Term
| Endocrine and Nervous System Functions |
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Definition
control all body functions
maintain homeostasis |
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Term
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Definition
| the tendency of an organism to maintain a constant internal environment. Bodies internal environment works constantly to remain WNL |
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Term
| Nervous System Attributes |
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Definition
controls homeostasis
nerve impulses conducted along axons of neurons
stimulates or inhibits release of neurotransmitters |
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Term
| Endocrine System Attributes |
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Definition
| controls homeostasis through the release of hormones into bloodstream thereby delivering hormone to the target cell throughout the body |
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Term
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Definition
can be anywhere in the body
hormones attach to receptor on cell (lock and key)
if no receptor, hormones flow by cell |
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Term
| Cell Affected by the Nervous System |
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Definition
| other neurons, muscle cells, gland cells |
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Term
| Endocrine System Cells Affected |
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Definition
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Term
| Time to Onset of Action and Duration (Nervous) |
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Definition
milliseconds
very brief duration |
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Term
| Time to Onset of Action and Duration (Endocrine) |
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Definition
seconds to hours to days
long duration |
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Term
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Definition
| a chemical messenger that alters physiological activity of target cells in the body |
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Term
| Action of Hormones on Target Cells |
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Definition
1. stimulates or inhibits target cell
2. stimulates or inhibits release of other hormones
onset of effects are slower but longer in duration than neurotransmitters |
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Term
| Endocrine vs. Exocrine Glands |
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Definition
| endocrine glands secrete hormones directly into the bloodstream, exocrine glands secrete products (enzymes, sweat, tears) into ducts that deliver into body cavities |
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Term
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Definition
Steroids, thyroid hormones, and nitric oxide
Enter target cells, combine with receptors in nucleus to form complexes which activate specific genes |
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Term
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Definition
prostaglandins and leukotrienes
protein and peptide hormones that attach to cell membrane but do not enter the cell |
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Term
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Definition
| each hormones has a special molecular structure, is potent, attaches to receptors on target cell |
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Term
| Control of Hormonal Secretion |
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Definition
| concentration of each hormone precisely regulated, normal ranges can be very narrow, body constantly working to achieve homeostasis. Homeostasis monitored using feedback systems and direct stimulus |
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Term
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Definition
Cycle of events in which status of body is continually
monitored, evaluated, changed, re-monitored, re-evaluated |
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Term
| Components of a Feedback System (Variable) |
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Definition
| Variable being monitored. Example is blood pressure |
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Term
| Components of a Feedback System (Stimulus) |
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Definition
disruption that changes controlled condition
ex - decrease in BP due to hemorrhage |
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Term
| Components of a Feedback System (Receptor) |
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Definition
structure that monitors condition
ex - baroreceptor in aorta |
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Term
| Components of a Feedback System (Control Center) |
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Definition
sets range of values at which controlled condition should be maintained
evaluates input from receptors and generates output commands
ex - cardio center in medulla |
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Term
| Components of a Feedback System (Output) |
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Definition
Nerve impulses, hormones or other chemical signals
ex - increased sympathetic impulses, decreased parasympathetic impulses, increased secreations of epi and norepi |
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Term
| Components of a Feedback System (Effector) |
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Definition
body structure that recieves output from control center
e.g. - cardiac and smooth muscle increases heart stroke and volume, constricts blood vessels |
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Term
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Definition
typically how hormone secretion is controlled
reverses original stimulus
ex - temp |
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Term
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Definition
enhances or intensifies original stimulus
ex - parturition |
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Term
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Definition
stimulation comes directly from the nervous system
ex - fight or flight response |
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Term
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Definition
integrating link between nervous and endocrine systems, receives sensory signals,regulates hunger, thirst, sleep cycles, aggressive behavior.
works and acts on pituitary which releases 9 hormones |
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Term
| TSH (Thyroid-Stimulating Hormone) |
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Definition
Source - Anterior pituitary
Target - thyroid gland
Effect - stimulates growth and development of thyroid and secretion of thyroid hormones T3 and t4 |
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Term
| ACTH (Adrenocorticotropic Hormone) |
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Definition
Source - Anterior pituitary
Target - cortex of the adrenal gland (adrenal cortex)
Effect - stimulates the growth development of adrenal cortex and the production of aldosterone and cortisol |
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Term
| FSH (Follicle-Stimulating Hormone) |
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Definition
Source - anterior pituitary
Target in Female - ovaries
Effect in female - stimulates follicle growth and development
Target in Male - testes
Effect in male - stimulates sperm production |
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Term
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Definition
Source - anterior pituitary
Target in females - ovaries
Effect in females - causes ovulation of the mature follicle
Target in males - testes
Effect in males - stimulates production of testosterone |
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Term
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Definition
source - anterior pituitary
target - mammary glands
effect - stimulates milk production in mammary glands of lactating females |
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Term
| GH or STH (Growth Hormone) |
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Definition
Source - anterior pituitary
Target - bones and skeletal muscle
effect - stimulates growth and development of bones and skeletal muscle, regulates some aspects of metabolism |
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Term
| MSH (Melanocyte-Stimulating Hormone) |
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Definition
Source - anterior pituitary
Target - melanocytes in skin
Effect - stimulates increased pigmentation |
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Term
| Posterior Pituitary Hormones |
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Definition
| two hormones produced by the hypothalamus and secreted by posterior pituitary are ADH and Oxytocin |
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Term
| ADH (Anti-Diuretic Hormone) |
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Definition
Source - posterior pituitary
Target - kidneys
Effect - causes retention of water which decreases urine output |
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Term
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Definition
Source - posterior pituitary
Target - uterus and mammary glands
Effect - stimulates milk letdown, uterine contractions that expel fetus or retain spermatozoa |
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Term
| Pineal Gland or Pineal Body |
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Definition
produces melatonin that affects mood and sleep-wake cycles
not a well-understood gland |
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Term
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Definition
| composed of two lobes that sit on either side of the neck below the larynx. produces thyroid hormone and calcitonin |
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Term
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Definition
Source - Thyroid gland
Target - all cells in the body
Effect - increases rate of metabolism, needed for normal growth and development and maturation of the nervous system |
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Term
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Definition
Source - Thyroid gland
Target - osteoblasts in the bone
Effect - decreases blood calcium levels by stimulating uptake of calcium into bone |
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Term
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Definition
| attached to the lateral lobes of the thyroid glands, produces PTH |
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Term
| PTH (Parathyroid Hormone) |
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Definition
Source - Parathyroid Gland
Target - acts on osteoclasts of the bone + kidneys and intestines
Effect - increases blood calcium levels by stimulating the breakdown of bone, causes kidneys to conserve Ca, causes intestines to absorb Ca from food |
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Term
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Definition
located near cranial end of the kidneys
made up of a cortex and medulla |
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Term
| Hormones of the Adrenal Medulla |
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Definition
epinephrine and norepi
Source - adrenal medulla
Target - CVS, RS, liver
Effect - increases HR/BP, increases RR, liver breaks down stored glycogen and releases glucose in blood, fight or flight response |
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Term
| Hormones of the Adrenal Cortex (Mineralocorticoids) |
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Definition
Aldosterone
Source - adrenal cortex
Target - kidneys
Effect - conservation of Na and water and excretion of K to help maintain BV and pressure |
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Term
| Hormones of the Adrenal Cortex (Glucocorticoids) |
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Definition
cortisol and cortisone
Source - adrenal cortex
Target - immune system, liver, heart and uterus
Effects - anti-inflammatory, gluconeogenesis, breakdown of lipids and proteins, helps body resist stress, depresses immune system and delays wound healing |
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Term
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Definition
endocrine and exocrine functions
located posterior to stomach, attached to duodenum |
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Term
| Pancreas Endocrine Functions |
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Definition
| secretes insulin and glucagon |
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Term
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Definition
Source - Pancreas
Target - cell membranes
Effect - causes cell membrane to become permeable to glucose, amino and fatty acids
decreases blood glucose levels |
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Term
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Definition
Source - pancreas
Target - liver
Effect - stimulates breakdown of glycogen
increases blood glucose levels |
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Term
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Definition
ovaries - secrete estrogen and progesterone
testes - secrete testosterone |
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Term
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Definition
responsible for the development and maintanence of female reproductive structure
increases protein anabolism
lowers blood cholesterol |
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Term
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Definition
hormone of pregnancy
prepares endometrium for implantation
prepares breasts to secrete milk |
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Term
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Definition
activates spermatogenesis
responsible for development of secondary male sex characteristics, anabolic effect builds up muscles and bones, regulates libido |
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Term
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Definition
| a deficiency of circulating T3/T4 |
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Term
| Etiology of Hypothyroidism |
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Definition
| Hypothyroidism (primary) usually caused by the destruction of the thyroid gland where the immune system attacks the gland or the gland degenerates (atrophy) |
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Term
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Definition
| accounts for 95% of all hypothyroidism cases in dogs |
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Term
| Secondary, Tertiary, and Congential Hypothyroidism |
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Definition
Secondary - dysfunction of the pitutary
Tertiary - congential defects of the hypothalamus
Congential - thyroid gland dysgenesis (defective development) |
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Term
| Hypothyroidism and Iodine Deficiency |
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Definition
| hypothyroidism can be due to insufficient iodine levels in diet but is rarely seen, iodine important in the function of T3/T4 |
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Term
| Signalment of Hypothyroidism |
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Definition
| almost always dogs but can affect other species, usually middle-aged to older animals but can occur at any age. |
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Term
| General Clinical Signs of Hypothyroidism |
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Definition
weight gain without increased appetite
lethargy
weakness
exercise intolerance
bradycardia
heat-seeking behavior |
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Term
| Skin Disorders from Hypothyroidism |
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Definition
dull, dry, coarse coat
hyperpigmentation on flank, belly
skin becomes thick and oily
bilateral symmetrical alopecia
secondary skin infections |
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Term
| Skin Disorders Associated with Hypothyroidism Cont. |
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Definition
alopecia typically the most observed clinical sign by owners
diminished T3/T4 affects hair growth
telogen phase - no follicle growth
decrease in SQ fatty acids/ vitamin E leads to scaly appearance and dry coat |
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Term
| Ocular Disorders Associated with Hypothyroidism |
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Definition
| KCS and uveitis though there is little clinical evidence to support this |
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Term
| Reproductive Disorders Associated with Hypothyroidism |
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Definition
| anestrus, abortion, decreased libido |
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Term
| Testing of Hypothyroidism |
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Definition
Submit T3/T4/TSH sample to lab
thyroid medications such as levothyroxine may interfere with test results
periodic testing as pt will be on lifetime meds |
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Term
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Definition
daily oral hormone supp
must be continued for the animals whole life, usually use L-thyroxine
re-evaluation occurs 6-8 wks after initiation of tx, clinical signs should reverse with therapy
owners may notice change within first week of tx |
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Term
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Definition
commonly called feline hyperthyroidism as its most commonly seen in cats
caused by increased T3/T4 in blood |
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Term
| Etiology of Hyperthyroidism |
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Definition
| caused most often by an adenoma of the thyroid gland, called functioning adenoma as it causes overproduction |
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Term
| Etiology of Hyperthyroidism Cont. |
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Definition
can be caused by increased iodine levels in cat food
soy disrupts thyroid function
BPA - coating in cans that is an endocrine disrupter
1/300 cats diagnosed with hyperthyroidism |
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Term
| Signalment of Hyperthyroidism |
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Definition
| usually in middle-aged to older cats but can occur at any age |
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Term
| Clinical Signs of Hyperthyroidism |
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Definition
significant weight loss (emaciation)
voracious appetite
tachycardia
hyperactivity
poor, rough hair coat
goiter - enlargement of one or both thyroid lobes |
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Term
| Testing for Hyperthyroidism |
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Definition
| differential dx may be obtained based on clinical signs, palpable thyroid nodule, increased serum T4 concentrations |
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Term
| Tx for Hyperthyroidism (Medical) |
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Definition
Methimazole (Tapazole)
kills off part of the thyroid tissue
pt may not tolerate it well with V/D |
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Term
| Tx for Hyperthyroidism (Surgical) |
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Definition
| surgical removal of part of the thyroid gland that has the adenoma, critical that parathyroid glands aren't removed as well |
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Term
| Tx for Hyperthyroidism (Radiation) |
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Definition
use of iodine 131
concentrates in the overactive tissue and kills abnormal tissue
must have nuclear license to admin
must isolate for 7-10 days
considered best option for tx |
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Term
| Post Tx for Hyperthyroidism |
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Definition
hyperthyroidism can mask underlying kidney dz
increaed T3/T4 increases kidney metabolism
creatine levels would be elevated |
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Term
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Definition
| Also called cushings dz, it is the chronic overproduction of the glucocorticoid cortisol |
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Term
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Definition
| increases blood sugar, supresses immune system, metabolism of fats, carbs and proteins |
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Term
| Three Forms of Hyperadrenocorticism |
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Definition
pitutary dependent
adrenocortical tumor
iatrogenic |
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Term
| Pituitary Dependent (PDH) |
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Definition
comprises of 85-90% of cushings, 90% of those cases in dogs caused by pituitary tumors
causes excessive secretion of ACTH from anterior pituitary
results in hypertrophy of the adrenal glands, excessive production of glucocorticoids, negative feedback loop becomes ineffective |
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Term
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Definition
comprises of 10-15% of naturally occurring cases, unrelenting production of cortisol from the tumor
renders negative feedback loop ineffective |
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Term
| Iatrogenic Hyperadrenocorticism |
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Definition
caused by exogenous administration of corticosteroids, used for control of autoimmune disorders and chronic inflammation
natural cortisol production shut down due to negative feedback mechanism |
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Term
| Signalment for Hyperadrenocorticism |
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Definition
usually middle aged to older dogs, commonly seen in poodles, dachshunds, terriers
males and females equally affected |
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Term
| General Clinical Signs of Hyperadrenocorticism |
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Definition
pt may show one or multiple clinical signs, no one sign is diagnostic and absence of one or more signs does not rule out
onset of signs very slow, owner may not notice for months |
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Term
| General Clinical Signs of Hyperadrenocorticism Cont. |
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Definition
distended, pendulous abdomen
weight gain, increased appetite
lethargy
PU/PD
poor hair coat, excessive bruising
recurrent skin/UT infections |
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Term
| Dx of Hyperadrenocorticism |
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Definition
1. Bloodwork - all need baseline samples drawn
2. ACTH Stim - give an injection of ACTH, measures cortisol output which is greatly elevated in cushingnoid pt |
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Term
| Dx of Hyperadrenocorticism LDDS |
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Definition
| LDDS - animal is fasted, given an injection of Dex SP, follow-up samples taken 4-8 hrs later, cushingoid pts. will not suppress cortisol in response to injection |
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Term
| Dx of Hyperadrenocorticism HDDS |
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Definition
| used to differentiate between forms of cushings, dog with adrenal tumor will not suppress at all, dog with pituitary tumor should respond with suppressed cortisol levels |
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Term
| Tx of Hyperadrenocorticism (Mitotane) |
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Definition
aka lysodren
selectively causes the necrosis of certain cells in the adrenal gland, but has no effect on pituitary tumors
Often used in the tx of PDH because of difficulty of surgical removal, instead, drug targets the hypertrophy of adrenal glands
occasionally used in tx of adrenal tumors in animals that are at poor surgical risk |
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Term
| Tx of Hyperadrenocorticism (Ketaconazole) |
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Definition
| common antifungal med but also inhibits the production of cortisol at high doses, used when there is an intolerance to lysodren |
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Term
| Tx of Hyperadrenocorticism (Surgery) |
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Definition
| may be indicated with adrenal tumors, but must leave some - animal can't live without adrenal glands |
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Term
| Tx of Hyperadrenocorticism (Other) |
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Definition
anipryl - tx for PDH, reduces ACTH prod. by increasing dopamine, clinical trials however showed no consistent resolution in dogs
vetoryl - interferes with cortisol synth |
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Term
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Definition
also called addisons dz
comes in primary and iatrogenic forms |
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Term
| Primary hypoadrenocorticism |
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Definition
| atrophy or destruction of the adrenal cortex, may be immune-mediated or iatrogenic |
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Term
| Iatrogenic Hypoadrenocorticism |
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Definition
| long-term admin of glucocorticoids causes atrophy of the adrenal cortex followed by a sudden stop of admin |
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Term
| Etiology of Hypoadrenocorticism |
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Definition
decreased blood levels of aldosterone
results in oversecretion of Na and retention of K in bloodtsream |
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Term
| Clinical Signs of Hypoadrenocorticism (The Great Pretender) |
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Definition
C/S mimic those of other disorders
intermittent V/D
acute weakness and depression leading to collapse
shock, decreased BP, coma
key signs - bradycardia, bloodwork shows increased K and decreased Na |
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Term
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Definition
Hyperkalemia disrupts normal sinus rhythm which results in arrhythmia
decreased BP due to hypovolemia which can lead to renal failure/shock/death |
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Term
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Definition
Difficult, rule out other diseases first
ACTH stim test - gold standard, results will indicate an abnormally decreased ACTH plasma cortisol concentration, blood samples obtained one hour prior and post ACTH stim |
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Term
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Definition
correct hypotension and electrolyte imbalances with Iv fluid therapy (no K)
obtain blood sample for ACTH
admin of glucocorticoids
DOCP - mineralocorticoid injections given monthly typically in combo with prednisolone |
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Term
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Definition
| aggressive managment of addisonian crisis will result in stable pt within 24-48hrs, owners cont at home therapy and pt reevaluated once a month, then every 3-6 mo., clinical signs should cease if therapy is apporopriate |
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Term
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Definition
| due to decreased blood levels of insulin. a group of disease entities characterized by a relative or absolute deficiency of insulin, results in decreased utilization of glucose, amino acids, and fatty acids, leads to hyperglycemia and glucosuria |
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Term
| Normal Blood Glucose Levels |
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Definition
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Term
| Signalment of Diabetes Mellitus |
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Definition
| Both dogs and cats, typically middle-aged to older animals |
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Term
| Causes of Diabetes Mellitus |
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Definition
Primary - Islet cell destruction in pancreas (chronic or autoimmune)
Secondary - insulin resistance may be due to islet cell exhaustion/loss of function |
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Term
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Definition
overweight pts are pre-disposed but weight loss can occur in pts with prolonged DM
polyphagia
weakness/lethargy
PU/PD
hyperglycemia
glucosuria
increased healing time/susceptibility to infections
diabetic cataracts |
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Term
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Definition
admin of exogenous insulin
weight control and dietary management |
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Term
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Definition
Overdose of insulin can lead to hypoglycemia
DKA |
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Term
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Definition
NOT a disease of the pancreas
symptoms - PU/PD, similar to DM so must be distinguished
occurs when posterior pituitary under produces ADH |
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Term
| Diabetes Insipidus Results in |
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Definition
| without adequate blood levels of ADH the kidneys will not reabsorb water causing PU/PD |
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Term
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Definition
Desmopressin/Vasopressin to supp hormone
lots of water
prognosis good as long as pet allowed unlimited access to water |
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