The endocrine system Flashcards
Steroid hormones:
Derived from ____
Mostly made in ____
Mode of action ____
Duration of action ____
Need carrier to travel through blood? ___
Derived from cholesterol
Mostly made in the gonads and adrenal cortex
Are able to travel through the membrane, so they bind either intracellularly or intranuclearly to create a conformational change that can alter DNA to change gene production
Slow onset but long-lived
Does need a carrier to travel through blood bc they’re lipid soluble
Peptide hormones:
Derived from ____
Mode of action ____
Duration of action ____
Need carrier to travel through blood? ___
Derived from amino-acid chains
Charged so they cannot enter the cell, work instead by binding to receptors that then transmit secondary messengers that can start a cascade (ex: G protein-coupled receptors). Can also cause amplification bc they can bind to more than one receptor before degradation
Short onset but act very quickly
Do not need carriers to travel through blood
Amino-acid derived hormones:
Derived from ____
The two categories are ____
Derived from amino acids with some modifications (ex: tyrosine having iodine bound to it)
Two categories:
Catecholamines (norepinephrine and epinephrine)- G protein coupled, fast onset
Thyroid (triiodothyronine and thyroxine)- intracellular binding, slow onset
What is the difference between tropic and direct hormones?
Tropic hormones rely on an intermediary to reach the target tissue
Direct hormones are able to reach the target tissue on their own
If the hypothalamus releases Gonadotropin releasing hormone, the anterior pituitary releases:
FSH or LH
If the hypothalamus releases Growth-hormone releasing hormone, the anterior pituitary releases:
Growth hormone
If the hypothalamus releases thyroid releasing hormone, the anterior pituitary releases:
TSH
If the hypothalamus releases corticotropin releasing factor, the anterior pituitary releases:
Adrenocorticotropic hormone
Released by the posterior pituitary
Released during uterine contractions and for milk letdown
Oxytocin
Released by the posterior pituitary
Stimulated by the increased concentration of solute in the blood and encourages kidneys to reabsorb H2O
Vasopressin (antidiuretic hormone)
This part of the brain regulates both parts of the pituitary gland through the paracrine release of tropic hormones, and is regulated by negative feedback (think HPA axis)
Hypothalamus
The ____ pituitary is connected to the hypothalamus by the hypophyseal portal system, where tropic hormones are released, reach the pituitary stem, and bind to stimulate the release of more hormones. This part of the pituitary gland is able to make its own hormones
Anterior
The hypothalamus sends axons into the ____ pituitary. This part of the pituitary is not able to make its own hormones
Posterior
The hypothalamus sends axons into the ____ pituitary
The anterior pituitary has four tropic and three direct hormones. They are:
Tropic:
FSH and LH, TSH, and adrenocorticotropic hormone (vasopressin)
Direct:
Prolactin, endorphins and growth hormone
The thyroid is controlled by TSH released from the anterior pituitary. It’s two roles are to promote ___ homeostasis and set _____ rate
Promote calcium homeostasis and set the basal metabolic rate
This hormone, produced by the thyroid, decreases plasma calcium levels by increasing calcium absorption in the kidneys, decreasing calcium absorption in the gut, and increasing the storage of calcium in the bones
Calcitonin
These hormones are both versions of tyrosine modified with either 3 or 4 iodines, and are secreted by the thyroid to maintain metabolic rate, including cellular respiration and fatty acid utilization
T3 and T4 (triiodothyronine and thyroxine)
This hormone originates in the parathyroid gland, and is antagonistic to calcitonin, which means it raises blood calcium levels, and activates Vitamin D for calcium absorption
Parathyroid hormone
The adrenal cortex is located on top of the ____ and secretes these three classes of corticosteroids: ____
On top of the kidneys
Secretes: Glucocorticoids, mineralcorticoids and cortical sex hormones
These corticosteroids are in charge of regulating glucose levels, and include cortisol and cortisone
Glucocorticoids
These corticosteroids are in charge of regulating water and salt homeostasis, which includes maintaining blood osmolarity
Mineralcorticoids
These corticosteroids are in charge of regulating the androgens and estrogen. Males and females are very sensitive to changes in the concentration of the non-dominant hormone for their sex
Cortical sex hormones
The ______ is located inside the adrenal cortex and secretes the catecholamines, including norepinephrine and epinephrine
Adrenal medulla
The ____ has both exo and endocrine functions, and whose cells include Alpha, beta, and delta
Pancreas
In the pancreas, these cells are responsible for secreting glucagon, which promotes glucose production
Alpha
In the pancreas, these cells are responsible for secreting insulin, which promotes glucose storage and therefore is antagonistic to glucagon
Beta
In the pancreas, these cells are responsible for secreting somatostatin, which inhibits both glucagon and insulin
Delta
This hormone is a mineralocorticoid and is responsible for increasing blood volume and pressure by increasing the amount of sodium reabsorbed in the kidneys, which also takes H2O with it to maintain osmolarity
Aldosterone
