BIO Review 1

What is a hormone?

A chemical messenger secreted by an endocrine gland into the bloodstream that affects target cells.

What are the main functions of hormones?

Regulate metabolism, growth, development, reproduction, homeostasis, stress responses, blood glucose, fluid balance, and blood pressure.

What is a circulating hormone?

A hormone released into the bloodstream that travels to distant target cells.

What is a local hormone?

A hormone that acts near the site where it is released.

What is a paracrine?

local hormone that acts on nearby neighboring cells.

What is an autocrine?

A local hormone that acts on the same cell that secreted it.

What are the classes of lipid-soluble hormones?

Steroid hormones, thyroid hormones (T3/T4), and nitric oxide (NO).

What are the classes of water-soluble hormones?

Amines, peptides/proteins, and eicosanoids.

How do water-soluble hormones act?

They bind to receptors on the cell membrane and use second messengers.

How do lipid-soluble hormones act?

They cross the cell membrane, bind intracellular receptors, and affect gene expression.

Which type of hormone acts faster: water-soluble or lipid-soluble?

Water-soluble hormones.

Which type of hormone usually has longer-lasting effects?

Lipid-soluble hormones.

What is a synergistic effect?

Two or more hormones work together to produce a greater effect than either alone.

What is a permissive effect?

One hormone must be present for another hormone to exert its full effect.

What is an antagonistic effect?

Two hormones have opposite effects.

What are the 3 ways hormone secretion is regulated?

Humoral, neural, and hormonal stimuli.

What is humoral regulation?

Hormone release in response to changes in blood levels of ions or nutrients.

What is neural regulation?

Hormone release in response to nerve impulses.

What is hormonal regulation?

Hormone release in response to another hormone.

What controls the anterior pituitary gland?

The hypothalamus.

What gland is often called the “master gland”?

The pituitary gland.

What are the hormones of the anterior pituitary?

GH, TSH, ACTH, FSH, LH, PRL (and sometimes MSH).

What does GH do?

Stimulates body growth, protein synthesis, fat breakdown, and raises blood glucose.

What does TSH do?

Stimulates the thyroid gland to release T3 and T4.