Human Endocrine System

7.1

Human Endocrine System

Endocrine system

Endocrine system is one of the system in the body that coordinates body functions that involve chemical substances.

The endocrine system secretes hormones and causes an increase in:

The Endocrine System Secretes Hormones

Endocrine gland

Endocrine gland: special glands that secrete hormone

Ductless glands
Coordinates the activity of the body by responding to the stimulus from the environment
Hormone secrete directly into the blood circulatory system to be distributed to the whole body

Hormones

Target organ

Has a suitable receptor that is able to recognise and respond to the specific hormone

Main endocrine glands

Endocrine gland	Hormone and function
Pituitary gland	Antidiuretic hormone (ADH) Control the quantity of water reabsorbed by the kidneys
Pituitary gland	Growth hormone (GH) Stimulates growth in children Maintains healthy body composition in adults Maintains the muscle and bone mass of adults
Thyroid gland	Thyroxine Controls the rate of metabolism Controls the physical and mental development in children
Adrenal gland	Adrenaline Prepares your body to act in an emergency situation
Pancreas	Insulin Controls the glucose level in the blood by converting excess glucose into glycogen to be stored in the liver
Ovary	Oestrogen Controls the female secondary sexual characteristics Stimulates the production of ova
Ovary	Progesterone Maintains the thickness of the wall of the uterus for the implantation of embryo
Testis	Testosterone Controls the development of male secondary sexual characteristics Stimulates sperm production

Causes and effects of hormonal imbalance

Hormone	Effect
Tyroxine	Deficiency Low rate of metabolism Inability to tolerate cold Cretinism Myxedema Goitre Excessive High rate of metabolism Sweating Seeping difficulties Thyroid gland enlargement Protruding eyeballs Swollen neck
Testosterone	Deficiency Delay in reaching puberty Low sperm count Excessive Male characteristic in women
Oestrogen	Deficiency Development of female secondary sexual characteristics to be disrupted Excessive Female characteristic in men
Growth hormone	Deficiency Dwarfism Excessive Uncontrolled growth Gigantism
Antidiuretic hormone (ADH)	Deficiency Poor reabsorption of water at the collecting duct in the kidney Excessive production of urine Excessive thirst Diabetes insipidus Excessive Headache Dizziness
Insulin hormone	Deficiency Failure of excessive glucose to be converted to glycogen Increase in blood glucose level Diabetes mellitus Excessive Low glucose levels Hypoglycaemia Excessive thirst