Anatomy of the adrenal gland Flashcards
What is the adrenal (suprarenal) gland?
- A yellowish retro-peritoneal organ, that lies on the superomedial part of each kidney
- The right one is triangular/pyramidal
- The left one is semilunar in shape
- They are not covered by the peritoneum, instead surrounded by connective tissue and embedded in perirenal fat
What is the vertebral relation of the adrenal gland?
T11
What separates the adrenal gland from the kidneys?
The perinephric fat
What encloses the adrenal gland?
The RENAL FASCIA (true capsule) is formed by the connective tissue around the kidneys
- A common fascial sheath that encloses the kidney and the adrenal gland
- It covers the whole kidney even the portion underneath the adrenal gland
What attaches the adrenal gland to the (crura) of the diaphragm above?
The RENAL FASCIA
What are the relations of the renal fascia?
It splits and encloses the kidney after that it splits and encloses the suprarenal glands, and after that, it fixes itself to the inferior surface of the diaphragm.
What are the different types of fat around the kidneys and adrenals?
1) Perirenal fat: Around the kidney, protects it inside the renal fascia
2) Pararenal fat: a thick layer of fat located more posteriorly outside the renal fascia
What will happen if someone loses weight suddenly?
The kidney will go down, but the adrenals will stay up due to their attachment to the crura of the diaphragm
What is the anterior relation of the right (triangular) adrenal gland?
1) Liver
2) IVC
What is the medial relation of the triangular adrenal gland?
IVC
What is the posterior relation of the right (triangular) adrenal gland?
Diaphragm
What is the anterior “superior” relation of the left (semilunar) adrenal gland?
Stomach
What is the anterior “inferior” relation of the left (semilunar) adrenal gland?
1) Pancreas
2) Splenic vessels
What is the Posterior relation of the left (semilunar) adrenal gland?
Diaphragm
What is the Medial relation of the left (semilunar) adrenal gland?
Abdominal aorta
What are the parts of the adrenal glands?
1) Outer cortex (80-90%)
2) Inner medulla (10-20%)
What is the embryological origin of the outer cortex?
Mesodermal origin
What is the embryological origin of the inner medulla?
Neuroectodermal (neural crest, which also gives rise to the sympathetic and parasympathetic ganglia)
- They are considered to be modified sympathetic and postganglionic, who have lost their axons and dendrites during development and became secretory cells
Summary
The adrenal glands consist of an outer connective tissue capsule, a cortex and a medulla. Veins and lymphatics leave each gland via the hilum, but arteries and nerves enter the glands at numerous sites.
The outer cortex and inner medulla are the functional portions of the gland. They are two separate endocrine glands, with different embryological origins:
Cortex – derived from the embryonic mesoderm.
Medulla – derived from the ectodermal neural crest cells.
The cortex and medulla synthesise different hormones.
Describe the arterial blood supply of the adrenal gland
1) Superior: Inferior phrenic artery
2) Middle: Aorta
3) Inferior: Renal artery
What is the venous supply of the right (triangular) adrenal gland?
The right suprarenal vein, which drains into the inferior vena cava
What is the venous supply of the left (semilunar) adrenal gland?
The left suprarenal vein, drains into the renal vein then the renal vein will drains into the inferior vena cava
Why should we ligate the right adrenal gland vein first in surgery?
The right suprarenal vein is very short so it can be easily cut off in surgery by mistake. That’s why you need to take care of it and ligate it first
- Not ligating the vessels before an adrenal gland surgery can cause a lot of its hormones to be released as a response to you playing with the glands in the surgery and this will affect the stability of the patient
What is the nerve innervation of the adrenal cortex?
Only by the vasomotor innervation
- Preganglionic nerves arising from spinal cord 🡪 travel through the sympathetic trunk 🡪 through the celiac ganglia 🡪 postganglionic nerves to the blood vessels present in the cortex to supply vasomotor innervation