BIOL 251 Chapter 16 Endocrine System (Part 2)

List the endocrine glands

-hypothalamus

-pituitary gland

-thyroid gland

-parathyroid gland

-Adrenal glands

-pancreas

-pineal gland

-thymus gland

-reproductive glands

-part neuronal and part endocrine in function

-locate in the diencephalon below the thalamus

-control the activity of pituitary glands

Hypothalamus

-is pea shaped, attached to the hypothalamus of the brain by a stalk called infundibulum, present on the sella turcica of sphenoid bone

-master endocrine gland

Pituitary gland (hypophysis)

What two lobes does the pituitary gland have?

-posterior pituitary

-anterior pituitary

Lobe of pituitary gland that is neural tissue (neurohypophysis)

Posterior pituitary

Lobe of pituitary gland that is glandular tissue (adenohypophysis)

Anterior pituitary

The posterior pituitary is composed of neural tissue called

Pituicytes

The posterior pituitary is part of the brain and maintains neural connection with the hypothalamus via

Hypothalamic-hypophyseal tract (nerve bundle)

The supraoptic nuclei of the hypothalamus secrets what neurohormone?

Antiduretic hormone (ADH)

The paraventricular nuclei of the hypothalamus secrets what neurohormone?

Oxytocin

-regulates water balance

-osmoreceptors monitor solute concentration

-this hormone targets kidney tubules —> reabsorb more water

Antidiuretic hormone (ADH)

High concentrations of ADH —> vasoconstriction

What is this also referred to as?

Vasopressin

-there is no direct neural contact with the hypothalamus

-there is a vascular connection the hypotheses portal system

Anterior pituitary hypothalamic relationship

Hypophyseal portal system:

-stimulate the synthesis and release of hormones of anterior pituitary

Releasing hormones

Hypophyseal portal system:

-shut off the synthesis and release of hormones

Inhibiting hormones

Anterior pituitary hormones that are nontropic hormones

-growth hormone (GH)

-prolactin (PRL)

Anterior pituitary hormones that are tropic hormones:

-thyroid stimulating hormone (TSH)

-adrenocorticotropic hormone (ACTH)

-follicle stimulating hormone (FSH)

-Luteinizing hormone (LH)

Difference between nontropic and tropic hormones?

Tropic hormones regulate the secretary action of other endocrine glands

-released by somatotropic cells of anterior pituitary

-stimulates breakdown of fats to be used as energy source

-increases glycogen breakdown in liver; which releases glucose into the blood

-increases protein synthesis

-The release of this is chiefly regulated by hypothalamic hormones

Growth hormone (GH)

Hypothalamic hormone that stimulates GH release

-secretion in response to low blood glucose

Growth hormone-releasing hormone (GHRH)

Hypothalamic hormone that inhibits GH release

-secretion in response to high blood glucose

Growth hormone-inhibiting hormone (GHIH)

(Hunger hormone produced by stomach) also stimulates GH release

Ghrelin

Results from hyposecretion of GH during childhood

Pituitary dwarfism

Results from hypersecretion of GH during childhood

Gigantism

Results from hyposecretion of GH during adulthood after the epiphyseal plates of the long bones have fused

Acromegaly

Hypersecretion of GH is a result from what?

What is the treatment?

-result from an anterior pituitary gland tumor which releases excessive GH

-treatment is surgery

-secreted by _________ cells of the anterior pituitary

-stimulates milk production by the breast

Prolactin (PRL)

Release of prolactin is stimulated by this hormone

Prolactin releasing hormone (PRH)

Release of prolactin is inhibited by this hormone, which is also known as dopamine

Prolactin inhibiting hormone (PIH)

Hormone from the anterior pituitary gland that stimulates production and release of thyroid hormones by the thyroid gland

Thyroid stimulating hormone (TSH)

Hormone from hypothalamus that triggers the release of TSH from the anterior pituitary gland

Thyrotropin-releasing hormone (TRH)

-the release of this from the anterior pituitary gland is stimulated by corticotropin releasing hormone (CRH) from the hypothalamus

-stimulates the adrenal cortex to release corticosteroid hormones (ex. Cortisol)

Adrenocorticotropic hormone (ACTH)

Internal and external factors such as fever, hypoglycemia, and stressors triggers the deals of

Corticotropin releasing hormone (CRH)

Hormone from hypothalamus that triggers the release of gonadotropin hormone from the anterior pituitary gland

Gonadotropin-releasing hormone (GnRH)

Two gonadotropin hormones are secreted from anterior pituitary gland, what are they?

Follicle stimulating hormone

Luteinizing hormone

Hormone that stimulates follicle development in ovaries and stimulates sperm development in testes

Follicle stimulating hormone (FSH)

Hormone that triggers ovulation of an egg in females and stimulates testosterone production in males

Luteinizing hormone (LH)