BTEC Level 3 90 Credit Diploma in Applied Science
Samuel James
Unit 12 – Physiology of Human Reg & Reproduction
Endocrine System
The endocrine system involves all glands and also organs which are directly involved in secretion of
hormones into bodily fluids. These hormones are essential for normal bodily function and are used
in the regulation of growth, sexual function and multiple other areas. An example of this regulation
is the pituitary gland which releases a hormone called thyroid-stimulating hormone (TSH), when
levels of thyroxine drop below a certain level within the blood. This release of TSH, causes the
thyroid to produce more thyroxin and therefore increase it back to normal levels. The glands within
the endocrine system are known as ductless glands due to the reason that they have no ducts. Non-
endocrine glands exist is the system such as the pancreas are not referred to as ductless glands as
they have use ducts to secrete their hormones. (WebMD, 2018)
Hormones are used within the body as chemical messengers which are transported around the body
via the bloodstream to both tissues and organs. These are essential to normal bodily function within
males and females and an imbalance of these can cause negative effects. The reason negative effects
can occur with a hormonal imbalance is due to the huge part that hormones play in the body’s
chemistry. Within the body, endocrine cells are responsible for the secretion of 50 different
hormones. (Hormone, 2018)
The endocrine system is composed of; the pituitary gland, thyroid gland, parathyroid gland,
pancreas, adrenal gland, ovaries (females only) and testes (males only). The pituitary gland is called
the ‘master gland’ due to its huge effect on the endocrine system and is located at the base of the
brain. This name is given to the pituitary gland due to most glands in the body being controlled by it,
except for some which operate on their own. The pituitary gland controls hormones responsible for
growth ranging to the production of sperm from the testes. With the multiple functions the pituitary
gland provides, this means that many disorders can occur from this gland solely. An example of a
disorder which is directly caused from the pituitary gland is giantism. Giantism occurs when excess
secretion of growth hormone occurs. This can be due a tumour pressing down on the pituitary gland
for example. Although the pituitary gland controls the majority of the glands, it is also controlled by
a region in the brain called the hypothalamus. The hypothalamus produces the hormones;
Adrenocorticotropic hormone, thyrotropin-release hormone, growth hormone-releasing hormone
and oxytocin. (WebMD, 2018)
The hypothalamus is located in the base of the brain and provides several functions within the body
that are vital. Some of these functions include; the release of hormones, regulation of emotional
behaviour, regulation of body temperature and the managing of sexual behaviour. The
hypothalamus is composed of three regions, the anterior, middle and posterior region, which all
have different roles. The anterior region of the hypothalamus produces multiple hormones such as
CRH, TRH and GnRH. The middle region of the hypothalamus contains both the ventromedial and
arcuate nuclei which are used in the release of growth-hormone and control of appetite. The
posterior region of the hypothalamus is involved in the regulation of body temperature. (Schullman,
2018)
The thyroid gland is located within the upper part of the neck and is responsible for the secretion of
thyroxine (T4), the hormone I mentioned previously. Thyroxine is responsible for both the
development of physical and mental ability and can have negative affects if the levels are either
decreased or increased over normal levels. If thyroxine levels are below healthy, physical changes
can be observed such as obesity and thick skin. This is also one of the reasons the pituitary gland is
known as the master gland due to it releasing TSH, when levels of thyroxine drop. This mechanism is
Samuel James
Unit 12 – Physiology of Human Reg & Reproduction
Endocrine System
The endocrine system involves all glands and also organs which are directly involved in secretion of
hormones into bodily fluids. These hormones are essential for normal bodily function and are used
in the regulation of growth, sexual function and multiple other areas. An example of this regulation
is the pituitary gland which releases a hormone called thyroid-stimulating hormone (TSH), when
levels of thyroxine drop below a certain level within the blood. This release of TSH, causes the
thyroid to produce more thyroxin and therefore increase it back to normal levels. The glands within
the endocrine system are known as ductless glands due to the reason that they have no ducts. Non-
endocrine glands exist is the system such as the pancreas are not referred to as ductless glands as
they have use ducts to secrete their hormones. (WebMD, 2018)
Hormones are used within the body as chemical messengers which are transported around the body
via the bloodstream to both tissues and organs. These are essential to normal bodily function within
males and females and an imbalance of these can cause negative effects. The reason negative effects
can occur with a hormonal imbalance is due to the huge part that hormones play in the body’s
chemistry. Within the body, endocrine cells are responsible for the secretion of 50 different
hormones. (Hormone, 2018)
The endocrine system is composed of; the pituitary gland, thyroid gland, parathyroid gland,
pancreas, adrenal gland, ovaries (females only) and testes (males only). The pituitary gland is called
the ‘master gland’ due to its huge effect on the endocrine system and is located at the base of the
brain. This name is given to the pituitary gland due to most glands in the body being controlled by it,
except for some which operate on their own. The pituitary gland controls hormones responsible for
growth ranging to the production of sperm from the testes. With the multiple functions the pituitary
gland provides, this means that many disorders can occur from this gland solely. An example of a
disorder which is directly caused from the pituitary gland is giantism. Giantism occurs when excess
secretion of growth hormone occurs. This can be due a tumour pressing down on the pituitary gland
for example. Although the pituitary gland controls the majority of the glands, it is also controlled by
a region in the brain called the hypothalamus. The hypothalamus produces the hormones;
Adrenocorticotropic hormone, thyrotropin-release hormone, growth hormone-releasing hormone
and oxytocin. (WebMD, 2018)
The hypothalamus is located in the base of the brain and provides several functions within the body
that are vital. Some of these functions include; the release of hormones, regulation of emotional
behaviour, regulation of body temperature and the managing of sexual behaviour. The
hypothalamus is composed of three regions, the anterior, middle and posterior region, which all
have different roles. The anterior region of the hypothalamus produces multiple hormones such as
CRH, TRH and GnRH. The middle region of the hypothalamus contains both the ventromedial and
arcuate nuclei which are used in the release of growth-hormone and control of appetite. The
posterior region of the hypothalamus is involved in the regulation of body temperature. (Schullman,
2018)
The thyroid gland is located within the upper part of the neck and is responsible for the secretion of
thyroxine (T4), the hormone I mentioned previously. Thyroxine is responsible for both the
development of physical and mental ability and can have negative affects if the levels are either
decreased or increased over normal levels. If thyroxine levels are below healthy, physical changes
can be observed such as obesity and thick skin. This is also one of the reasons the pituitary gland is
known as the master gland due to it releasing TSH, when levels of thyroxine drop. This mechanism is
