A chemical signaling system that uses hormones for long-distance communication, impacting growth, metabolism, and homeostasis.
Hypothalamus
A brain region that regulates the pituitary gland and serves as a major connection between the nervous and endocrine systems.
What is the role of the thyroid gland?
The thyroid gland regulates metabolic rate and calcium homeostasis.
Insulin
A hormone produced by the pancreas that lowers blood sugar levels.
What is cortisol?
Cortisol is a steroid hormone produced by the adrenal cortex that manages stress responses.
Steroid Hormones
Lipid-soluble hormones that can cross cell membranes and typically modify gene expression.
What are water-soluble hormones?
Hormones that cannot cross cell membranes and bind to cell surface receptors, often using second messengers for signal transduction.
Paracrine Signaling
A type of cell signaling where cells release chemicals to communicate with nearby cells.
What is the function of the pituitary gland?
The pituitary gland secretes hormones that regulate various bodily functions and other endocrine glands.
Adrenal Medulla
The inner part of the adrenal gland that secretes epinephrine and norepinephrine in response to stress.
What is the role of the pancreas in the endocrine system?
The pancreas maintains blood sugar homeostasis by secreting insulin and glucagon.
Neurohormones
Hormones produced by neuroendocrine cells that link the nervous and endocrine systems.
What is the function of growth hormone?
Growth hormone stimulates growth, cell reproduction, and cell regeneration.
Calcitonin
A hormone secreted by the thyroid that lowers blood calcium levels.
What is the HPA axis?
The hypothalamic-pituitary-adrenal axis, a negative feedback loop that controls stress responses.
Epinephrine
Also known as adrenaline, it is a hormone that prepares the body for fight-or-flight responses.
What are gonads?
Endocrine glands that produce gametes (sperm and eggs) and secrete sex hormones.
Leptin
A hormone produced by fat cells that inhibits appetite.
What is the role of the anterior pituitary gland?
The anterior pituitary gland secretes hormones that regulate other endocrine glands and various bodily functions.
Parathyroid Hormone
A hormone that increases blood calcium levels by stimulating bone resorption, decreasing calcium excretion in the kidneys, and increasing calcium absorption in the gut.
What is the function of melatonin?
Melatonin, produced by the pineal gland, regulates circadian rhythms and induces sleepiness.
Tropic Hormones
Hormones that stimulate other glands to secrete hormones.
What is the function of oxytocin?
Oxytocin stimulates uterine contractions during labor, milk ejection during breastfeeding, and plays a role in social bonding.
Aldosterone
A mineralocorticoid hormone that helps regulate water and electrolyte balance in the kidneys.
What is the role of the posterior pituitary gland?
The posterior pituitary gland stores and releases hormones produced by the hypothalamus, such as oxytocin and antidiuretic hormone (ADH).
Thyroid Hormones (T3 and T4)
Hormones synthesized from tyrosine that regulate metabolic rate, heart rate, and heat production.
What is the function of glucagon?
Glucagon is a hormone produced by the pancreas that raises blood sugar levels.
Ghrelin
A hormone that stimulates appetite, acting opposite to leptin.