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NBME 11 block 2 q 1 to 50 - maryam2009
#41
I do not know why I cannot post the explanation for Qs 29
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#42
33. D
As a medical term, precocious puberty describes puberty occurring at an unusually early age. In most of these children, the process is normal in every respect except the unusually early age, and simply represents a variation of normal development. In a minority of children, the early development is triggered by a disease such as a tumor or injury of the brain. Even in instances where there is no disease, unusually early puberty can have adverse effects on social behavior and psychological development, can reduce adult height potential, and may shift some life-long health risks. Central precocious puberty can be treated by suppressing the pituitary hormones that induce sex steroid production.
The term is used with several slightly different meanings that are usually apparent from the context. In its broadest sense, and often simplified as early puberty, "precocious puberty" sometimes refers to any physical sex hormone effect, due to any cause, occurring earlier than the usual age, especially when it is being considered as a medical problem. Stricter definitions of "precocity" may refer only to central puberty starting before a statistically specified age based on percentile in the population (e.g., 2.5 standard deviations below the population mean),[1] on expert recommendations of ages at which there is more than a negligible chance of discovering an abnormal cause, or based on opinion as to the age at which early puberty may have adverse effects. A common definition for medical purposes is onset before 8 years in girls or 9 years in boys.
One possible treatment is with anastrozole. Histrelin acetate (Supprelin LA), Triptorelin or Leuprolide, any GnRH agonists, may also be used. GnRH agonists stimulate the pituitary to release Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). However, when used regularly, GnRH agonists cause a decreased release of FSH and LH. GnRH produced by the hypothalamus is pulsatile, allowing for a physiologic release of FSH and LH.
http://en.wikipedia.org/wiki/Precocious_puberty
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#43
34-B Inhibitory synapses
The neurotransmitter at inhibitory synapses hyperpolarizes the postsynaptic membrane.

Example: gamma aminobutyric acid (GABA) at certain synapses in the brain.
•The GABAA receptor is a ligand-gated chloride channel. Binding of GABA to the receptors increases the influx of chloride (Cl−Wink ions into the postsynaptic cell raising its membrane potential and thus inhibiting it.

This is a fast response — taking only about 1 millisecond.

•Binding of GABA to GABAB receptors activates an internal G protein and a "second messenger" that leads to the opening of nearby potassium (K+) channels. As you might expect, this is a slower response, taking as long as 1 second.
In both cases, the resulting facilitated diffusion of ions (chloride IN; potassium OUT) increases the membrane potential (to as much as −80 mv). This increased membrane potential is called an inhibitory postsynaptic potential (IPSP) because it counteracts any excitatory signals that may arrive at that neuron.
A hyperpolarized neuron appears to have an increased threshold. Actually, the threshold voltage (about −50 mv) has not changed. It is simply a question of whether the depolarization produced by excitatory synapses on the cell minus the hyperpolarizing effect of inhibitory synapses can reach this value or not.
Mutation of the GABA, (no receptor) secundary to the mutation DECREASED THE influx of Cl-

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#44
29.CC

For moderate exercise, mean arterial PCO2 does not change.

@god99

You are welcome and thank you for posting the answers
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#45
35-F ADH is secreted in response to increased plasma osmolarity and dicreased blood volume, binds to receptors on principal cells, causing increased number of water channels and increased water reabsortion in the collecting tube. FA pag 396
The main effector organ for fluid homeostasis is the kidney. ADH acts by increasing water permeability in the collecting ducts and distal convoluted tubules, specifically it acts on proteins called aquaporins which open to allow water into the collecting duct cells. This increase in permeability allows for reabsorption of water into the bloodstream, thus concentrating the urine.
Diabetes insipidus (DI) is a condition characterized by excessive thirst and excretion of large amounts of severely diluted urine, with reduction of fluid intake having no effect on the latter. There are several different types of DI, each with a different cause. The most common type in humans is central DI, caused by a deficiency of arginine vasopressin (AVP), also known as antidiuretic hormone (ADH). The second common type of DI is nephrogenic diabetes insipidus, which is caused by an insensitivity of the kidneys to ADH. It can also be an iatrogenic artifact of drug use.Wikipedia




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#46
36 C bridging cortical veins
subdural haematoma



37 A esophageal varices
liver cirrhosis -->portal hypertension -->Ascites, splenomegaly, esophageal varices, caput medusae, haemarrhoids

38 B Zona glomerulosa -->Aldosterone
other options C -zona fasciculata, D -zona reticularis, E -adrenal medulla


39 B microangiopathy
diabetic retinopathy
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#47
40 B chemokine receptor
HIV entry requires interaction with CD4 receptors and CCR5 receptors

41 C???
its not A for sure

42 A ---Adenocarcinoma
description best fits adenocarcinoma, most common type of lung cancer in non smokers

43 A is wrong for sure

44 A oocyte donation
turners sundrome --- streak ovaries-- no germ cells

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#48
@nf2011
Hi
welcome and thank you for posting the answer,
please answer the Q with more explanation and details and if there is a Q that you are not sure about it,please make a separate post and bring it to discuss,then post the correct answer here.TY
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#49
45 B inheritance of amplified CYP2D6 locus
rule out A induction --->increased dose should induce a response
C inactive alleles & D inhibitor --> small doses should do the trick
E tolerance ----> initiall doses should induce a response

48 D lower midbrain (weber syndrome)
guessed it , got right

49 E zolpidem
Zolpidem (Ambien) is a prescription medication used for the short-term treatment of insomnia, as well as some brain disorders. It is a short-acting nonbenzodiazepine hypnotic that potentiates gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, by binding to GABAA receptors at the same location as benzodiazepines. It works quickly (usually within 15 minutes) and has a short half-life (2–3 hours).
Zolpidem has not adequately demonstrated effectiveness in maintaining sleep, however it is effective in initiating sleep




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#50
anyone want NBME 11 block 1 questions ????
I have all the blocks (took it online) but in different order
write down your email ids i will send it to u after my exam on 23 may
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