Endocrine System Flashcards
Function of the endocrine system
Work with the nervous system to respond to internal and external changes
Differences between the endocrine system and the nervous system
Nervous system uses NTs
Endocrine uses hormones
Nervous is a more localised response
Endocrine is a global response
Nervous system is fast but short lasting
Endocrine response is slow but long lasting
Both cause change in target cells by binding to receptors
Circulating Hormones
released from secretory cells and travel in the blood stream and have their effect in another part of the body
Local Hormones
act locally on neighbouring cells (paracrines)
or on the same cell that produces them (autocrines)
How can hormones affect cells
stimulating the synthesis of enzymes
increasing/decreasing the rate of enzyme synthesis
activating/deactivating an existing enzyme or membrane channel
Protein based hormones overview
water soluble
chains of amino acids
cannot cross cell membranes
bind to receptors outside the cell
examples: sex hormones, peptide hormones, ADH, oxytocin
Lipid based hormones overview
Lipid soluble
can cross membranes
goes into cells
remain in circulation longer
examples: thyroid hormones and nitric oxide
What happens when protein based hormones attach to receptors
activated G proteins causing a cascade of intracellular reactions
Lipid based hormones attaching to receptors
go through phospholipid bilayer
bind to receptors inside the cell to create a hormone-receptor complex that enters the nucleus
Process of negative feedback
the body recognises a change in environment
hormone is released
hormone acts on target cells
restoration of equilibrium
hormone production stops
Examples of things controlled by a negative feedback mechanism
Temperature, BGL & BP
Process of positive feedback
a change occurs, causing a secretion of hormones
hormones act on the original site of the stimulus and increase the reaction causing more secretion
function of calcitonin
released by the thyroid gland when calcium levels increase
increases osteoblasts
deposits calcium into the bone
restores normal calcium concentration in blood
function of parathyroid hormone
released by the thyroid gland when calcium levels decrease
increase osteoclasts
takes calcium from bones and this goes into blood
restores normal calcium concentration in blood
symptoms of hypothyroidism
cold
weight gain
low energy
high cholesterol
symptoms of hyperthyroidism
energetic
weight loss
neck swelling
physiological response to the release of adrenaline
increased HR and RR
vasoconstriction
bronchodilation
glycogen is converted to glucose
fats broken down into ATP
Function of glucagon
released when blood sugar is low
breakdown of glycogen stores
breakdown of triglycerides in adipose tissue
Function of insulin
released when blood sugar is high
promotes glucose absorption
conversion of glucose into glycogen in the liver
glucose uptake in cells
3 types of diabetes
diabetes mellitus - dysfunction of pancreas
diabetes insipidus - vast quantities of dilute urine
gestational diabetes
characteristics of type 1 diabetes
juvenile onset
autoimmune or genetic
non-functional pancreas/ no insulin produced
cannot be prevented or reversed
characteristics of type 2 diabetes
adult onset
insulin resistance due to obesity or age
partially functioning pancreas
can be reversed
