Search results
Results from the WOW.Com Content Network
The cortex of the adrenal gland is derived from mesoderm, whereas the medulla is derived from the neural crest, which is of ectodermal origin. [12] The adrenal glands in a newborn baby are much larger as a proportion of the body size than in an adult. [38] For example, at age three months the glands are four times the size of the kidneys.
The adrenal cortex is the outer region and also the largest part of the adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. It is also a secondary site of androgen synthesis. [2]
The adrenal medulla affects energy availability, heart rate, and basal metabolic rate. Recent research indicates that the adrenal medulla may receive input from higher-order cognitive centers in the prefrontal cortex as well as the sensory and motor cortices, providing credence to the idea that there are psychosomatic illnesses. [3]
Electrical impulses carried by the sympathetic nervous system are converted to a chemical response in the adrenal gland. Chromaffin cells contained in the adrenal medulla act as postganglionic nerve fibers that release this chemical response into the blood as a circulating messenger. The sympathoadrenal system can activate and discharge ...
Schematic of the HPA axis (CRH, corticotropin-releasing hormone; ACTH, adrenocorticotropic hormone) Hypothalamus, pituitary gland, and adrenal cortex The hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis) is a complex set of direct influences and feedback interactions among three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a ...
At birth, the adrenal glands weigh approximately eight to nine grams (twice that of the adult adrenal glands) and are 0.5% of the total body weight. At 25 weeks, the adult adrenal cortex zone develops and is responsible for the primary synthesis of steroids during the early postnatal weeks.
The adrenal cortex originates from the thickening of the intermediate mesoderm. [3] At five to six weeks of gestation, the mesonephros differentiates into a tissue known as the gonadal ridge. The gonadal ridge produces the steroidogenic cells for both the gonads and the adrenal cortex. [4] The adrenal medulla is derived from ectodermal cells ...
An example of a neuroendocrine cell is a cell of the adrenal medulla (innermost part of the adrenal gland), which releases adrenaline to the blood. The adrenal medullary cells are controlled by the sympathetic division of the autonomic nervous system. These cells are modified postganglionic neurons. Autonomic nerve fibers lead directly to them ...