Understanding the Endocrine System: Glands, Hormones, and Functions

Running head: BIOLOGY
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Introduction:
The endocrine system is defined as the chemical messenger system encompassing
feedback loops of hormones which are released by the internal glands of an organism to act on
the cells. The effects of the hormones of the endocrine system are dependent on the program
responses of the cells that are targeted (Bouillon et al. 2015). Some may cause short term effects
such as elevation of the heart rate and some have long term effects like increase of height. This
paper will discuss the different part of the endocrine system in following paragraphs.
Discussion:
1.1 main endocrine glands and describe the hormones that are produced by them:
While the significant number of body organs make hormones, major glands which
together produce endocrine involve pituitary, thyroid, parathyroid, adrenals, pancreas, and ovary
for females and testis for male (Melmed et al. 2015). Out of all endocrine glands that are part of
the endocrine system, pancreas is part of both systems such as the digestive and endocrine
system. The prime reason behind this is that it secretes hormones into the bloodstream for
targeting specific organs and secretes enzymes in the digestive system for proper digestion of the
organ.
The pituitary gland secretes hormones such as growth hormone, prolactin, corticotrophin,
antidiuretic, and oxytocin. Thyroid gland secretes hormones such as thyroxine, triiodothyronine.
The parathyroid gland secretes hormones such as calcitonin and parathormone. The adrenal
gland secretes hormones corticosteroids, catecholamines epinephrine, norepinephrine, and
androgens. Pancreas gland secretes hormones such as Somatostatin, insulin, secretin, glucagon,

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gastrin, amylin, gastrointestinal hormones, and pancreatic polypeptides (Sherwood, L. 2015).
The ovarian gland secrets the estrogen, progesterone and testis gland secrets testosterones
(Sherwood, L. 2015) ( appendix 1).
1.2. Explain the function of the major hormones of the endocrine system
As discussed above, there are seven major glands which secrete the hormones which
regulate the normal function of the body.
Considering the pituitary gland, growth hormone I which stimulates the growth of body
tissues and bone and provide minerals. Prolactin stimulates milk production for breastfeeding
babies. Thyrotropin is used for stimulating thyroid glands for making thyroid hormones.
Corticotrophin is used for stimulating the adrenal gland and the antidiuretic regulates the water
balance by controlling the functions of the kidney (Ahmed 2018). Oxytocin triggers the
contraction of hormones. Considering the thyroid gland, thyroxin controls and triggers an active
form of triiodothyronine (Www.innerbody.com 2019). Triiodothyronine, on the other hand,
controls almost the majority of the function of the body. It also controls the rate at which cells
burn fuels from food to make energy. Considering parathyroid hormones, calcitonin and
parathormone both stimulate the growth of the bone by stimulating the use of calcium and
phosphorus (Nicolaides, et al. 2015). Considering adrenal glands, corticoids increase the
gluconeogenesis, retain sodium, excrete potassium and stimulates secondary sex traits.
Epinephrine and norepinephrine increases the heart rate, muscle contraction, glycolysis, and
vasoconstrictions. Considering the pancreas glands, somatostatin is considered as growth
hormone inhibiting hormones which regulate and affects neurotransmission. Insulin controls the
anabolism, of the body by degrading the carbohydrate present in the bloodstream. Secretin is the
hormone which stimulates the secretion of the liver as well as pancreas (Hutchinson, Burholt and

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Hamley 2017). Glucagon controls the catabolism by participating in the process of making
carbohydrate when the body requires it the most. Gastrin is a peptide hormone which stimulates
the secretion of the gastric acid by regulating parietal cells and it assists in gastric motility.
Amylin is the hormone which is used controlling the function of glucagon, delays gastric
emptying (Hay et al. 2015). Gastrointestinal hormones regulate the gut mucosal growth for
facilitating the function of the digestive system. Pancreatic polypeptides regulate the function of
the pancreatic secretion activities. Considering ovarian glands and mammy glands, progesterone
and estrogen facilitate female development, maintain pregnancy, implant an egg in the uterus
and development of mammary gland (Berryhill, Trott and Hovey, 2016).Considering hormones
of testis gland, testosterone facilitates male growth and sexual activities in male (Jung et al.
2018)
1.3: bloodstream’s role in the distribution of hormones to target organs:
There are different kinds of hormone such as water-soluble hormones and lipid soluble
hormones traveling through the bloodstream to work on the targeted organ and regulate the
associated function of the targeted organ. Water soluble hormones travel in the blood dissolved
in the plasma (Melmed et al. 2019). The plasma diffuses from the capillaries into tissue fluids
which further travels to target cells. The lipid soluble hormones such as steroid and thyroid
hormone bind to the plasma proteins by traveling through the blood. By binding to the plasma
protein they travel to the targeted cells (Melmed et al. 2019). Majority of the lipid soluble
hormones are bound to the plasma protein of blood, only very few amount of hormones are
freely traveling in the blood. They are highly hydrophobic in nature and hence they are bound to
plasma protein to avoid the contact of water. It is a crucial factor to note that majority of the lipid
soluble proteins are inactive in nature and partially water-soluble which enable them to travel