Ch:25 The Endocrine System Flashcards
An endocrine gland has NO ______; thus, their secretions are picked up and transported to their site by the bloodstream.
ducts
Endocrine has NO ducts
Steroid hormones are synthesized from _________.
Cholesterol
Steroid hormones are lipid _____… thus can pass through the cell membrane and bind to nuclear receptors.
soluble
What is an example of a peptide hormone?
Insulin
Amine hormones are called _______.
catecholamines
Catecholamines are made from the amino acid ______.
Tyrosine
Are amine hormones hydrophobic or hydrophilic?
Hydrophilic (H2O soluble)
A neurohormone called _______ is also a catecholamine.
Dopamine
ESSENTIAL CONCEPT: An endocrine gland secretes a hormone, it travels through the ______ to its target site. At the site, the hormone enters the cell by passing through the membrane. The hormone binds to a receptor and it likely enters the nucleus. In the nucleus, activation of ______ synthesis occurs. mRNA then can enter cytoplasm to make proteins.
Blood; mRNA
Hormones are often involved what is called a _______. This simply refers to a series of chemical rxns which are initiated by a molecular binding on a receptor.
cascade
What is the difference between H2O-soluble hormones and Lipid-soluble hormones? (hint: receptors)
“A VERY IMPORTANT CONCEPT, FOLKS!!”
H2O-soluble hormones bind to cell-surface receptors
Lipid-soluble hormones bind to intracellular receptors
What is the link between the nervous and endocrine systems?
Hypothalamus (located in the brain)
What hormones does the hypothalamus synthesize?
ADH (vasopressin) and Oxytocin
Where is vasopressin (ADH) and oxytocin synthesized and where are they stored?
ADH (vasopressin) and Oxytocin are synthesized in the hypothalamus but stored in the POSTERIOR pituitary
What is the function of Oxytocin?
STIMULATES MILK SECRETION
stimulates contractions of the uterus and stimulates mammary glands to assist in milk ejection
What is the function of ADH (vasopressin)?
Involved with H2O retention by the kidneys.
If there is severe blood loss (hemorrhage), by retaining more H2O, this increases the blood volume, hence the blood pressure. Thus, this hormone decreases urine volume.
Some hormones of the anterior pituitary are called tropic hormones, meaning ____________.
stimulate other endocrine glands to release their hormones
What 7 hormones are secreted by the anterior pituitary?
- Growth Hormone (GH): Somatotropin
- LH: (Luteinizing Hormone)
- FSH (Follicle Stimulating Hormone)
- TSH (Thyroid Stimulating Hormone)
- ACTH (Adrenocorticotropic Hormone)
- Prolactin: NON-tropic
- MSH (Melanocyte-Stimulating Hormone): NON-tropic
What is another name for Growth Hormone?
Somatotropin
What is the purpose of Growth Hormone?
- involved in bone growth
- increases DNA, RNA and protein synthesis
- Stimulates the liver to release IGFs… insulin growth factors which allow for bone and cartilage growth
- Increases blood sugar
What is the purpose of FSH?
Ovarian follicle in women, spermatogenesis in males
What is the purpose of LH?
Stimulates ovulation, progesterone secretion, corpus luteum formation in women, and stimulates testosterone secretion in men?
What is the purpose of TSH?
Stimulates thyroid to make hormones and release them
Which hormone from the anterior pituitary stimulates ovulation, progesterone secretion, corpus luteum formation in women and testosterone secretion in men?
LH
Which of the 7 anterior pituitary hormones are NOT TROPIC?
Prolactin and MSH
MEANING THEY DON’T CAUSE CASCADES
What are the 5 TROPIC-hormones of the anterior pituitary?
- GH
- LH
- FSH
- TSH
- ACTH
(ALL CAUSE CASCADES)
“A VERY IMPORTANT CONCEPT”
What is the purpose of ACTH?
stimulates the adrenal cortex to secrete glucocorticoids such as cortisol
ACTH (Adrenocoricotropic Hormone)
What is the purpose of Prolactin?
stimulation of mammary gland growth and milk production
oxytocin is involved in milk SECRETION not production
Where is MSH secreted from and what’s it’s function?
secreted from Anterior Pit. and regulates the function of melanocytes, involved with skin, hair eyes and pigmentation
What 2 hormones are produced in the thyroid and which is more abundant?
T3: (has 3 iodine atomes)
T4: thyroxine (MORE ABUNDANT)
What are the thyroid hormones involved in?
growth, cell differentiation, control of O2 consumption and basal metabolic rate
What is Hyperthyroidism and what does it cause?
too much thyroid hormone causing an increase in metabolism, weight LOSS, profuse sweating and high blood pressure
What is HYPOthyroidism and what does it cause?
you are often cold, gain weight and feel tired all the time
***How does the body compensate for hypothyroidism?
***by increasing the TSH from the anterior pit. It attempts to “entice” the thyroid to make more thyroid hormone. This is not good. Why?
Constant TSH hormone causes the thyroid to enlarge… we call this a goiter***
What is most common cause of hypothyroidism?
Hashimoto’s Disease (autoimmune disease)
When blood calcium is too high, what does the thyroid secrete to lower it?
Calcitonin
Calcitonin will INHIBIT osteoclastic activity, and will promote bone formation by osteoblasts
What is the difference between the thyroid and parathyroid?
Thyroid secretes calcitonin to lower blood calcium levels
Parathyroid secretes PTH to increase blood calcium levels
What organ contains both endocrine and exocrine function?
Pancreas
endocrine: insulin and glucagon
exocrine: proteases, amylases and lipase as well as bicarbonate
Where is insulin and glucagon released from?
Beta cells of the pancreas secrete Insulin
Alpha cells of the pancreas secrete Glucagon
***What hormone released by the pancreas inhibits secretion of insulin and glucagon?
Somatostatin
Which of the following is an autoimmune disease?
A. Type I diabetes
B. Type II diabetes
Type I diabetes
Beta cell destruction… WBCs mistake them for invaders
Where are the adrenal glands located?
On top of the kidney (adRENAL… renal)
What glands has both endocrine and neuroendocrine function?
Adrenal glands and Pituitary glands
The Adrenal Medulla cells are intimately connected with the _______ nervous system.
Sympathetic
The medulla makes epinephrine (80%), norepinephrine (20%) and catecholamines
What is the function of catecholamines?
Catecholamines can dilate or constrict blood vessels
- Blood is increased to areas of heart, brain and skeletal muscles (dilation)
- Blood is decreased to areas such as skin, kidneys and digestive organs (constriction)
What does the Adrenal CORTEX produce?
Glucocorticoids (cortisol)
How do glucocorticoids affect blood glucose?
Raises blood glucose levels
What is the function of cortisol?
- stimulate gluconeogenesis in the liver
- fatty acid breakdown
- causes breakdown of skeletal muscle where the amino acids are made into glucose when needed
What mineralocorticoid does the adrenal CORTEX produce?
Aldosterone
Give examples of each:
- Glucocorticoids
- Mineralocorticoids
Glucocorticoids = Cortisol
Mineralocortocoids = Aldosterone
What is the duty of Aldosterone?
Increases blood pressure
Aldosterone stimulates kidney cells to reabsorb SODIUM along with water. This increases blood volume, hence increases the blood pressure
What is the difference between cortisol and aldosterone?
Cortisol = increases blood GLUCOSE
Aldosterone = increases blood PRESSURE
Cortisol is a glucocorticoid that increases blood GLUCOSE
Aldosterone is a mineralocorticoid that increases blood PRESSURE
What is the major difference between the adrenal medulla and the adrenal cortex?
Medulla = glucocorticoids (Cortisol)
Cortex = mineralocorticoids (Aldosterone)
What are gonads?
Testes and Ovaries
- primary reproductive organs which make and secrete gametes (sperm and eggs) and some sex hormones
The gonads make and secrete 3 types of steroid hormones: What are they?
- Estrogen
- Progesterone
- Androgens (Testosterone)
What is the function of estrogen?
made in the ovaries- triggers the LUTEAL SURGE to release an egg (2ndary oocyte) from he follicle
Besides ADH and oxytocin, what other hormone does the hypothalamus make?
GnRH (gonadotropin-releasing hormone)
What hormone stimulates the release of FSH and LH from the anterior pituitary?
GnRH (secreted by the hypothalamus)
What hormone does dopamine inhibit?
prolactin
Dopamine inhibits prolactin
***When does the pineal gland stimulate melatonin production and when does it inhibit melatonin production?
***Stimulates melatonin production in darkness (at night) and inhibits melatonin production when there is light (during the day)
Melatonin makes you sleepy so it only makes sense that it production is only stimulated at night in the dark
What hormones does the placenta make?
estrogen and progesterone
What hormone do pregnancy tests look for?
hCG (Human Gonadotropin)
Does the heart have any endocrine function?
Yes, it releases the hormone ANP (Atrial Natriuretic Peptide) to lower blood pressure by relaxing the arterioles and inhibiting the reabsorption of NA+ by the kidney
What 2 hormones are made in the kidney and what are their functions?
Erythropoietin: stimulates RBC production
Renin: increases blood pressure
What is Ecydysone? (hormone)
an insect hormone involved in molting and metamorphosis
What are prostaglandins?
modified fatty acids involved with promoting fever and inflammation
prostaglandins inhibit platelet aggregation in blood… they act as VASODILATORS
What is down regulation?
Elevated insulin in the blood is a specific example. With the high insulin, it is possible to see a reduction in receptors. This is what is seen in Type 2 diabetes
