Blocks 33, 34 Flashcards Preview

UWORLD STEP 1 > Blocks 33, 34 > Flashcards

Flashcards in Blocks 33, 34 Deck (29):
1

Smoker with decreased vision in one eye described as blurry and distorted. Decreasing vision over past year making it hard to drive. Needs bright light to read the newspaper. Grayish discoloration of the macula with areas of adjacent hemorrhage.

Age-related macular degeneration (AMD)

Result of advancing age and environment (smoking).

This description is WET AMD: acute vision loss with metamorphopsia (distortion of straight lines). Progressive extracellular matrix accumulation can eventually result in retinal hypoxia, which stimulates VEGF production and causes subretinal neovascularization with formation of leaky vessels.

2

Highly oxygenated blood in a fetus is found in what vessels?

Umbilical vein --> IVC via ductus venosus

3

What structure is located on the outside of a histone core and helps package nucleosomes into more compact structures by binding and linking the DNA between adjacent nucleosomes?

H1 Histone

4

Abnormal narrowing of the spinal canal occurring most commonly in the lumbar region. Compression of nerve roots causes lower extremity pain, numbness/parasthesia, and weakness. Symptoms are POSTURE DEPENDENT. Lumbar flexion (walking uphill or pushing a cart) relieves the pain.

Spinal Stenosis

Ligamentum Flavum thickening due to increased load on the posterior aspect of the spinal column due to lost disc height.

5

EBV infections cause atypical cells of what type in infectious mononucleosis?

EBV infects B-lymphocytes by binding to CD21. CD8+ t cells clonally expand in response to EBV infected B lymphocytes in an effort to destroy the virally infected cells. The CD8 cells can be seen on peripheral smear (downey cells)

6

Pt. with membranous nephropathy, flank pain, hematuria, and right sided varicocele has what?

Renal vein thrombosis as a result of nephrotic syndrome.

Lost in urine: antithrombin 3, immunoglobulins

*This patient is showing signs of the loss of Antithrombin 3. Lost immunoglobulins will predispose the a patient for infections like pneumococcal infections.

7

A low volume of distribution means the drug is trapped where? What properties of the drug make it's VoD low?

Drug is trapped in the plasma compartment

High MW

High plasma protein binding

High charge

Hydrophilicity

8

Calcium ions are released from the sarcoplasmic reticulum during excitation-contraction coupling in SKELETAL muscle... how do they work to cause muscle contraction?

Calcium binds troponin C, tropomyosin shifts to expose the actin binding sites for myosin, contraction can occur

9

If a male patient has permanently inactive FSH receptors, what substance will be decreased?

FSH stimulates sertoli cells to release Inhibin B to send negative feedback on FSH. Inhibin B would be low

10

Difficulty seeing for 6 months. Eyes get tired easily especially in the late afternoon/evening. Weakness of extraocular muscles. CT scan shows an anterior mediastinal mass.

Myasthenia gravis, autoimmune disease caused by antibodies directed against nicotinic ACh receptors on the post-synaptic membrane of the NMJ.

 

*Most pts. have thymic abnormalities (thymoma) which looks like an anterior mediastinal mass

11

Conversion of grams of protein to Calories.

1 g protein = 2 Calories of energy

12

When an optic nerve is damaged, shining light into that eye will cause what effect on both pupils? What about when light is shined into the unaffected eye?

Light into bad eye: neither pupil constricts because the nerve can't see the light.

Light into good eye: both pupils constrict because motor pathways are intact.

13

Acute affect of corticosteroids on each cell type: neutrophil, lymphocyte, monocyte, basophil, eosinophil

Inreased Neutrophils (demargination)

Decreased lymphocyte, monocyte, basophils, and eosinophils

14

Progressive onset of heart failure in the setting of a recent viral infection...

Dilated cardiomyopathy caused by viral myocarditis

Dilation and enlargement of the heart chambers with decreased ventricular contractility

15

During a surgery to remove an infected appendix, which landmarks is most helpful in identifying the diseased organ?

Teniae Coli

At the rectosigmoid junction, the teniae coli form 3 distince longitudinal bands that travel on the outside of the entire colon before converging at the root of the vermiform appendix.

16

Italian (mediterranean) man with microcytic anemia, increased Hemoglobin A2, and target cells on peripheral smear has what?

B Thalassemia Minor

Affects beta chain production and can be caused by a variety of DNA mutations affecting the transcription, processing, and translation of betal globin mRNA

17

Defense mechanism in which an individual responds in a manner opposite to ones actual feelings.

Reaction Formation

18

Chronic renal hypoperfusion will cause what change in what cells?

Hypertrophy and hyperplasia of the juxtaglomerular cells because they respond to low blood flow via the renin-angiotensin-aldosterone system. 

19

47 y/o man with worsening shortness of breath for several months. Not a smoker. Wheezing and poor air movement on exam. AST and ALT are super super elevated. Liver biopsy histo was given. What is causing the lung issue?

Alpha-1-antitrypsin deficiency is an autosomal codominant disorder affecting the lungs and liver.

Severe panacinar emphysema due to unchecked destruction of alveolar walls. 

Liver disease = intrahepatocyte accumulation of polymerized AAT that can progress to cirrhosis and hepatocellular carcinoma.

20

Tyramine hypertensive crisis can happen in a patient who consumes tyramine while on what type of medication?

MAOI - block the degradation of dietary tyramine, allowing it to enter the systemic circulation and cause severe hypertension and other signs of sympathetic hyperactivity.

 

21

Esophageal dysmotility in CREST scleroderma is a result of what?

Atrophy and fibrous replacement of the muscularis in the lower esophagus.

Symptoms of GERD

22

10 year old boy with shortness of breath, palpitations. Fever, poor appetite, fatigue. Tachypnea, tachycardia, hypotension. New holosystolic murmur. Cardiac biopsy

Acute Rheumatic Fever's most serious manifestation is myocarditis.

New murmur is likely mitral regurg

Biopsy = interstitial fibrosis with central lymphocytes and macrophages as well as scattered multinucleated giant cells (Aschoff body) is pathognomonic for ARF related myocarditis

23

Primaquine is added to Chloroquine in the treatment of P vivax and P ovale for what purpose?

To eradicate the intrahepatic stages (hypnozoites) of these malarial species, which are responsible for relapses.

24

Pt with type 2 diabetes with severe hypoglycemia after a day of extended walking. Ate less dinner because she was tired. Only medication is an oral drug for diabetes. Condition rapidly improves after administration of an intravenous bolus of dextrose. What medication is most likely to cause this?

Sulfonylureas carry a significant risk of hypoglycemia. The risk is increased by exercise, missed meals, chronic malnourishment, or organ dysfunction.

Glyburide and Glimepiride are long acting and have a higher incidence of hypoglycemia.

Glipizide has a lower incidence due to a shorter half life.

25

What is the first line treatment for trigeminal neuralgia?

Carbamazepine

Inhibits neuronal high-frequency firing by reducing the ability of sodium channels to recover from inactivation.

26

During the process of basement membrane invasion as a cancer tries to spread, what substance is most likely to be increased in the tumor cells?

Metalloproteinases

Proteolytic enzymes that degrade the components of the ECM and basement membrane. They facilitate basement membrane penetration, which distinguishes an invasive tumor from carcinoma in situ.

27

What part of the stomach is preferentially infected by H. Pylori?

Antrum in the prepyloric area (where there are few acid-secreting parietal cells)

28

A pt with chronic alcoholism has what vitamin deficiency? What part of the citric acid cycle will be affected?

Thiamine

Thiamine is a necessary cofactor for pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase, and transketolase.

29

During an oophorectomy, what structure must be ligated to prevent heavy bleeding?

The suspensory ligament of the ovary contains the ovarian artery, vein, lymphatics, and nerves. The ovarian artery is the major blood supply to the ovary and therefore must be ligated.