A & P Exam 4 Flashcards
The endocrine system works with the ____ system to maintain homeostasis.
nervous
How does the endocrine system communicate with the rest of the body?
Hormones travel through bloodstream & act of specific target cells
Reaction to stimuli is ____ and duration of effects is ____ compared to the nervous system.
slow
long
Chemical messengers produced by endocrine glands and secreted directly into blood vessels.
hormones
A cell that has receptors for a particular hormone is referred to as the ___ of that hormone.
target
Hormone secretion is usually controlled by what?
negative feedback system
Some endocrine glands, such as ____ ____ and _____ ____ are under direct stimulation from the nervous system.
adrenal medulla
posterior pituitary
Secretion of ____ and _____ from the adrenal medulla is stimulated by sympathetic nervous system.
epinephrine & norepinephrine
Are these major or minor endocrine organs? Pituitary gland, thyroid, parathyroid, adrenal gland, pancreas (islets), gonads.
Major
Are these major or minor endocrine organs? Kidneys, stomach, small intestine, placenta, thymus, pineal body.
minor
This endocrine gland is part of the diencephalon section of the brain. Its functions include appetite control, body temp regulation, control of wake-sleep cycles, controls activities of pituitary gland. Portal system of blood vessel links this with the anterior pituitary gland.
Hypothalamus
What structure in the hypothalamus secrete releasing and inhibitory hormones into portal blood vessels?
Modified neurons
Including secreting releasing & inhibitory hormones, what else does the hypothalamus secrete? (2)
Antidiuretic hormone (ADH) Oxytocin
ADH & Oxytocin are transported to the ____ ____ for storage. They are released into the bloodstream by nerve impulses from the hypothalamus.
posterior pituitary
The pituitary gland is also known as the ____, which means to grow beneath.
hypophysis
This part of the pituitary gland is the most rostral portion. It is stimulated by hypothalamus and direct feedback from target organs and tissues to produce its hormones.
Anterior pituitary
The anterior pituitary is also known as the
adenohypophysis
This is the caudal portion of the pituitary gland. It does not produce any hormones; stores and releases hormones produced by the hypothalamus.
Posterior pituitary
The posterior pituitary is also known as the
neurohypophysis
Growth hormone is released from ____ gland. It is also known as somatotropin and somatotropic hormone.
anterior pituitary
Secretion of growth hormone by the pituitary is controlled by the ______ and ______ (somatostatin) from the hypothalamus.
growth hormone releasing hormone
growth hormone inhibitory hormone
____ is the only pituitary hormone that does not function through a target gland but instead exerts its effects on almost all tissues of the body.
GH (growth hormone)
This hormone: promotes growth in young animals, helps regulate metabolism of proteins, carbs, and lipids, increases protein synthesis in all cells of body, increases mobilization of lipids from storage in fat tissue and their breakdown for energy, decreases rate of glucose utilization.
GH
GH decreases rate of glucose utilization, also called
anti-insulin effects
In short, ___ enhances body protein, uses up fat stores, conserves carbs.
GH
Growth Hormone deficiency; congenital deficiency usually due to destruction of somatotrophs by a cyst; primarily seen in German Shepherds; lack of growth
Pituitary dwarfism
Excess secretion of GH prior to closure of physis
Pituitary Gigantism
Excessive secretion of GH after closure of physis; most commonly a fuctional adenoma of the somatotropic cells in the pituitary; older male cats; increase in body size, diabetes due to anti-insulin effects of GH.
Acromegaly
Secreted by AP, helps trigger and maintain lactation. Production & release continues as long as the teat or nipple continues to be stimulated by nursing or milking.
prolactin
Secretion of prolactin from the AP is normally inhibited by what hormone from the hypothalamus?
Prolactin inhibitory hormone
When the lactating teat is stimulated, the hypothalamus secretes what hormone which stimulates the AP to release prolactin?
Prolactin-releasing factor
Thyroid Stimulating Hormone (TSH) is also known as
thyrotropic hormone
This hormone secreted by the AP stimulates growth & development of thyroid gland & causes it to produce its hormones.
TSH
Secretion of TSH is regulated by feedback from the thyroid gland. It has direct effects on AP gland & through changes in _______ hormone produced by the hypothalamus.
thyrotropin-releasing hormone
This hormone secreted by the AP stimulates growth & development of the adrenal cortex & release of some of its hormones.
Adrenocorticotropic Hormone (ACTH)
ACTH is regulated by feedback from the hormones of the adrenal gland to the (2)
hypothalamus & AP
ACTH can also be released quickly as a result of stimulation of the hypothalamus by
stress
To override the inhibitory feedback system, the hypothalamus sends a burst of _____ hormone to the AP causing ACTH to be released quickly.
corticotropin-releasing hormone
This hormone is secreted by the AP. In females, it stimulates oogenesis and stimulates cells lining the follicles to produce and secrete estrogens. In males, it stimulates spermatogenesis.
Follicle-Stimulating Hormone (FSH)
This hormone secreted by the AP completes process of follicle development in ovary, increasing amounts of estrogens feedback to AP & cause reduced production of FSH and increased production of ___.
Luteinizing hormone (LH) LH
LH levels reach a peak when follicle is fully mature which usually causes
ovulation
After ovulation, LH stimulates cells in the empty follicle to multiply and develop into the
corpus luteum
The corpus luteum produces ___ hormones necessary for the maintenance of pregnancy.
progestin
In the male, LH stimulates ____ ___ within the testes to development and produce testosterone.
interstitial cells
This hormone secreted by the AP is associated with control of color changes in the pigment cells of reptiles, fish, and amphibians.
Melanocyte-Stimulating Hormone (MSH)
Administration of artificially large amounts of ___ to higher mammals can cause darkening of the skin from melanocyte stimulation.
MSH
The posterior pituitary gland, also known as ____, develops from the embryo’s nervous system & looks like nervous tissue under the microscope.
neurohypophysis
The PP stores what 2 hormones produced in the hypothalamus?
antidiuretic (ADH) and oxytocin
The PP periodically releases ADH & oxytocin into the bloodstream in response to ___ impulses from the hypothalamus.
nerve
This hormone secreted from the PP has it effects on the uterus, causing contraction of the myometrium at the time of breeding & at parturition; causes milk letdown.
Oxytocin
ADH helps prevent ____, loss of large quantities of water in the urine
diuresis
Receptors in the ____ detect changes in osmotic pressure of blood that result from dehydration/hemoconcentration.
Hypothalamus
ADH travels to the ____ and causes resorption of more water from urine and returns it to the bloodstream. It also causes vasoconstriction.
kidney
ADH deficiency; pituitary (lack of ADH) or nephrogenic (no response to ADH); PU/PD, inability to concentrate urine; modified water deprivation test; dDAVP (derivative of ADH), continuous access to water.
Diabetes insipidus
insipid means tasteless
What stimulates the thyroid gland to secrete thyroid hormone?
TSH
This gland consists of 2 lobes on either side of the larynx.
Thyroid gland
Thyroid hormone is produced in the ____ of the thyroid gland.
follicles
Each thyroid follicle consists of simple, cuboidal glandular cells surrounding a globule of thyroid hormone precursor called
colloid
What are the 2 thyroid hormones?
T3, triiodothyronine
T4, tetraiodothyronine
Thyroid hormones have negative feedback on what 2 endocrine glands?
hypothalamus and pituitary
Which thyroid hormone is produced in greater abundance but converts to the other before producing effects on target cells.
T4
These are effects of what hormones: influences development & maturation of CNS; growth & development of muscles and bones; calorigenic effect - regulates the metabolic rate of all body cells; allows animal to generate heat & maintain constant internal body temp.
Thyroid hormones
Production of thyroid hormones increase with exposure to ____ and then increases metabolic rate to generate more heat.
cold
TH affects metabolism of proteins, carbs, and lipids much like ___ does. Encourages synthesis of proteins if adequate energy sources, encourages breakdown of lipids for energy, discourages using carbs as energy source.
GH
Deficiency of thyroid hormone
Hypothyroidism
Hypothyroidism is most commonly what type? Lymphocytic thyroiditis and idiopathic atrophy of the thyroid gland.
primary hypothyroidism
CSX of what? Lethargy, weight gain, cold intolerance, alopecia.
Hypothyroidism
DX of what disease? Free T4 by ED, T4, TSH, Csx
Hypothyroidism
TX of hypothyroidism
thyroid hormone supplementation
Excessive thyroid hormone
Hyperthyroidism
Etiology of hyperthyroidism: ___ or ____ of thyroid gland typically in middle aged to older cats.
hyperplasia or neoplasia
CSX of what disease? PU/PD, polyphagia, weight loss, v/d, tachycardia, hyperactive
hyperthyroidism
DX of what disease: T4, free T4, Csx
hyperthyroidism
TX for hyperthyroidism
antithyroid drugs, sx, radioactive iodine
What disease? lack of iodine>decrease T4>increase TSH> hyperplasia of thyroid gland
goiter
Besides T3 & T4, the thyroid gland also secretes
calcitonin
Calcitonin is produced by ____ (____) cells located between thyroid follicles.
C cells (parafollicular cells)
This thyroid gland secretion helps maintain blood calcium levels, prevents hypercalcemia by encouraging excess calcium to be deposited in the bones.
calcitonin
___ is involved in muscle contraction, blood clotting, milk secretion, and formation & maintenance of the skeleton
calcium
Small, paled nodules in, on, or near the thyroid glands.
Parathyroid glands
What hormone do the parathyroid glands produce?
parathyroid hormone (PTH) or parathormone
This hormone helps maintain blood calcium levels and prevent hypocalcemia.
PTH
PTH prevents ___ by converting Vit D into its active form calcitriol, causes kidneys to reabsorb calcium, releases calcium from bones.
hypocalcemia
What is the active form of Vit D?
calcitriol
This causes intestines to absorb calcium from food and releases calcium from bones.
Calcitriol
____ __ is carried in the bloodstream to the liver, where it is converted into the prohormone calcidiol.
Vit D
Circulating calcidiol can be converted into ____, the biologically active form of vit D, either in the kidneys or by monocyte-macrophages in the immune system.
calcitriol
A decreased production of PTH by the parathyroid gland.
primary hypoparathyroidism
Primary hypoparathyroidism is ___ in dogs and cats.
rare
CSX of primary hypoparathyroidism are consistent with _____; weakness, seizures.
hypocalcemia
DX of primary hypoparathyroidism
measure serum PTH & ionized calcium
TX for primary hypoparathyroidism
calcitriol & calcium supplements
Neoplasia of the parathyroid gland; causes hypercalcemia.
Primary hyperparathyroidism
With progressive renal disease, renal synthesis of calcitriol is also reduced. This causes
renal secondary hyperparathyroidism
Commonly seen in reptile not getting enough calcium or Vit D>increases PTH> mobilized calcium from bones> rubber jaw
Nutritional secondary hyperparathyroidism (NSHP)
The adrenal glands consist of what 2 glands?
adrenal cortex
adrenal medulla
Which organ are the adrenal glands located near?
kidneys
What are the 3 layers of the adrenal cortex?
Zona glomerulosa
Zona fasiculata
Zona reticularis
The adrenal cortex is under direction of which AP hormone?
ACTH
What type of hormones are produced by the adrenal cortex?
steroid hormones
What are the 3 main groups of steroid hormones released from the adrenal cortex?
Glucocorticoids, Mineralocorticoids, Sex hormones
What are the different types of glucocorticoids? (3)
cortisone, cortisol, corticosterone
These hormones produced by the adrenal cortex are under the direction of ACTH; have a hyperglycemic effect; also help maintain blood pressure & help the body resist the effects of stress.
Glucocorticoids
Glucocorticoids are secreted by which 2 layers of the adrenal cortex?
zona fasiculata & zona reticularis
Sex hormones are secreted by which 2 layers of the adrenal cortex?
zona fasiculata & zona reticularis
The adrenal cortex produces androgens and estrogens, which are __ hormones, in small amounts.
sex
Mineralocorticoids (e.g., aldosterone) are secreted by which layer of the adrenal cortex?
zona glomerulosa
ACTH has only a mild impact on regulating secretion of this adrenal cortex hormone.
mineralocorticoids
This adrenal cortex hormone regulates levels of important electrolytes (NA & K) in the body by: telling the kidneys to reabsorb NA & H2O follows; telling the kidneys to eliminate K.
Mineralocorticoids
Secretions of this adrenal cortex hormone are regulated by electrolyte concentrations, blood volume, arterial pressure, renal function, etc.
mineralocorticoids
This part of the adrenal gland develops from nervous tissue & resembles nervous tissue microscopically. It produces epinephrine & norepinephrine.
Adrenal Medulla
What is the adrenal medulla controlled by?
sympathetic autonomic nervous system
Excessive production of cortisol
hyperadrenocorticism
Hyperadrenocorticism in dogs
Cushing’s
What disease: usually pituitary tumor, adrenal tumor, iatrogenic
CSX: PU/PD, polyphagia, panting, pot-belly, alopecia
DX: measure cortisol levels with ACTH stim test or low-dose dexamethasone suppression test
TX: trilostane - acts on adrenal cortex to block synthesis of steriods.
hyperadrenocorticism or Cushings
Hypoadrenocorticism is also called
Addison’s
What type of hypoadrenocorticism: idiopathic atrophy of all layers of adrenal cortex resulting in deficiency of both mineralocorticoids and gludocorticoids.
Primary adrenocortical insufficiency
What type of hypoadrenocorticism: reduced secretion of ACTH resulting in deficiency of glucocorticoids only
Secondary adrenocortical insufficiency
CSX: lethargy, anorexia, vomiting
DX: electrolytes, ACTH stim test
TX: mineralocorticoid supplement +/- glucoorticoid supplement
Hypoadrenocorticism/Addisons
Hyperadrenocorticism in ferrets is do to an
excessive production of sex hormones
What disease: hyperplasia or neoplasia of adrenal cortex linked to early spay/neuter
CSX: alopecia, swollen vulva in females, prostatic cysts in males
DX: adrenal panel to evaluate levels of sex hormones
TX: adrenalectomy, Lupron, melatonin, deslorelin
hyperadrenocorticism in ferrets
This organ is located near the duodenum and has both exocrine and endocrine functions.
Pancreas
Groups of cells scattered throughout the pancreas with endocrine functions.
Islets of Langerhans (Pancreatic Islets)
Alpha cells produce
glucagon
Beta cells produce
insulin
Delta cells produce
somatostatin
This hormone is regulated mainly by blood glucose concentration. It raises blood glucose levels by stimulating liver cells to convert glycogen to glucose and by stimulating gluconeogenesis.
Glucagon
This hormone is regulated by blood glucose concentration. It lowers blood glucose levels by causing glucose, amino acids, and fatty acids to be absorbed into the body cells.
Insulin
This hormone secreted by the pancreas is the same as growth hormone inhibitory hormone. It is secreted when food is ingested. It inhibits secretion of insulin, glucagon, & GH; diminishes activity of the GI tract.
Somatostatin
This pancreatic hormone prevents rapid exhaustion of food, making it available over a longer period of time.
Somatostatin
Loss of beta cell function resulting in hypoinsulinemia. CSX: PU/PD, polyphagia, wgt loss. DX: CSX along w/persistent, fasting hyperglycemia & glucosuria. TX: insulin injections
Diabetes mellitus
Neoplasia of beta cells that causes increased insulin production. CSX: weakness, seizures from hypoglycemia. DX: hypoglycemia, hyperinsulinemia. TX: SX, corticosteriods.
Insulinoma
What organ produces erythropoietin?
Kidneys
This hormone stimulates bone marrow to increase production of RBCs.
erythropoietin
Production of erythropoietin is stimulated by
hypoxia
As RBC production increases, more O2 feeds back to kidneys and slows production of
erythropoietin
Kidney failure results in ____ because of kidneys’ inability to produce erythropoietin.
anemia