Hypothalamin hormones

[Amrik]

i wanted to how hormones secreted by the hypothalamus reaches the posterior pituitary lobe...do they travel through the hypothalamic - hypopheseal artery?

[Dr.Stein]

I am sorry my dear, I got trouble with connection so I left you in YM without explaining this

Here, I pay my debt for you

Hypothalamus consists of many neurons which secret hormones i.e. releasing factor (-RF/-RH) and inhibiting factor (-IF/-IH), called as nucleus (singular) or nuclei (plural). Thus the hormones are called as "neurohormones".

Nuclei supraorbitalis and nuclei paraventricularis are two of those nuclei, which have long axon. Their body cells locate in hypothalamus, while their axons pass thru the stalk (infundibulum) to reach posterior pituitary. Oxytocin and Vasopressin (ADH) are actually neurohormones secreted by those nuclei, NOT hormones secreted by posterior pituitary. Those hormones are stored there, because the terminal bulb of those nuclei locate in posterior part of pituitary. No blood vessels include in this case.

Here is the pic to give you more explanation:
Click the picture to see larger view

[Amrik]

yupp....actually i have just noticed my mistake...i wanted to ask about anterior pituitary...but its also cleared now...hypothalamic - hypophoseal blood vessels (artery if i am not wrong) transport the hormones secreted by the hypothalamus directly to the anterior pituitary!
but this was something new...i knew only hormones travels through the axon to the posterior...others are new stuffs!
Thank you Doc!...i am compiling my information about the Endocrine gland...when i finish it i will send it to you..and if you are free you could tell me how it is and what all things i should add and remove, you know a teacher's point of view is the best!

[Dr.Stein]

From my pic, you also can see how hypothalamus connects anterior pituitary too, right?

Sure, I always have time for everyone who wants to study. But not for the instant thing And I will do my best t help you. I love these kind of people

Have you got my one-page handout? Actually that's an Introduction part. The rest will be longer and complicated. If you make a good paper of your Endocrine System, I will ask your permission to use it in my class. I will tell my students where I got the paper

[Amrik]

Doc another question...in females LH not only causes ovulation but also the production of testosterone in the ovaries...these testosterone are converted into estrogen right? what converts them...i read somewhere that adjacent granulosa cells converts testosterone to estrogen...if it is correct what really is this adjacent granulosa cells? can you explain a bit more

yup, its ok you can use it in your class, i would be delighted ...knowledge should be shared...nobody can steal your knowledge so why being a miser keeping it all by ourselves

[Dr.Stein]

Yes, both in male and female, LH produces androgen, especially testosterone. In male, LH sometimes is called as ICSH (Interstitial Cell-Stimulating Hormone).

Yes, you are correct, in female, testosterone is secreted by granulosa cells a.k.a. follicle cells of the ovary. By the existence of enzyme aromatase, this male sex hormone is converted into estrogens. Three major estrogens are estradiol, estriol and estrone.

About granulosa cells or follicle cells, they are cells where oocyte is swaddled within its follicle (pocket).

Take a look at this figure.
Click the picture to get larger view.



A figure of a developing ovarian follicle. The red cell in the centre is oocyte, the purple cells surrounds are follicle cells a.k.a. granulosa cells a.k.a granulocytes. The white part is follicle's antrum (room) which contains follicle's liquor, a viscous fluid that is rich in steroid reproductive hormones, especially androgens and estrogens.

[Amrik]

Alright Doc.....Thanks alot!

[Amrik]

sorry for duble posting but
Doc...What is the function of calcitonin? It is alright now...i already know it!

[MrMistery]

so LH and ICSH are the same thing? Are you sure doc? Cause if you are, i'm gonna call the ministery of eduacation and complain that the textbook they sent me is a piece of crap...

[Amrik]

@Mr.Mistery
Andrew.....in your textbook what is the function of ICSH?

[MrMistery]

it says "the antherior pituitary gland secretes LH and ICSH, which stimulate the secretion of testosteron"
........

[Dr.Stein]

so LH and ICSH are the same thing? Are you sure doc?

Pretty sure!