T1 l6:Adrenal Cortex - Hormones, Physiology Flashcards
what percentage is the medulla and the cortex of the adrenal gland
10% is the adrenal medulla and 90% outer adrenal cortex
what is the main function of the adrenal medulla and cortex
The adrenal cortex is responsible for homeostasis (stress, sex, sodium, and glucose) response and the adrenal medulla is responsible for stress
what from the diet is used to synthesize cortisol
Cholesterol
give an example of a glucocorticoid
Cortisol
give an example of the mineralocorticoids
Aldosterone
what is the basic synthetic pathway
How from cholesterol you can derive cortisol , aldosterone and testosterone
which area is cortisol made from
Zone fasciculata
what zone is androgens synthesised from
Zone reticularis
does the adrenal cortex secrete large volumes of sex hormones
no only small volumes such as testosterone and oestrogen
what can occur to sex hormones with adrenal disorders
A large secretion of them
How do you control the glucocorticoid secretion- give the flow chart and abbreviations of the chemicals
Hypothalamus: CRH
Anterior pituitary gland: ACTH
Adrenal cortex: Cortisol
describe the secretion of ACTH and how it varies during the day
and the effect of prolonged stress
The secretion of ACTH is pulsatile:
peak in the early morning, at the time of waking
nadir in the middle of the night.
Increased secretion at time of prolonged stress.
Cortisol secretion can be related to which cycle and what type of travel
The sleep wake cycle,
Long haul travels
Describe the percentages of how glucocorticoids travel through the blood
10% free in the blood
15% albumin
75% corticosteroid binding globulin
what [is pregnancy associated with
CBG-transcortin which increases the plasma protein concentrations
how is adrenal steroids secreted when they are lipid soluble
They are glucuronidated in the liver to form water soluble forms which are excreted in the urine
What are the effects of cortisol (5)
• Antagonizes the effects of insulin on cellular uptake of glucose
• Stimulates glycogenolysis
• Stimulates hepatic gluconeogenesis.
• Lipolysis
Vasoconstriction (in response to catecholamines)
what does cortisol cause in excessive concentrations
Fat deposit in the face, trunk in the intrascapular region of the shoulders
what periphery effects does cortisol have in the periphery
It inhibits protein synthesis results in amino acid uptake and protein synthesis - net loss of skeletal protein
can glucocotricoids affect aldosterone receptors
Yes sometimes and also mineralocorticoid actions of glucocorticoids only apparent at high concentrations
what psychological effect can glucocorticoids cause
Feelings of elation
what is the stimulus for ACTH and corticosteroid release
Stress
how do glucocorticoids affect the body’s defense systems at many levels
inhibit the cellular immune system:
They suppress the lymphoid tissue,
reduce antibody production
• They stabilize leucocyte membranes and reduce the release of proteolytic enzymes.
• They inhibit phospholipase A2 and reduce the synthesis of the inflammatory mediators.
what does glucocorticoids do to your inflammatory response
They suppress their inflammatory response
how is the inflammatory response suppressed
It removes the pain and decreases the immobilization induced by the oedema
steroid-induced sedation also causes a lack of awareness of the severity of the situation.
what causes the initial conversion of cholesterol into pregnenolone
ACTH
what system influences the secretion of aldosterone
The renin-angiotensin system
what other factors directly stimulate aldosterone
trauma, anxiety, hyperkalaemia and hyponatraemia and inhibited by atrial natriuretic peptide (ANP)
what is the % of aldosterone that is protein bound
50%
what occurs after intracellular receptor activation by aldosterone
expression of ion channels that transport sodium and potassium ions across the cell membrane.
which tubule does aldosterone stimulate re-absorption from
distal tubule
and collecting duct
what is sodium exchanged for via aldosterone
potassium and H+ ions
what other hormone does aldosterone work with to control blood volume and pressure
ADH
what are adrenocorticosteroids used for
Replacement therapy & for their immunosuppressive/anti-inflame effects
what conditions can adrenocorticoids affect
Arthritis
Asthma
Allergies
Leukaemia
what are mineralcorticoids used for
replacement therapy
give an example of a mineralcorticoid drug
Fludrocortisol
what are the adverse effects that are associated with the use of glucocorticoids
Steroid usage may suppress wound healing and may exacerbate infections due to their immunosuppresant effects.
Long term use in children may cause inhibition of growth, and in adults may result in osteoporosis.
The development of diabetes mellitus and other symptoms of Cushing’s syndrome also often accompanies steroid therapy.
suppression of the hypothalamic-pituitary axis.
what can occur due to chronic admin of exogenous glucocorticoids
suppression of ACTH secretion leading to atrophy of the adrenal cortex
are steroids addictive or is there a misunderstanding
they are not addictive but :
the adrenal cortex is unable to secrete endogenous hormones and the patient suffers an Addisonian crisis, which may be fatal. This consequence overcome by the gradual reduction of the dose of the exogenous steroid
Other consequences of suppression of the anterior pituitary may include disturbances of sex hormone secretion resulting in symptoms such as menstrual disturbances
what is the use of cortisol as a drug
is a natural glucocorticoid secreted by the adrenal cortex. It acts via specific intracellular glucocorticoid receptors to influence gene expression. Glucocorticoids are typically used for hormone replacement therapy, as anti-inflammatory agents and immunosuppressants. Hydrocortisone is the drug of choice for replacement therapy
what is another name for cortisol
Hydrocortisone
