endocrinology 4 - adrenal cortex Flashcards
Name the 3 zones of the cortex?
What does the zona reticularis produce?
sex hormones
(low affinity androgens)
What does zona fascicularis produce?
glucocorticoids (cortisol)
What does the zona glomerulosa produce?
aldosterone
name 3 types of cholesterol (steroid hormones)
aldosterone
cortisol
sex hormones
What type of secretion regulates glucocorticoid release?
diurnal rhythm (it has a circadian rhythm but can be induced)
–> inducible in response to stress
i.e a rhythmic inducible release
Name the primary glucocorticoid
cortisol
What hormone is released from the hypothalamus to stimulate ACTH?
CRH
ACTH promote cholesterol to make cortisol
What tissue doe cortisol have an effect on?
IMMUNE system
liver
muscle
adipose tissue
What does ACTH bind in the adrenal cortex?
membrane-bound receptors on cells of zona fasciculata
What is the long-term mediator of stress response?
cortisol
Does cortisol help with hypoglycaemia?
yes
opposes insulin
How does cortisol prevent hypoglycaemia?
stimulates gluconeogenesis
breaks down fat and uses A as energy source
breaks down protein into AA for use as energy source
What is gluconeogenesis?
glucose form non-carbohydrate source
(not glycogen)
can use glycogen if it really needs to
How does cortisol have an effect on immune function?
supress inflammatory immune response
Does cortisol help with proper development?
yes
What effect does cortisol have on brain function?
mood
learning and memory
What are the non-essential functions of cortisol?
growth
reproduction
What hormones does cortisol have an effect on?
required for full glucagon and catecholamine activity
stimulates expression of their receptors
enhance cardiovascular drive and respiratory
androgens male or female?
male/female
What do low affinity androgens make?
testosterone (male)
estrogen (female)
these are made in non-adrenal tissues
Where are low affinity androgen secreted from?
cortex
What does aldosterone regulate?
minerals e.g. na and k
What does the liver constitutively release?
angiotensinogen
(does not have an effect)
What does the kidney release if blood volume decreases?
release renin
What does angiotensinogen and renin make?
angiotensin I
ACE converts this to
agII
What is the effect of agII on the kidney?
stimulates aldosterone
What is the effect of aldosterone on the kidney?
increase na permeability/reabsorption
increase water conservation
hold onto water and maintain electrolyte balance
What is the aldosterone receptor?
mineralocorticoid receptors (intracellular)
What is a drop in blood volume?
haemorrhage or dehydration
(*increase na levels)
Where in the kidney does ag II bind?
binds receptors on the surface of zona glomerulosa cells
this activates biosynthesis of aldosterone
What is the syndrome associated with hypercortisolism?
cushings syndrome
What is a predictable sign of hypercortisolism?
diabetagenic (hyperglycaemia) –> excessive gluconeogenesis
tissue wasting –> muscle, fat and bone breakdown
‘plumping’ of trunk and ‘moon face’ –> redistribution of fat
mood disorder/immunosuppression
hypertension (enhanced adrenaline and/or aldosterone-like effects incraesed blood pressure)
What area have tissue wasting in hypercortisolism?
muscle
fat
bone breakdown
(skinny legs)
moon face
What is the primary cause of hypercorticolsim?
adrenal tumour that autonomously produces cortisol (not controlled by ACTH)
What is the secondary cause of hypercorticolism?
pituitary tumour autonomously secretes ACTH (not controlled by CRH or -ve feedback)
cushings disease
What is an iatrogenic cause of hypercorticolism?
occurs following glucocorticoid therapy for another condition
- commonly used as topical or systemic anti-inflammatory drugs
treatment for hypercorticolism?
removal of tumour
stop glucocorticoid therapy - has to be gradual
What syndrome is associated with hypocorticolism?
addisons disease
What is addisons disease associated with?
hypoglycaemia
hypotension
hyponatremia/hyperkalemia- loss of salt balance
–> dehydration and cardiovascular risk
mood disorders/ weakness/lethargy
skin pigmentation
What is the primary cause of adrenal insufficiency?
loss of adrenal cortical function (90%)
tuberculosis, invasive tumours, autoimmune attack, genetic
following minor stress/illness
What percentage loos of adrenal function occurs before symptoms of adrenal insufficiency is apparent?
90%
What are the causes of secondary adrenal insufficiency?
pituitary disease –> ACTH deficiency
symptoms less dramatic - aldosterone not affected (ACTH independent)
What is the treatment for adrenal insufficiency?
daily oral administration of glucocorticoids and mineralocorticoids
careful dietary/fluid management
treatment of causative disorder
How is cushings syndrome relevant to dentistry?
suppressed immune/inflammatory systems
–> risk of infection/ poor wound healing
diabetic consideration
emotionally liable (jumpy, hyperactive)
hypertension (LA effected)
What are the implications for addison’s disease for the dentist?
pigmentation
hypotension
they are on steroid management
