2. Endocrine System
• The endocrine system includes the
endocrine glands and their hormones
• The function of the endocrine system is to
secrete hormones into the bloodstream.
• Hormone: A Chemical messenger which
targets a specific group of cells, in order to
cause some activity or stop doing an
activity.
3. Endocrine System
• Exocrine glands release their secretions into
ducts, or tubes
– Liver Bile released into the gallbladder, then through a
duct into the small intestine
– Pancreas releases pancreatic juice into the small
intestine via a duct
• Endocrine Glands are called ductless glands
– Release hormones directly into the bloodstream
– Blood transports hormones throughout the body
– Each hormone acts on only a certain kind of tissue
called its target tissue
5. Human Endocrine Glands
• Pituitary
• Thyroid
• Parathyroid
• Adrenal
• Pancreas (Islets of
Langerhans)
• Gonads (Testes and Ovaries)
• Tymus gland
• Pineal gland
6. Pituitary
• Pituitary gland is situated at the base of brain in
hallow called sella turcica of sphenoid bone.
• It consists of two main lobes.
1. Anterior lobe {Anterior Pituitary}
2.Posterior lobe {Posterior Pituitary}
8. Anterior Pituitary Hormones
Hormone Function
Stimulates the adrenal cortex to Synthesise
its hormones
Luteotrophic Hormone (LTH)
Growth Hormone (GH) It is necessary for the normal growth
and development of the body
Thyroid Stimulating Hormone (TSH) To stimulate the thyroid to produce
thyroxin
Adrenocorticotrophic Hormone
(ACTH)
Follicle Stimulating Hormone (FSH)
Overy in female to Synthesise Oestrogen
Testes in male to Synthesise
Spermatozoa
Luteinizing Hormone (LH)
Stimulates the production of
Progesterone and testosterone
Stimulates the milk production in
females
9. Disorder of Anterior Pituitary
Hormone
• Over secretion of growth hormone:
– Gigantism in childhood and Acromegaly in adults
(bones of face, hands and feet enlarge)
• Under secretion of growth hormone:
– Dwarfism in childhood
10. Posterior Pituitary
Hormone
• The posterior lobe of pituitary secretes 2 types of
hormones.
• 1.Oxytocin.
• 2.Vasopressin(ADH)
• Function of Oxytocin:-
• Contraction of uterus during labour.
• Ejaculation of milk from breast.
• Function of Vasopressin(ADH):-
• Decreasing urine output by increasing tubular reabsorption in kidney.
• Increasing BP by constricting capillaries and arterioles.
11. Thyroid gland
• Thyroid gland is situated in lower part of neck on the thyroid
cartilage.
• Releases hormone thyroxin
• Function is to regulate rates of metabolism in the body
– Essential for normal physical and mental development
• Oversecretion of thyroxin:
– Results in nervousness and weight loss
• Undersecretion of thyroxin:
– Results in cretinism (mental retardation, small size) in
children
12. Secretion of thyroid hormone
• The thyroid gland synthesizes and secretes 2 hormones
• 1.Thyroxine
• 2.Tri-iodothyronine
The synthesis of these hormones occurs in the
following 4 stages.
1.Iodide is removed from plasma and conc. In the thyroid
gland.
2.Iodide is oxidised to iodine
3. Iodide combines with the amino acid tyrosine and forms .
A. monoiodotyrosine.(MIT) B. Diiodotyrosine(DIT)
13. • 4. Two molecules of DIT combine to form Thyroxine.
(TETRAIODOTHYRONINE)
• One molecule each of DIT and MIT unite to form Thyroxine
(TRIIODOTHYRONINE)
Regulation of secretion:
• The secretion of thyroid hormones is controlled by thyroid
stimulating hormone(TSH).
Functions of thyroid hormone.
• This hormone influences growth and metabolism.
• The major Functions are
1. Increase in oxygen consumption and heat production in
tissues.
2. Increases in BMR
3. Increases the absorption and utilisation of glucose.
14. • 4. Anabolic effects like growth promotion and protein
synthesis.
• 5. Increase in the rate of cholesterol synthesis in liver.
• 6. Myelination of CNS.
• 7.Storage of Iodine
15. Disordes of Thyroid
Hypothyroidism
1.Critinism: Leads to mental retardation in fetus.
2.Myxoedema: Leads to physical retardation after birth.
3.Endemic goiter: Due to deficiency of iodine in food leads to
enlargement of thyroid
gland.
Hyperthyroidism
1. Grave`s desease: It produces protrusion of eyeball,
rapid pulse and nervousness.
16. Parathyroid
• The parathyroid glands are 4 in number
• They are embedded on the posterior surface
• Located in back of thyroid gland (in neck)
• Hormone released is parathormone
• It is composed of 2 types of cells namely
• a]Chief cells b]Oxyphillcells
17. Functions
• To control metabolism of calcium
– Necessary for normal nerve and muscle
function, blood clotting, healthy bones and
teeth
18. Disorder of parathyroid
hormone
1. Hyperparathyroidism of parathormone results
in nerve disorders, brittle bones and clotting
problems this condition is called as ostetis
fibrosa.
2. Hypoparathyroidism leads to lower calcium
which can cause tetany.
19. Adrenal Glands (Supra
renal gland)
• Located at the top of each kidney
• Adrenal gland can be divided into 2 parts
they are
1.Medulla(inner)
2. Cortex(outer)
20. Medulla
• It secrets Adrenaline and Nor-Adrenaline
Cortex
• It has 3 distinct layers
LAYERS HARMONES
1.Outer layer Zona glomerulosa Mineralo corticoid
2.Middle layer Zona faciculata Gluco corticoid
3.Inner layer Zona reticularis Sex steroid
21. Functions of Adrenal gland
• Mineral corticoids regulates mineral and water
balance in body
• Glucocorticoids regulates Carbohydrate,
protein and fat metabolism.
Promotes conversion of fats and proteins to glucose
• Sex steroids regulates the sex hormone like testosterone
in male and estrogen in female
• Adrenaline raises the blood sugar levels and increases
heartbeat and breathing rates.
22. Disorder of Adrenals
1. Cushing`s syndrome:
This is Due to hyper secretion of cortisol.
2. Addison`s diseases:
This is due to hypo secretion of
Glucocorticoids.
3. Pheochromocytoma:
This is due to hyper secretion of adrenalin
and nor adrenaline.
23.
24. Pancreas
• pancreas lies on the posterior abdominal wall
• It extends between the C shaped curvature of duodenum
and spleen.
25. Islets of Langerhans(Pancreatic
cells)
Cells Hormones functions
Alfa cells Glucagon It promotes Glycogenolysis in liver
Beta cells Insulin It maintenance blood glucose level
Delta cells Somatostatine It inhibits the excess secretion of
Glucose and Glucagon
Gamma cells Pancreatic polypeptide It promotes the secretion of
pancreatic digestive enzymes
26. Disorders of Pancreas
• Oversecretion of insulin results in low blood
sugar
• Undersecretion of insulin results in high blood
sugar
– This can lead to a condition known as
diabetes
27. Diabetes-Type 1
• Type 1- Usually found in children and young
adults; the body doesn’t make enough insulin
– Symptoms:
• Frequent urination
• Unusual thirst
• Extreme hunger
• Unusual weight loss
• Extreme fatigue and Irritability
28. Diabetes- Type 2
• Type 2- Either the body doesn’t produce
enough insulin, or the cells ignore it.
– If you consume too much sugar over a long
period of time, your body has to release large
amounts of insulin. This can result in your
cells building up a tolerance for insulin,
which means they won’t be affected by it.
– Symptoms:
• Any of the type 1 symptoms
• Frequent infections
• Blurred vision
• Cuts/bruises that are slow to heal
• Tingling/numbness in the hands/feet
• Recurring skin, gum, or bladder infections
29. Gonads (Testes and
Ovaries)
There are 2 types of sex glands
1.Ovaries: It secrets oestrogen and
progesterone in females.
2.Testis: It secrets testosterone in males.
30. Functions of gonads(sex glands)
1. Oestrogen :
It regulates the menstrual cycle.
It involves in the development of secondary sex
characters.
The secretion of oestrogen is controlled by FSH
2. Progesterone:
Maturation and development of breast and uterus
Preaparation of uterus to receive the fertilised ovum.
3. Testostterone:
Stimulation of spermatogenesis`
Growth of penis, Scrotum and Prostate.
Development of secondary sex characters.
Secretion of gonads is controlled by LH
31. Tymus gland
This gland is present in upper chest cavity on the trachea.
It is located between the sternum and heart.
It consists of two lobes.
Each lobe consists of number of lobules.
Thymus is bigger in size at birth.
It grows in size until puberty. Later it gradually decreases
in size
32. Functions of Thymus gland
It involves in the production of
lymphocytes.
It plays some role in sexual development.
33. Pineal gland
It is the smallest gland which is situated
in the brain.
It is reddish gray in colour and measures
10 mm in length.
34. Function of pineal gland
It secretes hormone known as melotonine at
night
Which controls the CNS functions like sleep-
wake cycle.
It act as biological clock because it prevents
sleeplessness (Insomnia).