17 Adrenal Glands Flashcards
Where are the adrenal glands located?
On top of kidneys- attached to diaphragm
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/374/514/a_image_thumb.jpeg?1555332217)
What are the main components which make up the adrenal glands?
- Capsule
- Cortex
- Medulla
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/374/515/a_image_thumb.jpeg?1555332272)
What layers make up the cortex of the adrenal glands?
Zona glomerulosa, zona fascicolata, zona reticularis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/374/516/a_image_thumb.jpeg?1555332309)
What hormone does each layer of the cortex produce?
CORTICOSTEROIDS:
1) zona glomerulosa- mineralcorticoids (SALT)
2) zona fasiculata -glucocorticoids (SUGAR)
3) zona reticularis- glucocorticoids+small amounts of androgens (SEX)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/374/517/a_image_thumb.jpeg?1555332415)
What cells is the medulla made up of?
Chromaffin cells
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/374/518/a_image_thumb.jpeg?1555332447)
What do the chromaffin cells produce?
80% Adrenaline, 20% Noradrenaline
What are steroid hormones synthesised from?
Cholesterol
How do steroid hormone function?
=Lipid soluble–> bind to nuclear receptors–> modulate gene transcription
Give examples of steroid hormones.
Glucocorticoids
Mineralocorticoids
Androgens
Oestrogen
Progestins
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/376/443/a_image_thumb.jpeg?1555332569)
How do corticosteroids exert their actions?
1) Diffuse across plasma membrane
2) Bind to glucocorticoid receptors- cause dissociation of CHAPERONE PROTEINS
3) Receptor ligand translocates to nucleus- receptors bind to glucocorticoid response elements:
* (GREs)/transcription factors*
![](https://s3.amazonaws.com/brainscape-prod/system/cm/271/376/444/a_image_thumb.jpeg?1555332672)
Name the most abundant mineralocorticoid.
Aldosterone
What are the carrier proteins for aldosterone?
Albumin (+transcortin)
How does aldosterone exert its effects?
- =steroid hormone
- Regulates gene transcription -intracellular
- Lipophilic
What is the function of Aldosterone?
Regulates plasma sodium and potassium- arterial blood pressure
Where in the body does aldosterone exert its actions?
DISTAL TUBULES and COLLECTING DUCTS of NEPHRON
Promotes expression of Na+/K+ pump, promotes reabsorption of Na+ and excretion of K+
Which part of the adrenal cortex synthesises and releases aldosterone?
Zona glomerulosa
![](https://s3.amazonaws.com/brainscape-prod/system/cm/274/344/396/a_image_thumb.jpeg?1555332756)
What is the RAAS (renin-angiotensin-aldosterone system)?
System that regulates :
- blood pressure
- fluid electrolyte
- balance
What organs/tissues are involved in the RAAS?
- Lungs
- Liver
- Kidney
- Adrenal glands (cortex)
- Arterioles
- Posterior pituitary
Outline how the RAAS works in 5 steps.
- Decreased renal perfusion- drop in blood pressure, increased sympathetic tone from baroreceptor activation- increased renin release from kidney
- Angiotensinogen constitutively released into blood by liver
- Angiotensinogen cleaved by renin to angiotensin I
- ACE (angiotensin converting enzyme) released in lungs cleaves angiotensin Itoangiotensin II
-
Angiotensin II causes:
- Vasoconstriction
- Adrenal Cortex releases aldosterone: Increased water and Na+reabsorption into blood (increased expression of sodium potassium pump)
- Posterior pituitary releases ADH: Translocation of aquaporin channels aids reabsorption of water back into the blood
![](https://s3.amazonaws.com/brainscape-prod/system/cm/274/344/946/a_image_thumb.jpeg?1555333818)
What type of drug may be given as an antihypertensive?
ACE inhibitors
What causes primary hyperaldosteronism?
Defect in adrenal cortex eg:
- Bilateral idiopathic adrenal hyperplasia (most common)
- Conn’s syndrome: Aldosterone secreting adrenal adenoma
- LOW RENIN LEVELS= high aldosterone:renin ratio
What causes secondary hyperaldosteronism?
Overactivity of RAAS
- Renal artery stenosis
- Renin producing tumour= rare
- HIGH RENIN LEVELS (low aldosterone:renin ratio)
What’s the best way to distinguish between primary and secondary hyperaldosteronism?
High renin levels= secondary
Low renin levels= primary
What are the signs/symptoms of hyperaldosteronism?
- High BP
- Left ventricular hypertrophy
- Stroke
- Hypernatraemia
- Hypokalaemia