Physiology

Question 1

mechanism for PTH

Answer 1

1) work via its R on osteoblasts by indirect mechanism ⟹ increase RANK ligand, M-CSF ⟹ osteoclast presursor diff into mature ⟹ bone reabsorption
2) inhibits the release of osteoprotegrin (a decoy for RANK ligand receptor, which impeded the RANK interaction)

net result for PTH: Ca2+ re-absorption, urine excretion of P

Question 2

function of calcitonin

Answer 2

made by thyroid gland; inhibits osteoclast, decrease bone reabsorption, increase bone mineral density;

effect opposite to PTH

Question 3

ECG presentation for AF?

Answer 3

No P-wave (no regular atrial contraction); replaced by “f-wave” (fibrillatory)

narrow QRS wave, inregular R-R interval

In AF, the determinant for ventricular contraction rate is the AV node refractory period

Question 4

Kartagener’s syn

Answer 4

microtubular dynein arm defect: immotile cilia

infertility, recurrent sinusitis, bronchiectasis

卡特在戛纳：不孕症

Question 5

cardiac abnormality associated with Downs?

Answer 5

ASD

failure of the endocardial cushions of the AV canal to fuse completely ; patients usually also have cleft in the anterior MV and in the septal leaflet of the TV ⟹ AV regurgitation

Question 6

DiGeorge Syn

Answer 6

乔治弟弟没胸没屁屁（无胸腺）, 没法乐死 （associated with TOF)

chr 22q11.2 deletion: thymic aplasia, failure of parathyroid formation from the defective 3rd and 4th pharyngeal pouches

hypocalcemic tetany, recurrent viral and fungal infections (no T cells); TOF!!!

Question 7

Wegener’s disease

vs. Churg-Struass Syn

Answer 7

瓦格纳一看美女就流鼻血，其实是个肾衰的中性人

C-ANCAs, cytoplasmic-staining anti-neutrophil cytoplasmic Ab) cause granulomatosis with polyangiitis

Px: nectrotizing vasculitis of the upper and lower RI (nasal ulceration, sinusitis, hemoptysis) + rapidly progressive glomerulonephritis (produce RF)

斯特劳斯和瓦格纳对应（p-ANCA),
斯特劳斯有多动症（写了太多圆舞曲），神经质而且过敏

成人哮喘及过敏，嗜酸性粒细胞增多，多动脉炎，单、多神经炎，付鼻窦

Question 8

Dx: wide, split S2?

Answer 8

characteristic for ASD

most important damage: pulmonary HT (can cause reversed R-L shunt: late onset cyanosis - Eisenmenger Syn)

Question 9

Lambert-Eaton syn

Answer 9

autoimmune paraneoplastic syndrome, myasthenic symptoms, Ab against presynaptic Ca2+ channel can’t release Ach

often associated with small cell lung cancer

Question 10

AFR (acute rheumatic fever)

Px: heart? CNS?

Dx criteria?

Answer 10

heart: days to 6 wks after “sore throat”: vegetation on MV, AV

CNS: Sydenham chorea, 2-3 mo after streptococcus infection

Dx requires 2 major Jones criteria + 2 minor Jones criteria:

• Major: carditis, polyarthritis, chorea, erythema marginatum, s.c. nodules
• minor: fever, arthralgia, ↑ ERS or C-reactive protein, prolonged PR interval

Question 11

H produced by the posterior pituitary gland?

Answer 11

1. vasopressin: increase permeability of the renal collecting ducts to water ⟹ ↑ water reabsorption
2. oxytocin

Question 12

mechanism for Adenosine, Ach to reduce HR?

Answer 12

pacemaker AP:

• phase 0 (upstroke): opening of L-type (long-lasting) Ca2+ channel
• phase 3 (repolarization): opening of K+ channel
• phase 4 (pacemaker potential): 慢Na+通道开放, K+ channel close: - 50 mV, then T (transient)-type Ca2+ channel open: - 40 mV, L-type Ca2+ channel open

Adenosine and Ach activates K+ channels and inhibit L-type Ca2+ channels

Question 13

心脏听诊：

1. apex murmur
   - mid systolic click?
   - S2-to-opening snap time interval: indicator of?
   - audible S3: indicate?
2. murmur at right sternal border
3. holosystolic murmur at left sternal border; attenuate with the handgrip
4. fixed splitting of S2
5. continuous precordial murmur, during both diastolic and systolic:
6. systolic, crescendo-decrescendo murmur, start after S1 and end before the A2 component of S2

Answer 13

1. MV
   MR: holosystolic murmur at apex, radiate to axilla (腋窝）- presence of audible S3 is the indicator of severity

mid systolic click? MV prolapse

S2-to-opening snap time interval: indicator of MV stenosis severity

-audible S3: in young patient: indicate severity of MV regurgitaiton; in older patients: ↑ LVESV (occurs in the setting of LV systolic failure)

2. AV
   if “crescendo-decrescendo” systolic murmur: aortic regurgitation
3. holosystolic murmur at left sternal border: VSD
   (handgrip ↑ Afterload)
4. fixed splitting of S2: ASD
   5: PDA (patent ductus arteriosus)
5. AS (aortic stenosis)

Question 14

职业性肺病的histologic表现：

1。 nodular interstitial densities, mostly in the apical region; calcified hilar ndes, (eggshell calcification) + bifrefringent particles

2. lower lobes, involvement of pleural + pleural effusion ; ferruginous bodies (beaded rods with iron-containing coat)

Answer 14

1。 silicosis

2. asbestosis

Question 15

Dx:

African American, malaise, nocturnal fevers, cough + bilateral hilar adenopathy + biopsy shows non-caseating granulomas

Answer 15

sarcoidosis

if caseating granulomas: TB

Question 16

PaO2 threshold to develop hypoxic 2nd erythrocytosis?

Answer 16

65 mmHg (SaO2 < 92%)

Question 17

mechanisms to clear the particles from airway:

1. 10- 15 uM in size
2. 2.5-10 uM
3. < 2 uM

Answer 17

1. cough and upper airway trapping
2. mucociliary transport
3. phagocytosis

Question 18

major player in asthma?

Answer 18

IL-5 released by Th2 cells

activate eosinophils (granule-coated); “crystalloid bodies” - “charcot-Leyden crystals” (contain eosinophil membrane protein)

Question 19

Among numerous inflammatory cytokines in asthma, pharamcological antagonists against only 2 of these cytokines are affective to control asthma: what are these 2 factors?

Answer 19

leukotrienes (LTC4, LTD4, LTE5)

Ach

Question 20

What are the major mechanisms for hypoxemia? And what’s the A-a gradient in each case?

Answer 20

从肺泡 - 肺血流 - 体循环：

1、alveolar hypoventilation

2. gas diffusion impaired
3. V/Q mismatch
4. R-L shunt

A-a is normal in 1, and ↑ in 2-4

Question 21

Nephrotic vs. Nephritic syn: Which is associated with classic proteinuria (> 3.5 g/day)?

Answer 21

Nephrotic (o = pr”o”tein)
no inflammotory response; slight ↓ GFR
(ex: DM nephropathy)

• nephritic syn: RBC, WBC casts, active inflammatory response, significant ↓ GFR
  (ex: Alport Syn, damage collagen in the basement mem)

Question 22

In kidney, what substances are:

1. only filtered, no reabsorption or secretion?
2. filtered + re-absorption?
3. filtered + reabsorption + secretion

Answer 22

1. inulin, mannitol
2. glucose, Na+, urea
3. PAH (para-aminohippurate, 对氨基马尿酸盐）， creatinine

Question 23

肾功能常用计算：

GFR?
FF?

Answer 23

GFR = creatinine clearance

FF = GFR/ RPF (renal plasma flow)

RPF = PAH clearance

clearance of any substance = (urine concentration * urine flow rate)/ plasma concentration

If RBF is unknown, it can be calculated from RBF (renal blood flow):
RPF = RBF * (1-hematocrit)

Question 24

which cell types have glucose transport that responds to insulin?

Answer 24

only skeletal muscle cells and adipocytes

among the 5 GLUTs, only GLUT4 is regulated by insulin. They locate in the cytoplasm of skeletal muscle cells and adipocytes, and translocate onto cell membrane with insulin

Question 25

secretin: cells produce this hormone? stimulator? function?

Answer 25

produced by S-cells in the duodenum (最容易被酸腐蚀）; respond to increased 【H+] in the duodenum.function: promote HCO3- secretion from pancreatic ductal epithelium to neutralize H+ pancreatic juicy: isotonic, [Na+], [Cl-] = plasma [HCO3-] > plasma, [Cl-] < plasma

Question 26

trypsinogen: converted by which E? where?

Answer 26

converted by enterokinase in the intestinal brush border; then active trypsin can also activate trypsinogen secretion of pancreatic E (including trypsinogen) is stimulated by cholecystokinin and cholinergic stimulation

Question 27

1 g protein = ? cal 1 g CHO = ? cal 1 g fat = ? cal

Answer 27

1 g protein or CHO = 4 cal 1 g fat = 9 cal

Question 28

Zollinger-Ellison Syn

Answer 28

gastrinoma tumor mostly locates in the distal duodonum, also in pancrease and the fudus of stomach; excess gastrin - HCL - ulcer

Question 29

stimulators/inhibitors for gastric acid production?

Answer 29

stimulators: Ach, histamine, gastrin (associated with Zollinger-Ellison syn) inhibitor: PGE2

Question 30

producing cells of VIP? function of VIP?

Answer 30

produced in the pancrease functions: stimulate intestinal water secretion, counteracts gastrin in the stomach; promote HCO3- secretion in the pancrease

Question 31

somatostatin: producing cells? function?

Answer 31

= Growth hormone-inhibiting hormone 生长激素抑制素 produced by numerous tissues (hypothalamus, stomach, intestine, pancrease) in response to low pH its production is inhibited by vagal stimulation somatostatin inhibits the release of GH, TSH, gastrin, CCK, VIP, secretin, insulin, glucagon