ANATOMY AND PHYSIOLOGY - Adrenal Glands Flashcards
Which structure surrounds the adrenal glands?
Fibrous capsule
What are the two main layers of the adrenal gland?
Cortex and Medulla
Which arteries make up the subcapsular plexus located just under the fibrous capsule of the adrenal glands?
The superior, middle and inferior branches of the renal artery make up the subcapsular plexus
What is the difference between the cortical arterioles and the long cortical arterioles?
The cortical arterioles branch from the subcapsular plexus and branch into capillary beds within the cortex, long cortical arterioles branch from the subcapsular plexus and branch into capillary beds within the medulla
Which veins drain the adrenal glands?
Central medullary vein drains into the caudal vena cava or the renal vein
What is the embryological origin of the adrenal cortex?
The adrenal cortex has a mesodermal origin
What is the main function of the adrenal cortex?
Steroid hormone synthesis and secretion
What are the three zones of the adrenal cortex?
Zona glomerulosa
Zona fasciculata
Zona reticularis
Which of the three zones of the adrenal cortex can change size depending on the physiological conditions?
Zona reticularis can change in size depending on the physiological conditions
Which hormone stimulates the beginning of steroid hormone synthesis in the adrenal cortex?
Adrenocorticotropic hormone (ACTH) secreted by the anterior pituitary gland
Which hormones are produced by the zona glomerulosa?
Mineralocorticoids (mainly aldosterone)
What are the cells in the zona glomerulosa which produce mineralocorticoids?
Trabeculae cells
Describe the histological appearance of trabeculae cells
Trabeculae cells are columnar cells with prominent nuclei
List the three physiological changes that stimulate the renin-angiotensin-aldosterone mechanism
Change in blood pressure
Change in sympathetic innervation
Change in Na+ concentration in the filtrate
Describe how the renin-angiotensin-aldosterone mechanism regulates aldosterone secretion from the trabeculae cells
- Decreased blood pressure, increased sympathetic nervous system innervation and/or decreased Na+ concentration in the filtrate stimulates the juxtaglomerular cells to secrete renin
- Renin coverts angiotensin (produced by the liver) into angiotensin I which circulates the body and is converted into angiotensin II in the lungs by the angiotensin conversion enzyme (ACE)
- Angiotensin II stimulates increased aldosterone secretion from the trabeculae cells of the adrenal cortex
What are the main functions of aldosterone?
Regulation of Na+ and K+ secretion from the distal nephron (DCT and collecting ducts) and reabsorption of Na+ into the salivary and sweat glands