Lesson 11 Endocrine system Flashcards
This is the coordinating center of the endocrine system, consolidates signals derived from thoughts, feelings, autonomic function, environmental cues, and peripheral endocrine feedback.
Hypothalamus
This is a pea-sized organ located in the center of the brain, is called the master gland because it regulates all the body’s endocrine glands. It can be compared to a dispatcher because, in response to a signal from the hypothalamus, it releases one of its many tropic hormones
pituitary
this secretes growth hormone (GH), prolactin (PRL), ACTH, thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
Anterior pituitary
This synthesizes ADH and oxytocin (OXT), which are stored and released by the posterior pituitary. ADH is also called arginine vasopressin (AVP), and GH is also called somatotropin.
hypothalamus
This stores and releases ADH and oxytocin (OXT)
posterior pituitary
this regulates each of the hypothalamic-pituitary-hormone axes, a process that maintains hormone levels within a narrow range.
Negative feedback
When an individual is running in a marathon, the hypothalamus receives signals from the body that the muscles and organs have extra metabolic needs. The hypothalamus secretes _________1________. which stimulates the ____2______ gland. This then secretes ______3______, which stimulates the adrenal gland to secrete the hormone _____4_____. These levels in the blood rise, the pituitary senses increased level and shuts off stimulus to ___5____. this is an example of _____6____.
- corticotrophin-releasing factor (CRF)
- pituitary
- ACTH
- cortisol
- adrenal gland
- endocrine negative feedback system
For instance, prolonged, excessive stimulation of an endocrine gland often results in receptor insensitivity and may decrease its number of receptors in a process known as what?
Downregulation of receptors (caused by excessive, prolonged dose of glucocorticoid drugs)
What is the most common reason for upregulation of receptors?
a reduction in the receptor stimulation by hormones.
what are the 2 categories of endocrine gland dysfunction?
hypofunction and hyperfunction
This dysfunction caused by the endocrine gland itself
Primary endocrine disorder
This dysfunction caused by abnormal pituitary activity
secondary endocrine disorder
This dysfunction caused by a hypothalamic origin
tertiary endocrine disorder
These tumors can cause such problems as growth disturbances, electrolyte imbalances, and infertility. They classically cause visual disturbances because of their proximity to the optic chiasm in the brain.
pituitary tumors
These are the etiologies for what?
tumors, cranial radiation, traumatic brain injury, subarachnoid hemorrhage, infectious and inflammatory disorders, and postpartum pituitary necrosis (Sheehan’s syndrome). The pituitary adenoma, a benign, epithelial neoplasm, is the most common tumor of the pituitary gland.
hypopituitarism
These hormones are secreted by which part of the pituitary gland?
*Thyrotropin, or TSH
* Gonadotropins, or FSH and LH
* Somatotropin, or GH
* Corticotropin, or ACTH
* Prolactin, or PRL
Anterior pituitary
What is unique about the posterior pituitary? (how is it different from the anterior?)
does not produce its own hormones; it stores hormones. The hypothalamus produces ADH (also referred to as AVP) and OXT. These two hormones are released into the hypothalamic–hypophyseal tract to the posterior pituitary, where they are stored.
How is the endocrine system impacted by hypopituitarism?
results in secondary failure of the target endocrine glands
What are the most serious concerns for hypopituitarism?
drenal insufficiency, hypothyroidism, and diabetes insipidus (DI), the last of which occurs because of a lack of posterior pituitary secretion of ADH.
What are the clinical presentations in the neonate and infant?
dwarfism, developmental delay, various visual and neurological symptoms, seizure disorder, and a number of congenital malformations.
How do adults present for hypopituitarism
radual symptoms of hypothyroidism, adrenal insufficiency, and ADH deficiency. The clinical presentation may be weakness, weight loss, and hypotension caused by adrenal insufficiency, or weight gain, sluggishness, and depression caused by hypothyroidism. Lack of ADH causes excessive urination and dehydration, a syndrome known as DI.
What are the clinical presentations when hypopituitarism is acute
a rapidly deteriorating state of hypotension; severe dehydration; neurological deficits; and abnormalities in electrolyte levels, glucose levels, body temperature, and heart rate.
What are the diagnostic findings for someone with hypopituitarism
low serum levels of pituitary tropic hormones, such as TSH, ACTH, FSH, LH, GH, PRL, and ADH, and low corresponding endocrine organ hormones, such as thyroxine (T4), cortisol, and estrogen.
How is hypopituitarism treated?
varies depending on which tropic hormones are lacking. Hormone replacement and surgical excision of the tumor, if present, are the treatment measures.
This is a disorder of hypopituitarism that originates in the posterior pituitary, also called the neurohypophysis. The disorder involves ADH, and there are two categories of disease: either a lack of secretion of ADH from the posterior pituitary, or the kidney fails to respond to ADH.
Diabetes Insipidus
This occurs because of a lack of secretion of ADH from the posterior pituitary
central diabetes insipidus
This occurs when the kidney fails to respond to ADH.
nephrogenic diabetes insipidus
What can cause Central Diabetes Insipidus?
tumors such as craniopharyngiomas or head trauma that causes injury of the posterior pituitary or the hypothalamic–hypophyseal tract. Other causes include pituitary surgery, inflammatory disorders, infection, or exposure to chemical toxins.
What can cause nephrogenic diabetes insipidus
nephrotoxic drugs such as lithium, obstructive uropathy, ischemia of the kidney, hypokalemia, or hypocalcemia.
True or False, the same pathophysiological process occurs in both nephrogenic DI and central DI.
True: The nephron does not perform antidiuresis, meaning that the nephron does not reabsorb water from the tubule fluid. As a consequence, the body loses high amounts of water in the urine, causing polyuria and highly dilute urine. The bloodstream loses water, which concentrates its sodium content, causing hypernatremia, polyuria, dilute urine, and dehydration.
What syndrome can present similarly to DI?
psychogenic polydipsia: the patient drinks excessive amounts of water and therefore has excessive, very dilute urine.
Name the disorder for the following symptoms: frequent urination (polyuria) and thirst (polydipsia). In addition, because of dehydration, neurological problems can occur, including confusion, disorientation, myoclonus, seizures, and, in severe cases, coma.
DI: Diabetes Insipidus
What is the differentiating factor between DM and DI?
serum glucose: Serum glucose is elevated in DM, but not in DI.
The following treatment is used for what disorder?
administration of desmopressin or synthetic vasopressin. Chlorpropamide, thiazides, or carbamazepine can also be used. Surgical treatment
DI
This is the most common cause of hyperpituitarism.
A PRL-producing adenoma, also called prolactinoma
In children, a GH-secreting tumor causes ___1___, whereas in adults, it causes ____2___
- Gigantism
- Acromegaly (bones increase in size, limited to the bones of your hands, feet and face)
What are the symptoms for females of prolactinoma (most common pituitary adenoma)?
menstrual abnormalities, amenorrhea, galactorrhea, vaginal dryness, and osteopenia occur.
What are the symptoms for males of prolactinoma (most common pituitary adenoma)?
hypogonadism, decreased libido, erectile dysfunction, and infertility occur.
What type of adenoma stimulates the adrenal gland to produce excess cortisol, and the presentation is called Cushingoid appearance. The signs include obesity; stunted growth; swollen face, called moon facies; acne; ruddy complexion; hirsutism; fat in the posterior neck area, called buffalo hump; and striae, also known as stretch marks.
ACTH-secreting adenoma
These adenomas are rare but can present with signs and symptoms of hyperthyroidism, including nervousness, tremulousness, palpitations, weight loss, visual disturbances, headaches, and hypersensitivity to heat.
TSH-secreting adenomas