3 The Endocrine System Free Online FlashCards

What is the endocrine system’s main role?

It uses hormones to coordinate body functions over long distances and help maintain homeostasis.

What determines whether a cell responds to a hormone?

A target cell must have the appropriate receptor. The number of receptors and the cell’s internal signaling machinery also affect its response.

How do peptide and protein hormones usually bind to target cells?

They are generally water-soluble and bind to receptors on the cell surface.

How do insulin and glucagon illustrate antagonistic hormone effects?

Insulin and glucagon have antagonistic effects: insulin promotes glucose uptake and storage, while glucagon prompts the liver to release glucose.

How are oxytocin and ADH linked to the hypothalamus and posterior pituitary?

The hypothalamus regulates the pituitary and makes oxytocin and ADH; the posterior pituitary stores and releases those hormones.

What are the major roles of thyroid hormones T₃ and T₄?

Thyroxine (T₄) and triiodothyronine (T₃) influence metabolic activity, growth, and development.

What does parathyroid hormone do to blood calcium?

Parathyroid hormone (PTH) raises blood calcium and helps regulate calcium balance.

How does negative feedback regulate the TRH–TSH–thyroid axis?

The hypothalamus releases TRH, prompting pituitary TSH release; TSH stimulates the thyroid to produce T₃ and T₄. Rising thyroid hormone levels inhibit further TRH and TSH release.

What is a humoral stimulus for hormone release?

A humoral stimulus is a change in a blood-borne substance. For example, rising blood glucose stimulates pancreatic cells to release insulin.

How does insulin help lower blood glucose after a meal?

After a meal, rising blood glucose stimulates pancreatic beta cells to release insulin. Insulin promotes glucose uptake and storage, including as glycogen in the liver and muscles.

How do steroid hormones usually affect target cells?

They pass through the cell membrane and usually bind to receptors inside the cell. The hormone–receptor complex can influence gene activity.

How do amine hormones differ in receptor location?

Amine hormones are derived from amino acids. Epinephrine and norepinephrine use cell-surface receptors, while thyroid hormones act mainly through intracellular receptors.