Adrenal Medulla and the Hormones Secreted

It was very late in the evening, and yes! I can’t sleep, even if my body wants to, but my mind doesn’t. And I do know the reason why, I just keep myself unaware of the feeling what I’m going through. The feeling which everyone wishes to feel with somebody and for some people, it’s the feeling that they don’t want to go through anymore. Wait! I’m not supposed to discuss this. Back to the real topic which is the “ADRENAL MEDULLA and the Hormones it Secretes".

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According to all the books and internet resources I’ve read lately, the adrenal medulla is the interior fraction of the adrenal gland that plays a big job in the SYMPATHETIC-ADRENAL MEDULLARY SYSTEM. The ADRENAL MEDULLA is totally surrounded by cortical epithelium. It is composed chiefly of chromaffin cells.

Out body's response to the stress (like exercise), the medullary cells releases catecholamines into the blood. 17:3 is the ratio of the epinephrine to norepinephrine when secreted by the medullary cells. It is also the site of the conversion of TYROSINE (an amino acid) into the stress hormone, EPINEPHRINE and NOREPINEPHRINE.

THE HORMONES AND ITS FUNCTIONS

EPINEPHRINE- a catecholamine which naturally occur in the body. It is synthesized from tyrosine in the adrenal medulla and released along with norepinephrine into the bloodstream. The following are some of its functions.

a. CARDIOVASCULAR EFFECT: strengthens the hearts contractility and increases the rate of contraction therefore, cardiac output increases which in return supplies more oxygen to the muscles putting the body in an alert or heightened state.

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b. RESPIRATORY EFFECT: a powerful bronchodilator. In case of asthma attacks, epinephrine rapidly relieves dyspnea and increases the tidal volume of the lungs.

c. HYPERGLYCEMIA EFFECT: inhibits insulin-induced glucose uptake in skeletal muscle and adipose tissue leading to a rapid increase in plasma glucose concentration.

NOREPINEPHRINE- a stress hormone which have an effect on the part of the brain where awareness and responding actions are controlled. Along with adrenaline or the epinephrine, it also underlies the flight-or-flight response by setting off the release of glucose, and mounting the blood flow to skeletal muscle. The following are some of its functions.

a. VASCULAR EFFECT: the noradrenaline hormone dilates the blood vessels during vasoconstriction. When the blood vessels are dilated, there is an increase flow of blood due to the decrease of vascular resistance. In short, it will lead to a decrease ion blood pressure.

b. HYPERGLYCEMIA EFFECT: norepinephrine increases the production of the glucose (not as the same amount with epinephrine, its less than) but increases glucose uptake and its utilization in skeletal muscle and in adipose tissue by the potent beta3 andrenergic receptor that is independent of insulin action. This now explains the principle that lies beneath in the immediate source of energy during stressful situations.

OTHER EFFECTS:

• dilation of the pupil
• hair stands on end ("gooseflesh" in humans)
• clotting time of the blood is reduced;
• increased ACTH secretion from the anterior lobe of the pituitary.

All of these effects prepare the body to take immediate and vigorous action.

Thats all up to now.

I hope that this post helped you

alot with your concerns. :)

p.s.

with the currently music your listening to right now (the one embedded in my profile) tell me what do you think is the relation of this song to my topic (post it as a comment) and ill be giving free globe load for the first one who will get it correctly/nearest to the answer (for mt4 people only).. :)

Reference/s:

· Medical physiology: principles for clinical medicine by Rhoades, Rodney

· http://www.ehow.com/facts_5007996_what-functions-norepinephrine.html

· http://en.wikipedia.org/wiki/Adrenal_medulla

· http://www.ehow.com/about_5380460_epinephrine-vs-norepinephrine.html

Photo credits:

• http://bohone09.wikispaces.com/file/view/A4adregl.jpg/84661429/A4adregl.jpg
• http://school.discoveryeducation.com/clipart/images/look---.gif
• http://www.rch.org.au/publications/cah_book_redo/media/picture03.jpg