Hormones

This presentation is about human endocrine system in which all the topics are covered like what is hormones, functions of endocrine system, glands of endocrine system, hormones of endocrine system mechanism of action of hormones, diseases and disorders, counter regulatory hormones, etc.

1. HORMONES
PRESENTED BY–
MD KAMIL
DEPARTMENT OF FOOD SCIENCE & TECHNOLOGY
MAULANA ABUL KALAM AZAD UNIVERSITY OF TECHNOLOGY WEST BENGAL

2. CONTENTS
ACKNOWLEDGEMENT
INTRODUCTION
CLASSIFICATION OF HORMONES
ENDOCRINE SYSTEMS
GLANDS AND HORMONES OF ENDOCRINE
SYSTEM
FUNCTIONS OF ENDOCRINE SYSTEM
DISEASES AND DISORDERS OF ENDOCRINE
SYSTEM
MECHANISM OF HORMONES ACTION
COUNTER REGULATORY HORMONES

3. INTRODUCTION
Hormonesare chemical messengers
that are secreted directly into the
blood, which carries them to organs and
tissues of the body to exert their
functions. There are many types of
hormones that act on different aspects
of bodily functions and processes.
Some of these include:
•Development and growth
•Metabolism of food items
•Sexual function and reproductive
growth and health
•Cognitive function and mood
•Maintenance of body temperature and
thirst

4. CLASSIFICATION OF HORMONES

5. ENDOCRINE SYSTEM
An endocrine systemis a group of ductless
glands where the secretory cells diffuse the
hormones directly into the bloodstream.
Endocrine systems, also referred to as
hormone systems, are found in all mammals,
birds, fish, and many other types of living
organisms. They are made up of:
•Glands located throughout the body;
•Hormones that are made by the glands and
released into the bloodstream or the fluid
surrounding cells; and
•Receptors in various organs and tissues that
recognize and respond to the hormones.

6. Hypothalamus-The hypothalamus
links our endocrine and nervous
systems together. The hypothalamus
drives the endocrine system.
Pituitary gland-The pituitary gland
receives signals from the
hypothalamus. This gland has two
lobes, the posterior and anterior lobes.
The posterior lobe secretes hormones
that are made by the hypothalamus.
The anterior lobe produces its own
hormones, several of which act on
other endocrine glands.
GLANDS OF THE ENDOCRINE SYSTEM

7. Thyroid gland-The thyroid gland is
critical to the healthy development
and maturation of vertebrates and
regulates metabolism.
Adrenal glands-The adrenal gland is
made up of two glands: the cortex and
medulla. These glands produce
hormones in response to stress and
regulate blood pressure, glucose
metabolism, and the body's salt and
water balance.

8. Pancreas-The pancreas is
responsible for producing glucagon
and insulin. Both hormones help
regulate the concentration of
glucose (sugar) in the blood.
Gonads-The male reproductive gonads, or
testes, and female reproductive gonads, or
ovaries, produce steroids that affect growth
and development and also regulate
reproductive cycles and behaviors. The major
categories of gonadal steroids are androgens,
estrogens, and progestins, all of which are
found in both males and females but at
different levels.

9. HORMONES OF THE ENDOCRINE SYSTEM
Hormones of the hypothalamus and pituitary gland –
1.Growth hormone
2.Thyroid-Stimulating hormone
3.Adrenocorticotropic hormone
4.Prolactin
5.Gonadotrophin
6.Oxytocin
7.Antidiuretic hormone
Hormones of the Thyroid Gland-
1.Thyroxine and Tri-iodothyronine
Hormones of the Parathyroid Gland-
1.Parathyroid harmone

10. Pituitary Hormones

11. HORMONES OF THE ENDOCRINE SYSTEM
Hormones of the Adrenal Glands-
1.Mineralocorticoids
2.Glucocorticoids
3.Androgens
4.Epinephrine or Adrenaline and
Norepinephrine or Noradrenaline
Hormones of the Pancreas –
1.Insulin
2.Glucagon
Hormones of the Gonads-
1.Estrogen
2.Progesterone
3.Testosterone

12. FUNCTIONS OF ENDOCRINE SYSTEM
The following are some of the functions of the endocrine system –
1.The most important function of the endocrine system is to maintain the homeostasis of
the body in order to ensure that the biochemical processes of different organs operate in
a stable setting.
2.The hormones of the endocrine system are responsible for balancing the growth and
differentiation of the body cells in order to enable the development of the individual.
3.The endocrine system also enhances the ability of the body to respond to different
stressful internal and external factors.
4.Since the endocrine system consists of the reproductive organs of the body, these are
essential for the development of reproductive behavior in individuals.
5.The endocrine system also performs different integrative functions of balancing the
functions of different systems.
6.Endocrine glands like the thyroid gland are essential for the proper working of different
metabolic processes.
7.The endocrine system remains in a close association with the nervous system and thus
helps in maintaining a balanced relationship.

13. DISEASES AND DISORDERS OF ENDOCRINE SYSTEM
Disorders in the endocrine system occur as a result of hypersecretionor hyposecretionof
the hormones.
A.Diseases and Disorders of the pituitary gland
Hypersecretion
•The hypersecretion of the anterior
pituitary hormones can result in
gigantismand acromegaly.
•These conditions are the result of over
secretion of the growth hormone-
releasing hormone by the hypothalamus.
•Gigantism can be observed in the form of
large bones and increased height.
Acromegalyis characterized by large
extremities as a result of the thickening
of the bones and soft tissues.
Hyposecretion
•The hyposecretion of the pituitary gland
can result in a number of disorders like
ischaemic necrosis, dwarfism, and
Frohlich’s syndrome.
•Dwarfism is a commonly understood
disorder as a result of the deficiency of the
growth hormone in childhood.
•The hyposecretion of the ADH can result in
a rare condition called diabetes insipidus,
characterized by the loss of reabsorption of
water by the renal tubules in the kidney.

14. B. Diseases and disorders of the thyroid gland
Hypersecretion
•The hypersecretion of thyroid hormone is
called hyperthyroidismas a result of increased
levels of T3 and T4.
•Hyperthyroidism can result in a group of
diseases like Grave’s diseaseand toxic nodular
goiter.
•Grave’s disease accounts for about 75% of the
total cases of hyperthyroidism. It is an
autoimmune condition where antibodies
function as the thyroid-stimulating hormone.
•In the toxic nodular goiter, one or more
nodules of the gland are affected by the goiter
and become activated to secrete T3 and T4.
Hyposecretion
•Hyposecretion of thyroid hormone is
called hypothyroidismwhich is often
observed in the form of a simple goiter.
•Simple goiter can be detected by the
enlargement of the thyroid gland due
to the lack of T4 and T3 hormones.
•It also affects different metabolic
processes in the body and might
require surgical removal of the excess
thyroid tissue.

15. C. Diseases and disorders of the adrenal gland
Hypersecretion
•The hypersecretion of the cortisol by
the adrenal cortex results in
Cushing’s syndromecharacterized by
excessive tissue breakdown,
adiposity of the face, diminished
protein synthesis and osteoporosis.
•Similarly, the hypersecretion of
mineralocorticoids like aldosterone
affects kidney functions, resulting in
excessive reabsorption of ions and
water.
Hyposecretion
•The hyposecretion of
glucocorticoids results in reduced
gluconeogenesis, low blood
glucose levels, and muscle
weakness.
•The hyposecretion of the
mineralocorticoids affects the
function of the kidney and causes
blood sodium deficiency and
potassium excess.

16. D. Diseases and disorders of the parathyroid gland
Hypersecretion
•The hypersecretion of
parathyroid hormone results in
increased blood calcium levels
and is often caused as a result of
a benign parathyroid tumor.
•The effects of
hyperparathyroidism include
muscle weakness, anorexia,
constipation, and formation of
renal calculi.
Hyposecretion
•The hyposecretion of
parathormone causes
hypocalcemiabut is much rarer
than hyperparathyroidism.
•It is often observed in the form of
tetany, anxiety, or paraesthesia.
Tetany results in a painful spasm of
the skeletal muscles in the form of
bending inwards of the hands,
arms and feet.

17. E. Diseases and disorders of the pancreatic islets
•Diabetes mellitus is the most common endocrine disorder that often
leads to a varying degree of variation of carbohydrate and fat
metabolism.
•Diabetes mellitus is caused by the complete absence or deficiency of
insulin which affects glucose metabolism.
•Diabetes mellitus is of two types;Type 1 diabetes mellitus and Type 2
diabetes mellitus.
•Type 1 diabetes mellitus occurs in children and can be life-threatening if
the onset is sudden.
•Type 2 diabetes mellitus is the more common form of the disorder
accounting for about 90% of the total cases.
•The onset of Type 2 diabetes mellitus is usually gradual and can go
undetected for a long period of time.

18. Mechanism of Hormone action
Hormones are the chemical messenger secreted directly in the blood stream
by endocrine gland. They are target specific and bind to the specific receptor.
On the basis of binding of hormone on their specific receptor, the mechanism
of hormonal action is categorized into two group. They are –
1.Fixed membrane receptor mechanism
2.Mobile receptor mechanism

19. 1.Fixed membrane receptor mechanism
•The hormones that are protein or amines in compositions such as
Growth hormone, ADH, oxytocin, Insulin, Adrenaline, FSH, TSHetc
shows this mechanism of action.
•These hormones are water soluble and cannot passes through the lipid
membrane and they have their target receptor on the cell membrane.
The receptor are fixed on the cell membrane, so hormone can bind on
the specific receptor.
•Binding of hormone on specific receptor on target cell activates the
enzyme Adenylcyclasein the cell membrane and causes production of
cyclic AMP (cAMP).
•cAMP act as secondary messenger. It diffuse through the cell membrane
and activates (Protein Kinase) various enzymatic reaction to cause
biochemical changes. After the target cell responded to the changes,
cAMP is deactivated by a group of enzyme Phosphodiesterase.

20. Fixed membrane receptor mechanism of hormone action( Eg. FSH)

21. 2.Mobile receptor mechanism
•The lipid soluble hormones such as steroid hormones and Fatty acids
hormones can easily passes through the plasma membrane.
•They have their receptor inside the cell, freely floating in the
cytoplasm. Binding of hormone to the specific receptor activates the
enzymatic activity of the cell for biochemical changes.
•Some hormones (testosterone, progesterone, estrogen, cortisol,
thyroxine) have their receptor localized inside the nucleus, the
hormone-receptor complex are carried inside the nucleus.
•The hormone-receptor complex initiate transcription of the DNA to
form specific mRNA.
•mRNA initiate protein synthesis in the cytoplasm. The protein
(enzyme) causes biochemical changes in the cell.

22. Mobile receptor mechanism of hormone action (Oestrogen)

23. COUNTER REGULATORY HORMONES
A counterregulatory hormone is a hormone that opposes the action of
another.
Glucose Counterregulation
The action of insulin is counterregulated by
glucagon, epinephrine(adrenaline),
norepinephrine(noradrenaline), cortisol, and
growthhormone. These counterregulatory
hormones the term is usually used in the plural
raise the level of glucose in the blood by promoting
glycogenolysis, gluconeogenesis, ketogenesis, and
other catabolic processes. In healthy people,
counterregulatory hormones constitute a principal
defense against hypoglycemia, and levels are
expected to rise as the glucose falls.

24. Effects of counterregulatory hormones on glucose regulation

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