Lecture 3 Flashcards
(12 cards)
Hypothalamic Pituitary Adrenal axis
the interaction between the hypothalamus, pituitary and adrenal gland. Key to body’s stress response. Most important response to the initiation of the pathway is the release of cortisol from the adrenal cortex. Aim of stress response is to provide glucose for the body to deal with stressor.
Central endocrine glands
Hypothalamus is directly connected to the pituitary gland. Look at images!!
Posterior pituitary gland
doesn’t produce hormones. Not a ‘true’ endocrine gland
anterior pituitary gland
the secretion and production of hormones is under control of the hypothalamus. ‘True’ endocrine gland
Adrenal gland
Has cortex and medulla that synthesise and secrete different hormones. Cortex is largest part and is composed of 3 layers (zona glomerulosa, zona fascicilata and zona reticularis) where they each produce unique hormones
Feedback loop
stress triggers hypothalamus to release Corticotropin releasing hormone (CRH) which travels to pituitary gland. Adrenocorticotropin hormone (ATCH) is then secreted via exocytosis and travels to adrenal gland. Cortisol is secreted via exocytosis and fats and proteins are broken down, releasing energy. CRH and ATCH release is then inhibited by cortisol.
**Diverts energy from immune system
Adrenal Medulla
Secretes catecholamines (adrenaline, noradrenaline and dopamine)
Function of adrenal cortex
secrete cortisol in zona fasciculata
Action of cortisol
increase: appetite, BP, insulin resistance, gluconeogenesis, lyposysis
decrease: wound healing, inflammatory activity, bone formation
Hypercorticolism
Cushing’s syndrome, tumours of adrenal/pituitary gland, exogenous admin
hypocorticolism
not as common, Addison’s disease, congenital adrenal hyperplasia
Cushing’s Syndrome
Could arise from steroid meds over long time or pituitary adenoma. Severe muscle, bone and skin breakdown (proteins breakdown), dampens the inflammatory and immune response, affects mood and brain function, increase: BP, BGL, obesity
