ENDOCRINE GLANDS
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What does Endocrine Glands Do
Endocrine Glands secrete certain Chemicals known as hormones.
Hormones are extremely important secretions for the regulation of body activities.
The full set of Endocrine Glands Consist of 9 Types of Glands. (Apan sab nai Padhneka)
Need for the Regulation of the Body Activities
The Activities of Our Body are Highly complex, and they need to be regulated so that, every
activity takes place at proper time and at correct sequence
This kind of Regulation is done to Some extent by nervous system, but it also Brought about by
some chemical regulators, called Hormones.
Hormones
Hormones are Secretions from specific cells or glands in the body and all carried to all parts
through blood.
Most hormones are secreted by special glands called endocrine glands.
Endocrine - Secret Internally
They are also called as ductless glands, because their secretions are poured directly into the
blood, and not through any special ducts.
Endocrine System
1) Endocrine System Consist of several glands or glandular cells, which bring about the overall
common function of chemical co-ordination in the body.
2) Almost all Endocrine Glands act in a co-ordinated manner.
3) They activate each other and work as a system of organs called ENDOCRINE SYSTEM.
4) The system is Defined as the group of organs, performing the overall common function.
5) Endocrine Glands Secrete certain chemicals called hormones.
General Properties of Hormones
- Hormones are Secreted from their source, directly into the blood.
- They act on target organs or cells, usually which are away from the source
- They regulate the physiological process by chemical means and affect the enzyme system of
the body
- Hormones produced in one species usually show similar influence in other species.
- They are produced in very small quantity and are biologically very active.
- Chemically Some hormones are Peptides, Amines and Steroids.
- Their Excess or deficiency may lead to serious consequences.
- Hormones are not stored in the body and are excreted from the system
1) ADRENAL GLAND. [4 cm L, 3 cm T]
Effects of Effect or
Sr.No Body Part Biological Advantage
Adrenaline Sensation
Beats Faster, Blood Sends more glucose and oxygen to Thumping
1 Heart
Pressure Increases the muscles Heart
Breathing Centre Faster and Deeper Increased oxygenation of blood,
2 Panting
of the Brain Breathing rapid removal of Carbon Dioxide
Arterioles of the Less blood going to skin, more blood Person Turns
3 Constricts them
skin goes to muscle Pale
Arterioles of the Less blood goes to digestive
4 Constricts them Dry Mouth
Digestive System system, more blood goes to muscle
Tense feeling,
5 Muscles of Body Tenses them Ready for Immediate action
shivering
Conversion of Glucose available in blood for
6 Liver No Sensation
Glycogen to Glucose energy production
Conversion of fats Fatty acids available in blood for
7 Fat Deposit No Sensation
into fatty acids muscle contraction
ADRENAL GLAND
Adrenal Medulla Adrenal Cortex
— Secretes adrenaline, called EPINEPHRINE and — Secretes many hormones, but best known
NORADRENALINE. hormone is cortisone (which surpasses
— Adrenaline is a hormone, which prepared the inflammation)
body to meet any emergency situation to fight, ie
to face danger or to run away. In General Cortical Hormones
— Extra Energy and strength is provided to body — Increase blood glucose concentration
in that situation. — Influence Fat and Protein Metabolism
— Extra Hormone is released into the blood at the — Regulate Salt and water balance in the body
time of emotional stress. Mineralocorticoids Glucocorticoids — Adapt the body to extreme stress, i.e Extreme
— When Excited or Angry, our adrenals produce heat or cold, burns, infections, etc.
lot of adrenaline - Regulates Mineral — Certain cortical hormones behave like sex
- Regulates Carbohydrates,
Metabolism, specially Na+ and hormones. There are both male and female
Proteins and Fat Metabolism.
K+ Ions hormones in both the sexes.
Hypo-secretion Hyper-secretion
— Causes Addison’s disease
— Causes Cushing’s Syndrome
— Symptoms are Loss of
— Symptoms are obesity, high
energy, loss of weight, nausea,
blood sugar, weakness, salt
low blood sugar, sensitivity to
and water retention
heat and cold.
REMEMBER -
— Pancreas is both , duct as well as ductless gland.
— As a duct gland, its secretion is poured into duodenum for It is wrong to say “Insulin converts glucose to
PANCREAS
digestion. glycogen”.
— As a ductless glands It has a special group of hormone secreting
cells called islets of lagerhands. Instead “Insulin enables the cells to absorb
— It Produces 3 Hormones, Insulin, Glucagon and Somatostatin, glucose and use it OR convert it into
from 3 different kinds of cells, I.e Alpha, Beta, Delta glycogen
Insulin Under-Secretion of Insulin
- Insufficient secretion of insulin causes diabetes.
— Insulin secreted by Beta cells check rise of
sugar level in blood This it does in 2 principal
A Diabetic Person
ways
— Has high concentration of sugar in blood
[Hyperglycaemia]
— Excretes a great deal of urine loaded with sugar
1) It promotes Glucose utilisation in the Body
— Feels thirsty due to loss of water due to lot of
cells, thereby reducing the blood sugar level.
urination
— Loss weight and becomes weaker and weaker,
2) It Stimulates deposition of extra glucose of the
sometimes person may also loose eye sight
blood as glycogen in liver and muscle.
Glucagon
— Glucagon is secreted from Alpha Cells Over-Secretion of Insulin
— It stimulates the breakdown of Glycogen in the
liver to glucose, thus is raises sugar level in the — Sugar level in the blood is lowered
blood. [Hypoglycaemia]
— Brain may enter a state of coma, if the level
becomes too low even for a minute
Meanings -
— Thyroid is a bilobed [Butterfly
1) Metabolism - The term metabolism is commonly used to refer specifically to the
shaped ] Structure situated in front
THYROID
breakdown of food and its transformation into energy.
of the neck just below the larynx.
— Two lobes are joined by a narrow
2) Ossification - Abnormal bone formation
isthmus [Interconnection]
— It secretes two hormones
3) Basal Metabolism - the rate at which the body uses energy while at rest to maintain
THYROXINE and CALCITONIN
vital functions such as breathing and keeping warm.
Thyroxine Under-Secretion (hypothyroidism)
— Thyroxine regulates the Basal Metabolism. 1) Simple Goitre - It is an enlargement of the thyroid and is visible
as a swelling in the neck. This is caused due to insufficient quantity
— Increase in secretion of Thyroxine increases of iodine in food. Common in Hilly areas where iodine is less in soil
metabolism and decrease in secretion lowers the
metabolism 2) Cretinism - It is a condition which effects the growth of children
showing dwarfism and mental retardation. This is caused due to
— It also influences the General growth of the early degeneration of Thyroid.
body, ossification of bones, body temperature,
mental development, etc 3) Myxoedema - It is a condition that affects the adult, if his thyroid
does not function properly. In this person becomes sluggish, with
swelling of face and hand
Over-Secretion (hyperthyroidism)
Note
Excess of Thyroxine secretion may also cause a kind of goitre called
Thyroid Deficiencies are common in many parts exophthalmic goitre.
in India.
Use of Iodised Salt n food is recommended Symptoms are
because iodine is the active ingredient in the
production of thyroxine. a marked increase in metabolic rate , rapid heartbeat, shortness of
breath, eyes are protruded, forms a goitre in neck.
Myxoedema
Exophthalmic
Goitre
— The pituitary gland is the small projection which hangs from the base of the mid brain below hypothalamus
PITUITARY — It is popularly called master gland because it seems to control practically all other endocrine glands
— The pituitary glands has 2 different lobes, ANTERIOR and POSTERIOR.
— The front part of the POSTERIOR is different from the rest of the Lobe and is called INTERMEDIATE LOBE.
— Intermediate lobe is almost absent in human, but much larger and more functional in some lower animals
Hormones from Anterior Pituitary Hormones from Posterior Pituitary
Posterior lobe produces 2 hormones, named VASOPRESSIN and OXYTOCIN
1) Growth Hormone
— Growth hormone is essential for normal growth. It is also called SOMATOTROPIN 1) Antidiuretic Hormone OR Vasopressin (ADH)
— The Deficiency of GH in childhood leads to dwarfism. — Constricts Blood vessels with the rise in blood Pressure.
— The Over-secretion of GH in childhood leads to GIGANTISM. — It also acts on Kidney increasing reabsorption of water from the Kidney Tubules.
— If Over-secretion of GH suddenly occurs in Adulthood, there is excessive growth of — Deficiency of ADH causes diabetes Insipudus (water Diabetes) resulting in loss of
Bones in the Face, hands and feet. water and person becomes thirsty.
— Person develops Large Nose and thick Lips.
— This condition is called acromegaly 2) Oxytocin
— It stimulates Vigorous contraction of the uterus in the pregnant mother, leading to
the birth of baby.
2) Thyroid Stimulating Hormone (TSH) — It also Stimulates Milk ejection
— It activates Thyroid to secrete thyroxin
3) Gonad Stimulating Hormones (GSH)
— It Regulates the Activities of Testes and
Ovaries.
NOTE -
4) Adrenocorticotropic Hormone (ACTH) — Diabetes Means Passing out Excessive Amounts of Urine
— It regulates the Activity of adrenal cortex — If urine contains sugar due to insufficient insulin, is called Diabetes Mellitus
— If urine contains no sugar, then it is called diabetes Insipidus
