happens in the early distal convoluted tubule

makes urine fully dilute by reabsorbing Na and Cl.

urine is at its lowest osmolality here

H2O is impermeable in the early portion. becomes variable later on with Vasopressin

13

what is Hepatitis B's replication sequence

dsDNA --> (+)RNA template --> dsDNA

HBV replicates via reverse transcriptase, even though it is a DNA virus

it occasionally goes to a single strand mode

14

what is the only ssDNA virus

Parvovirus B19

15

what is the histologic progression of an ischemic stroke

12-48 hrs:
Red neurons (eosinophils! and loos of Nissl substance!!)

1-3 days:
necrosis + neutrophils

3-7 days:
macrophage/microglia and myelin phagocytosis

1-2 weeks:
reactive gloss and vascular proliferation
(liquefactive necrosis)

>2 weeks:
glial scar formation w/ astrocytes

16

Run through Aortic/Pharyngeal arch derivatives

1st:
maxillary artery
CN 5
"1st is maximal"

2nd:
stapedial artery and hypoid artery
CN 7
"Second = Stapedial"

3rd:
Common Carotid artery and proximal internal Carotid
CN 9
"C is 3rd letter"

4th:
on left, aortic arch
on right, proximal R subclavian artery
CN 10
"4th arch = 4 limbs = systemic"

6th:
proximal pulmonary arteries and (L) ductus arteriosus
CN 10
"6ulmonary arch"

17

run through pharyngeal pouch derivatives

1st:
ears

2nd:
tonsils

3rd:
inferior parathyroid
thymus

4th:
superior parathyroid
parafollicular C cells of thyroid

18

what stimulates neutrophil migration to inflammation

Leukotriene B4

"Neutrophils arrive B4 others"

19

what does PGI2 do

PGI2 inhibits platelet aggregation and promotes vasodilation

"Platelet gathering Inhibitor"

20

what does complement do

they're inflammatory anaphylotoxins that trigger histamine release from mast cells

21

what does interferon-gamma do

activates macrophages, increases MHC expression, and promotes Th1 cell differentiation

produced primarily by activated T cells and NK cells

22

what does Thromboxane A2 do

increases platelet aggregation and vasoconstriction

23

what are the 3 important chemotactic agents

LTB4
C5a
IL-8 (clean up on aisle 8)

24

what does hydroxyurea do

increases HbF synthesis

reserved for sickle cell pts with frequent pain crises

25

what is the defect in xeroderma pigmentosum

NER, a defect in an ENDONUCLEASE

pts have increased sensitivity to UV light and cannot repair pyrimidine dimers

26

what is caused by a defect in DNA mismatch repair

HNPCC or Lynch syndrome

high incidence of colorectal, endometrial, and ovarian cancer (CEOs)

this is EXONUCLEASE proofreading defects

27

what do Ras mutations cause

commonly pancreatic or colorectal cancer

28

what do p53 mutations cause

Li-Fraumeni syndrome (wide range of malignancies at a young age)

29

what is Fanconi anemia

mutations in genes responsible for repairing DNA crosslinks

causes:
aplastic anemia
short stature
ABSENT THUMBS
increased malignancy risk
PCT defect, where everything is excreted

30

what is gold standard for detecting a microdeletion

FISH