Endocrine System includes Endocrine Glands which releases hormone in bloodstream. Hormones Chemical messengers Secretions

1. Endocrine System
Submitted by:
Garima Mittal
Asst. Professor, Dept. of Pharmacy,
PIET, Samalkha, Panipat

2. The Endocrine System is made up of the Endocrine Glands that secrete Hormones.
Hormones are body's chemical messengers/ organic substance secreted by endocrine
glands that functions in the regulation of physiological activities and in
maintaining Homeostasis. They travel in the bloodstream to the tissues or organs. They work
slowly, over time, and affect many different processes, including: Growth and development,
Metabolism (how a body gets energy from the foods you eat).
Although there are eight major endocrine glands scattered throughout the body, they are still
considered to be one system because they have similar functions, similar mechanisms of
influence, and many important interrelationships.
Some glands also have non-endocrine regions that have functions other
than hormone secretion.
For example, the Pancreas has a major exocrine portion that secretes digestive enzymes and an
endocrine portion that secretes hormones. The ovaries and testes secrete hormones and also
produce the ova and sperm. Some organs, such as the stomach, intestines, and heart, produce
hormones, but their primary function is not hormone secretion.
Various glands which are responsible for hormonal secretions are mentioned below with their
functions:
Endocrine System

4. Glands Location Secretions Functions
1. Hypothalamus
gland
- Secretes all the
Releasing
hormones
(Stimulating or
inhibiting) and
controls the
pituitary activity.
Located in the brain,
between the
pituitary gland &
thalamus
Corticotrophin-releasing
hormone (CRH)
Gonadotropin-releasing
hormone (GnRH)
Prolactin-controlling
hormones (PCH)
Thyrotropin-releasing
hormone (TRH)
Regulate metabolism and immune response
instructs the pituitary gland to release more
hormones that keep the sexual organs working
Command the pituitary gland to either start and
stop milk production in lactating mothers
Activate the release of thyroid hormones that
regulate metabolism, energy levels, and growth
Hypothalamus regulate many other functions like:
Maintain pH of body fluids, Body Thirst, Emotions,
Sleep Cycle, Electrolytic Balance, etc.
2. Pituitary gland
- Pea shaped gland
Divided into 3 parts:
At the base of brain Secrete growth
hormones,
Metabolic hormones
Major functions are:
Growth, Metabolism, Reproduction, Lactation,
etc.
A. Anterior
Pituitary/
Adenohypophysis
Growth hormone (GH)
Prolactin (PRL)
Thyroid stimulating
hormone (TSH)
Adrenocorticotropic
hormone (ACTH)
Follicle-stimulating
hormone (FSH)
Luteinizing
Hormone (LH)
Promotes growth of body tissues
Promotes milk production from mammary glands
Stimulates thyroid hormonerelease from thyroid
Stimulates hormone release by adrenal cortex
Stimulates gamete production in gonads
Stimulates androgen production by gonads

5. B. Posterior Pituitary
/Neurohypophysis
Oxytocin
Anti-diuretic hormone
(ADH/Vassopressin)
Stimulates uterine contractions during
childbirth
Stimulates water reabsorption by kidneys
C. Intermediate Zone
Melanocyte-stimulating
hormone
Stimulates melanin formation in
melanocytes
3. Adrenal gland
It has two layers:
A. Adrenal cortex
B. Adrenal medulla
Present on the top of
the kidney
Secrete hormones that helps
immune system, blood
pressure & response to stress
Adrenaline triggers the body’s fight or
flight response
A. Adrenal cortex
(divided into 3 zones)
a. Zona Glomerulosa
b. Zona Fasciculata
c. Zona Reticularis
Mineralocorticoid
(Aldosterone)
Glucocorticoid hormone
(Cortisol)
Weak Androgens
(Dehydroepiandrosterone)
Regulate salt and water balance
Reacts to body stress (fright and flight
response)
Help in development of male sexual
organs and features
B. Adrenal medulla
Secretes stress
hormones
Inner region of
adrenal gland
Secrete
Adrenaline/ Epinephrine/
Nor-Adrenaline/nor
Epinephrine
These hormones are released in
response to stress conditions and induce
increased vascular smooth muscle
contraction, pupillary dilator muscle
contraction, and intestinal sphincter
muscle contraction.
Other significant effects include
increased heart rate, myocardial
contractility, and renin release

6. 4. Thyroid gland Located in the neck
region
Secrete T3 or T4 hormones
called Thyroid hormones
Calcitonin hormone
T3 and T4 collectively regulate
carbohydrate, lipid and protein
Metabolism
Responsible for CNS activity and
brain development
Responsible for Cardiovascular and
gastrointestinal stimulation
Responsible for Bone and Tissue
Growth and development
It helps in calcium homeostasis
(absorption and desorption)
5. Pancreas
-It has various types of
cells that secrete different
types of hormones:
a. Alpha Cells
b. Beta cells
c. Delta cells
a. PP Cells
b. Epsilon Cell
Present in first part
of the small
intestines
Secrete Enzymes during
digestion (Exocrine function)
Secrete hormones (Endocrine
function)
Glucagon
Insulin
Somatostatin
Pancreatic Peptide
Ghrelin
Digestive enzymes help in digestion
of food
Raises blood Glucose levels
Lowers blood glucose levels
Inhibits growth hormone released
from pituitary gland
Regulate digestive secretion and
motility
Orexigenic (Appetite stimulant)
6. Pineal Gland mid-line of the brain Melatonin Receive information about the state
of the light-dark cycle from the
environment and convey this
information to produce and secrete
the hormone melatonin to maintain
Circadian Rhythm.

7. FEW IMPORTANT FACTS ABOUT GLANDS AND HORMONES:
• The hypothalamus also directly influences growth hormones. It commands the pituitary gland to either increase or decrease their presence in
the body, which is essential for both growing children and fully developed adults.
• Hormones can be made from any other organ than just glands.
• Vitamin D act as vitamin as well as hormone by increasing testosterone concentration in men on exposure to sunlight.
• Estrogen is made from testosterone and male consists both the hormones in their body for good health.
7. Parathyroid Gland Behind the thyroid & at
the bottom of neck
Parathyroid hormone Regulation of calcium levels in the
blood
8. Gonads -
Testes: The male
reproductive Gonads
Ovaries: The female
reproductive Gonads
Male and female
reproductive organs
Gonadal steroids as
hormones:
Androgens in males:
Testosterone
Female hormones:
Estrogens, Progestins,
inhibin, and Relaxin
All of the above are found in both
males and females but at different
levels.
They all affect the growth and
development and also regulate
reproductive cycles, features and
behaviors.
9. Thymus Gland Upper chest behind your
sternum
Thymosin Delays the ageing process of the
body
And helps in maturing the immune
cells.