Histology of the Endocrine System

A comprehensive set of flashcards covering key vocabulary and concepts related to the histology of the endocrine system.

Endocrine System

A system of glands that secrete hormones directly into the bloodstream.

Hormones

Chemical messengers produced by glands in the endocrine system that regulate various physiological processes.

Axis

A sequence of glands that signal each other, such as the hypothalamic-pituitary-gonadal axis.

Pituitary Gland

Also known as the hypophysis, it is divided into the anterior lobe and posterior lobe.

Anterior Lobe

Also called adenohypophysis, it produces various hormones including GH, TSH, and ACTH.

Posterior Lobe

Also known as neurohypophysis, it stores hormones produced by the hypothalamus.

Hypothalamus

Brain region that controls the pituitary gland and releases hormones that regulate endocrine functions.

Chromophils

Cells in the anterior pituitary that are further divided into acidophils and basophils.

Acidophil Cells

Type of chromophil that stains readily and produces growth hormone and prolactin.

Basophil Cells

Type of chromophil that produces hormones like TSH, ACTH, and gonadotropins.

Chromophobes

Cells in the anterior pituitary that have little or no staining capacity.

Hormonal Secretion

Process by which hormones are released from glands into the blood.

Oxytocin

Hormone produced by the paraventricular nucleus, involved in childbirth and lactation.

Antidiuretic Hormone (ADH)

Hormone produced by the supraoptic nucleus, regulates water balance in the body.

Herring Bodies

Accumulations of hormone-bound granules found in the terminal axons of the neurohypophysis.

Pituicytes

Cells in the neurohypophysis that assist in the release of hormones.

Thyroid Gland

Endocrine gland that produces hormones regulating metabolism, composed of follicles.

Thyroglobulin

A large glycoprotein in thyroid follicles that is a precursor for T3 and T4 hormones.

Parafollicular Cells

Cells in the thyroid gland that secrete calcitonin to regulate calcium levels.

Parathyroid Gland

Gland that regulates calcium levels in the blood through parathyroid hormone (PTH).

Chief Cells

Cells in the parathyroid gland that secrete parathyroid hormone (PTH).

Oxyphil Cells

Larger, less common cells in the parathyroid gland thought to have a role in hormone regulation.

Adrenal Gland

Gland composed of an outer cortex and an inner medulla that produces various hormones.

Zona Glomerulosa

Outer layer of the adrenal cortex that produces mineralocorticoids, such as aldosterone.

Zona Fasciculata

Middle layer of the adrenal cortex that produces glucocorticoids.

Zona Reticularis

Inner layer of the adrenal cortex that produces androgens.

Chromaffin Cells

Cells in the adrenal medulla that produce catecholamines, such as epinephrine and norepinephrine.

Pineal Gland

Small gland in the brain that secretes melatonin, regulating sleep-wake cycles.

Pinealocytes

The main cells in the pineal gland, responsible for producing melatonin.

Glial Cells

Supportive cells in the pineal gland that assist pinealocytes.

Islets of Langerhans

Clusters of endocrine cells in the pancreas that produce hormones like insulin and glucagon.

Alpha Cells

Cells in the islets of Langerhans that secrete glucagon, raising blood glucose levels.

Beta Cells

Most numerous cells in the islets that secrete insulin, lowering blood glucose levels.

Delta Cells

Cells in the islets that secrete somatostatin, inhibiting insulin and glucagon secretion.

Epsilon Cells

Cells in the islets that secrete ghrelin, which stimulates appetite.

PP Cells

Cells in the islets that secrete pancreatic polypeptide, involved in appetite regulation.

Corticosteroids

Steroid hormones produced by the adrenal cortex that regulate various functions, including stress response.

Glucocorticoids

Hormones like cortisol produced by the adrenal cortex that influence metabolism and immune responses.

Catecholamines

Hormones produced by the adrenal medulla, including epinephrine and norepinephrine.

Retention

The process of holding onto substances such as water or minerals in the body.

Thyroid Follicles

Structures in the thyroid gland that contain thyroglobulin and are surrounded by epithelial cells.