Animals react to stimuli in many different ways because they have

nervous system and endocrine system (hormones)

Various organ should cooperate with one another to provide proper
reaction to the stimulus
The working together of various organs in an organism to produce a proper
response to a stimulus is called
Co-ordination.
Group of endocrine gland which produces various hormone and
enzymes is called endocrine system
The Endocrine system in our body have number of glands
which make, store and release chemicals called Hormone.

They are located in different parts of our body.

Different glands secret different hormone, that act on

different organ of our body.

The working of endocrine gland is controlled by “nervous

system”

Hormones act as a messengers between nervous system

and the organs of our body
Gland:
A gland is a specialized group of cells or tissues in the body that
synthesizes and secretes substances. These substances can be
hormones, enzymes, mucus, sweat, or other chemicals that serve
various functions.

Glands can be classified into two main types:

 hormone responsible for
lactation, breast development

Hypothalamic hormones are classified as either releasing or

inhibitory hormones because they inhibit or encourage the
release of hormones from the pituitary gland.
 Example
Glands of Emergency

Adrenaline
(Hormone)
Prepares body for maximum efficiency during
emergency condition
(danger,anger,excitement)

Emergency Nervous system Increases heartbeat

Adrenaline
stimulates breathing rate
situation (Hormone)
blood flow into muscles liver to
release stored glucose into
blood--- energy

Hormone Function:
Regulate heart rate, breathing rate, blood pressure
Carbohydrate metabolism
 Which gland is known as master gland?
The pituitary gland is sometimes called the "master" gland of the endocrine system because
it controls the functions of many of the other endocrine glands. The pituitary gland is no
larger than a pea, and is located at the base of the brain.

Which is the smallest gland in our body?

What Does the Pineal Gland Do? - pineal gland
A healthy pineal gland is about the size of a grain of rice. It's the smallest gland
in the body. It's shaped a bit like a pinecone. The pineal gland is part of your
endocrine system. Melatonin is the only known hormone synthesized by the pineal gland and is released in
response to darkness hence the name, “hormone of darkness” Being exposed to light at night can block melatonin
production.
It helps with the timing of your circadian rhythms (24-hour internal clock) and with sleep(Sleep - wake cycle)

The liver is the largest exocrine gland in the human body.

The largest endocrine gland? (ductless) Thyroid gland
 The main center in the body for the co-ordination of two systems
(Nervous and Endocrine) are
Hypothalamus and pituitary gland

The hypothalamus play an important role

in collecting information from other
regions of the brain and passing to
pituitary gland through blood vessels ,
bringing the activities of all other
Hypothalamus
endocrine gland
pituitary gland
Explain feed back mechanism for regulation of hormonal secretion with the help
of one example. 2014.
Ans. (a) The timing and amount of hormones released by various glands are
controlled by the ‘feedback mechanism’ that is in-built in our body.
Example, if the sugar level in the blood rises too much, it is detected by the cells
of the pancreas which responds by producing and secreting more insulin into the
blood; and as the blood sugar falls to a certain level, the secretion of insulin is
reduced automatically

prefixes used to indicate the amount of hormone

Hyposecretion(low): This refers to the underproduction or inadequate secretion of
hormones by the anterior pituitary gland.
Hypersecretion (more): This refers to the overproduction or excessive secretion of
hormones by the anterior pituitary gland.
Growth Hormone (GH): Stimulates growth, cell reproduction, and regeneration in humans and other animals. It plays
a crucial role in growth during childhood and helps maintain healthy body composition and metabolism in adults.

Adrenocorticotropic Hormone (ACTH): Stimulates the adrenal glands to release cortisol which are involved in the
body's response to stress, metabolism, immune function, and regulation of blood pressure.

Thyroid-Stimulating Hormone (TSH): Stimulates the thyroid gland to produce and release thyroid hormones,
primarily thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, growth, and energy expenditure.

Follicle-Stimulating Hormone (FSH): In females, FSH plays a crucial role in regulating the development, growth, and
maturation of ovarian follicles and in stimulating ovulation. In males, it stimulates the production of sperm in the
testes.

Luteinizing Hormone (LH): In females, LH triggers ovulation and promotes the formation of the corpus luteum in the
ovary, which produces progesterone. In males, LH stimulates the Leydig cells in the testes to produce testosterone.

Prolactin (PRL): Stimulates milk production in the mammary glands of the breast in females following childbirth. It
also has other functions in males and females related to reproductive health and behavior.

Melanocyte-Stimulating Hormones (MSH): Regulates pigmentation in the skin and hair by stimulating melanocytes to
produce melanin. It also has effects on appetite and sexual arousal.
 AP

Gigantism

Acromegaly Childhood

Extra growth of bones in

face, hands, feet
Hypersecretion (more): Hyposecretion(low)
 AP

Thyroxine : involve in maintaining

body temperature,
mental development,
Ossification (also known as
osteogenesis, is the process of bone
formation)
 AP

Iodine is a chemical element that is

essential for the production of thyroid
hormones. The thyroid gland, located in
the front of the neck, absorbs iodine
from the bloodstream and uses it to
synthesize two main hormones:
Butterfly shaped

Iodine deficiency can lead to insufficient production of thyroid hormones,

resulting in a condition known as hypothyroidism

Symptoms: Include fatigue, weight gain, cold intolerance, constipation,

dry skin, and hair loss.
 Hypothyroidism
Dwarfism +
Mental illness

Goiter

Swelling of face and hand

 Adreno-Cortico-Tropic Hormone (ACTH)
AP
Stimulates the adrenal glands to release cortisol

It helps your body: Respond to stress (cortisol is sometimes called the

"stress hormone")

Cortisol helps to maintain

blood pressure,
immune function and
the body's anti-inflammatory processes
Adreno-Cortico-Tropic Hormone (ACTH) AP
AP

(GnRH)
Gonadotropin-Releasing Hormone causes
the pituitary gland in the brain to make
and secrete the hormones
Luteinizing Hormone (LH) and
Follicle-Stimulating Hormone (FSH).
In men, these hormones cause the
testicles to make testosterone.
In women, they cause the ovaries to make
estrogen and progesterone.
Oxytocin: Oxytocin plays a vital role in several physiological PP
processes, including childbirth, lactation, and social bonding.
During childbirth, oxytocin stimulates uterine contractions,
aiding in labor and delivery. It also plays a crucial role in the
milk ejection reflex, facilitating breastfeeding. Additionally,
oxytocin is involved in social behaviors, such as trust,
empathy, and maternal-infant bonding.

Vasopressin (Antidiuretic Hormone, ADH): Vasopressin acts on

the kidneys to regulate water balance in the body. It helps to
conserve water by increasing water reabsorption in the
kidneys, reducing urine output, and concentrating urine.
Vasopressin also plays a role in regulating blood pressure by
constricting blood vessels when blood volume is low, hence
its name "vasopressin."
Imbalances in vasopressin can lead to conditions such as
diabetes insipidus (characterized by excessive urination and
thirst)
 not from the pituitary gland

produce parathyroid hormone, which plays a key role

in the regulation of calcium & phosphate levels in the
blood.
 not from the pituitary gland

Thymus Gland
a. The hormone secreted by this gland is called thymosin
b. Role in development of immune system
c. The gland shrinks after puberty,
Insulin: Regulates blood sugar levels by promoting the uptake of glucose into cells, thus lowering blood
sugar levels.
Glucagon: Increases blood sugar levels by stimulating the liver to convert stored glycogen into glucose
and release it into the bloodstream.
Somatostatin: Inhibits the secretion of both insulin and glucagon, helping to regulate the balance of
these hormones.
 Below the stomach, leaf like structure Pancreas
Secretes hormone Insulin
Lower the blood sugar/blood glucose level
Deficiency in insulin causes Diabetes or hyperglycemia
Over secretion of insulin causes Insulin shock or hypoglycemia

Pancreas is ducted and ductless gland

Ductless pancreas- hormone

insulin, glucagon,somatostatin

Pancreatic juice- duodenum-digestion

Maintain blood sugar level
Enables to absorb glucose
Excess of glucose as glycogen in the liver and muscle

Glucagon: Increases blood sugar levels by

stimulating the liver to convert stored
glycogen into glucose and release it into the
Plant bloodstream.