A&P 1 - The Endocrine System & Pancreas

Endocrine System

Synthesizes and secretes chemical messengers called hormones into the blood

Similarities between the nervous system and the endocrine system

• Both work to maintain homeostasis

• Use chemicals to communicate with other cells (Cell-cell communication)

How the nervous system is different than the endocrine system:

• Uses a series of neurons that DIRECTLY affect their target organs

• The effect is: IMMEDIATE but short-term unless repetitive

How the endocrine system is different from the nervous system:

• Uses hormones to INDIRECTLY communicate with target organ

• The effect is: LONGER lasting but can take days to occur

Paracrine Signals

Nearby cells or same tissue

Autocrine Signals

Same cell

Seven Endocrine Organs (Primary)

• Anterior pituitary gland

• Thyroid gland

• Parathyroid gland

• Adrenal cortices/gland

• Pancreas

• Thymus

• Ovaries or testes

Hormones

chemical messengers produced in the body that travel through the bloodstream to different organs and tissues

Amino acid-based hormones

Produced by: Hypothalamus, adrenal medullae, and thyroid gland

• Hydrophilic —> Can freely interact with water and freely travel through blood

• Can not cross the cell membrane

• Except Thyroid hormone —> Hydrophobic

Steroid hormone

Lipophilic Hormones

• Hydrophobic —> Needs a carrier protein to go through the bloodstream

• Glands that produce it: Adrenal cortices/gland, testes, and ovaries

• Can mix with fat and be stored in adipose tissue