The Adrenal Gland Flashcards
Where are the adrenal glands?
On the superior pole of each kidney- therefore, we have two adrenal glands
The adrenal glands are composed of two separate endocrine glands which have been rolled into one structure. What are the two glands which make up the adrenal gland?
Adrenal medulla
Adrenal cortex
Which type of gland is the adrenal medulla?
Neuroendocrine gland
What doe the adrenal medulla secrete?
Catecholamines- mostly epinephrine but also norepinephrine and dopamine
Which type of gland is the adrenal cortex?
True endocrine gland
Name the three classes of hormone secreted by the adrenal cortex.
Mineralocorticoids
Glucocorticoids
Sex steroids
Give an example of a mineralocorticoid secreted from the adrenal cortex.
Aldosterone
->involved in he regulation of sodium and potassium
Give an example of a glucocorticoid secreted from the adrenal cortex.
Cortisol
->involved in maintaining plasma glucose
Give an example of a sex steroid secreted from the adrenal cortex.
Testosterone
Which part of the adrenal gland is in the core?
Adrenal medulla
What is the body’s stress hormone?
Cortisol
What are epinephrine and norepinephrine associated with?
Stimulation of the sympathetic NS
RECAP- to make sure you are paying attention hehe
Which part of the adrenal gland is neuroendocrine?
Adrenal medulla
How many layers does the adrenal cortex have?
3
Name the three levels of the adrenal cortex from most superficial to deep.
Zona glomerulosa
Zona fasciculata
Zona reticularis
What does the zona glomerulosa secrete?
Aldosterone and other mineralocorticoids
What does the zona fasciculata secrete?
Glucocorticoids e.g. cortisol
What does the zona reticularis secrete?
Sex steroids
RECAP- what are steroid hormones derived from?
Cholesterol
All steroid hormones come from cholesterol but what differentiates them into different end products?
Different enzymes
->for example, enzymes needed to make aldosterone are only found in the zona glomerulosa
Which enzyme is required for the production of cortisol and aldosterone but not sex steroids?
21- hydroxylase
Defective 21-hydroxylase is a common cause of which congenital problem?
Congenital adrenal hyperplasia
In those with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, what does this result in?
Deficiency of aldosterone and cortisol.
Disrupted control of salt and glucose homeostasis
Why may those with congenital adrenal hyperplasia have malformed genitalia?
All the cholesterol in the adrenal cortex gets channelled into making sex steroids as cannot be made into aldosterone or cortisol.
Therefore, there is a lot higher conc. of sex steroids which deforms genetalis and can make it hard to distinguish between male and female.
A deficit in 21-hydroxylase results in adrenal hyperplasia. Why?
Cortisol cannot be synthesised so we lose that negative feedback loop. There will be hypersecretion of CRH and ACTH and there will be overstimulation of the adrenal gland leading to hyperplasia.
What type of hormone is cortisol?
Glucocorticoid hormone
95% of plasma cortisol is bound to which carrier protein?
Cortisol binding globulin
Is cortisol hydrophilic or lipophilic?
Lipophilic
->this is why they are bound to proteins in order to be transported in plasma
Glucocorticoids are well known clinically for their anti-inflammatory effects. How do these effects come about?
The glucocorticoids switch off transcription and translation of proteins that make up enzymes in inflammatory pathways
Therefore, glucocorticoids can be used in the treatment of many conditions. List some of them.
Asthma, rheumatoid arthritis, ulcerative colitis, organ transplants.
At what point of the day is the peak of cortisol release?
Early morning
->cortisol is our stress hormone and if you think about getting out of a warm bed in January, it’s stressful :)
Which type of enzymes does cortisol stimulate the formation of?
Gluconeogenic enzymes in the liver
How does cortisol aid with the production of glucose?
Stimulates the formation of gluconeogenic enzymes which enhance gluconeogenesis and therefore the production of glucose
How does cortisol provide gluconeogenic substrates for the liver?
Via proteolysis- cortisol stimulates the breakdown of muscle protein to provide these substrates.
As well as assisting in the breakdown of muscle protein, what else can cortisol assist in the breakdown of?
Adipose tissue via lipiolysis