ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Terminology
Endocrine System =
internal organs that secrete hormones
Hormones
=
‘chemical messengers’ responsible for specific
regulatory effects on organs
Glands
=
an organ specialised to secrete substance (hormones)
for further use in the body, or for elimination
Homeostasis
=
body equilibrium or stable internal environment of
body
Hyper secretion
=
over secretion of a substance
Hypo secretion
=
under secretion of a substance
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Main Endocrine Glands, hormones they secrete and the effects
of hyper/hypo secretion of hormones
1.
Pituitary (‘Master Gland’ as it controls activity of many other glands) – 2
lobes
a.
Oxytocin – Promotes contraction of uterine muscle and of lactating
cells in breast in later pregnancy (posterior lobe)
b. Antidiuretic Hormone (ADH or vasopressin) – Regulates water
absorption by kidneys (posterior lobe)
- Hyper secretion = oedema
- Hypo secretion = water diabetes
c.
Prolactin – Promotes milk production (anterior lobe)
d. Human Growth Hormone (HGH) – Regulates human growth in all body
systems (anterior lobe)
- Hyper secretion = gigantism/abnormal growth
- Hypo secretion = dwarfism
e. Thyroid Stimulating Hormone (TSH) – controls thyroid gland
(anterior lobe)
f.
Adrenocorticotrophin Hormone (ACTH) – controls adrenal cortex
(anterior lobe)
g.
Lutenising Hormone (LH) – stimulates ovaries to discharge mature
ovum. Promotes formation of the corpus lutenum (uterus wall) that
produces Progesterone (prepares uterus for fertilised ovum)
(anterior lobe)
h. Follicle Stimulating Hormone (FSH) – stimulates ovaries to produce
Oestrogen (female hormone) and to ovulate (anterior lobe)
i.
Interstitial Cell Stimulating Hormone (ICH) - stimulates ovulation in
females and stimulates androgen release in males
j.
Melanin Stimulating Hormone (MSH) – stimulates production of
melanin in basal layer of skin in reaction to sunlight (anterior lobe)
- Hyper secretion = darkening of the skin
- Hypo secretion = vitiligo, albinism (see skin handout)
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
2.
Thyroid Gland (body’s metabolic hormone)
a.
Thyroxin – produced in response to TSH (Pituitary). Stimulates basic
metabolic rate (BMR) = rate at which our cells use oxygen.
Regulates carbohydrate, protein and lipid metabolism, functioning of
nervous and cardio vascular systems and female reproductive cycle.
- Hyper secretion = Graves Disease (Thyrotoxicosis) – over active BMR
- Hypo secretion = Cretinism, Goitre – under active BMR
b. Triiodothyronine – very similar function to Thyroxin, yet containing
less amino acids
c.
3.
Parathyroid Glands
a.
4.
Parathormone – maintains calcium level in plasma, stimulates calcium
reabsorption in kidney and activates Vitamin D. This is necessary for
muscle contraction, blood clotting and nerve impulse transmission.
- Hyper secretion = soft bones (hyper-parathyroidism)
- Hypo secretion = low calcium levels; spasms in muscles
Thymus
a.
5.
Calcitonin – decreases blood calcium levels by causing calcium to
deposit in bones
- Hyper secretion = lowering of blood calcium level
T.Lymphocytes (Thymosin) – Lymphocytes originate from
haemoblasts (red blood cells in bone marrow). Some enter Thymus
and develop into T.Lymphocytes (defence cells against disease).
Thymosin triggers their secretion.
Dysfunction = Addison’s Disease and decreased immunity
Pineal
a.
Melatonin – secretion is affected by the amount of light entering
the eye. Associated with ‘body rhythms’ and inhibition of growth and
development of sex organs before puberty
b. Seratonin – ‘mood hormone’. Related to intestinal secretion and
contraction of smooth muscle and involved in blood clotting process.
- Hypo secretion = depression, S.A.D.
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
6.
Islets of Langerhans
The endocrine cells of the pancreas are called the Islets of Langerhans.
a.
Insulin - a hormone released by the pancreas that decreases raised
levels of glucose (sugar) in the blood to return the body to
homeostasis
Dysfunction = Hypo production of insulin results in type 1 diabetes,
leading to disturbed metabolism
b. Glucagon - A hormone produced by the pancreas that increases the
level of glucose (sugar) in the blood to return the body to
homeostasis
c.
7.
Glycogen - Converted glucose for storage. Glycogen plays a role in
controlling blood sugar levels.
Adrenal Glands – composed of 2 parts: Cortex (outer) and Medulla (inner)
Cortex
a.
Corticosteroids – produced from cholesterol and in response to
ACTH (Pituitary) and have a widespread effect on the body –
regulate carbohydrate metabolism, promote formation and storage
of glycogen and promote sodium (salt) and water reabsorption from
renal system.
Hyper secretion – Cushing’s Syndrome, hypertension, diabetes
b. Glucocorticoids (cortisone) – promote normal cell metabolism when
the body is under long term stress (i.e. increases blood glucose
levels)
c.
Sex hormones (Androgens and Estrogens) – sexual development and
maturity
Malfunction = excessive hair and lack of periods in women, breasts
grow in men
d. Mineralocorticoids - Hormones produced by the adrenal gland which
regulate the amounts of sodium, potassium, and chloride in the blood
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Medulla
a.
Adrenaline – ‘fight or flight’ – constriction of surface blood vessels,
dilating of blood vessels of muscles, heart and brain, converts
glycogen to glucose, increases metabolic rate, dilated pupils, dilated
bronchioles allowing increased air intake = ‘ready for action’,
whichever
b. Noradrenalin – balancer to above, maintenance of blood pressure
Adrenalin and Noradrenalin – the ‘stress’ hormones released in
response to stimulation of the sympathetic nervous system in
reaction to threat
8.
Ovaries
a.
Oestrogen – stimulated by FSH (Pituitary) and responsible for
female sexual characteristics
-Hypo secretion = Stein-Leventhal Syndrome or Polycistic Ovarian
Syndrome (PCOS) (irregular cycles, ovarian cysts, infertility,
enlarged ovaries)
b. Progesterone – prepares uterus for fertilised ovum
Dysfunction = infertility
9.
Testes
a.
Testosterone – male sex hormone, responsible for male sexual
characteristics
-Hyper secretion in women = virilism, hirsutism and Amenorrhoea
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Effects of Hormones During Puberty, Pregnancy and Menopause
Puberty in Females
The age of internal reproductive organ maturity is called menarche.
Ovaries are stimulated by the Pituitary to release FSH and LH. This causes:

Uterus, fallopian tubes and ovaries to become functional

Ovulation and menstrual cycles to begin

Growth of pubic and auxiliary hair

Breast development

Increase of rate of growth in height and in hip width

Increase in fat deposits at hip and breast
Puberty in Males
Pituitary gland releases LH which stimulates cells of the testes to increase
the production of testosterone, which influences the development of:

Growth of muscle and bone

Enlargement of larynx (voice breaks)

Growth of hair on face, chest abdomen and pubis

Enlargement of penis, scrotum and prostate gland

Maturation of and production of spermatozoa

Skin thickens and becomes oily
Pregnancy
If, during the menstrual cycle, the ovum is fertilised and the lining of the
uterus (endometrium) does not break down, the fertilised zygote (egg)
travels to the uterus and becomes embedded in the wall and produces the
hormone Human Chorionic Gonadtrophin (HCG) which is similar to LH. HCG
keeps the lining of the uterus intact, thus enabling it to secrete
progesterone for the first 3 – 4 months of the pregnancy so that no more
eggs are produced. During this time also, the placenta develops and produces
oestrogen, progesterone and gonadtrophins (control sexual development).
Also, during pregnancy, influenced by oestrogen and progesterone increases,
breast size increases and after the birth, the hormones Prolactin and
Oxytocin are produced (Pituitary) to produce milk
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Menopause (climacteric)
When a woman’s egg supply is exhausted she enters this phase, and during
this time the hormonal changes of puberty are reversed.

Ovaries are less responsive to FSH and LH

Ovulation and cycle becomes irregular, finally ceasing both due to the
reduced production of oestrogen and progesterone
As a result, the following may occur:

Flushing, palpitations due to unpredictable vasodilation

Breast shrinkage

Sparse pubic hair, atrophy of sex organs

Mood changes

Skin thinning

Loss of bone mass, possibly leading to osteoporosis

Increase in blood cholesterol levels
The Menstrual Cycle
Occurs in women every 26-30 days throughout childbearing years
(approximately 36 years).
Cycle = a series of changes that occur concurrently in ovaries and uterine
walls, stimulated by changes in blood concentrations of hormones LHRH
(Lutenising Hormone Releasing Hormones) that stimulated Pituitary to
release FSH and LH.
The Hypothalamus responds to these blood level changes of oestrogen and
progesterone. It is depressed by high levels and stimulated when they are
low.
HRT (Hormone Replacement Therapy)
Designed to replace the hormones lost during the decline in function of the
ovaries = oestrogen and progesterone.
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Effects of ‘Stress’ Upon the Endocrine System

The ‘adrenalin rush’ = fight or flight
As already stated under Adrenal Glands

Modern living stress can also bring about amenorrhoea in women (periods
cease prematurely) and lowered sperm production in men
Interrelationship of Endocrine System with…
1.
Nervous System = Together they work to achieve Homeostasis.
2. Circulatory System = Hormones are carried around the body in our blood.
3. Digestive System = Hormones are needed in the stomach, intestines and
pancreas for digestion to occur.
4. Reproductive System = Hormones control the system’s development and
pace.
5. Skin = Melanocytes in the basal layer produce Melanin once the
Melanocyte-stimulating hormone is stimulated by the sun, to protect us.
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
Cause/Effect of diseases/disorders
1.
Addison’s Syndrome
Hypo secretion of all adrenal hormones. Results in muscle weakness,
gastric problems, increased pigmentation of the skin, tiredness, mental
confusion, etc.
2. Amenorrhoea
Premature cessation of menstrual cycle.
Dysfunction of testosterone secretion. Women do have a small amount
usually, but if too much is produced periods can cease.
Or, due to stress, anaemia or rapid weight loss.
3. Cushing’s Syndrome
Adrenal glands over secrete cortisol, resulting in painful facial, neck and
body distortion, muscle wastage, suppression of growth hormones,
osteoporosis and Kyphosis, depressed immune system, psychotic
depression, peptic ulcers, etc.
4. Pre-Menstrual Syndrome
Due to over activity of hormones, at onset of menstruation mood changes
can occur, tenderness to breasts, bloating
5. Polycystic Ovarian Syndrome
Over secretion of female sex hormones.
Resulting in irregular periods, ovarian cysts, infertility, obesity.
6. Diabetes Mellitus
The inability of the body to produce or respond to insulin (which allows
the body to use glucose/sugar) properly. The two major forms of the
disease are juvenile (Type 1) and adult-onset (Type 2) diabetes. Diabetics
have an increased risk of coronary heart disease and stroke.
7. Diabetes Insipidus
An uncommon condition caused by inability of the kidneys to conserve
water as they filter waste from the blood, leading to increased urination
and excess thirst.
8. Endometriosis
Growth of endometrial tissue outside the uterus. The tissue may attach
itself to the reproductive organs or to other organs in the abdominal
cavity. Each month the endometrial tissue inbreeds with the onset of
menses. The resultant irritation causes adhesions in the abdominal cavity
and in the fallopian tubes. Endometriosis may also interfere with
ovulation and with the implantation of the embryo.
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ITEC Anatomy, Physiology & Holistic Massage Course
Endocrine System
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