Endocrine system

What is the primary function of hormones?

• influence metabolic activity of glands by electrochemical impulses

• function as enzymes that catalyze the breakdown food molecules

• act as chemical messengers that regulate the metabolic function of cells in the body

• activate extracellular enzymes

Answer explanation

The primary function of hormones is to affect cellular metabolism by altering plasma membrane permeability or membrane potential, stimulating synthesis of enzymes, activating or deactivating enzymes, inducing secretory activity, or stimulating mitosis

Steroid hormones are synthesized from amino acids.

• True

• False

Answer explanation

Steroid hormones are lipid-based hormones synthesized from cholesterol.

Tags

NGSS.HS-LS1-1

Which hormone aids in water resorption?

• antidiuretic hormone

• parathyroid hormone

• adrenocorticotropic hormone

• thyroid hormone

Answer explanation

Antidiuretic hormone (ADH) stimulates the kidney tubules to reabsorb water.

Tags

NGSS.HS-LS1-3

Secretion of __________ is increased in response to stress.

• luteinizing hormone

• follicle-stimulating hormone

• adrenocorticotropic hormone

• thyroid-stimulating hormone

Answer explanation

Stress is the primary trigger for the secretion of CRH from the hypothalamus, which in turn signals the anterior pituitary to secrete more adrenocorticotropic hormone (ACTH), which targets the adrenal cortex to promote the release corticosteroid hormones, most importantly glucocorticoids. Glucocorticoids elevate blood nutrient levels and blood pressure to ensure adequate nutrient delivery to the body during a prolonged stress response.

Tags

NGSS.HS-LS1-3

The adrenal medulla is stimulated to release catecholamines during a stress response.

• True

• False

Answer explanation

The adrenal medulla can be thought of as an extension of the sympathetic nervous system. In response to short-term stress, the hypothalamus sends neural signals along preganglionic sympathetic axons to the chromaffin cells of the adrenal medulla, triggering their release of epinephrine and norepinephrine into the bloodstream.

Tags

NGSS.HS-LS1-3

Low blood glucose concentration and high blood potassium concentration are examples of __________ stimuli for an endocrine gland.

• Hormonal

• Humoral

• anatgonistic

• neural

Answer explanation

Some endocrine glands secrete their hormones in direct response to changing blood levels of certain critical ions (such as K⁺) and nutrients (such as glucose). These stimuli are called humoral stimuli (from the Latin term humor, which refers to bodily fluids)

Tags

NGSS.HS-LS1-3

Which of the following is NOT representative of endocrine glands?

• They typically have a rich vascular and lymphatic drainage that receives their products.

• They use ducts to secrete their products into the surrounding tissue fluid.

• The products they synthesize and secrete are chemical messengers called hormones.

• They secrete products that reach their target cells by circulating through the bloodstream.

What area of the brain is designated by letter A?

• Limbic system

• Thalamus

• Hypothalamus

• Pineal Gland

Answer explanation

The hypothalamus contains nuclei that produce hormones that travel down neurons and are then secreted into the blood in the pituitary gland.

Which of the following is NOT an endocrine gland?

• Pituitary

• Thyroid

• Adenoid

• Adrenal

Answer explanation

Pharyngeal tonsils, when enlarged, are commonly called adenoids. They are lymphoid tissue, not endocrine glands.

Hypocalcemia could be caused by the ______.

• apoptosis of parathyroid cells

• failure of osteoclasts to respond to PTH (parathyroid hormone/parathormone)

• malfunction of the parathormone receptors in kidney tubule cells

• All of the listed responses are correct.

Answer explanation

Parathyroid hormone (parathormone) is secreted in response to hypocalcemia. It functions to stimulate osteoclast activity, enhances the reabsorption of calcium by the kidneys, and increases absorption of calcium ions by the intestinal mucosal cells.