BSC2086L E.1 Endocrine System

Developed for the Broward College course BSC2086/L Anatomy and Physiology II.

hypophysis

• Located inferior to the hypothalamus and connected to it by the infundibulum.

• Composed of independent anterior and posterior lobes.

• Also known as the pituitary gland.

infundibulum

The narrow stalk attaching the hypophysis to the hypothalamus.

adenohypophysis

• The anterior lobe of the hypophysis.

• Composed of glandular tissue.

• Regulated by the hypothalamus.

neurohypophysis

• The posterior lobe of the hypophysis.

• Composed of neurons originating in the hypothalamus.

growth hormone

• Hormone stimulating cell growth and division.

• Secreted by the adenohypophysis.

• Targets the bones, muscles, and other tissues.

• Abbreviated GH.

adrenocorticotropic hormone

• Hormone stimulating the secretion of adrenal cortex hormones.

• Secreted by the adenohypophysis.

• Targets the adrenal cortex.

• Abbreviated ACTH.

thyroid-stimulating hormone

• Hormone stimulating the secretion of thyroid hormones.

• Secreted by the adenohypophysis.

• Targets the thyroid gland.

• Abbreviated TSH.

follicle-stimulating hormone

• Hormone stimulating the development of ova and sperm.

• Secreted by the adenohypophysis.

• Targets the gonads.

• Abbreviated FSH.

luteinizing hormone

• Hormone stimulating the secretion of sex hormones.

• Secreted by the adenohypophysis.

• Targets the gonads.

• Abbreviated LH.

prolactin

• Hormone stimulating milk production.

• Secreted by the adenohypophysis.

• Targets the mammary glands.

• Abbreviated PRL.

antidiuretic hormone

• Hormone stimulating water reabsorption.

• Secreted by the neurohypophysis.

• Targets the renal tubules.

• Abbreviated ADH.

oxytocin

• Hormone stimulating uterine contractions during labor and delivery and the release of milk.

• Secreted by the neurohypophysis.

• Targets the uterus and mammary glands.

• Abbreviated OT.

thyroid gland

• Located in the anterior neck surrounding the trachea inferior to the larynx.

• Composed of butterfly-shaped right and left lobes connected by an isthmus.

• Composed of follicles.

thyroid follicle

• Composes the thyroid gland.

• Composed of simple cuboidal epithelium containing colloid protein.

follicular cell

• One of the cells composing a thyroid follicle.

• Secretes thyroxine and triiodothyronine.

• Appears dark when stained.

parafollicular cell

• One of the cells composing a thyroid follicle.

• Secretes calcitonin.

• Appears pale when stained.

• Also known as clear or C cells.

colloid protein

• Located inside a thyroid follicle.

• Stores thyroxine and triiodothyronine synthesized by the follicular cells.

thyroxine

• Hormone that regulates oxygen utilization and rate of metabolism of the cells.

• Secreted by follicular cells of the thyroid gland.

• Targets everywhere.

• Abbreviated T**₄.**

triiodothyronine

• Hormone that regulates oxygen utilization and rate of metabolism of the cells.

• Secreted by follicular cells of the thyroid gland.

• Targets everywhere.

• Abbreviated T**₃.**

calcitonin

• Hormone that reduces blood calcium levels via deposition and excretion.

• Secreted by parafollicular cells of the thyroid gland.

• Targets the bones and kidneys.

• Abbreviated CT.

adrenal gland

• Located superior to each kidney.

• Composed of an outer cortex and inner medulla.

• Also known as the suprarenal gland.

adrenal cortex

• The outer layer of the adrenal gland.

• Produces many corticosteroid hormones.

adrenal medulla

• The inner layer of the adrenal gland.

• Secretes hormones in response to stress.

mineralocorticoids

• Class of corticosteroid hormones that increase renal reabsorption of sodium and water.

• Secreted by the adrenal cortex.

• Targets the kidneys.

• For example, aldosterone.

glucocorticoids

• Class of corticosteroid hormones that increase blood glucose levels.

• Secreted by the adrenal cortex.

• Targets most cells.

• For example, cortisol.

androgens

• Class of hormones that are precursors of male and female sex hormones.

• Secreted by the adrenal cortex.

epinephrine

• Hormone that increases cardiac activity, blood pressure, and blood glucose levels.

• Secreted by the adrenal medulla.

• Targets most cells.

• Abbreviated EP.

norepinephrine

• Hormone that increases cardiac activity, blood pressure, and blood glucose levels.

• Secreted by the adrenal medulla.

• Targets most cells.

• Abbreviated NEP.

pancreas

• Located posterior to the stomach.

• Composed of exocrine acini and endocrine islets.

pancreatic acinus

• The exocrine part of the pancreas.

• Composed of acinar cells.

• Secretes digestive enzymes.

pancreatic islet

• The endocrine part of the pancreas.

• Composed of alpha and beta cells.

• Secretes glucagon and insulin.

• Appears lighter compared to acinar cells.

• Also known as an Islet of Langerhans.

insulin

• Hormone that lowers blood glucose level by promoting glucose uptake from the bloodstream.

• Secreted by beta cells of the pancreas.

• Targets everywhere.

glucagon

• Hormone that raises blood glucose level by promoting glycogen breakdown into glucose into the bloodstream.

• Secreted by alpha cells of the pancreas.

• Targets the liver.

thymus

• Located in the superior mediastinum of the thoracic cavity and posterior to the sternum.

• Composed of many lobules.

• Site of T lymphocyte maturation.

lobule

• Basic unit of the thymus.

• Contains an outer cortex and an inner medulla.

cortex

The outer layer of a thymus lobule.

medulla

The inner layer of a thymus lobule.

thymosin

• Hormone that promotes maturation of T lymphocytes.

• Secreted by the thymus.

pineal gland

• Located inferior to the posterior end of the corpus callosum.

• Regulates the circadian rhythm.

melatonin

• Hormone that regulates the circadian rhythm.

• Secreted by the pineal gland.

parathyroid gland

• Pea-like gland doubly located on the posterior of each side of the thyroid gland.

• Composed of chief cells.

parathyroid hormone

• Hormone that raises blood calcium levels.

• Secreted by the parathyroid glands.

• Abbreviated PTH.

testis

• The male gonad.

• Composed of seminiferous tubules and interstitial cells.

seminiferous tubule

• Basic unit of the testes.

• Produces sperm.

interstitial cell

• Located between the seminiferous tubules of the testes.

• Secretes testosterone.

testosterone

• Hormone stimulating the development of male secondary sexual characteristics.

• Secreted by interstitial cells of the testes.

ovary

• The female gonad.

• Produces ova.

follicular cell

• Surrounds an oocyte in the ovary.

• Secretes estrogen.

• Also known as a granulosa cell.

corpus luteum

• The remnants of a follicle after its ova has been released.

• Secretes progesterone.

estrogen

• Hormone stimulating the development of female secondary sexual characteristics and the preparation of the endometrium for fertilization.

• Secreted by follicular cells.

progesterone

• Hormone maintaining the endometrium during pregnancy.

• Secreted by the corpus luteum.