The Endocrine System

Pineal Gland

• 1. Pineal gland and melatonin

If you have a sleep disorder, it could be a sign that your pineal gland is not producing
the correct amount of melatonin. Some alternative medicine practitioners believe you
can detox and activate your pineal gland to improve sleep and open your third eye.
There is no scientific research to support these claims, though.

One way to control the melatonin in your body is to use melatonin supplements.
These will typically make you feel tired. They may help you realign your circadian
rhythm if you’ve been traveling to a different time zone or working a night shift.
Supplements may also help you fall asleep faster.
• 2. Pineal gland and cardiovascular health

A looked at past research on the connection between melatonin and cardiovascular health. Researchers found

evidence that melatonin produced by the pineal gland can have a positive impact on your heart and blood

pressure. They concluded that melatonin may be used to treat cardiovascular disease, though more research is

needed.

• 3. Pineal gland and female hormones

There’s some evidence that light exposure and related melatonin levels may have an effect on a woman’s

menstrual cycle. Reduced amounts of melatonin may also play a role in the development of irregular menstrual

cycles. Studies are limited and often dated, so newer research is needed.

• 4. Pineal gland and mood stabilization

The size of your pineal gland may indicate your risk for certain mood disorders. One study suggests that a lower

pineal gland volume may increase your risk of developing schizophrenia and other mood disorders. More research

is needed to better understand the effect of pineal gland volume on mood disorders.
5. Pineal gland and cancer

• Some research suggests that there may be a connection between impaired pineal gland function

and cancer risk. A recent study on rats found evidence that lowering pineal gland function through

overexposure to light led to cellular damage and increased risk for colon cancer.

• Another study found evidence that, when used with traditional treatments, melatonin may improve

the outlook for people with cancer. This may be especially true in people with more advanced

tumors.

• More research is needed to determine how melatonin affects the production and blocking of

tumors. It’s also unclear what dosage may be appropriate as a complementary treatment.
Malfunctions of the pineal gland

• If the pineal gland is impaired, it can lead to a hormone imbalance, which can affect other systems in your body.

For example, sleep patterns are often disrupted if the pineal gland is impaired. This can show up in disorders

such as jet lag and insomnia. Additionally, because melatonin interacts with female hormones, complications

may affect the menstrual cycle and fertility.

• The pineal gland is located near many other important structures, and it interacts heavily with blood and other

fluids. If you develop a pineal gland tumor, it may affect many other things in your body. Some early symptoms

of a tumor include:

• seizures

• disruption in memory

• headaches

• nausea

• damage in vision and other senses

 Pituitary Gland
The two sections of the pituitary gland produce a number of different hormones which act on different target
glands or cells.
Anterior pituitary
Adrenocorticotrophic hormone (ACTH)
Thyroid-stimulating hormone (TSH)
Luteinising hormone (LH)
Follicle-stimulating hormone (FSH)
Prolactin (PRL)
Growth hormone (GH)
Melanocyte-stimulating hormone (MSH)
Posterior pituitary
Anti-diuretic hormone (ADH)
Oxytocin
Functions of pituitary gland hormone
 DISORDERS OF PITUITARY GLAND

HYPERACTIVITY OF ANTERIOR PITUITARY

1. Gigantism
Gigantism is the pituitary disorder characterized by excess growth of the body. The subjects look like
the giants with average height of about 7 to 8 feet.
Causes
Gigantism is due to hypersecretion of GH in childhood or in pre-adult life before the fusion of
epiphysis of bone with shaft. Hypersecretion of GH is because of tumor of acidophil cells in the
anterior pituitary.
2. Acromegaly
Acromegaly is the disorder characterized by the enlargement, thickening and broadening of bones,
particularly in the extremities of the body.
Causes
Acromegaly is due to hypersecretion of GH in adults after the fusion of epiphysis with shaft of the
bone. Hypersecretion of GH is because of tumor of acidophil cells in the anterior pituitary.
3. Acromegalic Gigantism

Acromegalic gigantism is a rare disorder with symptoms of both gigantism and acromegaly.
Hypersecretion of GH in children, before the fusion of epiphysis with shaft of the bones causes
gigantism and if hypersecretion of GH is continued even after the fusion of epiphysis, the symptoms of
acromegaly also appear.

4. Cushing Disease

It is also a rare disease characterized by obesity.

Causes

Cushing disease develops by basophilic adenoma of adenohypophysis. It increases the secretion of

adrenocorticotropic hormone, which in turn stimulates the adrenal cortex to release cortisol. Cushing
disease also develops by hyperplasia or tumor of adrenal cortex. Usually, the disorder due to the
pituitary cause is called Cushing disease and when it is due to the adrenal cause, it is called
Cushing syndrome.
HYPOACTIVITY OF ANTERIOR PITUITARY

1. Dwarfism

Dwarfism is a pituitary disorder in children, characterized by the stunted growth.

Causes
Reduction in GH secretion in infancy or early childhood causes dwarfism. It occurs because of the following
reasons:
i. Tumor of chromophobes: It is a non-functioning tumor, which compresses and destroys the normal cells
secreting GH. It is the most common cause for hyposecretion of GH, leading to dwarfism
ii. Deficiency of GH-releasing hormone secreted by hypothalamus
iii. Deficiency of somatomedin C
iv. Atrophy or degeneration of acidophilic cells in the anterior pituitary.
iv. Panhypopituitarism: In this condition, there is reduction in the secretion of all the hormones of anterior
pituitary gland. This type of dwarfism is associated with other symptoms due to the deficiency of other anterior
pituitary hormones.
2. Acromicria
Acromicria is a rare disease in adults characterized by the atrophy of the extremities of the body.
Causes
Deficiency of GH in adults causes acromicria. The secretion of GH decreases in the following
conditions:
i. Deficiency of GH-releasing hormone from hypothalamus
ii. Atrophy or degeneration of acidophilic cells in the anterior pituitary
iii. Tumor of chromophobes: It is a non-functioning tumor, which compresses and destroys the normal
cells secreting the GH. This is the most common cause for hyposecretion of GH leading to acromicria
iv. Panhypopituitarism: In this condition, there is a reduction in secretion of all the hormones of
anterior pituitary gland. Acromicria is associated with other symptoms due to the deficiency of other
anterior pituitary hormones.
3. Simmond Disease
Simmond disease is a rare pituitary disease. It is also called pituitary cachexia.
Causes
It occurs mostly in panhypopituitarism, i.e. hyposecretion of all the anterior pituitary hormones due to
the atrophy or degeneration of anterior pituitary.
HYPERACTIVITY OF POSTERIOR PITUITARY

Syndrome of Inappropriate Hypersecretion of Antidiuretic Hormone (SIADH)

SIADH is the disease characterized by loss of sodium through urine due to hypersecretion of ADH.

Causes

SIADH occurs due to cerebral tumors, lung tumors and lung cancers because the tumor cells and
cancer cells secrete ADH.

In normal conditions, ADH decreases the urine output by facultative reabsorption of water in distal
convoluted tubule and the collecting duct. Urine that is formed is concentrated with sodium and other
ions. Loss of sodium decreases the osmalarity of plasma, making it hypotonic. Hypotonic plasma
inhibits ADH secretion resulting in restoration of plasma osmolarity.

However, in SIADH, secretion of ADH from tumor or cancer cells is not inhibited by hypotonic plasma.
So there is continuous loss of sodium, resulting in persistent plasma hypotonicity.
HYPOACTIVITY OF POSTERIOR PITUITARY

Diabetes Insipidus

Diabetes insipidus is a posterior pituitary disorder characterized by excess excretion of water through
urine.

Causes

This disorder develops due to the deficiency of ADH, which occurs in the following conditions:

i. Lesion (injury) or degeneration of supraoptic and paraventricular nuclei of hypothalamus

ii. Lesion in hypothalamo-hypophyseal tract

iii. Atrophy of posterior pituitary

iv. Inability of renal tubules to give response to ADH hormone. Such condition is called nephrogenic
diabetes insipidus.
HYPOACTIVITY OF ANTERIOR AND POSTERIOR PITUITARY

Dystrophia Adiposogenitalis

Dystrophia adiposogenitalis is a disease characterized by obesity and hypogonadism, affecting

mainly the adolescent boys. It is also called Fröhlich syndrome or hypothalamic eunuchism.

Causes

Dystrophia adiposogenitalis is due to hypoactivity of both anterior pituitary and posterior pituitary.
Common cause of this disease is the tumor in pituitary gland and hypothalamic regions, concerned
with food intake and gonadal development. Other causes are injury or atrophy of pituitary gland and
genetic inability of hypothalamus to secrete luteinizing hormone-releasing hormone.
 Thyroid Gland
The thyroid gland produces two hormones:

Triiodothyronine (T3), Thyroxine (T4)

Triiodothyronine (T3)

T3 is produced by the thyroid gland as well as in other tissues, via the removal of iodine from

Thyroxine (T4).

Thyroxine (T4)

T4 is also produced by the thyroid gland under the regulation of the pituitary gland and the

hypothalamus. It is secreted into the bloodstream and travels to organs such as the kidneys and liver.

Here, thyroxine is converted into its active form – triiodothyronine.

The Functions of the Thyroid Hormones

Thyroid hormones help with brain development and function It also

helps with muscle control as well as bone health Regulates the
metabolic rate of the body Also regulates the metabolism of fat,
proteins and carbohydrates Thyroid hormones also help with protein
synthesis Increases the body’s sensitivity to catecholamines Essential
for the development and differentiation of cells.
Thyroid Hormone Disorders
• A hormone is a chemical messenger that regulates various functions in the body. Hence, if there is
an imbalance, it can lead to drastic health repercussions.
• Thyrotoxicosis is a condition where there is excess triiodothyronine in the bloodstream
• Inflammation of the thyroid or a benign tumour can result in conditions such as Hyperthyroidism
• Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormone
• Tumours in the pituitary gland can also cause hypothyroidism
• Most cases of hypothyroidism are hereditary and are common among women
• Common symptoms of hypothyroidism include weight gain, depression, constipation and tiredness.
 Parathyroid Gland
Parathyroid hormone is secreted by the four parathyroid glands. These tiny glands are present in the neck behind
thyroid glands. Parathyroid hormone controls and regulates the levels of calcium in the blood and raise their levels
when they are too low. This gland performs its function through its actions on the bones, intestine, and the kidneys.

There are two main types of Parathyroid hormone :

Parathormone.
Calcitonin.
The primary purpose of parathyroid glands is to regulate calcium in the blood in a very strict range between 9.0 and
10.1. Parathyroids also manage the amount of calcium in the bones and determine their strongness. However, these
glands are present next to the thyroid gland and have no concerned function.
Bones – The parathyroid hormone (PTH) stimulates the release of calcium from stores of calcium present in the bones
into the bloodstreams.
Intestine – PTH increases the calcium absorption in the intestine by food through its impacts and effects on the
metabolism of vitamin D.
Kidneys – PTH minimizes the calcium loss in the urine and also stimulates active vitamin D formation in the kidneys.
What if the parathyroid hormone is too high?
Too much Parathyroid hormone causes higher calcium levels in the blood which leads to a disease
known as hyperparathyroidism.

Over secretion of parathyroid hormone can make a person depressed, irritable, insomnia, memory
loss, lack of energy and worried are the most common symptoms in patients with parathyroid
disease.
• It is of three types.
Primary hyperparathyroidism

Secondary hyperparathyroidism
Tertiary hyperparathyroidism
In primary and tertiary hyperparathyroidism, the level of calcium is high due to excessive secretion
of parathyroid hormone.

In secondary hyperparathyroidism, the level of calcium is low due to other factors like kidney disease.
What if the parathyroid hormone is too little?

• A too low parathyroid hormone is a rare condition which results in low levels of calcium in the
blood. It is treated medically with vitamin D analogues and oral calcium supplements.

• When the calcium level falls down people get tingling sensation or cramps in the hand muscles. A
sudden drop can cause an individual to feel weird, foggy like and the brain not functioning
accurately.
 Thymus
The thymus produces several hormones. Most notably, it produces thymosin, which stimulates T cell
production.
Researchers think thymosin acts upon the T cells that have matured in the thymus and prepares them for
use throughout the body.
When T cells mature within the thymus, they are not capable of fighting viruses, bacteria, and foreign
antigens. After the T cells leave the thymus, thymosin ensures they undergo complete maturation. This
makes them capable of performing their duties as part of the immune system and protecting the body from
harm.
Additionally, research indicates that thymosin and other thymic hormones inhibit aging.
Some of these effects involve helping preserve learning and memory capacity as people age.
The thymus also makes hormones that are similar to the hormones other glands in the body produce. They
include:
• Melatonin: a sleep-regulating hormone that comes from the pineal gland
• Insulin: a blood sugar regulating hormone made by the pancreas
• Growth hormone: a growth-regulating hormone from the pituitary gland
• Prolactin: a breast-development hormone from the pituitary gland
Hyperactivity of thymus
Various disorders can enlarge the thymus and cause it to become hyperactive, or overly active. These
may include:

• Tumors of the thymus.

• Cancers of the lymphatic system.
• Myasthenia gravis, an autoimmune disease involving muscle weakness.

• Systemic lupus erythematosus, an autoimmune disease affecting the skin, joints, brain, kidneys,
and other organs.
• Hyperthyroidism, the increased production of thyroid hormones.
Symptoms of a hyperactive thymus include:

• Inflammation of the tonsils.

• Runny nose.
• Enlargement of the lymph nodes.
Small size or atrophy of thymus

Usually, the thymus is largest in babies and young children. However, some preterm
newborns may have a small thymus. This can increase their risk of infections.

When people age, their thymus atrophies, or decreases in size. This raises their likelihood of
developing:

• Cancer

• Viral and bacterial infections

• Autoimmune diseases
 Pancreas
The pancreas contains endocrine cells that are gathered in clusters popularly known as the Pancreatic Islets or
Islets of Langerhans. These cells help in the secretion of primary pancreas gland hormones such as the vasoactive
intestinal peptide, glucagon, Gastrin, Somatostatin, and the insulin hormones. The pancreas hormone functions
include the following
• VIP or Vasoactive Intestinal Peptide Hormone: It aids you in the control of water absorption and secretion
from the intestines by indeed stimulating the islets of Langerhans to release salt and water into the intestine.

• Glucagon: It helps in maintaining normal blood sugar by working in tandem with the insulin although in a
different direction.
• Gastrin Hormone: It helps in digestion as well as stimulating various cells in the stomach in order to produce
acid that aids in digestion.
• Somatostatin Hormone: It is of use whenever the levels of other pancreatic hormones such as the glucagon or
the insulin get too high. This hormone is indeed secreted in order to maintain a balance of the salt and sugar in
the blood.

• Insulin secreted by the pancreas aids in regulating blood sugar by allowing many of the blood cells to absorb
and use blood sugar hence dropping the blood sugar levels.
The following is one of the disorders and diseases associated with the pancreas;
Diabetes Mellitus
Diabetes mellitus is a condition resulting from either the hyposecretion or hypoactivity of insulin.
Diabetes mellitus is of two types; type 1 diabetes mellitus results from the hyposecretion of insulin, whereas
type 2 diabetes mellitus results from the hypoactivity of released insulin.
The lack of insulin in the body results in increased blood glucose levels which then causes excess loss of glucose
via urine.
• Type 1 diabetes mellitus is common among children and is characterized by the immediate onset of
symptoms.
• Type 2 diabetes mellitus, in turn, occurs more in adults and often results in late-onset of symptoms.
Diabetes mellitus can be life-threatening in some conditions, resulting in kidney failure and other serious
conditions. In most cases, however, the condition is chronic and doesn’t result in death.
The treatment of diabetes mellitus is performed in the form of insulin shots which helps maintain the level of
insulin in the body.
 Adrenal Glands
• The adrenal cortex produces three hormones:
1. Mineralocorticoids: the most important of which is aldosterone. This hormone helps to maintain the body’s salt and
water levels which, in turn, regulates blood pressure. Without aldosterone, the kidney loses excessive amounts of salt
(sodium) and, consequently, water, leading to severe dehydration and low blood pressure.

2. Glucocorticoids: predominantly cortisol. This hormone is involved in the response to illness and also helps to regulate
body metabolism. Cortisol stimulates glucose production helping the body to free up the necessary ingredients from
storage (fat and muscle) to make glucose. Cortisol also has significant anti-inflammatory effects.

3. Adrenal androgens: male sex hormones mainly dehydroepiandrosterone (DHEA) and testosterone. All have weak
effects, but play a role in Precocious pubertyearly development of the male sex organs in childhood, and female body
hair during puberty.
• Adrenocorticotropic hormone (ACTH), secreted by the anterior pituitary gland, primarily affects release
of glucocorticoids and adrenal androgens by the adrenal gland and, to a much lesser extent, also
stimulates aldosterone release.
The adrenal medulla produces catecholamines:
• Catecholamines include adrenaline, noradrenaline and small amounts of dopamine – these hormones are responsible
for all the physiological characteristics of the stress response, the so called 'fight or flight' response.
Hyperactivity & Hypoactivity of Adrenal Glands

• Commonly, overproduction of aldosterone can occur, which causes a condition known as hyperaldosteronism

primary hyperaldosteronism. This causes high blood pressure, which is resistant to conventional blood pressure

control tablets, and salt disturbances. High blood pressure may cause headaches and visual problems. Some studies

have suggested that hyperaldosteronism may account for up to 5% of all people with high blood pressure and an

even higher proportion of those who have treatment-resistant hypertension.

• In rare cases, the adrenal glands can become either overactive or underactive. The two main glucocorticoid-related

disorders resulting from these are Cushing's syndrome and Addison's disease, respectively.

• Cushing's syndrome is due to overactive adrenal glands from excessive production of cortisol. The clinical findings

include thinning and bruising of the skin, obesity, diabetes, psychiatric disturbances, high blood pressure, muscle

weakness, osteoporosis, excessive facial hair and irregular periods in women. It can result in growth failure in

children. Patients with cortisol excess also have impaired wound healing and an increased susceptibility to infection.
• Addison's disease or adrenal insufficiency is due to underactive adrenal glands associated with lack of hormones.

Adrenal insufficiency may be acute or chronic. Symptoms of chronic adrenal insufficiency include low blood pressure,

fatigue, weight loss, anorexia, nausea, vomiting, abdominal pain, salt craving and low blood sugar. Skin and mucous

membranes may show increased pigmentation. The loss of secondary sex characteristics is seen only in women with

the disease. Acute adrenal insufficiency is a medical emergency and must be identified and promptly treated. The

hallmarks of acute adrenal insufficiency are circulatory collapse with abdominal pain and low blood sugar.

• Overproduction of androgens is also very rare but may result in excessive hair growth and menstrual period

disturbances.

• Tumours of the adrenal gland are mostly benign and do not result in over or underproduction of adrenal hormones.

Most tumours are discovered incidentally when people undergo scans for various other reasons. Adrenal cancer is

very rare. Adrenal tumours may require surgery if they are large or overproduce hormones.