Endocrine system Flashcards
what makes up the endocrine system?
it’s composed of ductless glands that secrete chemical messengers into the bloodstream
endocrine target organs
tissues/organs that hormones act upon
which glands in the endocrine system are responsible for sending signals?
hypothalamus and pituitary gland
what causes endocrine diseases?
hormone imbalances
negative feedback loop
more common, works in response to low or high levels of hormones
positive feedback loop
uncommon, occur when hormone levels continue to rise in response to stimuli
hormones
chemical substances produced by cells in one part of the body and transported to another part of the body where it influences and regulates cellular activity/organ function
what are the two types of hormones?
endogenous= made by the body
exogenous= made outside of the body
TSH
thyroid stimulating hormone
FSH
follicle stimulating hormone
ACTH
adrenocorticotropic hormone
LH
luteinizing hormone
GnRH
gonadotropin-releasing hormone
GH
growth hormone
MSH
melanocyte stimulating hormone
ADH
antidiuretic hormone
vasopressin
antidiuretic hormone, treats diabetes insipidus, concentrates urine
desmopressin
synthetic form of vasopressin so structurally similar
oxytocin
stimulates smooth muscle contraction and induces labor
affects the uterus and mammary glands
milk letdown hormone
diabetes insipidus
rare disease characterized by the inability to concentrate urine caused by posterior pituitary gland’s failure to respond to ADH stimulation
insulin
promotes uptake and use of glucose for energy in cells, lowers blood glucose levels
glucagon
promotes breakdown of liver glycogen into glucose
diabetes mellitus types
type 1: lack of insulin
type 2: insufficient use of insulin
hyperglycemia
high blood glucose
gluosuria
glucose in urine
insulin resistance
inefficient use of insulin
what are the clinical signs of diabetes mellitus?
increased appetite, weight loss, PUPD, cataracts
what species is diabetes mellitus more common in?
dogs especially obese females
what is a hallmark sign of diabetes mellitus?
persistent fasting hyperglycemia
what is important to know about cats with diabetes mellitus?
they can go into remission randomly
how and when is insulin administered for animals with diabetes mellitus?
SQ administration twice a day with meals
you should do different shot locations so one area doesn’t develop scar tissue
what are the adverse effects of insulin medication?
hypoglycemia and local reactions
what are the signs of hypoglycemia?
lethargy, weakness, ataxia, potentially seizures
what are the insulin drugs approved for vet use?
vetsulin: porcine zinc insulin, mainly used for dogs
prozinc: formulated with protamine and zinc, mainly used for cats
what are human-approved insulins that are sometimes used for dogs and cats?
neutral protamine Hagedorn (NPH) insulin, insulin Glargine (commonly used for cats), and insulin Detemir
what are some short-acting insulins?
only used for emergencies
administered IV, IM, or SQ
Humulin-R and Novolin-R
what two hormones are produced by the thyroid gland?
Thyroxine (T4) and Tri-iodothyronine (T3)
where is the thyroid gland located?
in the neck near the larynx
hypothyroidism
deficiency of thyroid hormone
more common in dogs
how can hypothyroidism be diagnosed?
total T4 blood test or thyroid stimulation test
what are the clinical signs of hypothyroidism?
decreased coat luster/alopecia, weight gain without an increased appetite, listlessness, intolerance to cold, reproductive failure, skin more susceptible to disease
hyperthyroidism
excessive activity of thyroid gland
more common in cats
how can hyperthyroidism be diagnosed?
a T4 or T3 blood test
what are the clinical signs of hyperthyroidism?
weight loss despite increased appetite, increased thirst, increased stool production, restlessness, increased vocalizations, tachycardia
how is hypothyroidism managed?
thyroid replacement therapy
what drugs are used for thyroid replacement therapy?
Levothyroxine sodium (synthetic form of T4)
Liothyronine sodium (synthetic form of T3)
how is hyperthyroidism managed?
inhibiting thyroid hormone production and may be followed by destroying/removing the thyroid gland
what drugs are used to manage hyperthyroidism?
Methimazole (anti-thyroid drug)
radioactive isotopes of iodine (destroys thyroid gland)
what regulates the adrenal cortex and what does the adrenal cortex produce?
the adrenal cortex is regulated by the hypothalamus (ACTH)
and it produces corticosteroids
what does the adrenal medulla produce?
epinephrine and nonepinephrine
hypoadrenocorticism
adrenocortical insufficiency
Addison’s disease
what are the clinical signs of hyporadrenocorticism?
nonspecific, lethargy, weakness, anorexia, vomiting, diarrhea, PUPD
hyperadrenocorticism
too much hormone
Cushing’s disease
what are the clinical signs of hyperadrenocorticism?
PUPD, dull hair coat, thinning hair, potbelly appearance
how is hypoadrenocorticism managed?
Deoxycorticosterone pivalate (DOCP): long-acting mineralocorticoid approved for dog use
glucocorticoids: Prednisone or Prednisolone, often given with DOCP
Fludrocortisone acetate: human-approved drug that can be used in animals
how is hyperadrenocorticism managed?
Mitotane: destroys adrenal gland which decreases cortisol production
Trilostane: decreases production of adrenocortical hormones
Ketoconazole: antifugal drug that also blocks enzymes needed to produce steroid compounds
gonads
produces germ cells
androgens
male sex hormones
what drugs are male hormone-like?
testosterone products and anabolic steroids
which male hormone drugs are testosterone products?
Synovex H, Component E-H with Tylan
controlled drugs
which male hormone drugs are anabolic steroids?
synthetic steroidal drugs with anabolic effects (promotion of muscle growth)
they have androgenic effects similar to testosterone
ex: Boldenone (Equipoise)- horses, Stanozolol (Winstrol-V)- horses, Einasteride- dogs
what drugs are female hormone-like?
estrogens and progesterones
which female hormone drugs are estrogen products?
Estriol (incurin): synthetic estrogen product that treats urinary incontinence/urine leakage
which female hormone drugs are progesterone products?
Medroxyprogesterone acetate
Altrenogest (Regu-Mate, Altren, Ovamed)
Melengesterol acetate (MGA): synthetic progesterone
prostaglandins
occur naturally in the body and there are 6 different classes (classified as A-F)
what do prostaglandin drugs do?
synchronize estrus, treat pyometra, cause abortions, induce pig parturition
which species are prostaglandin drugs used on?
large animals
what are some examples of prostaglandin drugs?
Dinoprost tromethamine (Lutalyse)
Cloprostenol sodium (Estrumate, estroPLAN)
what do gonadotropins do?
stimulate gonads to release LH and FSH
