Endocrine System Flashcards
Function of endocrine system
-maintenance of homeostasis-> mediated by hormones
-Regulated by feedback systems
Increased function endocrine system
-Primary: increased hormone by abnormal gland
-Secondary: increased hormone by normal gland that is excessively stimulated
Decreased function of endocrine system
-Primary: decreased hormone by abnormal gland
-Secondary: decreased hormone by normal gland that is inadequately stimulated
Pituitary gland structure
-Anterior lobe (adenohypophysis)
Pars intermedia
Pars tuberalis
-Posterior lobe (neurohypophysis)
pars nervosa
Infundibular stalk
Function of Adenohypophysis
-Growth hormone (somatotrophin)
-Luteotropic hormone (stimulate progesterone)
-Luteinizing hormone (stimulate estrogen)
-Follicle stimulating hormone (Follicle growth and spermatogenesis)
-TSH
-ACTH
-Melanocyte stimulating hormone
Function of neurohypophysis
-ADH
-Oxytocin
Acidophils
Somatotrophs and gonadotrophs
Basophils
Gonadotrophs and thyrotropes
Chromophobes
Corticotropes and melanotrophs
Pituitary increased hormone activity
Functional neoplasia
Increased stimulation by hypothalamus
Antehormone like substance
Dicreased pituitary hormone activity
Destructive lesions
Non responsive tissue targets
Decreased pituitary hormone activity
Destructive lesions
Non responsive tissue targets
Chromophobe adenoma
Functional adenoma
Chromophopes are unregulated and produce too much ACTH (Cushings) can cause diffuse hyperplasia of the adeoma, most likely to be microademona and be function less likely to be macroademoa which is more of a space occupying mass
Pars intermedia adenoma
Chromophobe adenoma in dogs, Can be functional or compressive. More common in horses could be from age related oxidative injury of dopaminergic neurons
Pituitary pars intermedia dysfunction in horses
Decrease dopamine results in increased activity of melanotrophs->POMC-> ACTH and other products
Can be from hyperplasia to micro/macroadenoma and cause hypothalamic compression
Adrenal glands normal
Signs of PPID
Increased hair growth
Increased adipose tissue deposition
Weight loss
Somatotroph adenoma
Mainly cats, dogs, sheep
Functional adenoma-> increase insulin like growth factor (acromegaly, diabetes mellitus)
Non functional adenoma-> panhypopituritism and hypothalamic compression
Pituitary cysts
Abnormal development in or around the pituitary gland. Can compress or damage surrounding structures
Craniopharyngeal duct cyst
Diabetes insipidus
Pituitary hypofunction
Pharyngeal hypophyseal cyst
Respiratory distress
Oropharyngeal ectoderm cyst
Panhypopituitarism
Juvenile hypopituitarism in German shepherds
Pituatary dwarfism
Failure of Rathkes pouch to differentiate adenohypophysis
Decreased growth hormone (insulin-like growth factor 1)
Retention of puppy hair progressing to alopecia
Craniopharyngioma
Neoplastic remnants of Rathkes pouch oropharyngeal ectoderm. See hypothalamic destruction and decreased hypothalamic trophic hormones. young dogs, rare
Non functionadenoma
Not secreting hormones, see issues because of pressure on hypothalamic areas
Pituitary abscesses
In cattle and secondary to nasal septal infections
Space occupying lesions. See blindness, depression, drooling, tongue prolapse, similar to rabies
Pituitary DIabetes insipidus
Destruction of neurohypophysis or Supraoptic nuclei of the hypothalamus. Decreased ADH
Hyperfunction of adrenal gland
Primary or secondary adrenal involvement
Hypofunction of adrenal gland
May be primary or secondary adrenal involvement
Adrenal cortical adenoma or carcinoma
Most arise from zona fasciculata. Less common glomerulosa in cats of reticularis in ferrets. Adenomas more common than carcinoma
Diffuse Adrenal hyperplasia
Occurs secondary to functional chromophobe adenoma of the pituitary (excess ACTH)
See hyperadrenocorticism
Nodular adrenal hyperplasia
Age related change in dogs, cats, horses, Some are functional and some non functional
Pheochromocytoma
Arise in chromaffin cells of the medulla. Most non function . Can get functional neoplasia resulting in hypertension due to NE. Can be benign or malignant
Adrenal hypoplasia or agenesis
Rare condition of dogs. Agenesis is fatal. See hypoadrenocarticism
Diffuse adrenal cortical atrophy
Common in dogs on long term glucocorticoid therapy resulting in inhibition of adrenal cortical function and subsequent atrophy. Uncommonly idiopathic or immune mediated
Injury to the adrenal galnd
Due to high vascularity
-Thrombosis due to DIC
-Adrenalitis due to infectious emboli
-Metastatic neoplasia
