Adrenal Glands - First Aid for the USMLE Step 1

The adrenal glands are part of the endocrine system in which they secrete hormones that mediate various factors to put the body in its equilibrium;   The adrenal glands secrete aldosterone, cortisol, and androgens from the cortex; it secretes dopamine, epinephrine, and norepinephrine from the medulla.  There are pathologies associated with it in which less hormone are produced or hormones are overproduced which destroys the equilibrium of the body.

Keep in mind that the adrenal glands are composed of two different embryological layers.  The adrenal cortex is from the mesoderm layer and the adrenal medulla is from neural crest cells of the ectoderm layer.

Adrenal Cortex
The cortex has three layers, as it's pictured in the First Aid book.  A pathology in each layer can cause various problems which is discussed further in the chapter in details.

Zona Glomerulosa
The first layer produces aldosterone for sodium retention, hence water retention.  When the body's blood pressure is low, the kidney's juxtaglomerula cells produces renin.  Renin then converts angiotensinogen, from the liver, to angiotensin I.  Then ACE (angiotensin converting enzyme), from the lungs, converts angiotensin I to angiotensin II.  Angiotensin II then stimulates aldosterone synthase enzyme, in the zona glomerulosa, to convert corticosterone to aldosterone.

Zona Fasciculata
The second layer produces cortisol for maintaining blood pressure with epinephrine via permissive effect.  Cortisol is important in inducing gluconeogenesis (proteolysis and lipolysis) in periods when glycogen stores are depleted.  Chronic stress induces prolonged release of cortisol.

Zona Reticularis
The third layer produces androgens, the precursor for testosterone, dihydrotestosterone, and estrogen.

Adrenal Medulla
The inner layer of the adrenal gland is composed of chromaffin cells.  The medulla produced catecholamines (dopamine, epinephrine, and norpeinephrine).  A pathology of the adrenal medulla in adults is pheochromocytoma and in children it's called neuroblastoma.  Since the adrenal medulla is from the neural crest cells, a biopsy of the chromaffin cells will be be S-100 positive.

I labeled the important structures in the figure below to be familiar with where the adrenal gland lies. The adrenal gland is also called the suprarenal gland because it's above the kidneys.

Adrenal Gland Drainage
The adrenal glands drain differently from each side.  The drainage path of the left adrenal gland is longer than the right because the left adrenal gland drains first to the left renal vein via the left adrenal vein to the inferior vena cava.  And the right adrenal gland drains directly to the inferior vena cava via the right adrenal vein.

NOTE: The gonads drain in the same manner as the adrenal glands.  The left ovary/testis first drain to the left renal vein via the left ovary/testis vein, then they drain to the inferior vena cava.  And the right ovary/testis drain directly to the inferior vena cava via the right ovary/testis vein.


Follow me on twitter and get updates automatically.

How to Start off Studying in the Morning

Most of us students are not morning people, and I can tell you from experience, that studying at night works best for me. However, studying in the morning is the best because you’ll have full of energy. Some of you probably feel tired in the morning, well that could be for two reasons which clearly would lead to tiredness right after awakening. First, if you didn’t get at least 7-8 hours of “consecutive” sleep then you will not feel well. When I say consecutive, I mean sleeping continuously sleeping without waking up in the middle of the night. Second reasons deals with over sleeping; if you over sleep then you will feel tired. Oversleeping can lead to tiredness because you glycogen stores will be depleted. Remember if you sleep for 10 hours or so, which means you haven’t eaten anything within that time frame so your body has little to no energy.

How to Charge Up for Studying
1. Jogging or other Cardio Workout
Jog in the Morning for 20 minutes; or walk and jog together in 30 minutes. Jogging in the morning is better than taking in all that caffeine which will irritate your stomach and make you urinate more often than normal. Jogging will also help you in vasodilating your cerebral arteries so more oxygen will enter your brain. More oxygen will allow for more metabolism of neurons.

2. Take a Good Shower
This should be obvious for everyone, but to some people it’s not. One of my friends in another state is studying and he told me he didn’t take a shower for over 2 days. As disgusting as it sounds, it’s reality, and common among some medical students. You have to take a shower in the morning to clear off the accumulated oil and to wake your self up. In the obvious sense, you should take a shower after jogging.

3. Multivitamins
Take a multivitamin pill everyday; this is something some people take for granted. Multivitamins are highly important because it has all the co-factors that are required in producing the neurotransmitters and other biochemistry functions, which are important in helping in focusing and enhancing memory and other body chemical reactions.

4. Omega-3 Fatty Acids from Fish Oil
Take 1000 mg of Fish Oil daily, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in combination.  Omega-3 Fatty acid is very helpful in myelination of neurons for faster brain processing and photographic memory. As you will study that increasing in myelination will lead to increase in space constant. Space constant measures how far along an axon an electrical impulse will travel. So in simple terms, increasing your space constant will allow you to think faster.
Warning: Do not over consume Fish oil.  Fish oils are natural blood thinners, so don’t take it with aspirin or other NSAIDs.  Also, buy the quality fish oil so it will be cleared off mercury.  Cheap fishoils are no good as they have little omega-3 fatty acids with no significance.  I tried a lot of those capsule fish oil and they stink and they were a waste.  So I tried a pure form with lemon flavor; I usually ordered the Carlson The Very Finest Fish Oil; and it works!  However, if you are near a Vitamin Shoppe store you can get their store brand for $7 less.

5. Ripe Bananas 
You would be surprised how well ripe bananas can help; it has a good concentration of tyramine. When you study the autonomic pharmacology section you will learn about tyramine and how in helps in neurostimulation. Ripe bananas will definately wake you up.   
USMLE Step 1 Fact: Tyramine is high in wine and in cheese, patients who take selegiline, a selective monoamino oxidase inhibitor type B, will have an emergency hypertension reaction.

What I mentioned will work for everyone if done consistently. Don’t expect it to help you right away, give it couple of days to see a significant difference. I have tried so many methods of studying in the morning and the best method for me is what I mentioned; try it and see if it works for you.
Follow me on twitter and get updates automatically.