Are steroid hormones lipophilic or hydrophilic?
Lipophilic
Are peptide hormones hydrophobic or lipophobic?
Lipophobic
What type of hormone can freely cross through the plasma membrane?
Steroid hormones
What kind of hormones bind to receptors on the cell surface and how to they initiate cell activity?
Peptide hormones bind to receptors on the cell surface, activating a series of intracellular molecules called secondary messengers which initiate cell activity.
What is the process of cell activity initiation by peptide hormones called and what does this mean?
Its called signal transduction because the external signal from the hormone is transduced via internal intermediaries.
What enables the amplification of the initial hormone signal and why?
The use of secondary messengers because more molecules are activated
What kind of hormone is insulin?
Peptide
What kind of hormone is glucagon?
peptide
What kind of hormone is leptin?
peptide
What kind of hormone is ADH?
peptide
What kind of hormone is oxytocin?
peptide
What kind of hormones are produced by the gonads (ie. estrogen, progesterone, testosterone)
steroid
What kind of hormone is thyroxin(e)?
steroid
Where do the signals for the release of thyroxin(e) originate and what hormone stimulates its release?
The hypothalamus starts the signal, and TSH is released from the anterior pituitary to stimulate the thyroid to release thyroxine
What are the functions of thyroxine?
Stimulates growth and metabolism by increasing cellular respiration which effects protein synthesis, regulates bone growth, and regulates protein, fat, & carbohydrate metabolism
What is the primary function of thyroxin?
To increase the basal metabolic rate
How is carbohydrate and lipid metabolism stimulated?
Via the oxidation of glucose and fatty acids
How does thyroxin help to control body temperature?
It is released in response to a decrease in body temperature, and increases metabolic activity, a consequence of which is the production of heat.
What inhibits thyroxine release?
Hot temperatures
What deficiency causes thyroid problems and how?
Iodine is a component of thyroxine so a deficiency of iodine leads to decreased thyroxine production which leads to thyroid enlargement and problems- disease known as goitre.
What is the adenohypophysis?
The anterior pituitary
What is the neurohypophysis?
The posterior pituitary
What is hypertonicity?
Too much glucose damaging cells
What is the role of beta cells in the pancreas?
To release insulin when blood glucose is high
What responses may beta cells stimulate?
- stimulate glycogen uptake by the liver and adipose tissue
- increase the rate of glucose breakdown by increasing the rate of cell respiration
What is the role of alpha cells in the pancreas?
To release glucagon when blood glucose is low
What responses may alpha cells stimulate?
- stimulate glycogen breakdown in the liver (glycogenolysis)
- Promote glucose release by the liver and adipose tissue
- decrease rate of glucose breakdown by reducing cell respiration rates
What is diabetes mellitus?
A metabolic disorder resulting from a prolonged period of high blood glucose concentration.
Which type of diabetes is insulin-dependent?
Type one
What is the difference in usual onset of type one vs type two diabetes?
Type one is usually early onset (during childhood) whereas type two is usually late onset (during adulthood)
What is the insulin problem in type one vs type two diabetes?
In type one, the body doesn’t produce sufficient insulin whereas in type two, the body doesn’t respond to insulin production.
What is the difference in cause of type one vs type two diabetes?
Type one diabetes is autoimmune: caused by the destruction of beta cells. Type two, however, is caused by down-regulation of insulin receptors.
How is type one diabetes treated vs how type two is treated?
Type one requires insulin injections to regulate blood glucose, whereas type two can be controlled by managing diet and lifestyle.
What is the difference between how endocrine and exocrine glands secrete their product?
Endocrine glands secrete hormones directly into the bloodstream but exocrine glands secrete their products through a duct.
What is an example of an organ that is not an endocrine gland but secretes hormones?
Adipose tissue secretes leptin.
What hormone does the pineal gland secrete, what kind of hormone is it, and what is its function?
Melatonin, steroid, biological clock/circadian rhythym
Where are FSH/LH secreted, what is their target organ, and what is their function?
Anterior pituitary gland, ovaries, menstrual cycle control- FSH stimulates egg cells, LH stimulates release of progesterone (in men FSH stimulates sperm development in testes and LH stimulates release of testosterone)
Peptide style
Where is ADH produced, secreted, what is its target organ, and what is its function?
Produced in hypothalamus, released from posterior pituitary, target organ is kidneys, function is osmoregulation.
Function: Water regulation (blood osmolarity regulation)- it regulates the absorption of water in the kidneys by increasing the permeability of the collecting duct causing more water to be reabsorbed.
Peptide style
Where is GH (growth hormone) secreted and what is its function?
It is secreted from the anterior pituitary and stimulates growth by stimulating liver and other cells to secrete cartilage cells which result in bone growth.
Peptide style
Where is oxytocin produced, released, what its target organ, and function? KIND?
Produced by hypothalamus
Released by posterior pituitary
Target is uterus- it signals birth contractions
Peptide style
Where is prolactin released from, what is its target and function?
Released from anterior pituitary, targets breast tissues, and stimulates milk production
Peptide style
Where is adrenaline/epinepherine/norepinephrie/noradrenaline released, what is its function, and what kind of hormone is it?
Adrenal gland
Short term stress response- flight or flight (increases heart rate, muscle strength, blood pressure, and sugar metabolism)
Steroid
Where is cortisol released, what kind of hormone is it, and what is its function?
Adrenal gland
Long term stress response: increase blood sugar to suppress immune system, and in metabolism of of fat/protein/carbs stimulates body cells to use fatty acid instead of glucose. Stimulates conversion of amino acid to glucose
Where and by what is glucagon produced/released?
Produced by alpha cells in the islets of langerhan released by the pancreas
What kind of hormones are insulin and glucagon?
peptide
What is glucagon’s target and function?
Target is liver-it is released when sugar is low and promotes breaking down of glycogen into glucose
Where is TSH released and what does it do?
Released from anterior pituitary and stimulates the thyroid to release thyroxin.
Where is aldosterone secreted from and what does it do?
It is secreted from the adrenal gland and controls blood pressure/osmolarity. It increases sodium ion release by kidney back into the blood stream and where salt goes, water follows.
Where is ACTH released from and what does it do?
It is released from the anterior pituitary and stimulates the production and release of cortisol from the adrenal glands.
What is a tropic hormone?
A hormone that works on other endocrine glands.
What is an example of a feedback loop?
The hypothalamus releases TRH in response to low levels of thyroxin, which stimulates the anterior pituitary to release TSH (thyroid stimulating hormone) which in turn stimulates release of thyroxin from the thyroid. This is a negative feedback loop going back to the hypothalamus.