Endocrine Flashcards
What is ectopic thyroid tissue common in dog and cats?
True
Ectopic thyroid tissue refers to thyroid tissue located outside its normal anatomical location.
How common is ectopic parathyroid tissue in dogs?
Approximately 3% to 6%.
Ectopic parathyroid tissue is relatively rare in dogs.
What is the incidence of ectopic parathyroid tissue in cats?
35% to 50%.
This indicates a higher prevalence of ectopic parathyroid tissue in cats compared to dogs.
What are the blood supply sources for the thyroid?
Cranial thyroid a. from common carotid a. & caudal thyroid a. from brachiocephalic a.
These arteries are essential for delivering blood to the thyroid gland.
What is the vascular drainage for the thyroid?
Cranial thyroid v. drains into internal jugular & caudal thyroid v. drains into internal jugular v.
This drainage system helps remove deoxygenated blood from the thyroid.
Which lymph nodes are involved in the lymphatic drainage of the thyroid?
Cranial deep cervical ln. (cranially) & caudal deep cervical ln. (caudally)
These lymph nodes play a role in the immune response and fluid balance.
What nerve innervates the thyroid gland?
Thyroid n. from cranial laryngeal n. from vagal n.
This nerve pathway is crucial for the thyroid’s function and regulation.
What is the outermost layer of the adrenal cortex?
Zona Glomerulosa
Zona Glomerulosa produces mineralcorticoids.
What is the primary function of aldosterone?
Electrolyte balance & blood pressure homeostasis
Aldosterone is a mineralcorticoid produced in the Zona Glomerulosa.
What hormones are produced in the Zona Fasiculata?
Glucocorticoids
Glucocorticoids have various metabolic effects.
What is the primary function of glucocorticoids?
Stimulate hepatic gluconeogenesis
This is a key metabolic function of glucocorticoids.
List some effects of glucocorticoids on the body.
- Inhibit glucose uptake and metabolism in peripheral tissues
- Inhibit protein synthesis
- Inhibit vasopressin
- Suppress inflammatory/immune system
- Stimulate lipolysis
- Stimulate gastric acid secretion
- Enhance protein catabolism
- Increase GFR
These effects contribute to the overall metabolic and homeostatic functions of glucocorticoids.
What triggers the secretion of glucocorticoids?
Hypothalamus produces corticotropin-releasing hormone -> pituitary secretes corticotropin -> glucocorticoid secretion
This is part of a hormone feedback loop.
What hormones are produced in the Zona Reticularis?
Androgens and estrogens
These are sex steroids produced in small volumes under normal conditions.
True or False: The Zona Reticularis produces a large volume of sex steroids under normal conditions.
False
The Zona Reticularis normally produces a small volume of sex steroids, which increases dramatically with pathologic conditions.
What is glandular hyperplasia?
Prostatic Hyperplasia
A condition found in younger dogs (less than 4-5 years old) characterized by symmetric enlargement confined to secretory cells
Glandular hyperplasia shows minimal changes in smooth muscle and fibroblasts and maintains a normal histologic structure.
Which hormone mediates prostatic growth in glandular hyperplasia?
Prostatic Hyperplasia
5α-dihydrotestosterone
Testosterone is metabolized by 5α-reductase to form 5α-dihydrotestosterone.
What type of enlargement is associated with glandular hyperplasia?
Prostatic Hyperplasia
Symmetric enlargement
This enlargement is confined to secretory cells.
What is complex hyperplasia, and in which age group is it found?
Prostatic Hyperplasia
A condition found in older dogs characterized by asymmetric enlargement involving both glandular and stromal elements
Complex hyperplasia occurs alongside a decline in glandular dihydrotestosterone.
What happens to the metabolism of androgens in the prostate gland in complex hyperplasia?
Prostatic Hyperplasia
Increased metabolism of androgens
This is paralleled by an increase in the number of nuclear androgen receptors.
What effect does complex hyperplasia have on nuclear androgen receptors?
Increased numbers of nuclear androgen receptors
This leads to greater responsiveness to androgens.
What is the reason for the increased size in complex hyperplasia?
Not through cell proliferation but due to a decreased rate of cell death
This indicates a complex interaction between cell survival and hormonal influences.
What elements are mostly involved in complex hyperplasia?
Stromal elements
Complex hyperplasia features asymmetric enlargement with both glandular and stromal components, including areas of stromal atrophy.
