Exam 1: Adrenals Flashcards
2 hormones of the adrenals
Outer cortex: steroids
Inner medulla: catacholamines
Without adrenal hormones
- deranged electrolyte levels cause circulatory collapse
- impaired carbohydrate metabolism (hypoglycemic coma) causes death
Medulla (ectoderm) secretes
Epinephrine and norepinephrine
Cortex (mesoderm) secretes
Steroid hormones: glucocorticoids, mineralcorticoids, androgens
Mineralcorticoids
Control of Na and K
Secretion controlled by renin-angiotensin System
Glucocorticoids
Affect body fuel metabolism
Secretion controlled by ACTH
Androgens
Similar function to testes
Secretion controlled by ACTH
Sustained stimulation of adrenal glands can ________ output
Increase
Fast acting medullary hormones signal
Physiologic adjustments
Slow acting cortical hormones maintain or increase
- Sensitivity to medullary hormones
- Capacity of tissue to respond to medullary hormones
Act as modulators
Precursor for adrenocorticcaal steroids
Cholesterol
____ are essential for life
Glucocorticoids
2 glucocorticoids
Cortisol and corticosterone
Drugs that inhibit glucocorticoids
Metyrapone and ketoconazole
Metyrapone
Used in diagnosis of adrenal insufficiency and cushings
Inhibits 11-Beta hydroxylase
Ketoconazole
Treats fungal infections
Inhibits cholesterol desmolase
Physiologic functions of glucocorticoids
- Increase gluconeogenesis and storage of glycogen
- Anti-inflammatory
- Suppresses immune response (thymus)
- Maintains vascular responsiveness (catecholamines)
- Inhibit bone formation
- Increase GFR
Cortisol affects _____, ______, and ____ metabolism to increase glucose synthesis
Protein, fat, and CHO
Cortisol decreases
- Utilization of glucose by tissues
2. Adipose insulin sensitivity
_______are essential for survival during fasting
Glucocorticoids
They increase gluconeogenesis
Actions of cortisol that inference with inflammatory response
- Induces synthesis of lipocortin
- Inhibits production of interleukin-2 and proliferation of T lymphocytes
- Inhibits release of histamine and serotonin from mast cells and platelets
Glucocorticoids prevent hypoglycemia by
Decreasing utilization of glucose by muscles and adipose
Decreasing responsiveness of tissues to insulin
Prolonged exposure to high glucocorticoids leads to
Diabetes mellitus
Increase in use of glucose and increase of gluconeogenesis
Increase in glycogen storage in liver and muscle
Maintaining vascular responsiveness to catacholamines
Maintains normal blood pressure
Less cortisol=______
More cortisol=_______
Hypotension
Hypertension
Inhibition of bone formation
- Decrease osteoblastic formation
2. Decrease intestinal calcium absorption so the synthesis of type 1 collagen decreases
Increase in GFR
Causes vasodilation of afferent arterioles and increase in renal blood flow
Glucocorticoids effects on CNS
- Decrease REM sleep
- Increase slow wave sleep
- Increase awake time
- Large bursts of ACTH and cortisol just before waking up
Glucocorticoids effect on lung development in fetus
Maturation of alveoli and produces surfactant
Cortisol secretion is ____ and _____
Pulsatile and diurnal
Lowest secretory rates of cortisol occur
In the evening and after falling asleep
Highest secretory rates of cortisol occur
Before waking and in the morning
What converts cortisol to cortisone
11 beta hydroxysteroid
Cortisol is ____ and cortisone is _____
Active and inactive
Sesame that’s one suppression test
Determines cause of hypercortisolism (tumor of anterior pituitary or adrenal)
Inhibited of ACTH secretion
- Increase blood cortisol levels
- Opioids
- Somatostatin
Stimulators of ACTH secretion
- Decrease blood cortisol levels
- Sleep-wake transition
- Stress
- Surgery
- Trauma
- Hypoglycemia
- Psychiatric disturbances
- ADH
- Alpha and beta adernergic agonists
- Serotonin
Major mineralcorticoids
Aldosterone
Synthesized in zona glomerulosa
Aldosterone
Other hormones with mineralcorticoids activity
11-deoxycorticosterone and corticosterone
Regulation of aldosterone
Renin-angiotensin-aldosterone system
ACTH has a tonic secondary effect on _______ secretion
Aldosterone
Excess aldosterone
- Increase sodium reabsorption
- Increase potassium and hydrogen excretion
- Increase ECF volume
- Hypertension
- Hypokalemia
- Metabolic alkalosis
Mineralcorticoid control of ECF volume
Decreases ECF volume
Mineralcorticoids control of plasma K+ concentration
Increases potassium concentration by increasing aldosterone secretion and potassium excretion by kidneys
Aldosterone deficiency
- Decrease Sodium reabsorption
- Decrease potassium and hydrogen excretion
- Decrease ECF volume (contraction)
- Hypotension
- Hyperkalemia
- Metabolic acidosis
Mineralcorticoids bind _______ and ______ with equal affinity
Cortisol and aldosterone
Why doesn’t cortisol overwhelm aldosterone mineralcorticoids since it’s concentration is 1000X higher than aldosterone?
Renal cells convert cortisol to cortisone with 11 beta-hydroxysteroid dehydrogenase
Cortisone has a low affinity for mineralcorticoid receptors
Allows changes in blood levels of aldosterone to be seen in kidney, not masked by high levels of cortisol
Adrenal androgens in males play a ______ role
Play a minor role because de novo synthesis of testosterone in testes is greater
Adrenal androgens in females play a _____ role
Major, contributes to pubic and armpit hair and libido
2 adrenal hormones converted to testosterone in the testes
Dehydroepiandrosterone (DHEA) and androstenedione
Andrenogenital syndrome
Increases synthesis of adrenal androgens
High levels of DHEA and androstenedione result in
- Masculinization in females (malformed genitalia)
- Suppression of gonadal function in both sexes
- Early development of pubic/auxiliary hair
- Increased urinary levels of 17-ketosteroids
21 beta hydroxylase deficiency
Increase androgen production
Decreased mineraldcorticoid and glucocorticoids production
Addison’s disease
Primary adrenocortical insufficiency
Cushing’s syndrome
Primary adrenal hyperplasia
Cushing’s disease
Excess ACTH
Conn’s syndrome
Aldosterone secreting tumor
Autoimmmune disease of the entire adrenal cortex
Addison’s disease
Addison’s disease characteristics
- Decrease synthesis of all adrenocortical hormones (glucocoritcoids, mineralcorticoids, adrenal androgens in women)
- Hyperpigmentation of the skin
Effect of decreased glucocorticoids in Addison’s disease
Hypoglycemia, anorexia, weight loss, nausea, vomiting, weakness
Decreased mineralcorticoids effects in Addison’s disease
Hyperkalemia, metabolic acidosis, hypotension
Effects of decreased adrenal androgens in women with Addison’s disease
Decreased pubic and auxiliary hair and decreased libido
Secondary adrenocortical insufficiency
- insufficient CRH
- insufficient ACTH (mainly)
- same symptoms as Addison’s except low ACTH levels and no hyperpigmentation
Adrenocortical insufficiency
- All organ systems go awry
- Cause of death is circulatory collapse is secondary to sodium depletion
- inadequate food intake, death from hypoglycemia
Chronic excess of glucocorticoids due to spontaneous overproduction by cortisol or pharmacological overdose
Cushing’s syndrome
Characteristics of Cushing’s syndrome
- Hyperglycemia
- Increase muscle wasting
- Decrease insulin sensitivity and greater tendency for fat mobilization
Physical characteristics of Cushing’s syndrome
-Fat in the face, shoulders, and abdomen (Moon face, buffalo hump,) -Striae -osteoporosis -poor wound healing -hypertension -menstrual disorders in females
Cushings Disease VS Cushing’s syndrome
In disease the ACTH is high
Primary hyperaldosteroinism is a characteristic of
Conn’s syndrome
Primary hyperaldosteronism
- caused by aldosterone secreting tumor
- Increase ECF volume
- Increase Sodium and water reabsorption
- increase hydrogen excretion
Treatment of Conn’s syndrome
Sprinolactone (aldosterone antagonist) and surgical removal of the tumor
21 beta hydroxylase deficiency
Unable to make 11-deoxycorticosterone
Without 11-deoxycorticosterone
- Adrenals cant produce mineralcorticoids or glucocorticoids
- Increased production of adrenal androgens
- High ACTH levels because no negative feedback with low cortisol
17 alpha hydroxylase deficiency
- Decreased androgens and glucocorticoids
- Increased 11-deoxycorticosterone and corticosterone (mineralcorticoids)
- Decreased aldosterone due to inhibited renin secretion (angiotensin II)
Adrenal medulla makes up ______ of adrenal gland
10-20%
Chromaffin cells have an affinity for
Chromium salts
Chromaffin cells are
Modified postganglionic neurons
Adrenal medulla is innervated by
Neurons from the intermediolateral horn cells in thoracolumbar spinal cord
Plays a crucial role in response to stress
Adrenal medulla
The adrenal medulla releases mostly
Epinephrine
How are 90% of catacholamines removed
Passage through most capillary beds
Medullary hormones effect on heart
Increase rate and force of contraction
Increase glycogenolysis
Medullary hormone effects on blood vessels
Vasoconstriction
Medullary hormone effect on adipose metabolism
In adipose
-increase lipolysis and blood FFA and glycerol
Increase glycogenolysis, gluconeogenesis and blood sugar
Medullary hormones on liver metabolism
Muscle metabolism changes due to medullary hormones
Increase glycogenolysis and lactate and pyruvate release
Metabolism changes due to medullary hormones on lungs, stomach, and skin
Lungs: dilation of bronchioles
GI: inhibit peristalsis, increase sphincter contraction
Skin: increase sweating
