Adrenal glands/adrenal gland dysfunction/ exogenous steroids Flashcards
where are the adrenal glands found?
they are located on top of both kidneys
what does the adrenal gland consist of?
medulla (centre of the gland) and the cortex
what is the adrenal medulla part of?
The medulla is part of the Sympathetic Nervous System
what is the adrenal medulla responsible for?
it is responsible for producing epinephrine and norepinephrine
what is the structure of the adrenal cortex?
the adrenal cortex is arranged in 3 layers
what are the 3 layers of the adrenal cortex?
zona glomerulosa –> zona fasciculata –> zona reticularis
what does the adrenal cortex do?
The adrenal cortex produce small amount of both androgens (mainly dehydroepiandrosterone) and estrogens
function of zona glomerulosa?
Mainly secrete mineralocorticoid aldosterone,
hormone that help control the balance of water and electrolytes in the blood
function of zona fasciculata?
Mainly secrete glucocorticoid cortisol,
hormone that influence the energy metabolism of most body cells and help resist stressors and
affect mainly carbohydrate and protein metabolism
function of zona reticularis?
Produce small amounts of adrenal sex hormones, or gonadocorticoids which only becomes important if overproduction is present
what process occurs in the adrenal cortex?
steroidogenesis - corticosteroids are synthesised from cholesterol
what is the principal steroid with mineralocorticoid activity?
aldosterone
what are the principle sites of action for aldosterone?
distal and collecting tubule of the kidney
what does aldosterone do at the distal and collecting tubules of the kidney?
Increases resorption of sodium
Increases resorption of water
Increases renal excretion of potassium
what would happen to a person without aldosterone?
a person rapidly dies from the circulatory shock because of the fall in the plasma volume.
what are some of the triggers that cause aldosterone release?
decreased sodium or increased potassium in the blood
decreased blood volume/blood pressure
what are glucocorticoids?
affect glucose, protein and fat metabolism and other effects
what are the principal steroids with glucocorticoid activity?
cortisol or hydrocortisone
how does cortisol increase blood glucose?
by
Stimulating hepatic gluconeogenesis
Decreasing glucose uptake by many tissues
what are some of the metabolic effects of cortisol?
Increases protein degradation in muscles
Facilitates lipolysis in adipose tissues and causes redistribution of fats to the abdominal area and back
what are the permissive effects of cortisol?
Cortisol must be present in adequate amounts to permit the catecholamines to induce vasoconstriction.
cortisol and stress -
Cortisol plays a key role in the adaptation to stress
how much cortisol may be secreted in stressful situations?
300 mg /day
does cortisol have any anti-inflammatory actions?
Cortisol also has anti-inflammatory and immunosuppressive actions at higher concentrations. They inhibit almost all inflammatory process
what may happen if there are excessive levels of glucocorticoids?
depress cartilage and bone formation,
promote changes in cardiovascular, neural, and gastrointestinal function
how do cortisol levels change through out the day?
Cortisol levels are at their maximum early in the morning and then gradually taper off during the day and are at their lowest shortly after going to sleep
what is addison’s disease?
occurs when the adrenal glands do not produce enough of the hormone cortisol and, in some cases, the hormone aldosterone
what are most cases of addison’s diseases caused by?
the gradual destruction of the adrenal cortex are caused by autoimmune disorders
what are some of the signs and symptoms of addison’s disease?
Chronic fatigue, muscle weakness, weight and appetite loss, hypotension, areas of hyperpigmentation in the skin
what is addisonian crisis?
Because the symptoms progress slowly, they are usually ignored until a stressful event like an illness or an accident causes them to become worse. This is called an Addisonian crisis, or acute adrenal insufficiency.
what are symptoms of an addisonian crisis?
A sudden penetrating pain in the lower back, abdomen, or leg, severe vomiting and diarrhea, dehydration, low blood pressure, loss of consciousness
what are the treatments for addison’s disease?
involves replacing the hormones that the adrenal glands are not making.
how can cortisol be replaced in the treatment of Addison’s?
Cortisol is replaced orally with hydrocortisone tablets.
can aldosterone be replaced in addison’s treatment?
If aldosterone is also deficient, it is replaced with oral doses of a mineralocorticoid fludrocortisone.
what is Cushing’s syndrome?
is a hormonal disorder of glucocorticoid excess
what are some of the causes of Cushing’s syndrome?
Pituitary adenoma - Cushing’s disease
Adrenal problems such as adrenal hyperplasia, tumours of an adrenal gland
Ectopic ACTH- Such as due to some types of lung cancer.
what is the most common cause of excess steroids in the blood?
long-term use of steroid medications for other disorders
what are signs and symptoms of Cushing’s syndrome?
Moon face, central body obesity, thin and bruised skin, glucose intolerance, hypertension, excess hair growth, osteoporosis, kidney stones, menstrual irregularity, and emotional liability, increased susceptibility to infections.
what does treatment of Cushing’s syndrome include?
Surgical removal or treatment of tumor
Drugs such as metyrapone, trilostane and aminoglutethimide which blocks synthesis of cortisol.
what is hyperaldosteronism (Conn’s syndrome)?
excess aldosterone leading to hypertension and low potassium
what is androgenital syndrome?
Results from excessive production of gonadocorticoids
what does Androgenital syndrome result in?
Hirsutism in female
Male pseudohermaphroditism in female infants
Precocious pseudopuberty in young boys
what is androgenital syndrome most commonly caused by?
an inherited enzymatic defect in the cortisol steroidogenic pathways
