Endocrine System: Hormones, Glands, and Signaling Mechanisms

What is the endocrine system used for?

Long-term regulation using hormones released into the bloodstream

How does endocrine signaling differ from nervous signaling?

Endocrine is slower, longer-lasting, and uses chemical messengers in the blood

What is a hormone?

A chemical messenger released into the blood that affects target cells with specific receptors

How do endocrine hormones reach their target tissues?

Through blood vessels

Why don't all cells respond to every hormone?

Only target cells with the correct receptor respond

What is negative feedback?

A process where rising hormone levels inhibit further hormone release

Why is the hypothalamus called neuroendocrine?

It receives neural input and releases hormones that control the endocrine system

What is the main role of the hypothalamus?

To monitor body conditions and regulate hormone release via the pituitary

What is the main function of the pituitary gland?

To release hormones that regulate other endocrine glands and body functions

How is the anterior pituitary connected to the hypothalamus?

By the hypothalamic-hypophyseal portal system (blood vessels)

How is the posterior pituitary connected to the hypothalamus?

By neurons

Which pituitary lobe produces its own hormones?

Anterior pituitary

Which pituitary lobe stores and releases hypothalamic hormones?

Posterior pituitary

What hormones are released by the posterior pituitary?

ADH and oxytocin

What is a hydrophilic hormone?

A water-soluble hormone that binds to membrane receptors

What is a hydrophobic hormone?

A lipid-soluble hormone that binds to intracellular receptors

Which type of hormone acts faster?

Hydrophilic

Which type of hormone has longer-lasting effects?

Hydrophobic

Where do hydrophobic hormone receptors bind?

Inside the cell (cytoplasm or nucleus)

Why do hydrophobic hormones have long-lasting effects?

They alter gene transcription