Level 1: CH.12 The Endocrine System: Glands and Hormones

VOCABULARY flashcards covering key terms and definitions from the endocrine system notes.

Endocrine system

System of glands that produce regulatory chemicals called hormones to regulate body processes.

Gland

A group of cells that produces regulatory chemicals (hormones).

Hormone

Chemical messenger released into tissue fluids, travels via blood to a target tissue to alter cell activity.

Negative feedback

Regulatory loop where the final product inhibits its own production to maintain homeostasis.

Target tissue

The specific tissue acted on by a hormone.

Receptor

Protein on or in a cell that binds a hormone to trigger a response.

Hypothalamus

Brain region that synthesizes ADH and oxytocin and regulates the pituitary.

Pituitary gland

Master gland with anterior and posterior lobes that kontrol other endocrine glands.

Anterior pituitary

Lobe that releases GH, TSH, ACTH, PRL, FSH, and LH.

Posterior pituitary

Lobe that releases ADH and oxytocin.

ADH (antidiuretic hormone)

Promotes water reabsorption in kidneys and raises blood pressure; deficiency causes diabetes insipidus.

Oxytocin

Stimulates uterine contractions and milk ejection.

Growth hormone (GH)

Stimulates growth of body tissues; promotes protein synthesis and energy mobilization.

Thyroid-stimulating hormone (TSH)

Stimulates the thyroid to release thyroid hormones (T3 and T4).

Adrenocorticotropic hormone (ACTH)

Stimulates growth and activity of the adrenal cortex.

Prolactin (PRL)

Stimulates milk production by the mammary glands.

Follicle-stimulating hormone (FSH)

Stimulates growth of ovarian follicles and sperm cell development.

Luteinizing hormone (LH)

Triggers ovulation; stimulates progesterone in females and testosterone in males.

Thyroxine (T4)

Thyroid hormone, less active than T3; increases metabolic rate.

Triiodothyronine (T3)

More active thyroid hormone; increases metabolic rate and heat production.

Goiter

Enlargement of the thyroid gland due to excessive thyroid stimulation.

Hypothyroidism

Underactive thyroid; often due to autoimmune destruction (Hashimoto).

Hyperthyroidism

Overactive thyroid; commonly Graves disease.

Graves disease

Autoimmune activation of thyroid cells causing hyperthyroidism.

Hashimoto thyroiditis

Autoimmune destruction of the thyroid gland causing hypothyroidism.

Parathyroid glands

Four glands on the posterior thyroid that regulate calcium via PTH.

Parathyroid hormone (PTH)

Raises blood calcium by bone resorption and kidney reabsorption; calcium balance is essential.

Calcitriol

Active form of vitamin D produced by kidneys in response to PTH; increases intestinal calcium absorption.

Calcium

Mineral essential for bones/teeth, muscle contraction, blood clotting, nerve transmission, and heart function.

Tetany

Involuntary muscle contractions from hypocalcemia or hypoparathyroidism.

Hyperparathyroidism

Excess PTH leading to bone resorption and high blood calcium.

Hypoparathyroidism

Low PTH causing low calcium and symptoms like tetany.

Adrenal gland

Glands with two parts: adrenal medulla (inside) and adrenal cortex (outside).

Adrenal medulla

Inner part; secretes epinephrine (adrenaline).

Epinephrine

Adrenal medulla hormone that increases heart rate, blood pressure, and glucose; dilates bronchioles.

Adrenal cortex

Outer part; secretes glucocorticoids, mineralocorticoids, androgens.

Glucocorticoids (cortisol)

Raise blood glucose; mobilize energy; suppress inflammation; important in stress response.

Mineralocorticoids (aldosterone)

Regulate electrolytes; increase sodium reabsorption and potassium excretion; helps regulate blood pressure.

Androgens (adrenal)

In females promote bone/muscle growth and libido; adrenal contribution to secondary sex characteristics.

Cushing disease

Hypersecretion of cortisol; causes hyperglycemia, moon face, central obesity, muscle loss.

Addison's disease

Hyposecretion of cortisol; fatigue, weakness, hyperpigmentation, electrolyte imbalance.

Pancreas

Has acini (digestive enzymes) and Islets (hormones).

Insulin

Lowers blood glucose by promoting uptake and storage; promotes protein/lipid synthesis.

Glucagon

Raises blood glucose by promoting glycogen breakdown and glucose synthesis.

Diabetes mellitus

Disorder where insulin production or action is inadequate, causing hyperglycemia and related issues.

Type 1 diabetes

Autoimmune destruction of pancreatic islets; insulin-dependent.

Type 2 diabetes

Insulin resistance; often associated with obesity; managed with lifestyle changes.

Hyperglycemia

High blood glucose.

Hypoglycemia

Low blood glucose.

Polyuria

Excessive urination.

Polydipsia

Excessive thirst.

Islets of Langerhans

Pancreatic islets that secrete insulin and glucagon.

Diabetes insipidus

ADH deficiency leading to excessive dilute urine and dehydration.

Negative feedback example thermostat

Illustration: when the room reaches set temperature, the thermostat turns heating off.

Iodine required for thyroid hormones

Iodine is essential for synthesis of T3 and T4.

Thyroid hormones increase metabolic rate

T3 and T4 raise cellular metabolism and heat production.