Endocrine System

Do all organs in the endocrine system have their sole function?

No.

• The pancreas has functions in both digestion and the endocrine system. In the endocrine system the pancreas helps maintain blood glucose levels

Hormones

Signals emitted from endocrine cells that travel through the bloodstream to target cells.

Process of Endocrine Signalling

1. Endocrine cells secrete hormones into the bloodstream

2. Hormones travel via fluids to the target cell

3. Hormone binds to a specific receptor on the target cell (lock & key model)

   a. The same type of receptor can be present on different cells, eliciting different responses

4. Physiological response is triggered

How is homeostasis maintained?

A balance is kept between hormone production and hormone degradation via feedback loops.

Example: Insulin

1. Stimulus: Blood glucose levels are high

2. Sensor: Receptor cells in the pancreas detect these increased glucose levels

3. Control: Within the endocrine gland, pancreas, beta cells secrete the hormone insulin into the bloodstream.

4. Effector: Insulin facilitates glucose intake from the bloodstream into muscle, liver and adipose cells via glucose transporters.

5. Blood glucose levels decrease as glucose is stored as glycogen.

Glands of the Endocrine system

Hypothalamus

• Pineal Gland

• Pituitary gland

Thyroid

Adrenal glands

Pancreas

Ovaries

Testicles