Ch 13 The Adrenal Glands

hormone function and control differ for

2 different glands in one organ

abundant arterial supply may contain as many as

50 to 60 terminal arterioles

cortex makes up

90% of the adrenal gland

increased concentration of adrenal hormone inhibits

CRH and ACTH and hormone synthesis

multiple endocrine neoplasia (MEN) syndrome

a group of autosomal dominant disorders characterized by benign and malignant tumors of the endocrine glands

clinical indication for decrease in Cortisol

addison disease from primary hypo function of cortex or secondary to hypofuncion of pituitary gland, iatrogenic adrenal insufficiency, adrenogenital syndrome, AIDS

clinical indication for decrease in 17-Ketogenic steroids (17-KS)

addison disease, cretinism, hypoadrenalism, hypopituitarism, simmonds disease

clinical indication for increase in ACTH

addison disease, ectopic ACTH syndrome, pituitary adenoma

clinical indication for decrease in Aldosterone

addison disease, primary hypoaldosteronism, salt-wasting syndrome, septicemia

lymph channels drain from

adrenal cortex and medulla to hilar area

thin, fibrous outer capsule attaches to gland by fibrous bands to provide adrenals with fascial supports; this prevents

adrenals from descending if kidneys are displaced or absent

clinical indication for increase in 17-Ketogenic steroids (17-KS)

adrenogenital syndrome, cushing syndrome, adrenal carcinoma, burns

clinical indication for increase in Aldosterone

adrenoma, aldosteronism, bilateral adrenal gland hyperplasia, cirrhosis

endoscopic ultrasound (EUS)

an ultrasound transducer on a thin flexible endoscope is inserted in the mouth or anus to visualize the walls of the upper or lower digestive tract and surrounding organs

right adrenal gland has a triangular appearance on

anterior, medial and superior aspect of superior pole of right kidney

hormone secretion controlled by

autonomic nervous system

specific ectodermal cells ascend from neural crest, migrate from origin, and differentiate into sympathetic neurons of

autonomic nervous system

like the glucocorticoids of adrenal cortices, epinephrine and norepinephrine help

body resist stress

superior and medial artery

branch of aorta

medulla secretes

catecholamine hormones

GA week 7 and 8

cells arrange into cords with dilated blood spaces to form thin capsule of CT enclosing gland and developing intimate relationship with kidney's superior pole

each gland has

central vein which courses length of each gland and exits at hilum

adrenal gland consists of two distinct parts

cortex and medulla

age 3 year

cortex differentiates into three zones: zona glomerulosa, zona fasciculata, zone reticularis

GA week 8

cortex products precursors to androgen, estriol and corticosteriods

GA week 5 and 6

cortex recognized bilaterally as a groove between developing dorsal mesentery and gonad

hormone secretion often controlled by negative feedback mechanisms > hypothalamus > secrete primary regulating factor-

corticotrophin releasing hormone (CRH) which triggers anterior pituitary lobe > release adrenocorticotropic hormone (ACTH)

at 3 years of age the cortex

develops into 3 layers in which each layer evolves functionally into specialized zones producing steroid hormones

arteries and veins

do not course together

left adrenal gland

draped in an elongated crescent or semilunar shape on medial aspect of left kidney's superior pole

medulla synthesizes 2 principle hormones

epinephrine (adrenalin) and norepinephrine (noradrenalin)

hypoglycemia, hypotension, hypoxia, hypovolemia and exposure to temperature extremes may stimulate secretion of

epinephrine and norepinephrine

chromatin cells which are pheochrome cells invade developing cortex to

establish primordium of adrenal medulla

some primitive autonomic ganglia differentiate further into endocrine cells, designated chromaffin cells and migrate to

form mass on medial surface of fetal adrenal cortex

incidentaloma

general term for an unexpected mass detected during imaging performed for unrelated disease

zona fasciculata regulation

high stress or low blood concentration; negative feedback mechanism

blood concentrations of ACTH increases: adrenal hormone activity increases > producing

higher concentration of hormones in bloodstream

Adrenocorticotropic hormone (ACTH)

hormone secreted by the pituitary gland that causes the adrenal gland to produce and release corticosteroids

chromatin AKA pheochrome cells

hormone-producing portion and surrounds large blood-filled sinuses

left suprarenal vein drains directly

inferior and medial into left renal vein

prompt discharge of hormones usually occurs without

influencing cortical secretion

zona reticularis 10%

inner layer that produces gonadocorticoids, estrogens and androgens

after birth

inner zone undergoes involution and thinner outer zone develops into adult adrenal cortex taking on yellow color

discoid distortion in shape of adrenal gland if

kidney fails to develop normally

abundant adipose tissue AKA perinephric fat surrounds each gland to separate it from

kidneys

left adrenal gland is

larger than right gland

frequently, left inferior phrenic vein and left suprarenal vein join before emptying into

left renal vein

intermediate cortical arteries

long branches that go through the cortex to the medulla

zona reticularis regulation

low blood concentration (negative feedback mechanism

adrenal cortex is derived from

mesoderm of same region that gives rise to gonadal tissue

zona fasciculata function

metabolism of lipids, proteins, carbohydrates; fat storage; anti-inflammatory and immune-suppress responses

zona fasciculata 75%

middle layer that produces glucocorticoids

each zone produces

minearlocorticoids, glucocorticoids, gonadocorticoids

extension to left renal hilus is a

normal variant for left adrenal gland

inferior area of anterior portion of left adrenal gland

not covered by peritoneum and lies posterior and lateral to pancreas

unlike cortical hormones, medullary hormones are

not essential to life

zona glomerulosa 15%

outer layer that produces aldosterone

adrenal cortex

outer parenchyma of the adrenal gland that makes up 90% of the organ's weight and secretes corticoids including cortisol and aldosterone

splenic artery and vein course between

pancreas and left adrenal gland

following arterial pathways, larger lymphatic vessels drain into

para-aortic and lumbar lymph nodes which drain into cistern chyli, thoracic duct, and eventually into subclavian vein

fight or flight response

physiologic response to stress

clinical indication for increase in Cortisol

pituitary tumor causing ACTH-dependent increase, Cushing disease

right adrenal gland

posterior and lateral to ivc, medial to right liver lobe, lateral to crus of diaphragm

right suprarenal vein empties directly into

posterior aspect of ivc as a short 4 to 5 mm vessel which exits on mid-anteromedial surface

few lymphatic vessels drain into

posterior mediastinal lymph nodes

superior part of anterior portion of left adrenal gland

posterior to peritoneal wall of lesser sac and covered by peritoneum of omental bursa separating gland from cardiac portion of stomach

clinical indication for decrease in ACTH

primary adrenocorticol hyper function and secondary hypoadrenalism

zona reticularis function

promotes normal development of bones and reproductive organs; secondary sex characteristics

right adrenal gland anterior surface is shaped like a

pyramid

depending on blood perfusion, medulla has

red, brown or gray color

zona glomerulosa function

regulates sodium and potassium levels which affect fluid and electrolyte homeostasis

zona glomerulosa regulation

release triggered by dehydration, sodium deficiency, hemorrhage or elevated potassium levels

glands are attached to anteromedial aspect within

renal fascia AKA gerota fascia

when blood concentration of one or more of adrenal hormones drop to low levels, cycle is

repeated

hormones of adrenal cortex, such as cortisol, are essential to life- so they must be

replaced if both adrenal glands are removed

adrenal glands are

retroperitoneal; generally anterior, medial and superior to kidneys

arteries are classified into three types

short capsular arterioles intermediate cortical arteries medullary sinusoids

venous blood is channeled almost completely through a

single, large venous trunk

posterior surface of left adrenal is in proximity to

splanchnic nerves

anticipation, presence of stress or pain > causes hypothalamus to signal sympathetic preganglionic neurons to

stimulate chromatin cells to increase output of epinephrine and norepinephrine

anterior portion of left adrenal gland can be separated into

superior and inferior parts

right adrenal gland posterior dorsal surface is separated into superior and inferior parts

superior convex portion rests on diaphragm and inferior concave portion is in contact with the superior-anterior surface of right kidney

three arteries supply each gland

superior, superior and medial, inferiorly

superior artery

suprarenal branch of inferior phrenic artery

inferiorly artery

suprarenal branch of renal artery

release of epinephrine and norepinephrine usually stimulated through

sympathetic nervous system

adrenal medulla is functionally part of

sympathetic nervous system developing from neural crest cells give rise to postganglionic sympathetic neurons

adrenal medulla

the inner portion of the adrenal gland that secretes catecholamines, epinephrine and norepinephrine

adrenal glands cortex and medulla are encapsulated by a

thick inner layer of fatty CT

epinephrine is about 80% of

total secretion

adrenal gland becomes

two endocrine glands in one organ

left adrenal is divided into a medial and a lateral area by a

vertical ridge where lateral area rests on kidney and medial posterior area lies on crus of diaphragm

cortex 3 layers

zona glomerulosa zona fasciculata zona reticularis

chromaffin cells also form organ of

zuckerkandl