endocrine system Flashcards
what is the function of the endocrine system
the release and control of the concentration of hormones, the maintenance of the internal environment to maintain homeostasis
is the secretion of most hormones controlled by negative or positive feedback
negative
what 3 elements is the endocrine system composed of
endocrine cells and glands, hormones, target cells ( cells that will respond to the hormones
where are hormones secreted into by endocrine cells
extracellular space
what does anatomically discontinuous mean?
it will only take effect when it reaches its target cell, it wont have any effect on the way when in the blood
what inputs do endocrine cells receive
neuron, hormone, ion, organic nutrient
how do hormones know they’ve come into contact with a target cell
Target cells have receptors for the specific hormone which is why they wont bind to the wrong cell
what are the main types of cell signalling
endocrine, neurohormones, panacrine and autocrine, intracrine
how does endocrine hormones signal other hormones
via the blood stream to target cells
how do neurocrine hormones send signals to target cells
released via synapses and travel via the bloodstream
how do paracrine hormones send signals to target cells
they act on adjacent cells
how do autocrine hormones send signals to target cells
they act on the cells that secreted them
where is the pineal gland located
near the thalamus into the brain
what hormone does the pineal gland produce
melatonin
what effect does melatonin have on the body
causes the body to feel drowsy and tired, becomes more active in low light intensities
what is the hypothalamus’ role in the endocrine system?
regulation of the endocrine organs that are structurally below it
what special cells does the hypothalamus contain
neuro-secretory cells (neurons that secrete hormones)
what doe the hypothalamus regulate the release of
TRH, GHRH, GHIH, GnRH, CRH, oxytocin, ADH
what are the two areas of the pituitary gland
posterior and anterior
what is the function of the posterior pituitary
produces oxytocin and anti-diuretic hormone (ADH)
what is the function of the anterior pituitary
produces thyroid stimulating hormone (TSH), growth hormone (GH)
where is the thyroid gland located
in the anterior neck
what 2 hormones are secreted by the thyroid gland
thyroxine (T4) and triiodothyronine (T3)
what does the hormones secreted by the thyroid gland do to the body
Regulates metabolism, increases protein synthesis, promotes glycolysis/ glucose uptake
what is the role of the parathyroid gland
regulates the level of calcium in the body by producing parathyroid hormone which increases calcium levels in the blood
what hormone is produced by the thymus gland and what is their role in the body
thymosins - they help to develop T-Lymphocytes during foetal development in childhood.
where is the adrenal medulla located
directly above each kidney
what does the adrenal medulla secrete
catecholamine
what effect does the adrenal medulla have on the body
fight or flight - increases HR and BP
Where is the adrenal cortex located
it is the outer few membranes of the adrenal gland which is situated above each kidney
what does the adrenal cortex secrete
30 different steroid hormones - some of which act as an anti inflammatory agent
where is the pancreas located
in the folds of the duodenum, located slightly behind the stomach
what does the pancreas secrete
digestive enzymes such as insulin
what is the role of insulin in reducing blood glucose
promotes glycogenesis (the break down of glucose to glycogen
what are the islets of langerhans
They’re a small group of cells that function as an endocrine gland ( contains Alpha, beta and delta cells)
what do each type of islets of langerhans secrete
alpha- glucagon, beta- insulin, delta- somatostatin
what is the role of alpha cells and how does this help control blood glucose levels
they release glucagon to control blood glucose levels, the glucagon stimulates the liver to release glucose stores
what is the role of beta cells and how does it help control blood glucose levels
they release insulin, insulin increases the rate at which glucose is taken up by cells which lowers the blood glucose level,
what is the role of delta cells and how does it help control blood glucose levels
they produce somatostatin which inhibits both glucagon and insulin
how does insulin increases the uptake of glucose
when the concentration of glucose is more than normal, insulin binds to an insulin receptor on the surface of the cell causing the glucose channel to open allowing glucose to move into the cell
what are the 3 main types of hormones
steroids, peptide hormones (insulin glycagon), amino acid derivatives
