Endocrine System Oh those crazy hormones The Function

Endocrine System Oh, those crazy hormones!

The Function Regulates overall: • Metabolism • Homeostasis • Growth • Reproduction WO W!

The Three Basic Parts • Endocrine Glands- organs that secrete substances into the bloodstream. • Hormones- the chemicals secreted by the endocrine glands • Target Cells- use the hormones

How it Works Hormone Receptor

Where are the glands?

Two Types of Hormones • Protein-based: cannot pass through the cell membrane • Steroid-based: can pass through the cell membrane

Important Glands & Hormones • Pituitary- too many to list • Pancreas- insulin (protein) • Ovary- estrogen (steroid) • Testes- testosterone • Thyroid- thyroxine • Adrenal Glands- adrenaline

The Pancreas & Insulin Pancreas detects increase in BSL Insulin increases Lowers BSL Insulin decreases Pancreas detects decrease in BSL

Negative Feedback A change in one causes an opposite change in another. Example: Insulin & Glucose (BSL)

Positive Feedback A change occurs and it is reinforced by the change in another. Example: Oxytocin & Breastfeeding

Causes of Disorders • Hyposecretion- too little hormone is being secreted • Hypersecretion- too much hormone is being secreted

Diabetes • Type 1 (juvenile) – body fails to produce enough insulin • Type 2 (adult-onset) – body does not respond to insulin properly

An insulin pump

Goiter • Enlargement of the thyroid gland • Caused by a lack of iodine (needed to make thyroxine)

Dwarfism (not all varieties) • Hyposecretion of growth hormone in childhood • Short stature, but normal proportions

P. T. Barnum and Tom Thumb

Dwarf horse

Giantism (not all types) • Hypersecretion of growth hormone in childhood • Very tall stature, but normal proportions

12 year old boy 6’ 5”

Robert Wadlow 8’ 11”

Sandy Allen 7’ 7. 25”

Current tallest woman Yao Defen 7’ 8. 5”

Current tallest man Bao Xishun 7’ 9”