3 Endocrine System Physiology Free Online FlashCards

What determines whether a cell responds to a hormone?

Only cells with the appropriate receptor respond to a hormone, even when it circulates widely.

How do endocrine glands release hormones?

Endocrine glands have no ducts; they release hormones into surrounding fluid, which carries them into circulation.

Where do peptide hormones and catecholamines generally bind their receptors?

Peptide and protein hormones, along with catecholamines such as epinephrine, generally bind cell-surface receptors and activate intracellular signaling pathways.

How does the hypothalamus signal the anterior pituitary?

The hypothalamus sends releasing or inhibiting hormones to the anterior pituitary through a specialized portal blood system.

Which glands are stimulated by TSH and ACTH?

TSH stimulates the thyroid, while ACTH stimulates the adrenal cortex.

What is negative feedback in hormone regulation?

A response reduces the original stimulus, limiting further hormone release; rising thyroid hormone levels suppress signals that stimulate the thyroid.

What is a humoral stimulus? Give one endocrine example.

A humoral stimulus is a change in blood chemistry; for example, high blood glucose stimulates pancreatic beta cells to release insulin.

How do insulin and glucagon differ in regulating blood glucose?

Insulin promotes blood glucose uptake and storage; glucagon helps raise blood glucose during fasting.

How does increased blood osmolarity affect ADH and the kidneys?

Increased blood osmolarity promotes ADH release, which helps the kidneys conserve water.

What response does the renin–angiotensin–aldosterone system support when blood pressure or volume falls?

When blood pressure or volume falls, the kidneys release renin, initiating a system that promotes vessel narrowing and sodium and water conservation.

How do steroid hormones typically affect target cells?

Steroid hormones typically cross the cell membrane and bind intracellular receptors, changing gene activity.

What is distinctive about thyroid hormone receptor location?

Although derived from amino acids, thyroid hormones act through intracellular receptors.