Week 6 (Sadie)
he goals of emergency therapy for an addisonian crisis are to (5)
1. Correct hypovolemia, 2. Correct electrolyte abnormalities (particularly hyperkalemia), 3. Correct hypoglycemia (if present), 4. Correct acid-base abnormalities (acidosis), 5. Correct glucocorticoid and mineralocorticoid deficiencies
Angiotensin II has three major functions:
1. Initiating vasoconstriction of the arterioles, decreasing blood flow 2. Stimulating kidney tubules to reabsorb NaCl and water, increasing blood volume 3. Signaling the adrenal cortex to secrete aldosterone, the effects of which further contribute to fluid retention, restoring blood pressure and blood volume
At high concentrations, cortisol is immunosuppressive. 3 methods
1. It inhibits prostaglandin production produced by damaged tissues 2. reduces secretion of histamine by mast cells 3. Cortisol decreases phagocytosis and suppresses antibody formation
RAAS (renin-angiotensin-aldosterone system)
1. Renin is released by kidneys in response to decreased blood volume; causes angiotensinogen (from liver) to split & produce angiotensin I 2. lungs convert angiotensin I to angiotensin II via ACE 3. angiotensin II stimulates adrenal gland to release aldosterone & causes an increase in peripheral vasoconstriction
3 main clinical signs of Addisonian Crisis
1. Severe dehydration 2. Hypovolemic shock 3. Bradycardia
What would the plasma profile in a patient with hyperadrenocorticism typically include? (4)
1. hyperglycemia 2. increased hepatic enzymes 3. decreased insulin 4. hypercholesterolemia
Zones of Adrenal Cortex (outer to inner)
1. zona glomerulosa 2. zona fasciculata 3. zona reticularis
Zona Glomerulosa _____ % of cortex Zona Fasciculata ____% of cortex Zona Reticularis ____% of cortex
15, 80, 5
Normal ______ ratio Cortex to Medulla
2:1
Which liver enzyme is frequently elevated in the serum during hyperadrencorticism?
ALP- increases are associated with cortisol
3rd types of cell locate din the pars distalis of the anterior pituitary (what do they secrete)
Acidophils: secrete GH, PRL Basophils: secrete ACTH, TSH, FSH, LH chromophobes
If both adrenal glands are removed, which hormone concentration is most likely to be elevated?
Adrenocorticotropin (ACTH)
Which hormone is a significant regulator of sodium absorption and potassium excretion in the colon?
Aldosterone
________ is the major mineralocorticoid. It is released in response to elevated blood _____, low blood , ______ blood pressure or blood volume.
Aldosterone K+, Na+, low
______ hypoadrenocorticism is the destruction of fasciculata and reticularis. Leads to high levels of _______ b/c there is no negative feedback from cortisol
Atypical, ACTH
A 7-year-old miniature Schnauzer presents with signs of hypothyroidism that is confirmed with laboratory diagnostic assays. The dog was diagnosed with hypoadrenocorticism eight months ago. The presentation of both diseases in the same dog is suggestive of what process?
Autoimmune polyglandular syndrome
How are glucocorticoids and mineralocorticoids similar?
Both are produced from cholesterol
glucocorticoids reduce inflammation by inhibition of genes regulating expression of _____ and __________
COX2, most inflammatory cytokines
In response to long-term stressors, the hypothalamus secretes _______, which in turn triggers the release of ________ by the anterior pituitary which triggers the release of the __________ by the adrenal cortex
CRH ( corticotropin- releasing hormone), ACTH (Adrenocorticotropic hormone), glucocorticoids (cortisol)
Iatrogenic Cushing's Disease: The HPA axis is normal but prolonged excessive administration of glucocorticoids leads to suppresses ______ and ______ causing bilateral adrenocortical ______
CRH and ACTH, atrophy
iatrogenic cushings suppress ______ and _______ concentrations causing __________
CRH, ACTH, bilateral adrenocortical atrophy
In a dog with pituitary dependent hyperadrenocorticism which of the following hormones would be expected to be decreased?
CRH- Since CRH is 'upstream' from the pituitary gland, hyperactivity of the pituitary gland should cause a decrease in CRH production since the excessive cortisol production (triggered by the ACTH coming from the pituitary) should be negatively feeding back to decrease CRH production at the level of the hypothalamus.
During ultrasonographic evaluation of the right adrenal gland in the dog, which is the first major vessel found medial to the gland?
Caudal vena cava
Which adrenal cells are functionally equivalent to postganglionic sympathetic neurons?
Chromaffin cells
Where is the unbound glucocorticoid receptor located?
Cytosol
What activates RAAS?
Decrease in renal perfusion (blood volume/pressure)
Replacement of glucocorticoids and mineralocorticoids in the acute setting can help improve clinical signs and clinicopathologic abnormalities in dogs, if primary hypoadrenocorticism is suspected and especially if hyperkalemia is documented. Which of the following drugs would meet this need specifically.
Desoxycorticosterone pivalate (DOCP)
what is seen in ACTH stimulation test of a dog with Cushings
Expectant to see dramatic increase in cortisol level following synthetic ACTH administration. (this test can confirm the diagnosis of Cushing's disease but not the origin)
Dogs in an acute hypoadrenocortical crisis may present with severe hypoglycemia and plasma volume depletion. Which of the following would be a targeted and recommended treatment for these findings?
Fifty percent dextrose added to isotonic intravenous fluids to produce a 5% dextrose solution
explain Iatrogenic Cushing's Disease
From exogenous administration of corticosteroids for prolonged periods of time (allergies/ autoimmune)
Glucocorticoids play a role in water diuresis(increased or excessive production of urine) by increasing the _______.
GFR
Anti insulin effect of glucocorticoids (Chronic administration of glucocorticoids can lead to development of steroid diabetes)
Glucocorticoids inhibit glucose uptake and metabolism in peripheral tissues
What lesion is typically associated with Histoplasma capsulatum infection in dogs and resulting insufficiency of the adrenal gland cortex?
Granuloma
_______ adrenalitis is caused by Histoplasma capsulatum, Coccidioides immitis, or Cryptococcus neoformans
Granulomatous
The Adenohypophysis produces these are 6 hormones:
Growth (Somatotropic) hormone STH Follicle-stimulating hormone FSH Luteinizing hormone LH Adrenocorticotropic hormone ACTH Thyroid-stimulating hormone TSH Prolactin
2 reasons why dogs with hyperadrenocorticism develop pendulous abdomens?
Hepatomegaly- Caused by increased deposits of lipid and glycogen from catabolic affects of cortisol Muscle wasting- Is a result of increased catabolism of structural protein combined with decreased protein synthesis in skeletal myocytes under influence of long term excessive cortisol
__________ decreases pacemaker tissue activity causing bradycardia
Hyperkalemia
Electrolyte imbalances associated with Hypoadrenocorticism
Hyperkalemia, hyponatremia, Hypochloremia
why can we see hyperpigmentation in dogs with addisons
Hyperpigmentation due to too much MSH as a response to the decrease in negative feedback cause no cortisol Lacking cortisol-->so no cortical is having an inhibitory effect on CRH--> CRH from the hypothalamus stimulates the anterior pituitary to produce MSH-->get hyperpigmentation
To which region of the brain is the hypophysis directly attached?
Hypothalamus
3 parts of the neurohypophysis (posterior lobe)
INFUNDIBULUM : proximal portion suspending from the hypothalamus (specifically tuber cinereum of hypothalamus) PARS NERVOSA: modest expansion from the infundibulum and major portion of neurohypophysis PARS CAVA : recess formed in infundibulum from invagination of the third ventricle
Low dose dex suppression test results in pituitary vs adrenal cushings
In Pituitary origin Cushing's disease- it is expected to see a small decrease in cortisol levels over the 4 and 8 hour post-injection samples compared to the pre-injection sample. This is because the negative feedback loop is diminished but not lost in pituitary origins. In cases of adrenal origin Cushing's disease, it is expected to see no decrease in cortisol levels over the 4 and 8 hour post-injection samples compared to the pre-injection sample. This is because the negative feedback loop is lost entirely in adrenal origins.
two major arteries supplying the pituitary gland
Internal carotid arteries Caudal communicating arteries
what is a normal urinalysis finding associated with hypoadrenocorticism
Isosthenuria- Cannot concentrate urine properly b/c aldosterone isn't working to absorb water and NA
aldosterone increases the excretion of ______ and the retention of , which in turn ______- blood volume and blood pressure.
K+, Na+, increases
The ______- adrenal gland is the larger of the two glands
Left
Which vessel provides direct venous drainage of the left adrenal gland in the dog?
Left renal vein
Which abnormality is RARELY seen in patients with hypoadrenocorticism?
Lymphopenia (an ill dog should have lymphopenia secondary to cortisol release- stress leukogram; but no cortisol is being produced)
ACTH binds to ___ receptor; signal transduction is mediated through ______ and _______
MC2 (g protein coupled receptor) , adenylate cyclase and intracellular CAMP
Which of the following tests is the optimal way to monitor effectiveness of fludrocortisone or desoxycorticosterone pivalate treatment in a canine patient with hypoadrenocorticism?
Measurement of serum sodium and potassium concentrations
how do we monitor hypoadrenocorticism? Would ACTH stimulation test help?
Monitor electrolytes No ACTH will not help, unless iatrogenic.
What is the embryonic origin of the adenohypophysis (anterior lobe)?
Mouth (stomodeum)
What is the embryonic origin of the neurohypophysis (posterior lobe)?
Neural ectoderm
what does ACTH stimulation test look like in a normal dog compared to a dog w Addison's
Normal dog: synthetic ACTH is given cortisol levels should increase Addison's dog: synthetic ACTH is given cortisol levels are remain low (same for primary and secondary)
4 parts of the adenohypophysis (anterior lobe)
PARS INTERMEDIA (intermediate lobe) : dorsal portion of adenohypophysis Caudal to the hypophysial cleft Hormone produced: α-melanocyte-stimulating hormone PARS DISTALIS : largest portion of the adenohypophysis; separated by the hypophyseal cavity from the pars intermedia PARS NERVOSA: axons from neurons of supraoptic and paraventricular nuclei of hypothalamus PARS TUBERALIS : the part of the adenohypophysis that extends as a cuff or collar around the infundibulum
________-dependent Cushing disease accounts for 80-85% of spontaneous hyperadrenocorticism _________ tumors account for remaining 15-20% of cases of spontaneous
Pituitary, Adrenocortical
___________ sympathetic fibers innervate the adrenal cortex
Postganglionic
__________ sympathetic fibers synapse inside the adrenal medulla
Preganglionic- This is an exception usually synapse outside organ on ganglia but the medullary tissue is neural in origin
What is the interpretation of an ACTH Stimulation Test in a dog: (Cortisol Serial 2) - Pre test: 0.7 μg/dL (normal 1.0-5.0 μg/dL) - 1 Hour Post test: 0.8 μg/dL (normal 8.0-17.0 μg/dL) (Normal resting or baseline cortisol concentration: 1-4 μg/dL)
Primary hypoadrenocorticism
how does endogenous ACTH help differentiate primary from secondary hypoadrenocorticism
Primary= Lack neg feedback, ACTH will be high Secondary= Pituitary Gland: ATCH will be low because not producing it
Which property of neutrophils is LEAST likely to be negatively affected by the administration of prednisone?
Release of mature neutrophils from bone marrow
Functionally, medullary cells of the adrenal gland are equivalent to which type of neuronal cell bodies?
Secondary sympathetic neurons
Which of the dog breeds is known to present with inherited hypoadrenocorticism?
Standard poodle
What statement best describes the mechanism by which glucocorticoids influence target cells?
They freely pass through the cell membrane and then bind to intracellular glucocorticoid receptors
why use the high dose dexamethasone suppression test for cushings testing
This is used to definitively determine the origin of Cushing's disease if there is no reduction in the cortisol levels seen during low dose testing. This is because a pituitary origin may exhibit resistance to the effects of dexamethasone. If the high cortisol levels persist after administration of high-dose dexamethasone over a 4 and 8 hour time period, then it can be definitively determined to be adrenal origin Cushing's disease.
what is the purpose of ACTH stimulation test
Trying to find out functional capacity of adrenal gland; fasciculata and reticularis layers- cortisol production
Histopathology of the adrenal glands of a dog that died with severe electrolyte imbalances reveals bilateral cortical atrophy with a lymphocytic infiltrate, characterized by special staining as CD4+ and CD8+ T cells. Assuming that cytotoxic T cells are effectors of the disease, what type of hypersensitivity reaction is most likely involved?
Type IV (Cell Mediated/ Delayed- Type)
how is baseline cortisol useful in ruling out hypoadrenocorticism
Wondering if a dog is dealing with renal disease or addisons disease Resting cortisol can help rule OUT addisons-->if cortisol is normal then you can rule out Addisons
cortical _______ are usually single, unilateral, well demarcated Often functional; producing excess corticosteroids
adenoma
_________ Accounts for 80-85% of spontaneous hyperadrenocorticism
adenomas in the pituitary (pituitary dependent cushings)
explain pituitary dependent cushings
adenomatous enlargement of the pituitary gland, resulting in excessive ACTH production which leads to excessive cortisol levels. Normal negative feedback inhibition of ACTH secretion by increased cortisol levels is missing
A measurement of endogenous ACTH can often distinguish between _____ or _______ origin
adrenal (primary) or pituitary (secondary)
Primary mineralocorticoid is ___________ which functions in the control of _________
aldosterone, blood pressure.
The overall effect of glucocorticoids is to inhibit ________ while stimulating the __________ to maintain adequate fuel supplies.
anabolism ( tissue building) ,catabolism (breakdown of stored nutrients)
what major vessel is bound to the medial border of the left adrenal gland
aorta
increased concentrations of exogenous cortisol result in notable ______ of the adrenal cortex (especially ACTH dependent zona fasiculata and reticularis)
atrophy
Occasionally a dog may experience two or more autoimmune endocrine disorders simultaneously called ___________, but this is very uncommon.
autoimmune polyglandular syndrome (Results suggested that the occurrence of multiple endocrine disorders was uncommon in dogs. The most common combinations of endocrine disorders in this population of dogs were diabetes mellitus and hyperadrenocorticism, followed by hypoadrenocorticism and hypothyroidism.)
The Hypophysis sits in a depression, the hypophysial fossa of the __________ bone
basisphenoid
Cortical ______- cells resemble adenoma but more mitoses and less well differentiated cells; necrosis common- invade adjacent adrenal cortex Extension into vena cava may occurs; can also metastasize to lungs
carcinoma
When nerve impulses carried by the sympathetic fibers reach the ___________- secreting chromaffin cells, they release their secretory products. Therefore, chromaffin cells are considered the equivalent of _________
catecholamine, postsynaptic neurons.
2 branches of phrenicoabdominal artery and what they supply
caudal phrenic artery- more cranial supplies caudal aspect of diaphragm cranial abdominal artery- more caudal supplies cranial aspect of abdomen
Often the capsule of the right adrenal gland is continuous with the tunica externa/adventitia of the _______ (vessel)
caudal vena cava
The adrenal veins of each gland terminate differently because of their position relative to the caudal vena cava: The right adrenal vein joins directly with the _________ The left adrenal vein enters the ________
caudal vena cava, left renal vein
adenohypophysis drains into the __________
cavernous sinus
A ____________ on each side of the hypophysis allows connection with the ophthalmic plexus (veins of the face) rostrally and the external jugular vein and vertebral venous plexus caudally
cavernous sinus (large venous channel)
histochemically the catecholamines _______ and __________secreted by the chromaffin cells are produced by different cell types
cell w/ dense core vesicles= norepinephrine cells w/ smaller less dense vesicles= epinephrine
Adrenal corticoids are synthesized from __________ The synthesis of catecholamines is from ________
cholesterol, tyrosine
Cells of the zona glomerulosa are relatively small and ________ or __________
columnar or pyramidal
The adrenal _______ Is a major steroid-producing organ The adrenal ________ augments together with the nervous system the general adaptation of the body to stress
cortex, medulla
The main activator of the HPA axis is ________ hromone
corticotropin-releasing hormone (CRH)
why do animals with hyperadrenocorticism heal poorly
cortisol suppress both inflammation and immune response- reduced resistance to bacteria, fungi, viruses disrupts would healing due to inhibition of fibroblast & collagen synthesis (scar tissue)
Sympathetic axons from the _________ ganglion pass branches to the hypophysis by way of the tunica externa of the _________ artery
cranial cervical, internal carotid
The adrenal gland is located near the __________ border of the kidney
craniomedial
Adrenal Gland: Robust capsule of __________ connective tissue envelops the cortex, and delicate connective tissue envelope separates the cortex and medulla.
dense irregular collagenous,
Phrenicoabdominal artery lies ______ to adrenal gland
dorsal underneath
The medulla is the heart of the adrenal gland it is darker and of ________ origin, originating from _______ tissue
ectodermal, sympathetic
The principal role of mineralocorticoids is to maintain _______ and _______ homeostasis. These actions are carried out at the level of the ________ in the kidney.
electrolyte balance and blood pressure, distal tubules
What is the first physiological increase during the stress response?
epinephrine
After the amygdala sends a distress signal, the hypothalamus activates the sympathetic nervous system by sending signals through the autonomic nerves to the adrenal glands. These glands respond by pumping the hormone ________ into the bloodstream.
epinephrine (also known as adrenaline) (As the initial surge of epinephrine subsides, the hypothalamus activates the second component of the stress response system — known as the HPA axis. T)
T/F Mineralocorticoid treatment is essential for treating an Addisonian crisis.
false- its not but idk why?
Zona ________ Is the largest zone of the cortex It typically composes 50% or more of the cortex
fasiculata
how to distinguish nodular hyperplasia from adenoma in adrenal gland
functional adenomas usually larger and contain many cells with foamy cytoplasm and lipid vacuoles
Zona ________ the outermost zone and constitutes 25% of the adrenal cortex
glomerulosa
_________ secreted in the cortex induce the enzyme that catalyzes the methylation of norepinephrine to produce epinephrine in chromaffin cells.
glucocorticoids
The principal secretion of the zona fasciculata is _________ that regulate glucose and fatty acid metabolism.
glucocorticoids (cortisol)
The zona reticularis produces _________ and __________
glucocorticoids and androgens.
Specific effects of glucocorticoids is stimulation of hepatic _________
gluconeogenesis
cortisol favors _______; raises level of blood glucose which increases _______ in the liver
gluconeogensis, glycogen
Cortisol acts on many different cells and tissues to increase the metabolic availability of ______ and ________ both of which are immediate sources of energy.
glucose and fatty acids
In conditions of long-term stress cortisol promotes: the catabolism of glycogen to ________ the catabolism of stored triglycerides into ______ and _______ the catabolism of muscle proteins into ________.
glucose, fatty acids and glycerol, amino acids
Neurohypophysis (posterior pituitary) contains ______ bodies which secretes _____ and ______
herring, ADH (vasopressin) and Oxytocin
Hyperadrenocorticism caused by a functional adenoma of the pituitary gland (ACTH-secreting)results in bilateral adrenal cortical ________ and ________
hypertrophy and hyperplasia.
Iatrogenic Cushing's Disease: in these animals ACTH stimulation test results are consistent with spontaneous _________ despite clinical signs of __________
hypoadrenocorticism, hyperadrenocorticism
Overall, we would expect to see hypoosmolality in patients with Addison's due to _______ and _________
hyponatremia and hypoglycemia.
Neurohypophysis is primarily composed of axons from the _________ regions
hypothalamic
Hypoadrenocorticism is the most common initial endocrinopathy observed in polyendocrine gland failure in dogs and is usually followed by the development of _________.
hypothyroidism
Cortisol also depress the ________ and ________ responses and, as a result of the latter, inhibit ______ healing.
immune and inflammatory, wound
fight or flight response on various body systems
increase heart rate, increase blood pressure, reduce blood flow to viscera and skin stimulate conversion of glycogen to glucose increase sweating induce dilation of bronchioles increase rate of respiration decrease digestion; decrease enzyme production by digestive system glands; decrease urine production
what is the immediate effects of ACTH
increase steroidogenesis by increasing cholesterol availability
A ________ serum cortisol concentration inhibits the release of more CRH and ACTH.
increased
explain adrenal dependent cushings
increased cortisol production due to adrenal cortical adenoma/ carcinoma (functional adrenal cortical neoplasms)
A common adverse effect of the chronic use of supraphysiologic steroid dosages, is atrophy of the adrenal gland. This has been attributed to which of the following mechanisms?
induced negative feedback on the hypothalamic adrenal axis.
primary hypoadrenocorticism is commonly a results of _______ disease or _______ destruction of the adrenal cortex
infectious, autoimmune (genetic)
Cortisol also decreases sensitivity of adipose and lymphoid tissue to _______ so less glucose is removed from the blood by these tissues, which leaves glucose for the brain and muscles
insulin
Glucocorticoids and ________ have similar effects on liver glycogen metabolism
insulin
Another effective method to rapidly decrease the plasma potassium concentration is administration of regular _______
insulin (Insulin helps drive the Na K ATPase pump so K goes into the cells)
In the pancreas, cortisol decreases _______ and increases _______
insulin, glucagon (Glucagon is a peptide hormone secreted by pancreatic cells to increase lipolysis and liver gluconeogenesis)
PU/PD mechanisms in hypoadrenocorticism
less aldosterone being produced, RAAS system isnt working so your body can't reabsorb Na+ as well, so it doesn't reabsorb as much water either so you drink and pee more because you aren't retaining any water
Glucocorticoids on fat metabolism: The effect on adipose tissue is to increase rate of _______ and to redistribute fat into the _______ and _______
lipolysis, liver and abdomen
Mechanism of adrenal hormone is similar to ________ hormones as they are able to penetrate through the cell membrane
lipophilic
the lymphatic vessels of the adrenal gland drain into the _______ lymph nodes
lumbar aortic
what are characteristic blood values in Addison in relation with lack of cortisol (3) and aldosterone(3)
lymphocytosis, eosinophilia, hypoglycemia, hyponatremia, hypochloremia, hyperkalemia
4 factors of stress leukogram
lymphopenia, neutrophilia, Monocytosis, eosinopenia
Epinephrine release results in a different pattern, known as physiologic leukocytosis or excitement leukocytosis, characterized by _________ (like the glucocorticoid response) and ________ (unlike the glucocorticoid response).
mature neutrophilia, lymphocytosis
The chromaffin cells are locate din the adrenal _________
medulla, neurons
Pars intermedia of the anterior pituitary secretes _________
melanocyte stimulating hormone (MSH)
The cortex is lighter in color, and radially striated It originates from ________ cells of the _________
mesenchymal, mesoderm
The cells of the zona glomerulosa secrete _________ compounds that function in the regulation of ______ and ________ (ions) homeostasis and water balance.
mineralocorticoids, sodium and potassium
Cortisol has ______ feedback action on both the hypothalamic release of CRH and the pituitary release of ACTH.
negative
_______ small nodules of hyperplastic cells within and outside of adrenal capsule; well defined spherical nodules in cortex or attached to capsule
nodular hyperplasia (usually multiple, bilateral, yellow)
N- methylating enzyme converts _______ to ________ and is _________ hormone dependent
norepinephrine to epinephrine, corticosteroid
Hyperkalemia is life threatening in the acute Addisonian crisis but can be reliably treated with aggressive intravenous fluid therapy using ________
normal saline (0.9% sodium chloride) -
Glucocorticoid receptors have to be bound to glucocorticoids in order for them to be translocated into the ________.
nucleus
_______ is the most frequent tumor of the adrenal medulla in animals; arise from ______ cells and resembles them
pheochromocytoma, chromaffin
Cranial adrenal branches from the __________ artery Middle adrenal branches from the _________ Caudal adrenal branches from the _______ and ________ arteries
phrenicoabdominal, abdominal aorta, lumbar and renal
The cells of the zona fasciculata are large and ________. _________ cells are common in this zone
polyhedral, Binucleated
the _______ lobe is formed by a downgrowth of hypothalamus
posterior lobe
The adrenal medulla is considered a specialized ________ sympathetic neuron devoid of an axon. The chromaffin cells of the medulla secrete stored catecholamines in response to cholinergic stimulation by __________ sympathetic fibers.
postganglionic, preganglionic (review this)
______ hypoadrenocorticism is the destruction of all layers of adrenal cortex; primarily _______ mediated
primary , immune (the disease has a genetic basis in several breeds of dogs)
First step in steroid hormone synthesis is to form _________ from cholesterol. These function as precursors to all other corticosteriods
progestogens (pregneneolone and progesterone) ;
The dorsal border of the right kidney is formed by the _______ muscle and the ________
psoas minor, crus of the diaphragm
The dorsal border of the left adrenal gland Is applied closely to the body of the ______ muscle and the transverse process of the ______ lumbar vertebra
psoas minor, second
Primary hypoadrenocorticism: Pre-renal azotemia results from decreased _______ and ________
renal perfusion and decreased glomerular filtration rate (GFR)
The zona glomerulosa is under feedback control of the ________ system.
renin-angiotensin-aldosterone
The cells of the zona ________ are noticeably smaller than those of the zona fasciculata, and their nuclei are more deeply stained.
reticularis
Zona ________ composes the innermost 25% of the cortex and appears as the darker zone of the cortex
reticularis
Both adrenal glands lie in a generous bed of _________
retroperitoneal fat
which adrenal gland is more cranial in position
right
The cranial two thirds of the right adrenal gland Is covered by the caudal extension of the __________ hepatic lobe of the liver
right lateral
________ hypoadrenocorticism is related to a pituitary problem; lack of ______ production
secondary, ACTH
what would the ACTH stimulation test look like in a dog with iatrogenic hypoadrenocorticism
should be high because there is a lack of cortisol for negative feedback
Osmolality is directly associated with ________ (ion)
sodium All animals that are hypernatremic are also hyperosmolal Hypoosmolality is always is associated with hyponatremia
Primary hypoadrenocorticism: Inability to retain _____ and ______ reduces extracellular fluid volume, leading to progressive development of hypovolemia, hypotension, a reduced cardiac output, an decreased perfusion of the kidneys and other tissues
sodium and chloride
Primary hypoadrenocorticism: Loss of aldosterone secretion results in impaired renal conservation of_____ and ______ and the excretion of ______
sodium and chloride , potassium (leading to the development of hyponatremia, hypochloremia, and hyperkalemia)
without aldosterone cells cannot hold on to _____ and _______ or excrete _______
sodium, chloride, potassium
explain endocrine alopecia
symmetrical on dorsal aspect- hair stuck in telogen phase
Innervation to the adrenal gland is predominantly ________ by way of the _________ plexus, which communicates with the major and minor ________ nerve, and the __________ plexus
sympathetic, suprarenal, splanchnic, celiacomesenteric
Glucocorticoids on proteins: Protein _______ is inhibited by glucocorticoids; causes increased protein _______
synthesis, catabolism (to release energy)
T/F Adrenocortical adenoma and carcinoma occur with equal frequency
true
T/F Unlike the cortex, the parenchyma of the medulla cannot be partitioned into zones according to cellular or tissue morphologic characteristics
true!
T/F The negative feedback of glucocorticoids occurs at all levels of the HPA axis, this includes the hypothalamus (TRH neurons) the anterior pituitary (corticotroph cells), and the adrenal gland (Zonas reticularis and fasciculata)
true!!!
Glucocorticoids inhibit _______ activity which leads to enhanced exertion of water
vasopressin
Phrenicoabdominal vein lies _________ to adrenal gland
ventral (lies on top of and across gland)
At the interface of the outer and inner cortices, there is a narrow band, the ___________ of small undifferentiated cells that make up the blastemic stem cells, which generate replacement parenchyma for both the inner and outer cortex
zona intermedia,
