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Introduction to
Psychology
Endocrine System

Defination
 The Endocrine System is made of glands
and tissues that secrete hormones.
 The Endocrine System is a set of glands
that regulates the activities of certain
organs by releasing their chemical
products into blood stream.
 These glands have no ducts or openings

 Controls many body functions
 Exerts control by releasing special chemical
substances into the blood called hormones.
 Hormones effects other endocrine glands or
body systems.

Glands of Endocrine System
Following glands are included in
endocrine system :
 Pituitary Gland
 Thyroid Gland
 Parathyroid Gland
 Thymus Gland
 Adrenal Gland
 Pancreas Gland
 Pineal Gland
 Gonad Gland

Pituitary Gland
 Located at the base of brain and
connected to the hypothalamus
 Divided into interior and posterior lobes
 Known as the master gland because of its
major influence in body’s activities

Hormones of the Pituitary Gland
 Divided into two lobes
 Anterior pituitary lobe is larger and produces
seven hormones.
 Posterior pituitary lobe is smaller and consist
primarily of nerve fibers and neuroglial cells.

Anterior pituitary
 The anterior pituitary synthesizes and
secretes the following important
hormones under the influence of
hypothalamus
◦ Adrenocorticotropic hormone (ACTH)
◦ Thyrotropin or thyroid stimulating hormone
◦ Prolactin hormone
◦ Growth hormone
◦ Gonadotropin hormone

Posterior pituitary
 Posterior pituitary releases the following
hormones
◦ Oxytocin hormone
◦ Antidiuretic hormone (ADH)

Thyroid and Parathyroid Glands
 Thyroid Glands
Locted in the anterior part of neck
It is butterfly shape organ and is
composed of two con-like lobes or
wings
Secretes three hormones
 Thyroxine
 Triiodthyronine
 Calcitonin

Thyroid and Parathyroid Glands
 Parathyroid Glands
 They are small endocrine glands in the neck
that produce parathyroid hormone.
 Humans have four parathyroid glands, which
are located behind the thyroid gland.
 Parathyroid glands control the amount of
calcium in the blood and within the bones
 It serves a completely different role than the
thyroid gland.

Thymus Gland
 The thymus gland is both an endocrine
gland and lymphatic organ.
 The thymus secretes a large number of
hormones
 It is composed of two lobes and is
located in front of the heart and behind
the sternum.
 Thymus is specialized organ in the
immune system.

Structure of thymus
 Structure of the thymus can be divided
into two parts
 Medulla
 Peripheral cortex
 The cortex and medulla play different
roles in the development ofT-cells.

Adrenal Glands
 Adrenal glands are situated just above the
kidneys one on each side.
 These are triangular shaped glands.
 They are chiefly responsible for releasing
hormones which are extremely important
to neural functioning and to the ability of
the body to cope with stress.

Adrenal Glands
 Two adrenal glands located at the top of
each kidney; each has two parts
Cortex – secretes 3 groups corticoids
• Mineralocorticoids
• Glucocorticoids
• Sex hormones
Medulla – secretes
• Epinephrine / adrenaline
• Nor – epinephrine / nor adrenaline

Pancreas Gland
 Located behind stomach
 Pancreas is a dual function gland i.e.
endocrine or exocrine gland
 Function as :
• Exocrine gland
oSecretes pancreatic juices into small intestine to
become digestive juices
• Endocrine gland
oProduces insulin and diabetes.

Pineal Gland
 Attached to the third ventricle of the
brain
 Produces the hormone melatonin
• Amount of light effects the amount of
melatonin secreted
• Causes body temprature to drop

Gonad Gland
 Gonads – sex organs
Ovaries – female sex organ
• Ova
• Estrogen and progesterone
Testes – male sex organ
• Sperm
• testosterone

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Introduction to psychology