The Endocrine system Flashcards
The endocrine system consists of organs known as _ that secrete _
glands
hormones
What are the 3 classifications of hormones
peptides
steroids
amino acid derivatives
peptide hormones are _ and cannot pass through the _ so they must bind to an _
polar
plasma membrane
extracellular receptor
Peptide hormones trigger a _ with the possibility of _ at each step
signaling cascade
amplification
List 3 common secondary messengers
cAMP
IP3 inositol
calcium
peptides are _ so they can travel freely in the bloodstream
water-soluble
Steroid hormones are derived from _ and can cross the cell membrane bc they are _
cholesterol
lipid soluble
steroid receptors are usually _ or _ ;location
intracellular or intranuclear
upon binding steroid hormone-receptor complexes experience a
conformational change
a common form of conformational change for steroid hormone-receptor complexes is _ ; what is it
dimerization
the pairing of 2 receptor-hormone complexes
Steroid hormones must be carried by _ in the bloodstream to travel around the body
proteins
Amino acid-derivative hormones include _ _ _ and are derived from 1-2 amino acids usually with a few _
epinephrine, norepinephrine, and thryoxine
modifications
What defines a catecholamine; examples,
Amino acid-derivative hormone that bind to G protein coupled receptors
epinephrine and norepinephrine
What is the difference between direct and tropic hormones
direct hormones are secreted then act directly on a target tissue; whereas tropic hormones require an intermediary to act.
most peptide and amino acid derivative hormones have names that end in _ and most steroid hormones have names that end in _
- in or ine
- one, ol, or oid
The duration of action of steroid hormones is _ than peptide hormones, but the speed of onset is _
longer
slower
What are all the endocrine glands
hypothalamus pituitary thyroid parathyroid glands adrenal glands gonads pineal gland
The hypothalamus is the bridge between the _ and the _. it regulates the pituitary gland through _
nervous and endocrine system
tropic hormones
to maintain homeostasis the release of hormones by the hypothalamus is regulated by _ ;concept
negative feedback
What is the hypophyseal portal system
a blood vessel system that directly connects the hypothalamus with the anterior pituitary
Describe the hypothalamic negative feedback mechanism
the hypothalamus releases CRF to the anterior pituitary. the anterior pituitary releases ACTH to the adrenal cortex and stimulates the secretion of cortisol. Cortisol serves as negative feedback for the anterior pituitary and the hypothalamus
The posterior pituitary does not receive _ hormones. rather, neurons in the hypothalamus send their axons down the pituitary directly into the posterior pituitary. which can then release _ and _
tropic
oxytocin and antidiuretic hormone (ADH/vasopressin)
FLAT PEG; importance and type
the hormones of the anterior pituitary FSH LH ACTH TSH (tropic) Prolactin Endorphins Growth hormone (GH) direct
Prolactin purpose; and location
stimulates milk production in the mammary glands
What do endorphins do
decrease the perception of pain
Growth hormone (GH); purposes; net reaction
promotes growth of bone and muscle
prevents glucose uptake in certain tissues
stimulates the breakdown of fatty acids
-This increases the availability of glucose overall and is stimulated by GHRH released via the hypothalamus
Importance of the epiphyseal plates
special regions where bone growth originates
What can cause gigantism or drawfism
an excess or deficit of growth hormone GH
importance of ADH; when is it sent out; where from
secreted via the posterior pituitary in response to low blood volume or increased blood osmolarity. It increases the permeability of the collecting duct in kidneys; increasing the reabsorption of water from the filtrate in the nephron.
importance of oxytocin; when is it sent out; where from
oxytocin is unusual and has a positive feedback loop. it allows for coordinated contraction of smooth muscle and may be involved in bonding behavior.
The thyroid is controlled by _
thyroid-stimulating hormone
What is the thyroid purpose
sets basal metabolic rate and promotes calcium homeostasis.
What hormones are important for the thyroids function
Triiodothyronine (T3) and Thyroxine (T4)
mnemonic and purpose of calcitonin
CalciTONin TONes down calcium levels in the blood
Parathyroid gland; function, purpose, horomone
secretes parathyroid hormone (PTH). PTH raises blood calcium levels, and activates vitamin D.
The adrenal glands are located on top of the _; consists of the adrenal _ and _. purpose
kidneys
cortex and medulla
secretes corticosteroids
What are the 3 functional classes of corticosteroids
glucocorticoid, mineralocorticoid, and cortical sex hormones
Glucocorticoids; purpose; examples
regulate glucose levels and affect protein metabolism; cortisol and cortisone.
Mineralocorticoids; purpose; examples
used in salt and water homeostasis. aldosterone.
function of aldosterone
increases sodium reabsorption in the distal convoluted tubule and collecting duct of the nephron.
Describe the renin-angiotensin-aldosterone system
decreases blood pressure causes juxtaglomerular cells of the kidney to secrete renin. renin cleaves angiotensinogen to angiotensin I. Angiotensin I is then converted to angiotensin II by angiotensin converting enzyme (ACE). angiotensin II stimulates the secretion of aldosterone in the adrenal cortex.
The 2 types of cortical sex hormones
androgens and estrogens
The adrenal medulla purpose
the secretion/production of the sympathetic hormones epinephrine and norepinephrine.
What is the islets of Langerhans
located in the pancreas, contain alpha, beta, and delta cells.
What do the 3 cell types in the pancreas secrete
alpha- secrete glucagon
beta- secrete insulin
delta- secrete somatostatin
glucagon purpose
secreted during times of fasting, increases glucose production by triggering glycogenolysis, gluconeogenesis, and the degrradation of protein and fat.
insulin purpose
secreted when blood glucose levels are high. induces the uptake of glucose and store it as glycogen
Describe the relationship between blood glucose and insulin
high blood glucose stimulates insulin secretion, which lowers blood glucose. low blood glucose inhibits insulin which increase blood glucose.
Differentiate the 2 types of diabetes mellitus
type 1 = caused by autoimmune destruction of the B-cells of the pancreas, results in low or absent insulin production
type 2= caused by resistance to the effects of insulin at the receptor level. obesity caused
What is somatostatin
an inhibitor of insulin and glucagon secretion.
pineal gland purpose
secretes melatonin and involved in circadian rhythms.
erythropoietin purpose
stimulates bone marrow to increase the production of erythocytes
atrial natriuretic peptide (ANP) purpose
released via heart to help regulate salt and water balance
thymosin purpose
important for proper T-cell development and differentiation
what results in acromegaly
overproduction of growth hormone in adults
iodine deficiency may result in
cretinism
the conversion of ATP to cAMP must caused by a _ hormone
peptide
dopamine secretion prevents _ release
prolactin
