Adrenal Gland Flashcards
(41 cards)
Where does the left and right adrenal vein drain into?
Left= renal vein Right- into inferior vena cava
Compare the amount of arteries and vein that’s supplies or drains the adrenal gland
Has lots of arteries BUT only ONE vein
Describe the micro anatomy of the adrenal gland and what molecules they secrete
Medulla- catecholamines Cortex- corticosteroids
Describe the layers of the adrenal cortex and the hormones they make and secrete?
Outer- Zona glomerulosa; Aldosterone
Middle- Zona fasiculata: cortisol
Inner- Zona reticularis: sex hormones- androgens and oestrogen
What is the importance of the Zona reticularis in animals? Compare with humans
Very important in producing sex hormones for animals, not so much humans as we have sex organs for that.
What layer encapsulates the whole adrenal gland
Capsule
Describe how hormones are secreted in adrenal glands
Hormones produced is transported into the many arteries which all empties into the adrenal vein
What is precursor molecules for all corticosteroids and how many carbon molecules
Cholesterol- 27 carbon
Describe the pathway for the formation of aldosterone from cholesterol
Cholesterol
Pregnenlone
Progesterone
11- Deoxycorticosterone
Corticosterone
Aldosterone
What enzymes are involved in the reaction from pregnenlone to Aldosterone. List in ORDER
3 beta hydroxy steroid dehydrogenase
21 hydroxylase
11 hydroxylase
18 hydroxylase
Describe the pathways for the formation of cortisol from cholesterol
Cholesterol
Pregnenlone
Progesterone
17-Hydroxy-progesterone
11-deoxycortisol
Cortisol
List the enzymes involved in formation of cortisol from progesterone in ORDER
17 hydroxylase 21 hydroxylase 11 hydroxylase
Where is the significance of this tightly controlled reaction requiring different enzymes.
Any small change in enzyme structure will have a massive impact on the pathway and hence on the body.
What is the function of aldosterone?
Control Blood pressure by reabsorbing sodium ions in DCT and renal collecting duct
Secret potassium and hydrogen ion in DCT and collecting duct
What other organs does aldosterone affect in reabsorption of sodium ions
Sweat glands, colon, gastric glands
Describe what happens when aldosterone reaches DCT
Enters renal cells and act as a transcription factor
Cell release sodium ion transporter to membrane
Sodium ions reabsorbed back into kidney and enters blood through sodium potassium pump; water follows sodium to increase BP.
K+ and H+ secreted
What enzyme is released when BP falls, what cells releases this?
Renin; by Juxtaglomerular apparatus
Explain the process of what causes renin release
Decreased renal perfusion pressure due to low BP Increased renal sympathetic activity (direct to JGA cell) Decreased Na+ load to top of loop of Henle
Explain the process of how renin causes aldosterone release?
Renin from kidney binds to Angiotensinogen from liver Angiotensin 1 is made Angiotensin 1 reacts with ACE to make angiotensin 2 Angiotensin 2 reaches Zona glomerulosa Activate the enzymes responsible for synthesis of aldosterone
How is cortisol regulated
Mainly ACTH
Some AVP
What are the physiological effects of cortisol
- Hepatic gluconeogenesis
- Fat metabolism
- Increased vascular permeability
- Immune suppression
- Peripheral protein catabolism
- Increased blood glucose concentration
- Excretion of water load
What’s the effect of ACTH on the adrenal cortex Zona fasiculata
Activate the following enzymes Side chain cleavage 3 hydroxysteroid dehydrogenase 17 hydroxylase 21 hydroxylase 11 hydroxylase
Describe how cortisol is released during the day
Diurnal rhythm by following the circadian rhythm Once at 8am and 4pm
What is addison’s disease
Primary adrenal failure; Hence aldosterone and cortisol deficiency
