14.1 Hormonal communication Flashcards
what is an endocrine gland?
a group of cells which are specialised to secrete hormones
how are endocrine glands stimulated?
through an electrical impulse
what is a hormone?
a chemical messenger secreted into the bloodstream
what are hormones specific to?
receptors on target cells which are found in the target tissue
what is the order of hormone action?
stimulus
receptors
hormone
effectors
response
what are the 2 types of hormones?
steroid (lipid)
non-steroid (protein)
why can a steroid hormone pass through the cell surface membrane?
are lipid soluble which allows them to pass through the phospholipid bilayer
how does a steroid hormone carry out its function?
- pass through cell surface membrane
- bind to steroid hormone receptors
- form a hormone receptor complex
- this acts as a transcription factor which facilitates the transcription of a specific gene
how does a non-steroid hormone carry out its function?
- bind to receptors on cell surface membrane
- triggers cascade reaction by chemicals called secondary messengers
properties of hormonal system?
- uses hormones
- quite slow
- long lasting
- carried in the blood
- widespread effect
properties of nervous system?
- uses nerve impulses
- very fast
- short lived
- carried by neurones
- localised effect
where are adrenal glands found?
top of the kidneys
how many adrenal glands?
2
what is the adrenal cortex?
outer region of adrenal gland
what is adrenal medulla?
inner region of adrenal gland
where are non essential hormones produced?
adrenal medulla
where are essential hormones produced?
adrenal cortex
what hormones are produced by adrenal cortex?
glucocorticoids
mineralocorticoids
androgens
what hormones are produced by adrenal medulla?
adrenaline
noradrenaline
function of adrenaline?
increases heart rate by directing blood to muscles and brain
function of noradrenaline?
increases heart rate
widens pupils
widens air passages
narrows blood vessels
causes high blood pressure
works with adrenaline
function of glucocorticoids?
regulates metabolism by controlling how body converts fats proteins and carbs into energy
function of mineralocorticoids?
maintains balance between salt and water concentrations in the blood
function of androgens?
male and female sex hormones
