Dr.Deepthi Kondagari - Best Endocrinologist in Hyderabad|Endocrinologist in Secunderabad
about endocrinology systemthe endocrine system main purpose into maintaining a homeostatic environment through the use of
hormones so when we think of the endocrine system we should think of hormones are
essentially signaling molecules, now the endocrine system works in close proximity with the nervous
the system in that both the endocrine system and the nervous system tries to maintain a homeostatic
environment by sending out signals the main difference between the two is that the nervous system is
quick response so when a stimulus arrives at a neuron the neuron can passion these signals these
commands as neurotransmitters that will then target particular cell the neurotransmitter will bind onto
a specific receptor that will cause the target cell to initiate assort-term quick response now the
the endocrine system, on the other hand, will send signals not to get to neurotransmitters but through
hormones and these hormones will travel via the bloodstream where it will then target cell and it's
specific receptors so what happens is with an endocrine cell is that what a stimulus or command comes
this will stimulate the endocrine cell to secrete hormones into the bloodstream like so these hormones
will then target and bind onto a specific receptor on target cell this will cause a target cell to initiate a
the long-term slow response so that is a major difference in that
Nervous System
the nervous system is a short-term quick response whereas the endocrine system is a long term slow
response the endocrine cell typically secrete hormones into the bloodstream this is normal this type of
signaling is called endocrine signaling hence the name endocrine system however hormones does not
always have to be secreted into the bloodstream to target a cell the endocrine cell can also secrete
hormones that target cell directly close to it like this cell for example and so went does this type of
secretion is known as peregrine signaling Para as an across and this will initiate a long-term slow
response when the endocrine cell is secreted when the endocrine cell sorry secretes hormones into the
bloodstream which is the basics for the endocrine system we have hormones in the bloodstream the
the hormone can travel in the bloodstream as a freeform which can be cleared quickly by the body free
form as in it's just a hormone traveling in the blood of the hormone can actually travel bound to a
protein these hormones that are bound to protein and trouble through the blood are typically lipid
hormones because lipids hate water they need to travel bound to proteins we call this protein-bound
hormones so
Hormones
now let's talk a little bit more about hormones, hormones as I mentioned our signaling molecules
hormones can be grouped into three types amino acid derivatives peptide hormones or lipid derivatives
lipid derivatives, for example, are steroid hormones or thyroid hormones if you know a little bit about
your hormones and so these hormones they will bind onto a target cell onto the specific receptor that
will initiate a desired response along-term response here I'm drawing these hormones binding on to
target receptors on this plasma membrane of the target cell to initiate response well peptide hormones
and most hormones derived from amino acid they bind to receptors on the play asthma membrane
whereas the lipid-derived hormones they cross the cell membrane and bind to receptors in the
cytoplasm as shown siren hormones and steroid hormones they cross the plasma membrane and bind
to receptors in the cytoplasm to initiate response and this is because the thyroid and steroid hormones
are lipid-derived okay
Hormones
we know a bit more about hormones these signaling molecules let's look and look at an example of an
endocrine response a good example is taken at blood glucose so here in the bloodstream we have low
glucose levels and this is not very good because wended glucose, glucose is a source of energy for
tissues in our body so low blood glucose is a stimulus and the body will have to try to fix this to
maintain homeostasis so it will tyro increase blood glucose levels and this is when the endocrine system
kicks in the stimulus which is low blood glucose levels will stimulate an endocrine cell known as the
pancreas cell actually it's called the alpha cell but let's call it pancreas cells for simplicity the pecker cell
will then secrete a hormone called glucagon into the bloodstream glucagon will travel through the
bloodstream to the liver which is the target cell glucagon is not a lipid hormone because one it is not
bound to a protein when it travels through the blood and two it binds to receptors on the cell
membrane, when glucagon binds to the receptors on the liver cell glucagon, will stimulate the liver to
break down glycogen to secrete glucose in the blood and so the response by this liver cell is that it will
secrete more glucose in the blooded increase blood glucose levels like soil this glucose is being
secreted out when the blood glucose level is increasing this will send a net this will be sent feedback back it will
send a feedback twill to send a negative feedback signal to stop stimulating the pancreas cell because
when you have normal to high blood glucose levels you don't need any you don't have low blood
glucose stimulation and you don't need any more glucose to be secreted I hope you understand this
concept of negative feedback so in the example, we just saw we looked at the hormone called glucagon
which is - created by the alpha cells of the pancreas now let's look at some other major hormones such
as glucagon and where they come from we will not look at what they do or I'll try to mention them but
we'll just look at what they are before we continue we should know that we have many hormones in the
a body that performs different functions or has different responses another terminology to learn is also
what's called endocrine glands
Endocrine glands are essentially groups of endocrine cells that are dedicated to performing a specific
function so let's look at the first two or three most important endocrine glands I think the first is
situated in the brain here thesis is known this the first one is known as the hypothalamus and this is an
endocrine us endocrine tissue and the hypothalamus is responsible for the production of ant diuretic
hormone and oxy toxin it is also responsible for the production of the regulatory hormones and we will
look at what these do probably the most important endocrine glands are the pituitary glands which are
located right below the hypothalamus here and there are two lobes of the pituitary glands there is the
anterior lobe and the posterior lobe secretes oxy toxin and ant diuretic hormone that
were produced by the hypothalamus so the hypothalamus produces these hormones and sends them to
the pitcher posterior posterior lobe which then the posterior lobe will secrete into the blood the
the anterior lobe of the pituitary glands actually secrete many hormones including ACTH which stands for a
drenocorti co tropic hormone TSH thyroid-stimulating hormone obviously stimulates the thyroid the GH
growth hormone for growth PRL prolactin for milk production in the breast and then FSH which is follicle
stimulating hormone and LH luteinizing hormone which is responsible for the reproductive systems
these hormones that are secreted by the anterior lobe they are regulated by the hormones from the
hypothalamus so if you remember the hypothalamus secretes regulatory hormones that regulate the
secretion of the anterior hormones if that makes any sense there's another are endocrine gland in the
Dr.Deepthi Kondagari - Best Endocrinologist in Hyderabad|Endocrinologist in Secunderabad
brain is known as pioneer gland which is around this area and it secretes melatonin is actually
responsible for the body clock now let's make our way down in the trachea or throat area we have
wrapping around the trick here we have the thyroid gland now the thyroid gland secretes few hormones
thyroxin which is abbreviated t4 and trued thyroxin which is t3 it also that's responsible for
metabolism essentially then you have calcitonin now
Thyroid Gland
the thyroid glad it also has another endocrine grandson it so if we zoom into this area here
we're looking at this person from a past point of view from the back so we have the thyroid gland
and then we have these four sorts of lobes on the thyroid gland these are known as the parathyroid
gland Para is enough to cause but it's just on its there are four parathyroid glands and these are behind the
thyroid gland and they secrete the hormone parathyroid hormone simple enough parathyroid hormone
is important in the regulation of calcium and phosphate enamel in our blood in our body now right
below the thyroid gland, we have another endocrine gland you can say known as the thymus now the
the thymus is not really a big dealing the inner crisis but it is a big deal in the immune system world but in
the endocrine world the thymus actually undergoes atrophy during adulthood and it begins
secretingthymosin, of course, this person we haven this person we have the lungs connected to the trachea
and the heart between the levels now if you didn't know the hot is also classified as an endocrine gland
because it secretes hormones the hut secretes the hormone naturally peptide which is responsible in
blood pressure regulation it actually decreases blood pressure when there is an increase in blood
pressure then we have the digestive tract now the digestive tract they secrete a lot of variety of
hormones and what I mean by the digestive tract I mean the stomach the duodenum the small
intestines etchant they produced many hormones such as gastrin somatostatin Coley cytokinins etc
another important well another very important endocrine gland or tissue is
the pancreas and it secretes two main hormones insulin and glucagon now we talked about glucagon in
that it increases blood glucose levels well insulin works opposite it decreases blood glucose levels and
you might know diabetes people they have very low insulin levels or type-2 diabetes they have
low into the levels or type 1they're depleted insulin levels and soya have a lot you know very high blood
glucose levels and you can't decrease this because you have no insulin and if you wait until the end of
the video I will provide links to some of these hormones so you can watch them in more detail and to
see what they do the kidneys also secrete hormones they secrete erythropoietin which stimulates red
blood cell production in the bone marrow and also secretes calcitriol which I don't know what it does
above the kidneys, we also have the very important adrenal glands if we take across-section of the
adrenal glands we have two adrenal glands of course because we have two kidneys if we cut across
section of the adrenal glands we have the adrenal cortex the outer part of the adrenal glands and then
we have the adrenal medulla the middle of the adrenal glands and this line I'm drawing for the adrenal
medulla it's meant to be the in the middle of the adrenal glands not on the outside it's a mistake
anyway, the adrenal cortex secretes cortisol and aldosterone cortical is essentially for stress and
aldosterone is to promote sodium reabsorption as well as potassium secretion in the kidneys and then
we have the adrenal medulla which secretes adrenaline and noradrenaline also known as epinephrine
or norepinephrine in America these hormones are important in the fight-or-flight response as well as
the rest and digest response adipose tissue which is essentially fat also stupid hormones it secretes
lepton which is important fat metabolism the far endocrine tissue or endocrine glands I want to talk
about other gonads now because we have a male and female version of humans we have two types of
gonads we have the testes for the male and the ovaries for females so the testes in the testes we have cells
those secrete androgens such as testosterone which is important for promoting male characteristics as
well as sperm production and then we have forth gonads the ovaries for the female we have important
hormones being secreted such as estrogen and progesterone which is important in female
characteristics and egg production okay so those were the main hormones that were secreted by the
main endocrine tissue or endocrine glands but I'd like to concentrate and look into more detail on the
pituitary glands which is very important in the crying gland because it for one secretes lot of hormones
and two it secretes hormones that regulate or stimulate the secretion of other hormones from other
endocrine tissue if that make any senses let's have a closer look at the pituitary glands the pituitary
the gland is located within the brain and easy way to remember this is it's located sort of below the
hypothalamus.
the pituitary glands consist of two lobes one is called the posterior pituitary which is at the back it's
also known as a neural hypothesis and then we have the anterior pituitary also known as an Edina
hypotheses I hope I'm pronouncing that foursome's right anyway let's first look at the posterior pituitary
and what its decrees well actually the hypothalamus it produces it synthesizes ant diuretic hormone and
oxy tocsin these hormones that are synthesized in the hypothalamus they are synthesized in these
neurons and these new neurons will then pass on these hormones to the sheerer pituitary and so from
here when stimulus arrives stimulating the secretion of these hormones the posterior pituitary can then
secrete its the posterior pituitary can secrete the ant diuretic hormone than diuretic hormone main
the function is toys for water retention so it targets the kidneys particularly the kidney tubules the posterior
the pituitary can also secrete the hormone oxy toxin, oxy toxin essentially targets the breast and it's
important so it's important for lactation and also is important for the contraction of the uterus during
childbirth so remember for the posterior pituitary the hormones itself are actually synthesized or made
within the hypothalamus, the posterior pituitary only secretes them now let's look at the anterior
pituitary now the anterior charger is different than the posterior pituitary in that the anterior pituitary
makes its own hormones however these hormones they can only so most of them can only be secreted
when there is some form of confirmation from the hypothalamus so the hypothalamus actually will
secrete a hormone that will regulate the secretion of the anterior pituitary hormones the hormone
once it once they are secreted they will cause either stimulation or inhibition of the anterior pituitary
hormones being secreted anyway whatever the case if it's all okay the anterior pituitary can
secrete pro-active nabs reverted P RL which will target that member the breast essentially for a milk
production and to your Patrice can also secrete growth hormone which targets many tissues such as the
bone for growth the anterior pituitary can't secrete gonad tropic hormones such as follicle-stimulating
hormone and luteinizing hormone which will target the testes or ovaries depending if it's male or female
anterior pituitary can also secrete thyroid-stimulating hormone which will stimulate stimulate
