Pituitary & Adrenal glands Flashcards
What hormones does the Pituitary gland produce?
TSH (Thyrotrophs) ACTH (Corticotrophs) GH (Somatotrophs) LH & FSH (Gonadotrophs) Prolactin (Lactotrophs)
What hormones does the Adrenal cortex produce?
Zona Glomerulosa (Mineralcorticoids) Zona Fasciculata (Glucocorticoids) Zona Reticularis (Androgens)
What hormones does the Adrenal medulla produce?
Adrenaline
What is the mechanism of action of ACTH?
Interacts with high affinity receptors on the cell surface in the zona fasiculata and reticularis
cAMP used as secondary messenger
Activation of cholesterol esterase
Cholesterol esters go to Cholesterol
What is the action of Cortisol?
Increases availability of all major substrates; proteolysis, lipolysis and gluconeogenesis.
What is the action of Aldosterone?
Stimulates Na+ reabsorption in exchange for K+
What is the action of Androgen?
Stimulate growth of male genital tract and male traits eg hair, anabolic muscle, height
What is the action of Oestrogen?
Stimulate growth of female genital tract and breasts. Also produce female characteristics eg broad hips and decrease cholesterol levels as well as being anabolic
Briefly explain the steroid family that includes Cortisol.
All lipophilic and have to be transported using carriers
Produced from Cholesterol using Progesterone
What is the mechanism of action of Cortisol?
Can cross the plasma membrane
Binds to cytoplasmic receptors
Enters the nucleus and interacts with sections of DNA to change rate of transcription of specific genes.
What is the mechanism of action of Adrenaline?
Binds to adrenoceptors on cell surface then has secondary messenger
How is Cortisol secretion effected by ACTH?
ACTH released from anterior Pituitary main controller
CRH produced by Hypothalamus effects ACTH levels
How is Adrenaline produced?
Tyrosine –> Dopa –> Dopamine –> Noradrenaline –> Adrenaline
What is likely to cause over secretion of Adrenaline?
Phaemochromocytoma
