Download The Endocrine System - healingenergies-at

The Endocrine System









The physical human body is made up of a multitude of different kinds of cells
but can only grow and develop and function properly if there is co-ordinated
interaction between these various kinds of cells. One of the ways in which
cells communicate with each other is by chemical signals. The chemical
signals are carried in the blood stream to the cells which they act upon by
molecules called hormones. These hormones are produced by a number of
glands and other body organs which collectively form the endocrine system.
Hormones can have powerful effects on the body so their production must be
in balance for the body to function properly and without adverse effect.
Excessive production of hormones may be harmful.
Some hormones exercise control over the other glands or muscles. Others
control or co-ordinate body activities such as growth and development.
Some glands, e.g. the thyroid gland and the adrenal glands are purely
endocrine glands, producing only hormones. Some other glands such as the
pancreas produce both external secretions and hormones.
Some of the glands do not function or produce hormones throughout the
complete lifespan of a human. For example, the thymus gland tends to be
active only during the early years whilst the reproductive organs of a woman
are only active between the onset of puberty and the onset of the menopause.
The effect of some hormones is short term, whilst the effect of others is long
term. For example, the hormone adrenaline has a short term effect whilst the
hormone thyroxine creates permanent effects in the body.
When hormones have performed their functions, they are transported in the
blood stream to the liver where they are eventually destroyed.
The pituitary gland plays an important role as a ‘controller’ or ‘master’ gland.
It is divided into three sections, the anterior lobe, the intermediate lobe and the
posterior lobe. These secrete hormones which control the activities of
particular glands.
There are two main types of hormones – (Type 1) proteins, peptides, and
modified amino acids and (Type 2) steroids. Both types work by finding
protein based receptor material in the appropriate part of the body which is
able to respond to the presence of the hormone. The binding of the hormones
to receptor material initiates a sequence of intracellular signals that may alter
the behaviour of the cell or stimulate (or repress) gene expression in the cell
nucleus. The mineral calcium is an important facilitator of the interaction
between the hormones and receptor material.
Some tables follow as examples to indicate the effect of some of the hormones
produced by the body and of their over- or under-production. After these is a longer
list (source Wikipedia) of hormones produced within the endocrine system. The key
learning objective here is to gain a simple conceptual understanding of hormones in
the human endocrine system. Once you understand the concept, you can research
further any possible link between hormonal imbalance and health conditions that your
clients might have. After the list are diagrams which show the location of the major
endocrine glands and diagrams showing the hypothalamus and pituitary glands in the
head.
www.healingenergies-at-londonwest.com
Examples of hormones
ENDOCRINE GLAND : Thyroid
Hormone produced : Thyroxine (contains iodine)
Trigger for the secretion of hormone : Reception of trigger hormone from pituitary
gland
Effects of hormone secretion : The regulation of the metabolic rate of the body,
ensuring that normal physical growth and normal mental growth takes place.
Effects of insufficient hormone secretion : Lack of physical and mental
development in a child. In extreme cases, cretinism can occur. Later in adult life,
thyroxine deficiency can result in an overweight sluggish physical body and simple
mindedness.
Effects of excessive hormone secretion : An unusually high metabolic rate. This can
result in a person having a lack of attention, difficulty concentrating, irritability,
restlessness and nervousness. The physical body might be very thin.
ENDOCRINE GLAND : Pancreas
Hormone produced : Insulin
Trigger for the secretion of hormone : Increased concentration of glucose in the
blood.
Effects of hormone secretion : Enables body cells to oxidise glucose to produce
energy in the cellular respiratory process. Excessive glucose is converted to glycogen,
enabling it to be stored in the liver and the muscles. The overall effect is to enable the
body to manage the glucose levels in the blood.
Effects of insufficient hormone secretion : Low insulin levels mean that the
transport of glucose across cell membranes is inhibited, and normal cellular
respiratory processes are thereby affected. Appetite can be affected adversely. Long
term low insulin levels can result in chronic hyperglycemia which is linked to
diabetes and resulting medical conditions such as damage to the eyes and nerves and
reduced effectiveness of the kidneys. .
Effects of excessive hormone secretion : Blood glucose levels become too low and
can result in hypoglycemia. Moderate hypoglycemia can result in a general feeling of
not being well due to body functions being affected. Severe hypoglycemia can result
in coma or in extreme cases death.
ENDOCRINE GLAND : Adrenal
Hormone produced : Adrenaline
Trigger for the secretion of hormone : A situation of fear, anger, anxiety
Effects of hormone secretion : Adrenaline has the overall effect of supporting a
person when facing a fight or flight emergency situation by increasing the amount of
energy available through the following. It has the effect of increasing the rate of
heartbeat and increasing blood pressure so that oxygen and glucose are carried faster
to the muscles. It causes constriction of the blood arteries in the skin so that more
blood flows to the muscles. It influences the conversion of stored glycogen to glucose
www.healingenergies-at-londonwest.com
to fuel cell activity. It causes an increase in the metabolic rate so that more energy can
be released in the cellular respiration process.
ENDOCRINE GLAND : Testes (testicles) in males
Hormone produced : Testosterone
Trigger for the secretion of hormone : Reception of trigger hormone from pituitary
gland
Effects of hormone secretion : It initiates and controls the development of the male
sex organs and secondary male sexual characteristics such as deepening of the voice
and the growth of facial hair.
Effects of insufficient hormone secretion : The full male sexual characteristics do
not develop fully.
Effects of excessive hormone secretion : Excessive masculinity.
ENDOCRINE GLAND : Ovaries in females.
Hormone produced : Oestrogen
Trigger for the secretion of hormone : Reception of trigger hormone from pituitary
gland
Effects of hormone secretion : It initiates and controls the development of the
female sex organs and secondary female sexual characteristics such as the menstrual
cycle.
Effects of insufficient hormone secretion : The full female sexual characteristics do
not develop fully.
Effects of excessive hormone secretion : Excessive femininity.
ENDOCRINE GLAND : Ovaries in females.
Hormone produced : Progesterone
Trigger for the secretion of hormone : Reception of trigger hormone from pituitary
gland
Effects of hormone secretion : The preparation and enlargement of the wall of the
uterus to receive a fertilized egg at the onset of pregnancy and to provide a home for
the foetus during the pregnancy. The enlargement of the mammary glands so that milk
can be produced.
Effects of insufficient hormone secretion : Risk of failure of the pregnancy as by
miscarriage.
Effects of excessive hormone secretion : The process of giving birth might not
happen at the correct time and a caesarean section might be needed.
ENDOCRINE GLAND : Pituitary (Anterior Lobe)
Hormone produced : Thyrotropin (Thyroid Stimulating Hormone)
Trigger for the secretion of hormone : Secretion stimulated by the reception of
thyrotropin releasing hormone (TRH) from the hypothalamus gland. Secretion
inhibited by the reception of somatostatin from the hypothalamus gland.
Effects of hormone secretion : Stimulates the thyroid gland to secret its hormone
thyroxine which affects the metabolism within the body.
Effects of insufficient hormone secretion : Inadequate stimulation of the thyroid
gland and therefore upon basic body metabolic processes. Depression is sometimes
www.healingenergies-at-londonwest.com
linked to insufficient levels of thyrotropin.
Effects of excessive hormone secretion : Over stimulation of the thyroid gland with
the body metabolic processes working in ‘overdrive’ and not at a rate that is matched
to body requirements. Resulting symptoms can include low weight combined with a
ravenous appetite, hyperactivity, irritability, tiredness and apathy, and problems with
body temperature and sensitivity to heat.
ENDOCRINE GLAND : Pituitary (Anterior Lobe)
Hormone produced : Prolactin
Trigger for the secretion of hormone : Secretion stimulated by the reception of
thyrotropin releasing hormone (TRH) from the hypothalamus gland.
Effects of hormone secretion : It helps to prepare the breasts of a pregnant woman
for the production of milk.
Effects of insufficient hormone secretion : Inadequate levels of milk production.
Effects of excessive hormone secretion : Spontaneous flow of milk from the breasts
when a baby is not taking milk.
ENDOCRINE GLAND : Pituitary (Anterior Lobe)
Hormone produced : Somatotropin. Also known as Growth Hormone
Trigger for the secretion of hormone : Secretion stimulated by the reception of
Growth Hormone Releasing Hormone (GHRH) from the hypothalamus gland.
Effects of hormone secretion : Growth Hormone binds to receptors on the surface
of liver cells which stimulates them to release into the blood stream another hormone
called Somatodin. Somatodin acts directly on the ends of the long bones in the body
and influences their growth.
Effects of insufficient hormone secretion : Long bone growth is stunted and the
long bones are too short for the body, resulting in shortness. In extreme cases,
dwarfism can result.
Effects of excessive hormone secretion : Long bone growth is excessive and the
long bones are too long for the body. In extreme cases, gigantism can result.
ENDOCRINE GLAND : Pituitary (Posterior Lobe)
Hormone produced : Antidiuretic Hormone (ADH)
Effects of hormone secretion : ADH works on the collecting ducts of the kidneys so
that water may be reabsorbed into the blood stream, thereby reducing the volume of
urine created. The overall effect is to ensure adequate fluid retention within the body.
Effects of insufficient hormone secretion : Excessive urination. This results in great
thirst and the need to drink high volumes of fluids to avoid dehydration.
Effects of excessive hormone secretion : Inadequate urination with subsequent
adverse symptoms such as electrolyte disturbance and water intoxication (poisoning).
Water intoxication is a disturbance in brain function that occurs when the normal
balance of electrolytes in the body is pushed beyond safe limits and in extreme cases
can cause death.
www.healingenergies-at-londonwest.com
The endocrine system and the hormones secreted

The Hypothalamus produces
o Thyrotropin-releasing hormone (TRH)
o Gonadotropin-releasing hormone (GnRH)
o Growth hormone-releasing hormone (GHRH)
o Corticotropin-releasing hormone (CRH)
o Vasopressin
o Somatostatin (SS; also GHIH, growth hormone-inhibiting hormone)
o Prolactin inhibiting hormone or PIH or Dopamine (DA)
o Prolactin releasing hormone

The Pineal Body produces
o Melatonin

The Pituitary Gland (hypophysis) produces
o Anterior pituitary lobe (adenohypophysis)
 Growth hormone (GH)
 Prolactin (PRL)
 Adrenocorticotropic hormone (ACTH, corticotropin)
 Lipotropin
 Thyroid-stimulating hormone (TSH, thyrotropin)
 Follicle-stimulating hormone (FSH)
 Luteinizing hormone (LH)
o Posterior pituitary lobe (neurohypophysis)
 Oxytocin
 Vasopressin (AVP; also ADH, antidiuretic hormone)
o Intermediate pituitary lobe (pars intermedia)
 Melanocyte-stimulating hormone (MSH)

The Thyroid Gland produces
o Triiodothyronine (T3), the potent form of thyroid hormone
o Thyroxine (T4), Also known as tetraiodothyronine, it is a less active
form of thyroid hormone
o Calcitonin

The Parathyroid Gland produces
o Parathyroid hormone (PTH)

The Heart produces
o Atrial-natriuretic peptide (ANP)
o Brain natriuretic peptide (BNP)
o Adenosine

Striated muscle produces
o Thrombopoietin
www.healingenergies-at-londonwest.com

The Skin produces
o Vitamin D3 (calciferol)

Adipose (or fatty) tissue produces
o Leptin
o Estrogens (mainly Estrone)

The Stomach produces
o Gastrin
o Ghrelin
o Neuropeptide Y (NPY)
o Secretin
o Somatostatin
o Histamine
o Endothelin

The Duodenum produces
o Cholecystokinin

The Liver produces
o Insulin-like growth factor (IGF)
o Angiotensinogen
o Thrombopoietin

The Pancreas produces
o Insulin
o Glucagon
o Somatostatin
o Pancreatic polypeptide

The Kidney produces
o Renin
o Erythropoietin (EPO)
o Calcitriol (the active form of vitamin D3)
o Thrombopoietin

The Adrenal Glands
o Adrenal cortex produces
 Glucocorticoids (chiefly cortisol)
 Mineralocorticoids (chiefly aldosterone)
 Androgens (including DHEA and testosterone)
o Adrenal medulla produces
 Adrenaline (epinephrine)
 Noradrenaline (norepinephrine)
 Dopamine
 Enkephalin
www.healingenergies-at-londonwest.com

The Testes
o Androgens (chiefly testosterone)
o Estradiol
o Inhibin

The Ovaries
o Progesterone
o Androstenedione
o Estrogens (mainly estradiol)
o Inhibin

The Placenta (when a woman is pregnant)
o Progesterone
o Estrogens (mainly Estriol)
o Human chorionic gonadotropin (HCG)
o Human placental lactogen (HPL)
o Inhibin

The Uterus (when a woman is pregnant)
o Prolactin (PRL)
o Relaxin
www.healingenergies-at-londonwest.com
www.healingenergies-at-londonwest.com
The Exocrine System
The Exocrine system is another group of body glands and organs that release
hormones. One of the differences with the endocrine system is that the hormones are
not released directly into the blood stream. The primary exocrine system organs are
the salivary glands, stomach, liver, pancreas, mammary glands and sweat glands.
Within the Exocrine system, serous cells secrete enzymes. We look at the importance
of enzymes as catalysts for the chemical reactions that take place within the body later
in this Chapter.
Mucous cells secrete mucus. Mucus performs different functions depending upon
where it is found in the body. In the respiratory tract, mucus helps to trap fine dust
and other particles. In the digestive tract, it can act as lubricant for food passing over
membrane surfaces such as going down the throat.
Some parts of the body such as the salivary glands secrete both enzymes and mucus.
www.healingenergies-at-londonwest.com
The Skin (Integumentary System)





The skin is the largest organ in the body.
Whilst the skeletal structure provides the support framework for the physical
body, the skin holds all the body organs and tissues within the physical form.
The skin has a number of other functions including giving some physical
protection to body tissue, helping to regulate the temperature of the body (by
releasing heat, sweating, shivering, holding the body hair, and by being linked
to the body metabolism), excretion of waste products (water, salts, various
organic compounds), the synthesis of Vitamin D (from exposure to sunlight),
and providing the sensory mechanisms of feeling by touch. The skin provides
a physical barrier to body fluids being lost from the physical body.
The primary cellular structure of the skin is the dermis. New cells are
produced at the bottom of the dermis. Older cells move towards the outer
surface of the skin where they die. The epidermis is a layer of dead cells which
are released physically from the body their useful life.
The epidermis contains a pigment called melanin which protects the DNA in
the skin cells from ultra-violet radiation. Excessive exposure to sunlight can
www.healingenergies-at-londonwest.com




overpower the melanin and affect the DNA in skin cells, leading to skin
cancer.
The blood system brings nutrients to the cells in the dermis and takes away
nutritional waste products.
The sweat glands are found within the dermis. They help to release waste
products into the sweat and are part of the body heat regulation process. The
evaporation of sweat released to the surface of the skin has the effect of
cooling the body.
The skin contains the hair follicles, from which hair grows.
The skin contains nerve endings that can react to heat and cold, and which can
feel physical pressure and damage to tissue.
www.healingenergies-at-londonwest.com