Term
| What is an endocrine axis? |
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Definition
The things/processes involved in an endocrine response.
Like:
Hypothalmus-->Pituitary--->Adrenal cortex
Or generically:
Stimulus --> Endocrine glands --> Hormones --> Response --> Target tissue |
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Term
| How do hormones work (in general how do they travel to the target tissue?) |
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Definition
| Hormones are released into the circulation by the secreatory/endocrine cell. It will then affect ANY CELL IN THE BODY WITH A RECEPTOR FOR THE HORMONE |
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Term
| What are the two ways hormones can be transported in the blood? |
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Definition
Dissolved (hydrophilic)
Or bound to carrier proteins (hydrophobic) |
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Term
| Which type of hormone (hydrophilic or hydrophobic) is secreted by exocytosis? |
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Definition
| Hydrophilic, cannot cross the lipid bi-layer |
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Term
| What is the difference between primary and secondary endocrine organs? |
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Definition
| A primary organ is on that has secretion of hormones as it's no. 1 function (i.e. pituitary) while a secondary one has it as a secondary function (i.e. heart) |
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Term
| In a generic sort of way, describe the structure of an endocrine gland |
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Definition
| The secretory cells are surrounded and permeated by an extensive capillary network to allow fast delivery of substrates and fast excretion of hormones |
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Term
| What are the 5 parts of the pituitary gland? |
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Definition
Posterior pituitary
Infundibulum (the stalk)
Pars nervosa
Anterior pituitary
Pars tuberalis (wraps around the infundibulum, like a tube)
Pars intermedia (it's in the middle..)
Pars distalis (anatomically it is the most distant from the hypothalamus. See what I did there?) |
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Term
| Which part of the pituitary gland is physically, anatomically and histologistical connected to the hypothalamus? |
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Definition
| The Posterior pituitary (infundibulum and pars nervosa) |
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Term
| Does the anterior pituitary share a capillary bed with the hypothalamus? |
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Definition
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Term
| What is a trophic hormone? |
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Definition
| One the stimulates the release of hormones from an endocrine gland |
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Term
| Define tertiary, secondary and primary endocrine disorders |
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Definition
Tertiary - the problem originates from the hypothalamus
Secondary - the problem originates from the second organ in the axis (pituitary for e.g.)
Primary - the problem originates in the final organ in the axis (adrenal cortex for e.g.) |
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Term
| From outside to in, what are the 5 layers of the adrenal gland? |
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Definition
| Capsule, zona glomerulosa, zona fasiculata, zona reticularis, medulla |
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Term
| What are the products of the adrenal gland (outside to in) |
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Definition
Aldosterone
Corticosteroids
Sex hormones
Catecholmines |
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Term
| What are some biological actions of cortisol? |
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Definition
Gluconeogenic (this is why you get a stress increase in glucose in some species)
Lipolytic
Protein catabolism
Insulin antagonism (see glucose)
Bone resorption
Anti inflam
Immune suppresive
RBC production
Down reg of ADH |
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Term
| What defines a 'Stress Leukogram'? |
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Definition
SMILED
Segmented neutrophils and Monocytes Increased
Lymphocytes and Esinophills Decreased
NB: Monocytes not always increased |
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Term
| What causes a Stress Leukogram? |
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Definition
Increased cortisol, leading to anti-inflam effects.
Marginalised neutrophils are mobilised, while lymphoid cell multiplication and eosinophils are supressed |
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Term
| Which disease process is primarily related to the metabolic effects of glucocorticoids? |
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Definition
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Term
| Which disese process is primarily related to a decreased in mineralocorticoid levels? |
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Definition
HypoA - Addisons - HOD
Hahahaha
Hypo is slow, HODor is slow, Addison likes to help slow people.. Hahahahahha
I've been staring at my computer for too long... |
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Term
| What are some of the causes for HyperA? |
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Definition
Gland dysfunction (primary, secondry or tertirary)
Stress induced (chronic stress - adrenal hyperplasia, but no real clinical signs)
Iatrogenic
Cortisol producing neoplasia, quite rare in the animals |
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Term
| What are some of the common clinical signs of HAD? |
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Definition
PU/PD
Polyphagia
Lethargy
Potbelly
Pnating
Muscle weakness
UTI (immune suppressed)
Truncal alopecia
Other skin changes |
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Term
| What is the most common cause of HAD in cats and dogs? |
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Definition
| Pituitary adenomas (80-85% of the time) |
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Term
| Which companion animal species is HAD more common in? |
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Definition
| Dogs, not a common condition in cats |
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Term
| What are some of the changes seen in HAD clin path? |
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Definition
Stress leukogram
Moderate to marked ALP increase
Mild ALT increase
Mild to moderate cholesterol increase
USG 1.006-1.015
NB, T4 down in 70% of cases
Other less common signs are increased glucose and BUN and UTI without inflamation |
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Term
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Definition
Serum cortisol
Urine cortisol:creatine
LDDT
HDDT
ACTH stimuation test
Blood ACTH
The aim is to differentiate between HAD and stress |
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Term
| Why is serum cortisol often an inaccurate measure? |
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Definition
| [Cortisol] will be increased by stress |
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Term
| What is the benifit of urinary cortisol:creatine? |
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Definition
Corrects for episodic variation due to short term stress.
This is a SeNsitive test as it rules OUT disease (SPIN and SNOUT).
If the ratio is less than 17 then there is strong evidence that the dog does not have HAD, while if it is greater than 17, the dog may have HAD.
Cortisol
-----------
Creatinine
Creatinine is a bigger word so it goes on the bottom |
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Term
| How does the low dose dex test work? |
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Definition
Give a small amount of dex at 4 and 8 hours and measure the cortisol response. A normal animal will suppress the cortisol production at 4hrs post injection, while a HAD animal may not. If there is no suppression then it is HAD.
ADH - no supression at all
PDH - Suppression at 4 hrs and then escape at 8 |
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Term
| How does the ACTH test work? |
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Definition
Cortisol is measured at +0 and +1hrs after a does of synthetic ACTH
HAD animals will hyper respond (large cortisol reserves) while HOD animals and iatrogenic HAD animals will hyporespond (no cortisol reserve) |
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Term
| Is LDDT or ACTH more usful in stressed and sick dogs? |
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Definition
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Term
| How can you differentiate between PDH and ADH? |
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Definition
HDDT
Endogenous ACTH assay (bloody hard)
Ultrasound
CT scan
POST MORTEM!!! YAY!! |
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Term
| What are some of the differneces in HAD seen in cats? |
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Definition
80% seen with diabetes mellitis
Similar clin path
fragile skin
Elevated sex hormones +/-
USG often >1.030 |
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Term
| What are some causes of HOD? |
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Definition
Bi-lateral adrenocortical atrophy (immune mediated?)
Iatrogenic
Treatment of HAD |
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Term
| Name a process that mineral corticoids play a key role in |
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Definition
Maintenance of ECF by Na resorption and K secretion
ESSENTIAL FOR THE HOMEOSTASIS OF BLOOD PRESSURE |
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Term
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Definition
| Pituitary pars intermedia dysfunction |
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Term
| How do you test for PPID? |
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Definition
| Test using the 20hr dex test |
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Term
| What are some of the clinical signs of PPID? |
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Definition
Hirsuitims (shagginess)
Muscle wastage
PU/PD
Laminits
Metabolic syndrome
hyperglycemia
hyperlipaemia |
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