Timed-Random Flashcards
What enzyme is responsible for the conversion of NE to Epi? What upregulates this enzyme?
Phenylethanolamine-N-methyltransferase (PNMT)
It is upregulated by cortisol
PPO vs HMO vs POS (Point of Service)
- Compare the monthly premiums
- Compare copayments and deductibles
- Is a PCP referral required for specialist visits?
- Size of network
- May go outside network?
Inheritance of CF
Autosomal recessive
What receptors on the juxtaglomerular cells are responsible for stimulating renin release? What drugs take advantage of this fact, to decrease BP?
B-1 receptors (which is why B-blockers can help dec. blood pressure)
Describe the specific effect of the superantigens assc. with TSS
THey interact with MHC II on APCs (macrophages) and w/ T-cell receptor to widely activate T cells.
(this leads to IL2 release from T cells, and TNF / IL1 release from macrophages, ultimately causing shock symptoms)
What are the (3) main sx of vitamin A overuse?
- Intracranial HTN
- skin changes
- Hepatosplenomegaly
What do RAS genes code for?
A family of small G-proteins involved in signal transduction in the Ras-MAPK pathway
Describe the activation of Ras proteins (2 steps)
- Growth factor ligand binds to a receptor tyrosine kinase on the cell membrane, causing autophosphorylation
- Proteins interact with Ras, promoting GDP removal and GTP binding!
Describe the work that activated Ras does.
It begins a phosphorylation cascare that results in the activation of mitogen-activated protein kinase, which enters the nucleus to influence gene transcription.
Under normal cricumstances, how does Ras protein become inactivated?
It has intrinsic GTPase activity , that allows it to hydrolyze the attached GTP
The KRAS gene is a member of what gene subfamily?
Ras
Name the (4) nerves/ vessels which enter the orbit via the superior orbital fissure
OSATO
- Oculomotor nerve
- Superior Ophthalamic vein
- Abducens nerve
- Trochlear nerve
- Opthalmic nerve (CN V1) branches
What is the most common cause of death in patients who have been struck by lightning?
Cardiac arrhythmias/ arrest
What hormone is often increased in liver cirrhosis? What can this lead to?
Estrogen (leading to gynecomastia + spider angiomas + hair loss + testiclar atrophy)
Which cells found in the lungs, contain elastase? How do they keep it controlled?
Macrophages (control w/ Tissue Inhibitos of Metalloproteinases- TIMPs)
and
Neutrophils (control w/ serum a1 antitrypsin)
The proximal ureter receives its blood supply from what artery? The distal ureter?
Proximal: renal artery
Distal: superior vesical artery
Acute bacterial parotitis
- Occurs most commonly in who?
- Bacteria most commonly involved?
- Dx
- Common in elderly, postoperative patients who are intubated or dehydrated
- S. Aureus
- Elevated serum amylase (in the presence of normal serum lipase/ no evidence of pancreatitis)
How does eithanol block gluconeogenesis?
Ethanol metabolism reduces NAD+ to NADH and increases the NADH/NAD+ ratio.
This inhibits all other pathways requiring NAD+, including reactions required for gluconeogenesis.
Describe the essential differences in excitation-contraction coupling in cardiac vs skeletal muscle
Cardiac Muscle: surface membrane depolarization → opening of voltage-sensing DHPR channel → Ca2+ dependent activatin of RyR2 channel (calcium induced calcium release)
Skeletal Muscle: surface membrane depolarization → conformational change in voltage-sensing DHPR channel → allosteric activaton of RyR channel (mechanical coupling)
Attributable Risk Percent (definition + calculation)
The excess risk in the exposed population that can be attributed to the risk factor.
ARPexposed = 100 x [(RR-1)/RR], where RR = relative risk
What are the (2) major effects of Clostridium perfingens?
- Late-onset food poisoning (consisting of transient watery diarrhea)
- Clostridial myonecrosis (gas gangrene)
What is the best ausculatory indicator of the severity of a patient’s mitral regurgitation?
Presence of an audible S3 (indicating a large volume of regurgitant flow re-entering the ventricle during mid-diastole)
What is the indication for drugs which act on H1 receptors vs H2 receptors
H1 = allergies
H2 = acid (GERD, ZE, etc.)
Both are histamine receptors
Isoproterenol
(MOA)
Nonselective B-adrenergicc agonist (leads to inc. vasodilation, inc. cardiac rate, and inc. contractility)
Lesions on the medial foot cause, what type of lymphadenopathy?
On the lateral foot?
Medial: Inguinal lympadenopathy
Lateral: popliteal and inguinal lymphadenopathy
What type of injury does Carbon tetrachloride (CCL4) cause, and how?
It causes free radical injury, after being oxidized by the P450 system. The result is CCl3 which causes lipid degradation and formation of H2O2
Isotretinoin
Indication and Contraindication
Indication: Used to tx severe acne w/ significant scarring
Contraindication: Pregnancy, due to high risk of teratogenicity
What is Annular Pancreas? What might it cause?
The ventral pancreatic bud abnormally encircles the 2nd part of the duodenum, forming ring of pancreatic tissue. May cause duodenal narrowing.
What molecule does insulin promote activation of, in order to increase glycogen synthesis?
Protein phosphatase, via the PI3K pathway
What type of cells are seen in the pulmonary vasculature in cases of an Amniotic fluid embolism?
Fetal squamous cells
Name the muscles/areas that the musculocutaneous nerve innervates/provides sensory innervation to (3)
- Movement to Major forearm flexors
- Movement Corcobrachialis
- Sensory to lateral forearm
What drug group is responsible for most of the overdoses in the country?
Opioids
What organelle serves as the primary site of ribosome synthesis and assembl?
The nucleolus (All ribosomal RNA except 5S RNA is transcribed here)
What are the two ways in which Beta-blokers ameliorate the sx of thyrotoxicosis?
- Decreasing the effect of adrenergic impulses on target organs
- Decreasing the rate of peripheral T4 to T3 conversion
What types of procedures are associated with enterococcus endocarditis?
Genitourinary instrumentation or catheterization
Aschoff bodies
What are they and with what dz process are they found?
What is another name for the cellular component?
They are interstitial myocardial granulomas, found in myocarditis due to acute rheumatic fever
The macrophages are aka as caterpillar cells
Describe the echocardiogram assc. with Transposition of the Great Arteries (TGA)
Aorta lying anterior to the pulmonary artery
In an MI, when does loss of cardiomyocyte contractility occur?
Within the first 60 secs (1 minute) after the onset of total ischemia.
What effect do Ach and adenosine have on cardiac pacemaker cells?
They reduce the rate of spontaneous depolarization of cardiac pacemaker cells by prolonging phase 4
What is the effect of excercise on LV EDP?
On systemic vascular resistance?
LV EDP is increased due to the increased return
Systemic vascular resistance decreases due to large levels of vasodilation in muscles
Patient presents due to lightheadedness/ passing out while buttoning a tight shirt collar.
- Most likely dz process
- What nerve is most assc. with this dz process?
- Carotid sinus hypersensitivity (triggered by pressure from the shirt)
- The afferent limb of the carotid sinus reflex is a branch of the glossopharyngeal nerve
Trousseau syndrome
Migratory superficial thrombophlebitis assc. with visceral CA
What are the main causes of pulsus paradoxus. Name one option for tx
Pericardial dz, asthma and COPD
Beta-adrenergic agonisists are useful for the asthma/COPD etiologies
When is an aortic stenosis murmur at its loudest?
The intensity is proportional to the magnitude of the LV to aorta pressure gradient during systole, (i.e. whenever aortic pressure is at its strongest)
Which ventricle forms the apex of the heart?
The left ventricle
(All other chambers lie medial to the midclavicular line)
Other than trauma, what is one major cause for cardiac tamponade?
Viral pericarditis w/ signficant pericardial fluid accumulation
(following a respiratory infection)
Describe the histo of myxomas
Scattered cells within a mucopolysaccharide stroma, with abnormal blood vessels and hemorrhaging
Most common site of injury during a traumatic aortic rupture
Aortic isthmus
What is the pathognomnic presentation for a large patent ductus arteriosus complicated by Eisenmenger syndrome?
Differential clubbing and cyanosis w/o blood pressure or pulse discrepancy
What is the most common CV manifestation associated with SLE?
Pericarditis
Almost 100% of cases of Hypertrophic Cardiomyopathy result from mutations in genes encoding what?
Beta-myosin heavy chain
(A cardiac sarcomere protein)
Most severe AE of the anthracyclines (rubicins)
Cumulative dose-related dilated cardiomyopathy, due to formation of free radicals in the myocardium
Beta Blocker MOA
They dec. AV nodal conduction, leading to an increased AV nodal refractory period
What are the (2) main effects of nitrates?
- Venodilation (as well as general vasodilation)
- Decreased preload (i.e. decreased LV EDV and EDP)
All told, this results in decreased left ventricular systolic wall stress and myocardial oxygen demand
Path of mitochondrial myopathy
What does muscle biopsy show?
Myopathy + Lactic Acidosis due to failure of oxidative phosphorylation. Muscle biopsy often show “ragged red fibers”
For neonates infected with Hep B, what is their…
- level of HBV replication?
- level of liver enzymes?
- risk of chronic infection?
- High HBV replication
- mildly elevated liver enzymes
- very high (90%) risk of chronic infection
PaO2
A measurement of the partial pressure of oxygen dissolved in the plasma only! (not in the RBCs)
When is anovulation most common?
In the first several years after menarche (immature H-P-Ovarian axis), and in menopause.
Explain the rapid onset and short duration of action for drugs similar to propofol
They are lipophilic and thus readily diffuse across membranes.
First accumulate in tissues with high blood flow (like brain, hence rapid onset), then dubsequently redistributed to organs receiving less blood flow, like fat or muscles (hence short duration)
MOA of SSRIs
Blockade of the serotonin transporter
Blood flow is directly proportional to the vessel radius raised to what power?
The 4th power
Effect of ACE-I on GFR
Decreases GFR (because AT-II can no longer constrict the efferent arteriole)
Role of muscarinic agonists, in glaucoma tx
Increase trabecular outflow of aqueous humor
Role of prostaglandin agonists in glaucoma
Increase uveoscleral outflow of aqueous humor
Role of B-blockers and a2 agonists in tx of glaucoma
Decrease secretion of aqueous humor via the ciliary epithelium
Naltrexone
- MOA
- Indication
- Mu-opiod receptor
- First line tx for moderate to severe alcohol use disorder (blocks the rewarding and reinforcing effects)
Elastase from what cells, are inhibited by alpha-1 antitripsin?
Neutrophils
Why might patients with signficant renal dysfunction demonstrate prolonged bleeding time?
Accumulation of uremic toxins impair platelet aggregation and adhesion (no effect on platelet count, PT or aPTT)
What rxns does Thyroid peroxidase catalyze? (3)
- Oxidation of iodide
- Iodination of thyroglobuin
- Coupling rxn between 2 iodized-tyrosine residues
How can malignant, nonseminomatous germ cell testicular tumors cause hyperthyroidism?
They secrete very high levels of hCG, which can bind the TSH receptor (leading to paraneoplastic hyperthyroidism)
What is the best determinate of oral bioavailability of a drug?
AUC (Oral)/ AUC (IV)
This assumes they’ve been administered at equal doses
Why is N-myc capable of being detected by DNA probes?
It is a transcription factor and thus is capable of binding DNA.
What prompt eosinophils to release their cytoplasmic granules to kill a parasite?
When parasites enter the body they are coated by IgG and IgE which bind to the Fc receptor on the eosinophil, prompting it to degranulate.
(Antibody-dependent cell-mediated cytotoxicity)
Eos also contribute to late stage hypersensitivity
What is moa of mineralocorticoid receptor antagonists? What diseases are they good for and who should they not be used for?
Give (2) examples
(Spironolactone and Eplerenone)
They prevent aldosterone from binding to its receptor in the distal renal tubules, leading to increased sodium excretion.
Indications: CHF and reduced left ventricular EF
Contraindications: Hyperkalemia and renal failure
What is NE extravasation and what is the treatment?
Blanching of vein into which NE is being infused due to NE leakage causing major a1 receptor activation and subsequent constriction.
Use phentolamine (alpha-receptor blocker)
Tetralogy of Fallot Pathophysiology and clinical presentation
VOIR:
- VSD
- Overiding aorta
- Infundibular pulmonary stenosis
- RVH
Presentation: Cyanosis; Improvement w/ squatting (increases SVR)
Define accuracy vs reliability
Accuracy: the degree to which the aerage measurment value matches that of the gold standard
Reliability: reproducibility of a result
What cranial nerves and what aortic arch derivatives are associated with each pharyngeal/aortic arch (1-6)
- CN V; Maxillary artery
- CN VII; Stapedial artery (regresses)
- CN IX; Common carotid and prox. internal carotid
- CN X (superior laryngeal); True aortic arch and Subcalvian arteries
- Obliterated
- CN X (recurrent branch); Pulmonary arteries and Ductus arteriosus
What are the normal adult pressures in the cardiac chambers, the pulmonary artery and the aorta (minimum and maximum)
RA: 0 and 8 mmHg
RV: 4 and 25 mmHg
PA: 9 and 25 mmHg
LA: 2 and 12 mmHg
LV: 9 and 130 mmHg
Aorta: systolic BP
How does A-fib look on an EKG? In this condition, what ultimately regulates the number of atrial pulses which reach the ventricle?
- On EKG, it is characterized by: absent P waves, irregularly irregular R-R intervals, and narrow QRS
- Ventricular response is based on transmission of the abnormal impulses through the AV node. The AV node refractory period regulates the number of impulses.
Dystrophic vs Metastatic calcification
What conditions do they each occur in?
Dystrophic: Occurs normally, w/ age, in damaged or necrotic tissues in the setting of normal calcium levels.
Metastatic: Occurs in normal tissue in the setting of hypercalcemia
Retinal Artery Occlusion
Presentation?
Pathogenesis?
What is the path most likely taken to occlude the artery?
Presentation: Acute, painless, monocular vision loss
Pathogenesis: Thromboembolic complications of athersclerosis in the internal carotid.
Path: Internal carotid –> Ophthalmic artery –> retinal artery