endocrine 2

Pituitary gland is a crucial part of the endocrine system, producing essential hormones that regulate various bodily functions.

The posterior pituitary stores and releases two vital hormones: Antidiuretic hormone (ADH) and Oxytocin.

The anterior pituitary produces six key hormones: Growth hormone (GH), Prolactin (PRL), Thyroid-stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH), Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH).

The hypothalamic-pituitary axis, also known as the HPA, is a complex communication system involving the hypothalamus, pituitary gland, and target glands.

The hypothalamus releases neurohormones that travel to the anterior pituitary via the hypothalamic-pituitary vascular portal system, regulating hormone production.

Negative feedback loops ensure hormone levels are maintained within a specific range. This involves signaling back to the pituitary to reduce or stop hormone production when specific levels are reached.

Pituitary gland disorders, such as diabetes insipidus, hyperthyroidism, or acromegaly, arise due to disruptions in the normal function of the pituitary gland and its hormone regulation.

Hormones produced by the pituitary gland target various organs and tissues throughout the body, influencing growth, metabolism, reproduction, and other vital functions.

The release of oxytocin in response to stimuli associated with suckling, such as the sound of a baby crying or the feel of a baby's touch.

Reflexes in the cervix and uterus trigger the release of oxytocin.

Oxytocin promotes contractions of the uterine smooth muscle, leading to the delivery of the fetus.

The process where a biological response amplifies its own stimulus, leading to a greater response. It's like a snowball effect!

The release of oxytocin during labor is regulated by a positive feedback loop.

The pituitary gland, a small endocrine gland located at the base of the brain, is responsible for regulating various bodily functions through hormone secretion.

The sella turcica is a saddle-shaped depression in the sphenoid bone of the skull that safely houses the pituitary gland.

The anterior lobe of the pituitary gland, also known as the adenohypophysis, is responsible for producing and releasing hormones that regulate various bodily functions.

The posterior lobe of the pituitary gland, also known as the neurohypophysis, stores and releases hormones produced by the hypothalamus.

The pituitary gland develops from two sources during embryonic development: the diencephalon (for the posterior lobe) and Rathke’s pouch (for the anterior lobe).

The anterior pituitary, being an endocrine gland, produces and releases hormones directly into the bloodstream.

The posterior pituitary, being a neural structure, stores and releases hormones produced by the hypothalamus, which are transported to the pituitary via nerve fibers.

The hypothalamus, a brain region, communicates with the pituitary gland using both neural signals (for the posterior lobe) and the hypothalamic-portal system (for the anterior lobe).

A hormone produced by the posterior pituitary gland, primarily responsible for triggering milk release from the mammary glands.

Specialized cells surrounding milk-producing alveoli in the breast. They contract to squeeze out milk.

The process of milk being forced out of the mammary gland.

The act of suckling stimulates sensory receptors in the nipple, leading to the release of oxytocin.

The brain region that controls the release of oxytocin.

Tiny sacs in the breast where milk is produced.

The process of milk production in the breast.

The pituitary gland, a small gland located at the base of the brain, responsible for releasing numerous hormones.

A positive feedback loop where oxytocin release triggers uterine contractions, which in turn stimulates more oxytocin release, leading to increasingly strong contractions.

A hormone released from the posterior pituitary gland that stimulates milk ejection from the mammary glands.

A hormone secreted by the posterior pituitary gland that helps regulate water balance in the body.

ADH is released when the body is dehydrated, promoting increased water reabsorption in the kidneys.

ADH promotes vasoconstriction, leading to increased blood pressure.

High plasma osmolarity, which is the concentration of solutes in the blood, triggers ADH secretion.

Low blood volume and pressure stimulate ADH secretion, especially in severe situations like hemorrhage.

ADH receptor subtypes (AVPR) are G-protein coupled receptors involved in various cellular signaling pathways. These receptors activate different secondary messengers, leading to diverse physiological effects.

AVPR1A receptors are mainly found in vascular smooth muscle, where they mediate vasoconstriction, leading to increased blood pressure.

AVPR1B receptors are primarily expressed in the brain, where they play a crucial role in neural signaling and neurotransmission.

AVPR2 receptors are highly expressed in the kidney tubules, specifically the distal tubule and collecting duct, facilitating water reabsorption.

ADH binding to V2 receptors stimulates adenylate cyclase, leading to elevated cAMP levels. This, in turn, promotes the insertion of aquaporin-2 water channels into the cell membrane and increases transcription of the aquaporin-2 gene.

Increased blood osmolality or decreased blood volume triggers ADH secretion from the pituitary gland.

ADH acts primarily on the kidneys to increase water reabsorption, restoring the body's osmolality and volume back to normal.

ADH, also known as vasopressin, is a hormone that plays a crucial role in regulating water balance by increasing water reabsorption in the kidneys.