L4 Suprarenal glands Flashcards
What is the gross anatomy of Suprarenal glands ?
- Surrounded by thick connective tissue capsule from which trabeculae extend into the parenchyma, carrying blood vessels and nerves
- Embedded in perirenal fat
- Enclosed by renal fascia which attaches them to the crura of the diaphragm ( so very little movement )
- Separated from the kidneys by a thin septum
How blood vessels, nerves , lymphatics, and veins enter the gland ?
Each gland has a hilum, where suprarenal veins and lymphatic vessels exit the gland
whereas
arteries and nerves enter the glands at various sites through the capsule
Why the adrenal gland Do not lie in the coronal plane ?
As they are sitting on the posterior wall where you have the bulging of vertebral column so both glands will face anterolaterally
Where do the lymphatics drain to ?
The lumbar lymph nodes ( which means that they are at the superior part just below the diaphragm )
What is the shape and surfaces of Right Suprarenal gland ?
Shape :
Pyramidal with 3 surfaces and a concave base
Surfaces :
- Posterior surface :
- posterior medially resting toward the diaphragm - Anterior surface :
- anterior laterally facing the liver - Thin medial surface :
- facing the inferior vena cava
Why it can be dangerous to approach the Right Suprarenal gland ?
As the IVC is near the gland and it can be damaged
What is the shape and surfaces of Left Suprarenal gland ? What are the organs that it is related to ?
- It is crescentic in shape and applied to the medial surface of the superior half of the left kidney
- It has 3 surfaces :
* A renal surface molded on the left kidney
* A posterior surface which lies on the left crus of the diaphragm
* An anterior surface which faces slightly laterally
What is the arterial supple to the suprarenal glands ?
They are 3 pairs
1. Superior supra-renal artery»_space; from the inferior phrenic artery
- Middle supra-renal artery»_space; directly from the lateral sides of abdominal aorta
- Inferior supra-renal artery»_space; from the renal artery
What is the venous drainage from the suprarenal glands ? ( similar to the gonads )
From right gland»_space; directly to IVC
From the left gland»_space; to renal vein then to IVC
What is special about superior supra renal artery ?
It will divide into small tribcule before entering the gland
Where does the hilum located in left and right glands ?
In right gland»_space;> in the middle
In left gland»_space;> inferiorly
What are the layers of peritoneum ?
- Parietal»_space; attached to the wall
- Visceral»_space; attached to the organs
The space between them called peritoneal cavity
What are the divisions of peritoneal cavity ?
- Greater sac
2. Lesser sac ( stomach bag )
Why does the lesser sac develops ?
- Due to the development of the digestive tract that will increase in size and some intestinal loops will get out the return back
- Rotation of stomach so the anterior will become left and grows slowly, whereas the posterior will become left and grows rapidly, this will lead to entrapping a space between them
What we call the location of both glands ?
Retro peritoneal as they are both in the lesser sac
What is the difference between hepatic and splenic ( colic ) flexure ?
In the right, conversion of ascending to transverse ( hepatic flexure )
In the left, conversion of transverse to descending ( splenic flexure )
What are the types of fat that surrounds the glands? What are there function ?
Surrounding the gland itself > peri-renal fat
Surrounding the renal fascia > para renal fat
It used for cushioning
What are the surgical approach of both glands?
Anterior and posterior
ANTERIOR
- Right :
* move the liver up
* cut the peritoneum
* move the inferior vena cava - Left : ( much easier due to less vasculature )
* move the stomach up
* cut the peritoneum
* take care of the other structures
What is the color of adrenal structure? and why ?
- Cortex is yellow
- as it is mainly producing steroids ( lipoidal materials ) - Medulla is brownish red
- due to high vasculature and the granules
What are the types of capillaries within the gland ?
- Vessels that will give Capillaries in the cortex then the venous blood that carry the steroids will go to medulla to be secreted ( but it is also important for its function )
- Vessels that will go all the way directly to the medulla giving the capillaries that will give oxygen to medulla
What are the structures of nervous system surrounding the glands ?
- Sympathetic ganglia ( T5-T9 )
- Greater splanchnic nerves ( made of large fibers )
- Celiac ganglia ( at the level of celiac artery )
What is the sequence of the nerves ?
- All of them start form intermediolateral column of the spinal nerve ( as they are sympathatic )
- Get out through the ventral root
- The preganglionic nerve ( myelinated ) will
- synapse in the sympathetic ganglia
- pass the the sym. ganglia to for the splanchnic nerve and synapse in celiac ganglia
- will not synapse any where and will go directly to the gland ( which act as post-ganglionic fibers )
What is the relation between the SNS and secretion of hormones ?
They are not related
- SNS will regulate blood flow to the gland
- ACTH and angiotensin II are responsible mainly on the secretion of the hormones
What are special about medullary cells ?
They act as post-synaptic neurons but without exons
What will happen if you cultured medullary cells ? And why ?
They will develop axons
The main reason of not developing axons in the medulla is the effect of cortisol
What is mostly secreted by the medulla ?
Epinephrine
What are the functions of cortical hormones that will be brought by the first type of capillaries ?
Cortisol :
- Prevents the development of axons
- Have a role in converting nor-epinephrine to epinephrine ( increasing phynalethanoamine methyltransferase )
What are the histology of the three zones ?
- G ( 15% )
- cells are in whirls - F ( 80%)
- cells are column-like - R ( 5%)
Why most cells are mostly free of organelles ?
As most of adrenocortical cells are producing steriods so they are filled with lipids that will go with processing
What are the most prominent organelles in cortical cells ? What their function ?
- Smooth ER
- Mitochondria with dark matrix
- No granules
Both they take part in lipid metabolism
What are the features of granules of medullary cells ?
- Nor-epinephrine
* larger
* darker - epinephrine
* smaller
* lighter
What is the origin of cortex and medulla ?
- Cortical cells originate from intermediate mesoderm ( mesenchyme )
- medulla is of ectodermal origin ( neural crest cells )
What is the development of the adrenal gland ?
During 5 th week of development, the mesothelial cells between :
-mthe root of the dorsal mesentery (of the developing gut)
And
- the developing gonad
proliferate and penetrate the underlying mesenchyme
- A These cells differentiate into large acidophilic cells which form the fetal cortex
- B.In the same time neural crest cells invade its medial aspect ( inner ) to form the medulla
- Another wave of cells invade the mesenchyme surrounds the original acidophilic cell mass and form the definitive cortex
- Soon after birth fetal cortex starts to regress and by the end of 1st year of age the definitive cortex differentiates into 3 layered adult cortex
What is the last layer of cortex to be formed and when ?
- Zona reticularis
2. At 3-4 years
