GHM L5 Flashcards
Diagram of Adrenal Gland
Diagram L5
-Capsule
-Zona Glomerulosa
-Zona Fasiculata
-Zona reticularis
-Medulla
Transverse section
-Capsule
-Cortex
-Medulla
Adrenal gland situated above kidney
Which hormones are secreted by the adrenal glands? State the function of these hormones and exactly where they are produced in the adrenal glands
ZONA GLOMERULOSA - MINERLCORTICOIDS
ZONA FASICULATA - GLUCOCORTICOIDS
ZONA RETICULARIS - ANDROGENS
ADRENAL MEDULLA - CATECHOLAMINES
State the 3 sections of the adrenal cortex
Zona glomerulosa
Zona fasiculata
Zona reticularis
State the functions of mineralcorticoids
MINERAL BALANCE REGULATION (influence salt + water balances)
ALDOSTERONE - primary mineralcorticoid
Mineralcorticoids are corticosterioids (class of steroid hormones)
State the function of glucocorticoids
Regulation of glucose metabolism
CORTISOL
State the function of androgens
Stimulate virilization / masculinisation
DHEA
State the function of catecholamines
Stimulate ANS
ADRENALINE
Give an example of a primary mineralcorticoid
Aldosterone
What are corticosteroid hormones ?
Mineralcortioids, Glucocorticoids
Class of steroid hormones
Describe the steps leading to aldosterone release in the adrenal cortex
Aldosterone produced by zola glomerulosa in adrenal glands
CRH - produced in PVN nucleus
Released from neurosecretory terminals of neurons
Into the anterior pituitary gland
Stimulates corticotropes to secrete adrenocorticotropic hormone ACTH
ACTH stimulates synthesis of cortisol, glucocorticoids, mineralcorticoids - e.g. aldosterone
STRESS causes HYPOTHALAMUS to release CRH
CRH to anterior pituitary
Anterior pituitry produces ACTH, goes to adrenal cortex
ADRENAL CORTEX produces ALDOSTERONE
ALDOSTERONE - increases water + Na+ absorption
Increases K+ excretion
Increase blood vol therefore, increase BP
REFER TO DIAGRAM L5
State the function of aldosterone and how it carries this out
Increase Na+ + water retention
Lower K+ conc
SECRETION OF H+ IN EXCHANGE FOR K+ (acid/base balane)
HOW?
-
State how the function of aldosterone is regulated
Low Blood Vol
Low BP
Low Na+
High K+
Describe the steps leading to cortisol release in the adrenal cortex
Stress stimulates PVN nucleus in hypothalamus to produce CRH (Corticotropin releasing hormone) into anterioir pituitary gland
Stimulates corticotropes in anterior pituitray glands to secrete ACTH (adrenocorticotropic hormone) into adrenal cortex
ACTH binds to receptors causes increase in cAMP
activation of kinases by phosphorylation
Increase in cholestrol esterase activity
Increase levels of free cholestrol, converted to pregenolone
This is the rate limiting step in steroid biosynthesis
ACTH stimulates synthesis of cortisol in adrenal cortex, cortisol released by adrenal cortex into blood
-Blood glucose levels
-Gluconeogenesis
-Immune response
-Blood pressure, Heart Rate
-CNS activation
State the functions of cortisol and how these functions are regulated
Maintenane of blood pressure
Slow immune system inflammatory response
Maintenance of blood glucose levels
Foetal surfactant
-STRESS
-STARVATION
-AEROBIC EXERCISE
State the cause and symptoms of Addison’s disease
PRIMARY ADRENAL INSUFFICIENCY
Redcued ACTH produced, therefore, INSUFICCIENT MINERALCORTICOIDS + CORTISOL
SYMPTOMS:
-skin darkening (melanocyte-stimulating hormone + ACTH share a precursor)
-LOW BLOOD PRESSURE
-SYNCOPE (LOSS OF CONSCIUSNESS + ABILITY TO STAND)
-HYPOGLYCEMIA
-SEVERE LETHARGY
-SEVERE VOMITING + DIARRHOEA, RESULTING IN DEHYDRATION
-HYPONATREMIA - LOW SODIUM LEVELS IN BLOOD
-HYPERALKAEMIA - ELEVATED BLOOD POTASSIUM LEVELS
-HYPERCALCEMIA - ELEVATED CALCIUM LEVELS IN BLOOD
State a treatment of Addison’s disease
STEROID REPLACEMENT
State two steroidal sex hormones
Oestradiol - type of oestrogen
Testosterone
State the functions of oestrogen
SECONDAY SEXUAL CHARACTERISTCS
REDUCES BOWEL MOTILITY
INCREASES PLATELET ADHESION
SUPPORTS ALVEOLI
CARDIO-PROTECTIVE
REDUCES BONE RESORPTION
IN MALES ONLY: REDUCES APOPTOSIS OF GERM CELLS
SALT + WATER RETENTION
INCREASED GROWTH HORMONE
State the functions of testosterone
SECONDARY SEXUAL CHARACTERITSICS
ANABOLIC - MUSCLE, BONE MASS INCREASED
LIBIDO
State the causes and symptoms androgen insensitivity syndrome
- Born phenotypically FEMALE
-Can be present at puberty because of absent menarche (absence of menstrual periods)
-BODY CANNOT RESPOND TO ANDROGENS
-GONADS NOT OVARIES BUT TESTES
Why does the zona glomerulosa only produce aldosterone?
- Cells in Zona glomerulosa conatain specific receptors for angiotensin II
-These receptors stimulate the production and release of aldosterone from zona glomerulosa cells - Cells in zona glomerulosa contain specific enzymes + transporters allowing them to selectiviely produce + secrete aldosterone
-e.g. aldosterone synthase
Describe the steps leading to aldosterone release in the adrenal cortex
Aldosterone produced by zola glomerulosa in adrenal glands
CRH - produced in PVN nucleus
Released from neurosecretory terminals of neurons
Into the anterior pituitary gland
Stimulates corticotropes to secrete adrenocorticotropic hormone ACTH
ACTH stimulates synthesis of cortisol, glucocorticoids, mineralcorticoids - e.g. aldosterone
STRESS causes HYPOTHALAMUS to release CRH
CRH to anterior pituitary
Anterior pituitry produces ACTH, goes to Dtadrenal cortex
ADRENAL CORTEX produces ALDOSTERONE
ALDOSTERONE - increases water + Na+ absorption
Increases K+ excretion
Increase blood vol therefore, increase BP
REFER TO DIAGRAM L5
State the function of the adrenal medulla
Secretion of catecholamines (dopamine, adrenaline, noradrenaline)
Composed of chromaffin cells - specialised cells in adrenal medulla - secrete adrenaline and noradrenaline
Chromaffin cells convert tyrosine (which is an amino acid
into catecholamines
ANS controls the above process, so, if ANS is activated, the above process is sped up, more catecholamine (adrenaline) released faster
Adrenaline »_space; noradrenaline
PDE breaks down the catecholamines
State the functions of dopamine
- Cognitive control + memory
- Reward perception (primary mediator)
- Positive reinforcement
- Motor system function
- Sexual arousal, orgasm
