Mod 5 Adreanal and Pineal Gland Flashcards
Where are the adrenal glands located? LABEL
The adrenal glands are located on the top of the kidneys (neural tissue)
What makes up the adrenal gland?
Medulla and cortex
What does the cortex do?
The cortex secretes hormones - multiple hormones (corticosteroids)
Label the levels of the adrenal gland
Capsule, cortex, medulla
What are the three categories of corticosteroids?
1) Mineralocorticoids
2) Glucocorticoids
3) Gonadocorticoids
What do mineralocorticoids do?
Mineralocorticoids regulate salt and water balance (aldosterone)
What do glucocorticoids do?
Glucocorticoids regulate metabolism and stress responses (mainly cortisol)
What do Gonadocorticoids do?
Gonadocorticoids have a minor roles compared with gonadal hormones (mainly androgens)
How are corticosteroids synthesised?
Corticosteroids are synthesised by a multistep involving cholesterol and intermediates.
How are corticosteroids released?
Corticosteroids are released: they are not stored in cells, so the rate of release depends on the rate of synthesis.
What are the three layers of the adrenal glands?
1) Zona glomerulosa
2) Zona fasciculata
3) Zona reticularis
What are the actions of corticosteroids?
lipid-soluble, binds intracellular receptors and modify gene activity
Mineralocorticoids?
- regulate mineral salts (electrolytes) in ECF like Na and K - aldosterone is most potent
- most abundant cation in ECF is Na+, where Na+ goes the water follows (blood pressure)
- the resting membrane potential is set by K+ which determines how easily AP is generated - nerve electrical activity
What does the Mineralocorticoids target?
Mineralocorticoids target the kidneys, they reabsorb Na+ and excrete K+
What are the Mineralocorticoids stimulated by?
The Mineralocorticoids are stimulated by a decrease in blood volume and blood pressure (via renin and angll, increase in K+ (direct) and severe stress (via ANP)
What are Mineralocorticoids inhibited by?
they are inhibited by an increase of blood volume and blood pressure via ANP and a decrease in K+
What are the effects of Mineralocorticoids?
brief effects so precise control of plasma electrolytes: transcription and translation of proteins involved in Na and K transport
Steps in Mineralocorticoids?
reduction in blood volume and pressure –> RAAS activation –> results in angiostensin ii hormones
RAAS steps?
Decrease in blood pressure in kidneys –> renin –> angiotensinogen –> angiotensinogen i –> angiotensinogen ii –> an increase in adolsterone release from the adrenal cortex
Hormone imbalance - Mineralocorticoids
Aldosteronism
cause: adrenal tumor or overactivity (primary), excessive RAAS activation (secondary)
What are the symptoms of Aldosteronism
hypertension, edema, non-responsive neurons. muscle weakness and paralysis
What are the treatments of Aldosteronism?
primary surgery, mineralocorticoid receptor antagonist; 2nd surgery and various drugs (h20 and Na+ loss)
What are gluticorticoids?
hormones (cortisol) that are involved in energy metabolism, the resistance of stress and blood pressure.
What do glucocorticoids target?
glucocorticoids target the liver for gluconeogenesis (formation of new glucose), mobilise fatty acids and amino acids. Other cells inhibit glucose and uptake of vasoconstriction
What are glucocorticoids stimulated by?
atch
what are glucocorticoids inhibited by?
glucocorticoids are inhibited by an increase in cortisol, stress can promote CNS to override the positive feedback (upon chronic stress, anti-flam and anti-immune effects)
Hormone imbalance of glucocorticoids
glucocorticoids EXCESS: cushing syndrome
causes: pit/adrenal cortex tumor, ACTH- releasing glucocorticoids.
Symptoms of Cushing’s syndrome?
increase in blood glucose, loss in muscle and bone protection, salt/water retention, hypertension, edema, “moon” face, fat to abdomen & posterior neck, bruising, poor wound healing,
severe infections, weakened muscles, spontaneous fractures
treatement fo Cushing’s syndrome
Treatment: surgery or discontinue glucocorticoid drug
Hormone imbalance of glucocorticoids: deficiency
Addison’s disease is caused by an underactive adrenal cortex usually deficits in glucocorticoids and mineralocorticoids
What are the symptoms of Addison’s disease
sympotoms of addison’s diease include weight loss, a decrease in plasma glucose and Na+, an increase of K+, dehydration, hypertension, bronze skin (negative feedback by corticosteroids), increase in ACTH (melanin)
Treatment of Addison’s disease?
Corticosteroids replacements
What are Gonadocorticoids?
- weak androgens (weak sex hormone)
- insignificant amount compared to those made by gonads from late puberty.
Targets: female axillary, public hair, libido, estrogen after menopause. S
Stimulated by ACTH
Gonadocorticoids imbalance: excess
excess Gonadocorticoids cause adenogenital syndrome/masculinization.
What does adenogenital cause?
a genetic mutation, affecting important enzyme function
What are symptoms of adenogenital syndrome?
not noticeable in adult males, however in younger males premature maturation of sex hormones and secondary sex characteristics, sex drive emerges. In females, masculine distribution of body hair and growth of clitoris.
Treatment for adenogenital syndrome?
glucocorticoid drugs
What are the hormones produced in the adrenal medulla?
Catecholamines
What is the adrenal medulla composed of?
It is composed of modified sympathetic postganglionic neurons: chromaffin cells
What hormones do the adrenal medulla secrete?
The adrenal medulla secretes catecholamines, adrenalin (Ad) and nonadrenalin (NAd)
How are catecholamines synthesised?
catecholamines are synthesised by a multi-step involving tyrosine –> dopamine –> NAd and Ad
storage: 80:20 (ad:NAd)
What do catecholamines do?
Water-souble, so it binds to plasma membrane receptors, reinforces and prolongs fight or flight response
what are catecholamines stimulated by?
acute stress, preganglionic sympathetic nerve endings in the medulla
What does adrenalin do?
Adrenalin stimulates metabolic activities, heart rate, bronchiole dilation
What does non-adrenalin do?
Non-adrenalin has a greater influence on peripheral vasoconstriction and increase in blood pressure
What can catecholamines be used for?
epi-pens for acute asthmatic attacks and severe allergic reactions
catecholamines imbalance: excess?
an excess causes medullary chromassin cell tumor
what are the symptoms of medullary chromassin cell tumor?
increase in metabolic rate, rapid heart rate, palpitations, hypertension (high blood press.), nervousness and sweating
adrenal catecholamines imbalance: deficiency
it’s not a problem, it reinforced Sympathetic NS
Long term stress response?
the hypothalamus activates the adrenal cortex via hormonal stimuli, this greatly reinforces the continuing short-term stress response
Steps in long term stress
1) stressors cause hypothalamic neurons to release corticotrophin- releasing hormone
(CRH)
2) CRH travels via the portal system of blood vessels to the anterior pit.
3) anterior pit. cells corticotrophs release (ACTH)
4) ACTH travels in blood to the adrenal cortex
5) adrenal cortex synthesized and releases glucocorticoids (cortisol) and aldosterone.
Short term stress
The hypothalamis activates the adrenal medulla via neural stimuli
Short term stress steps?
1) AP triggered by the hypothalamus in response to stressors activate the Symp. NS
2) AP travel along preganglionic sym. axons to adrenal medulla
3) the adrenal medulla secretes amino acid based hromones (epinephrone and some nonepinephrine)
4) Epinephrine and norepinephrine reinforce other sympathetic responses to get the body for exertion (fight or flight)
What does the pineal gland produce?
It produces melatonin, it controls our biological clock and physiological rhythms. It occurs in a tiny-pine cone-shaped organ in the centre of the brain
How is melatonin synthesised?
mutli-step derived from seritonine
What does the melatonin target?
targets the suprachiasmatic nucleus of the hypothalamus ( biological clock), physiological rhythms , such as body temp, sleep and appetite.
what is melatonin stimulated by?
indirect visual pathways: intensity and duration of daylight (diurnal cycle, peaks around night and lowest at noon.
Melatonin excess: deficiency?
insomnia, affected sleep patterns, infertility in females, anxiety, and depression
