Module 10 : Adrenal Glands Flashcards
two parts of adrenal gland
cortex and medulla
cortex develops from what in embryo
- mesoderm
medullar develops from what in embryo
- neural crest cells
neuroectoderm
adrenal cortex
- cortex develops first
cortex at 6th week gestation
- proliferation of the mesoderm from the posterior abdominal wall
- penetrates the retroperitoneum and becomes primitive adrenal cortex
adrenal cortex at 8th week gestation
- separates from the posterior peritoneal surface and is surrounded by retroperitoneal connective tissue
- becomes capsule
adrenal cortex at 3 years of age
- permanent adrenal cortex differentiates into 3 zones
3 zones of the adrenal cortex
- glomerulosa
- fasciculata
- reticualaris
adrenal medulla at 7 weeks gestation
- neural crest cells migrate and invade in the medial side of the cortex
- these cells differentiate into chromaffian cells of adrenal medulla
anatomy of adrenals
- paired organs
- retroperionteal
- SUPRARENAL GLANDS
- anterior medial and superior to kidneys
- surrounded by perinephric fat and gerotas fascia
- have a capsule
adrenal size - adults
- length 4-6cm
- width 2-3cm
- AP 0.3 - 0.6 cm
- 1/13 the kidney size
adrenal size - newborns
- proportionately larger compared to kidner
- 1/3 kidney size
adrenal shape
- pyramid
- semi lunar
- V Y or Z configuration
- left larger than right
right adrenal relationships
- posterior and lateral to IVC
- superior to right kidney
- posterior to left lower of liver
- medial to right lobe of liver
- lateral to crus of diaphragm
- posterior to duodenum
left adrenal relationships
- superomedial to left kidney
- posterior to stomach
- posterior to lesser sac
- lateral to crus of diaphragm
- inferior portion posterior to panc tail and splenic vessels
- posterolateral to aorta
blood supply
- vascular organ
- 3 arteries
+ superior suprarenal artery from inferior phrenic arteries
+ middle suprarenal artery off aorta
+ inferior suprarenal artery off renal artery - venous drainage
+ suprarenal vein
= right (short) drains into IVC , left (longer) drains into left renal vein
physiology of adrenal
- double endocrine gland
+ 2 glands wrapped in one - maintains homeostasis through hormone secretion
cortex - physiology
- thicker outer layer
- 90% of gland
- secretes steroid hormones
- essential for life (need at least one)
- release controlled by negative feedback system
steroid hormones
- mineral corticoids
- glucocorticoids
- gonadal hormones
negative feed back to cortex
- low levels of cortical hormones cause hypothalamus to secrete ACTHRF (adrenocorticotropic hormone releasing factor)
- this causes anterior pituitary to release ACTH (adrenocorticotropic hormone)
- this cases adrenal to produce hormones
zona glomerulosa
- outer layer
- secretes mineralocorticoids
+ aldosterone
= increases sodium and water reabsorption to increase blood volume and pressure
sona fasciculata
- middle layer
- secretes glucocorticoids
+ cortisone and hydrocortisone
= fat, protein, and carb metabolism
= suppresses immune respire
= resist mental and physical stress
zona reticularis
- inner zone
- secretes sex hormones
+ estrogens and androgens
medulla physiology
- central portion
- sympathetic nervous system
- responsible for fight or flight
- secretes catecholamines
catecholamines
- epinephrine = adrenalin
- norepinephrine
body response to epinephrin
- increased heart rate
- constricting vessels incrasign blood pressure
- increased breathingrate
- dilation of respiratory passage
- dicreased digestion more blood to muscles
- increase blood sugar for energy
lab tests for adrenals - blood
- assess cortical function
lab tests for adrenals - urine
- assess medullary function
ultrasound of adrenals
- overnight fast
- visualization depends on
+ age, size, perirenal fat, bowel gas
adults adrenal ultrasounds
- rarely seen
- just see area to rule out phathology
- homogeneous hypoechoic
newborns adrenal ultrasound
- easily identified
- thin echogenic core
- less echogenic rim
right adrenal windows
- intercostal using liver
- supine or LLD position
left adrenal windows
- decubitus or right anterior oblique
- intercostal use spleen or left kidney as window
- in LPO use liver and great vessels as window
