Endocrine System Flashcards
Endocrine vs nervous system in maintaining homeostasis.
Endocrine uses chemical signalling (hormones) while the nervous system uses electrical signalling (neural impulses).
Positive vs negative feedback
A positive feedback loop exsentuates the impulse while a negative feedback loop stops the impulse, preventing the signal from being transmitted.
What is a negative feedback loop example in the endocrine system?
The parathyroid glands secrete PTH which regulates the amount of calcium in the blood, if calcium decreases, PTH is secreted and brings the body back to homeostasis.
Where is the hypothalamus located and what does it do?
The hypothalamus is in the centre of the brain and secretes hormones such as (CRH, GnRH, and TRH) which stimulate/suppress the release of hormones in the pituitary gland, in addition to controlling water balance, sleep, blood pressure, etc.
What does the pituitary complex do and where is it located?
Located at the base of the brain, directly below the hypothalamus. Secretes TSH, ACTH, FSH, and LH.
Where is the thyroid located and what does it do?
Located at the base of the neck, and responsible for secreting thyroxine and calcitonin which regulates mood, heart rate, metabolism, and breathing.
Where is the parathyroid and what does it do?
The parathyroid is located behind the thyroid at the bottom of the neck, and produces PTH which regulates calcium in the blood.
Where are adrenal glands and what do they do?
Adrenal glands are located on top of the kidneys and secrete aldosterone and cortisol which controls the balance of water and salt by the kidneys, by keeping sodium in, and releasing potassium.
Where are islet cells and what do they do?
Located in the pancreas and produces insulin and glucagon which work to regulate the amount of sugar in the blood.
How do hormones circulate in the body?
Hormones usually travel through the blood stream but can also move through the fluid which surrounds cells.
Water vs fat soluble hormones
Water soluble hormones bind outside the cell while fat soluble binds inside the cell.
Why is the pituitary the master gland?
The pituitary gland controls many other endocrine glands such as the thyroid, adrenal, ovaries, and testes. The pituitary affects the thyroid by producing thyroid stimulating hormone (TSH).
Posterior vs Anterior pituitary
The anterior lobe produces/releases the hormones, while the posterior stores oxytocin and ADH.
What is a tropic hormone?
Any hormones from the anterior pituitary that affect the secretion of other hormones. Any hormone that has another endocrine gland as a target. Ex. TSH, FSH, LH.
How is Gigantism/Dwarfism caused?
Gigantism is often caused by the growth of a tumour in the pituitary gland, leading to excessive production of HGH. Dwarfism is usually caused by a mutation of the sperm cell before pregnancy.
