18. THE ENDOCRINE SYSTEM AND HOMEOSTASIS
- Circulating or local hormones of the endocrine system contribute to homeostasis by regulating the activity and growth of target cells in your body.
- Hormones also regulate our metabolism.
- As girls and boys enter puberty, they start to develop striking differences in physical appearance and behavior.
- Perhaps no other period in life so dramatically shows the impact of the endocrine system in directing development and regulating body functions.
- estrogens promote accumulation of adipose tissue in the breasts and hips,
- sculpting a feminine shape.
At the same time or a little later,
- increasing levels of testosterone in boys begin to help build muscle mass and enlarge the vocal cords, producing a lowerpitched voice.
- These changes are just a few examples of the powerful influence of endocrine secretions.
- Less dramatically, perhaps, multitudes of hormones help maintain homeostasis on a daily basis.
- They regulate the activity of smooth muscle, cardiac muscle, and some glands;
- alter metabolism;
- spur growth and development;
- influence reproductive processes;
- and participate in circadian (daily) rhythms established by the suprachiasmatic nucleus of the hypothalamus.
