The Endocrine System

The Endocrine System

• Consists of:– Glands: Tissue that secretes hormones– Hormones: Chemicals that are produced in

one area and are sent to a specifically targeted area

Thyroid &Parathyroid Glands

Adrenal Glands

OvariesTestes

Pancreas

Hypothalamus,Pituitary Gland& Pineal Gland

Thymus Gland

What does the endocrine system do?

1. Regulate processes i.e. growth, development, reproduction

2. Coordinate production, use, storage of ATP (energy)

3. Maintain homeostasis- nutrition, metabolism, excretion, salt/water balance

4. React to stimuli from outside body

5. Send chemical messages to cells (specific target on cell’s membrane)

How do hormones work within the body?

• Positive Feedback• Increase desired

response• Increase in hormone

1 an increase in hormone 2

• Negative Feedback• Reduce desired

response• Increase in hormone

1 decrease in hormone 2

•Feedback mechanisms- body’s response to hormones

How do hormones work at the cellular level?

1. Gland releases hormone into the blood

2. Receptor in target cell recognizes hormone

3. Proteins in between and activates enzymes

4. Secondary messengers

5. Enters nucleus

Malfunctions

• Hyper- positive feedback more hormone than normal produced

• Hypo- negative feedback less hormone than normal being produced

Malfunctions

• Goiter– Enlargement of thyroid

gland– Iodine deficiency

• Diabetes– Islets of Langerhans-

region of pancreas that contains insulin- producing cells (beta cells)

– These cells are destroyed reduction in insulin higher glucose levels in blood

Malfunctions

• Hypothyroidism– Less thyroid hormone produced by thyroid

• Fatigue• Depression• Weight gain/Water retention

• Hyperthyroidism– More thyroid hormone produced by thyroid

• Weight loss• Loss of hair• Eyes bulge• Fatigue• Tremor