This presentation will give you basic idea about endocrine system and their functions

1. ANIRBAN KUMAR
CLASS-XI-JCM-2

2. •CHEMICAL MESSENGERS
•ENDROCINE GLANDS

3. All the physiological activities are regulated by two
major systems in the body
1. Nervous system
2. Endocrine system
These two system interact with one another and regulate
the body function.
Endocrine system functions by secreting some chemical
substances called chemical messengers or chemical
mediators.

4. •The chemical messengers are mainly secreted from endocrine.
Glands.
•Some chemical messengers are also secreted by nerve ending
and the cells various other tissues also.
•All the chemical messengers carry the message(signal) from
the controlling cells(signaling cells) to the target cells.
•These messenger substances may be the hormones or hormone
like substances.

5. Generally the chemical messengers are classified into two types
1. Classical hormones secreted by endocrine glands.
2. Local hormones secreted from other tissues.
Recent method of classification has four types messengers.
1. Endocrine messengers
2. Neurocrine messengers
3. Paracrine messengers
4. Autocrine messenger

6. Endocrine messengers are the classical hormones, which
are secreted by the endocrine glands and transported by
blood to the target organ or tissues (site of action).

7. 1. Neurocrine messengers are also known as
neurotransmitters, neuro-hormones or neural messengers.
2. Neurotransmitters are released from the nerve ending
3. These chemical mediators carry the message from the nerve
ending to the target cells.
4. Some neurotransmitters move to the distant target cell
through the blood.
5. The neurotransmitters released at the synapses also belongs
to messengers.

8.  The paracrine messengers are the chemical messengers,
which diffuse from the control cells to the target cells through
the interstitial fluid.
Some of these substances directly enter the neighboring target
cells through gap junctions
Such substances are also called juxtacrine messengers

9. Autocrine messengers are the chemical messengers that
control the source cells which secrete them.
These are also called intracellular chemical mediators.
Some of the chemical mediators can act as more than one type
of chemical messengers eg. Noradrenalin and dopamine
function as classical hormones as well as neuro transmitters.
Similarly histamine acts as neurotransmitter and paracrine
messengers.

10. The endocrine glands play an important role in homeostasis
and controlling various other activities in the body by secreting
the hormones
The endocrine glands are also called ductless glands because
the hormone directly released into the blood.
The hormones are transported by blood to the target organs
or tissues in different parts of the body, where the action are
executed.

11. Endocrine Glands,Hormones,Functions& Structure
GLAND/TISSUE HORMONES MAJOR FUNCTIONS CHEMICAL
STRUCTURE
Hypothalamus Thyrotropin releasing
hormone(TRH)
Corticotropin-releasing
hormone(CRH)
Growth hormone-releasing
hormone(GHRH)
Growth hormone inhibitory
hormone(GHIH)
(somatostatin)
Gonadotropin-releasing
hormone(GnRH)
Dopamine or prolactin-
inhibiting factor(PIF)
Stimulates secretion of
TSH and Prolactin
Causes release of ACTH
Causes release of GH
Inhibits release of GH
Causes release of LH and
FSH
Inhibits release of
Prolactin
Peptide
Peptide
Peptide
Peptide
Amine

12. Contd.
GLAND/
TISSUE
HORMONES MAJOR FUNCTIONS CHEMICAL
STRUCTUR
E
Anterior
pituitary
Growth hormone
Thyroid –stimulating
hormone(TSH)
Adrenocorticotropic hormone
(ACTH)
Prolactin
Follicle-stimulating
hormone(FSH)
Luteinizing hormone(LH)
Stimulates protein synthesis and over all
growth of most cell and tissues
Stimulates synthesis & secretion of thyroid
hormone (thyroxine & triiodothyronine)
Stimulates synthesis & secretion of
adrenocortical hormone
(cortisol,androgens,aldosterone.)
Promotes development of female breasts
and secretion of milk.
Causes growth of follicle in the ovaries &
sperm maturation in sertoli cells of testis.
Stimulates testosterone synthesis in Leydig
cell of testis,stimulates ovulation, formation
of corpus luteum & estrogen and
progesterone synthesis in ovaries.
Peptide
Peptide
Peptide
Peptide
Peptide
Peptide

13. GLAND/ TISSUE HORMONES MAJOR FUNCTIONS Chemical
structure
Posterior pituitary Antidiuretic hormone
(ADH)
(also called vasopressin)
Oxytocin
Increases water re absorption
By the kidneys &causes vasoconstriction
&increased blood pressure,
Stimulates milk ejection from breasts &
uterine contractation
Peptide
Peptide
Thyroid Thyroxin (T4)
&Triiodothyronin(T3)
Calcitonin
Increases the rate of chemical reaction
in most of the cells thus increasing
metabolic rate.
Promotes deposition of calcium in the
bones.
Amine
Peptide

14. Gland/Tissue Hormones Major Functions Chemical
Structure
Adrenal
cortex
Cortisol
Aldosterone
Has multiple metabolic functions for controlling
metabolism of protiens, Carbohydrates and fats ,
also has anti-inflammatory effects.
Increases renal sodium reabsorption,potassium
secretion & hydrogen ion secretion.
Steroids
Steroids
Adrenal
medulla
Norepinephrine,
epinephrine
Same effects as sympathetic stimulation Amine
Parathyroid Parathyroid
hormone (PTH)
Controls serum calcium ion concentration by
increasing calcium absorption by the gut and
kidneys and releasing calcium from bones
Peptide

15. Gland/Tissue Hormones Major Functions Chemical
Structure
Pancreas Insulin (β
cells)
Glucagon (α
cells)
Promotes glucose entry in many cells, and in this way
controls carbohydrate metabolism.
Increases synthesis & release of glucose from the liver
into the body fluids.
Peptide
Peptide
Testes Testosterone Promotes development of male reproductive system and
male secondary sexual characteristics .
Steroid
Ovaries Estrogens
Progesterone
Promotes the growth development of female
reproductive system and female secondary sexual
characteristics.
Stimulates secretion of uterine milk by the endometrial
glands
Steroid
Steroid

16. Gland/Tissue Hormones Major Functions Chemical
Structure
Placenta Human chorionic
gonadotropin(HCG)
Human
somatomammotropin
Estrogens
Progesterone
Promotes growth of corpus luteum and
secretion of estrogens progestrogens by corpus
luteum .
Probably helps promote development of some
fetal tissue as well as mammary gland
-same-
-same-
Peptide
Peptide
Steroid
Steroid
Kidney Renin
1,25-
Dihydroxycholecalcife-
rol
Erythropoietin
Catalyses conversion of angiotensinogen to
angiotensin I (acts as an enzyme)
Increases intestinal absorption of calcium and
bone mineralization
Increases erythrocyte production
Peptide
Steroid
Peptide

17. Gland/Tissue Hormones Major Functions Chemical
Structure
Heart Atrial natriuretic peptide
(ANP)
Increases sodium excretion by
kidneys, reduces blood pressure .
Peptide
Stomach Gastrin Stimulates HCl secretion by
parietal cells.
Peptide
Small
intestine
Secretin
Cholecystokinin(CCK)
Stimulates pancreatic acinar cells
release bicarbonate and water.
Stimulates gallbladder
contraction and release of
pancreatic enzymes
Peptide
Peptide

18. What is a feedback mechanism
Feedback is
(generally)
information about
actions.

19.  In cybernetics and control theory, feedback is a
process whereby some proportion or in general,
function, of the output signal of a system is passed (fed
back) to the input. Often this is done intentionally, in
order to control the dynamic behaviour of the system.
Feedback is observed or used in various areas dealing
with complex systems, such as engineering,
architecture, economics, and biology.

20. Drawing a feedback loop
 Lines are usually drawn, directed from input through
the system and to output. The feedback is shown by
another arrowed line, directed from output outside
the system to an input, resulting in a loop on the
diagram, called feedback loop. This notion is
important; for example, the feedback loop is a
convenient place for a control device.

21. In nature
 In biological systems such as organisms, ecosystems,
or the biosphere, most parameters must stay under
control within a narrow range around a certain optimal
level under certain environmental conditions. The
deviation of the optimal value of the controlled
parameter can result from the changes in internal and
external environments. A change of some of the
environmental conditions may also require change of
that range to change for the system to function. The
value of the parameter to maintain is recorded by a
reception system and conveyed to a regulation module
via an information channel.

22. Positive and negative feedback
 Biological systems contain many types of regulatory
circuits, among which positive and negative feedbacks.
Positive and negative don't imply consequences of the
feedback have positive or negative final effect. The
negative feedback loop tends to slow down a process,
while the positive feedback loop tends to accelerate it.

23. Useful vocab
 negative feedback The stopping of the synthesis of
an enzyme by the accumulation of the products of the
enzyme-mediated reaction.
 negative feedback control Occurs when
information produced by the feedback reverses the
direction of the response; regulates the secretion of
most hormones.
 negative feedback loop A biochemical pathway
where the products of the reaction inhibit production
of the enzyme that controlled their formation.

24. Negative feedback
 Feedback and regulation are self related. The negative
feedback helps to maintain stability in a system in
spite of external changes. It is related to homeostasis.
Positive feedback amplifies possibilities of divergences
(evolution, change of goals); it is the condition to
change, evolution, growth; it gives the system the
ability to access new points of equilibrium

25. An example of a simple negative feedback
loop

26. What if you get cold?

27. What if your blood sugar changes?

28. Integrating organs with feedback

29.  For example, in an organism, most positive feedbacks
provide for fast autoexcitation of elements of
endocrine and nervous systems (in particular, in stress
responses conditions) and play a key role in regulation
of morphogenesis, growth, and development of
organs, all processes which are in essence a rapid
escape from the initial state.
 Homeostasis is especially visible in the nervous and
endocrine systems when considered at organism level.

30. Endocrine system
The endocrine system is a control
system of ductless glands that secrete
chemical messengers called hormones
that circulate within the body via the
bloodstream to affect distant organs.
Hormones act as "messengers", and are
carried by the bloodstream to different
cells in the body, which interpret these
messages and act on them. The endocrine
system does not include exocrine glands
such as salivary glands, sweat glands and
glands within the gastrointestinal tract.

31. What is a hormone?
 hor·mone (hôr'mōn')
n. A substance, usually a peptide or steroid, produced
by one tissue and conveyed by the bloodstream to
another to effect physiological activity, such as growth
or metabolism.

32. How are hormones classified
 Hormones are grouped into three classes based on
their structure:
 steroids
 peptides
 amines

33. Steriods
 Steroids are lipids derived from cholesterol.
Testosterone is the male sex hormone. Estradiol,
similar in structure to testosterone, is responsible for
many female sex characteristics. Steroid hormones are
secreted by the gonads, adrenal cortex, and placenta.

34. Steroid structure

35. Peptides and Amines
 Peptides are short chains of amino acids; most
hormones are peptides. They are secreted by the
pituitary, parathyroid, heart, stomach, liver, and
kidneys. Amines are derived from the amino acid
tyrosine and are secreted from the thyroid and the
adrenal medulla. Solubility of the various hormone
classes varies.

36.  The integration of body functions in humans and other
higher organisms is carried out by the nervous system, the
immune system, and the endocrine system.
 The endocrine system is composed of a number of tissues
that secrete their products, called endocrine hormones,
into the circulatory system; from there they are
disseminated throughout the body, regulating the
function of distant tissues and maintaining
homeostasis.
 In a separate but related system, exocrine tissues
secrete their products into ducts and then to the
outside of the body or to the intestinal tract.

37. Endocrine Hormones
 Classically, endocrine hormones are considered to be
derived from amino acids, peptides, or sterols and to act
at sites distant from their tissue of origin.
 However, the latter definition has begun to blur as it is
found that some secreted substances act at a distance
(classical endocrines), close to the cells that secrete them
(paracrines), or directly on the cell that secreted them
(autocrines). Insulin-like growth factor-I (IGF-I), which
behaves as an endocrine, paracrine, and autocrine,
provides a prime example of this difficulty.

38. What is the amount of hormones in the
blood?
 Hormones are normally present in the plasma and
interstitial tissue at concentrations in the range of 10-7M
to 10-10M.
 Because of these very low physiological concentrations,
sensitive protein receptors have evolved in target tissues
to sense the presence of very weak signals.
 In addition, systemic feedback mechanisms have evolved
to regulate the production of endocrine hormones.

39.  Once a hormone is secreted by an endocrine tissue, it generally
binds to a specific plasma protein carrier, with the complex
being disseminated to distant tissues.
 Plasma carrier proteins exist for all classes of endocrine
hormones. Carrier proteins for peptide hormones prevent
hormone destruction by plasma proteases.
 Carriers for steroid and thyroid hormones allow these very
hydrophobic substances to be present in the plasma at
concentrations several hundred-fold greater than their
solubility in water would permit.
 Carriers for small, hydrophilic amino acid--derived hormones
prevent their filtration through the renal glomerulus, greatly
prolonging their circulating half-life.
How do hormones travel in the blood!

40. Nonsteroid hormones (water soluble) do not enter the cell but bind to plasma membrane
receptors, generating a chemical signal (second messenger) inside the target cell.
Five different second messenger chemicals, including cyclic AMP have been identified.
Second messengers activate other intracellular chemicals to produce the target cell
response.

41. Action of nonsteroid hormones

42. Step two

43. Step Three

44. Action of steroid hormone
 The second mechanism involves steroid hormones,
which pass through the plasma membrane and act in a
two step process.

45.  Steroid hormones
bind, once inside the
cell, to the nuclear
membrane
receptors, producing
an activated
hormone-receptor
complex.

46.  The activated
hormone-receptor
complex binds to DNA
and activates specific
genes, increasing
production of proteins.

47.  Tissues capable of responding to endocrines have 2 properties in
common: they posses a receptor having very high affinity for
hormone, and the receptor is coupled to a process that regulates
metabolism of the target cells.
 Receptors for most amino acid--derived hormones and all peptide
hormones are located on the plasma membrane. Activation of these
receptors by hormones (the first messenger) leads to the
intracellular production of a second messenger, such as cAMP, which
is responsible for initiating the intracellular biological response.
 Steroid and thyroid hormones are hydrophobic and diffuse from
their binding proteins in the plasma, across the plasma membrane
to intracellularly localized receptors. The resultant complex of
steroid and receptor bind to response elements of nuclear DNA,
regulating the production of mRNA for specific proteins.
How do tissue react to hormones?

48. What we have seen so far..
 Stomach and intestines
 Gastrin
 Secretin
 Cholecystokinin (CCK)
 Somatostatin
 Neuropeptide Y

49. Getting a head start on hormones

50. List of hormones and organs related to
hormones
 Hypothalamus
 Thyrotropin-releasing hormone (TRH)
 Gonadotropin-releasing hormone (GnRH)
 Growth hormone-releasing hormone (GHRH)
 Corticotropin-releasing hormone (CRH)
 Somatostatin
 Dopamine

51. Hypothalamus to Pituitary

52. Pituitary gland
 Anterior lobe (adenohypophysis)
 GH (human growth hormone)
 PRL (prolactin)
 ACTH (adrenocorticotropic hormone)
 TSH (thyroid-stimulating hormone)
 FSH (follicle-stimulating hormone)
 LH (luteinizing hormone)
 Posterior lobe (neurohypophysis)
 Oxytocin
 ADH (antidiuretic hormone)

53. Integration of blood and hormones

54. A division of labour

55.  Pineal gland
 Melatonin
 Thyroid gland
 Thyroxine (T4), a form of thyroid hormone
 Triiodothyronine (T3), a form of thyroid hormone
 Calcitonin
 Parathyroid gland
 Parathyroid hormone (PTH)
 Heart
 Atrial-natriuretic peptide (ANP)

56.  Adrenal glands
 Adrenal cortex
 Glucocorticoids - cortisol
 Mineralocorticoids - aldosterone
 Androgens (including testosterone)
 Adrenal medulla
 Adrenaline (epinephrine)
 Noradrenaline (norepinephrine)

57. Adrenal gland and kidney
Kidney
•Renin
•Erythro
poietin
(EPO)
•Calcitrio
l

58.  Liver
 Insulin-like growth factor
 Angiotensinogen
 Thrombopoietin
 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages
/L/LiverHormones.html
 Islets of Langerhans in the pancreas
 Insulin
 Glucagon
 Somatostatin

59.  Skin
 Calciferol (vitamin D3)
 Adipose tissue
 Leptin

60.  In males only
 Testes
 Androgens
(testosterone)

61.  In females only
 Ovarian follicle
 Oestrogens
 Testosterone
 Corpus luteum
 Progesterone
 Placenta (when
pregnant)
 Progesterone
 Human chorionic
gonadotrophin (HCG)
 Human placental lactogen
(HPL)

62. Your challenge….
 Most hormones turn on and off a response
 You should be able to make feed back loops for
regulating levels of major chemical groups in the body.
 What are feedback loops for regulating:
 Oxygen and Carbon Dioxide
 Blood sugars ( you have seen it!)
 Blood salts
 Sexual and growth development

63. More challenges…
 Can you link feedback mechanisms to specific
systems?
 Could you make a comparative table pairing hormones
with organ systems?
 What disorders are associated with your adrenal gland,
thyroid gland, pancreas, bones and blood sugar
imbalance. (see on-line references)

64. A possible end..or beginning

65. Feedback
 This is my 1st
presentation, and I
apologies for any
mistake.
 So, please give your
feedback at
kumar.anirban3891@gm
ail.com

66. THANK YOU