Tuesday, Oct. 14 - The Human Body - The Endocrine and Reproductive Systems

The Endocrine System

The endocrine system sends messages around the body and releases hormones into the bloodstream. Then the hormones reach target cells within the body, receptors on the target cells react and trigger a response.

Example: When you feel nervous, the hormone epinephrine is released in the bloodstream. When it reaches the receptors on target cells, your heart rate increase and muscles become tense.

Hormones travel slowly in the bloodstream compared to nerve messages. So the endocrine system regulates processes that happen over a period of time – like cell growth, metabolism and reproduction.

Glands are the organs that produced and release hormones. Different glands produce different hormones.

Pituitary Gland

The pituitary gland is in the brain and controlled by the hypothalamus, and area that connects the nervous system and the endocrine system. This gland secretes 9 different hormones, including some that respond to stress and some that trigger reproductive cells.

• The Pineal gland (brain) secretes melatonin.
• The thyroid gland (neck) helps cells break down chemicals and produce energy
• Parathyroid gland (neck) regulates calcium
• Thymus gland (chest) helps body fight disease
• Adrenal glands (center of body) produce fight or flight response
• Pancreas (center of body) produces insulin and glucagon
• Reproductive glands control reproduction and have a lot to do with puberty

Reproductive System

The reproductive system is involved with sexual development and production of children. Endocrine glands are responsible for secondary sex characteristics and contribute to the production of sex cells.

Testosterone and estrogen are the hormones that mostly create the physical differences between men and women. Testosterone controls the male reproductive system and estrogen controls female reproductive system and breast development.