5.1.4 Hormonal communication Flashcards
examples of protein and peptide hormones
insulin
glucagon
adrenaline
examples of steroid hormones
oestrogen
progesterone
testosterone
what are protein and peptide hormones
attach to receptor on cell surface
not soluble in membrane so DON’T enter cell
what is a steroid hormone and can it pass through a membrane
can pass through membrane and enter cell
act as transcription factors
exocrine
cells produce hormones and collected in a duct and stored then transferred to where they’re needed
- not in the blood
endocrine
cells produce hormone directly into the blood stream for transport
hormones definition
chemical messengers as they carry info from one part of the body to another
what type of hormone can pass through the membrane such as nuclear envelope
steroid hormone
what do transcription factors do
work alone or with other proteins to regulate by promoting or blocking the RNA polymerase from binding
- act as repressor
where does RNA polymerase bind to when initiating the uncoiling of DNA
promotor region which is upstream of the structural gene
what is an endocrine gland
group of cells which are specialised to secrete chemicals called hormones and are secreted directly into the bloodstream
examples of endocrine gland
pancreas
adrenal gland
what does the pituitary gland do
produces growth hormone which controls growth of bones and muscles
anti-diuretic hormone which increases reabsorbtion of water in kidneys and gonadotrophins which control development of ovaries and testes
thyroid gland
produces thyroxine which controls rate of metabolism and rate that glucose is used up in respiration and promotes growth
adrenal gland
produces adrenaline which increases heart and breathing rate and raises blood sugar level
testis
produces testosterone which controls sperm production and secondary sexual characteristics
pineal gland
produces melatonin which affects reproductive development and daily cycles
thymus
produces thymosin which promotes production and maturation of white blood cells
pancreas
produces insulin which converts excess glucose into glycogen in the liver and glucagon which converts glycogen back to glucose in the liver
ovary
effects of adrenaline
increased HR
pupils dilate
more light to eye
smooth muscles of airways relax
blood glucose level increase
blood vessels dilate
non essential systems slow down - digestive system
why does HR increase when adrenaline is released
to deliver more O2 and glucose to the muscles
why do your pupils dilate in response to adrenaline being released
to allow more light to enter the eye
why do smooth muscles of airways relax in response to adrenaline being released
allows more O2 to enter and can increase breathing rate
why do blood vessels dilate in response to adrenaline being released
more blood flow to muscles
why does blood glucose level increase in response to adrenaline being released
more glucose to muscles for respiration
example of non essential system that slows down when adrenaline is released
digestive system
steps of adrenaline
-adrenaline receptor site has shape complementary to adrenaline
- adrenaline activates the enzyme adenyl cyclase
- adenyl cyclase converts ATP to cAMP which can activate other enzymes in the cell
what is a primary messenger
a molecule that transmits a signal around the body (outside cell)
what does the adrenal medulla do
makes and releases adrenaline in response to pain and shock
also makes noradrenaline which is a neurotransmitter
what type of hormone is adrenaline
peptide hormones
what does the adrenal cortex do
uses cholesterol to produce certain steroid hormones
what hormones does adrenal cortex release
mineralcorticoids and glucocorticoids
what do mineralcorticoids do and an example
control the concentration of Na and K in the blood
aldosterone
what do glucocorticoids do and an example
help control the metabolism of carbohydrates and proteins in the liver
cortisol
what is the centre of the adrenal gland
medulla
what surrounds the medulla in the adrenal gland
cortex
3 main areas in a kidney that you can see when you slice it open
cortex
medulla
pelvis
colour and structure of cortex when you slice open a kidney
dark outer layer
where the filtering of the blood takes place and it has very dense capillary network carrying blood from the renal artery to the nephrons
what does the pancreas do
releases hormones
exocrine function of the pancreas
amylase
trypserign
lipase
sodium hydrogen carbonate
what does sodium hydrogen carbonate do
neutralise stomach acid
what is amylase
a carbohydrase
what does trypserigen
an inactive form of trypsin
a protease- enzyme used in digestion
endocrine function of pancreas
released into pancreatic duct
only certain areas of pancreas do it
what part of pancreas do endocrine function
islet of langerhans cells
what do the beta cells of islet of langerhands produce
insulin
what do the alpha cells of islet of langerhands produce
produce glucagen
what are cells in the liver used for
storage of glucose
why are islet of langerhands surrounded by capillaries containing red blood cells
so hormones can be released into the blood stream
what is the normal blood glucose level
4 to 6 mmol dm-3
what happens if blood glucose is too low
detected by alpha cells that then secrete glucagon into blood cells
glucagon targets hepatocytes which have specific receptors
glycogenolysis occurs
use up fats in respiration
gluconeogenesis occurs
what is glycogenolysis
conversion of glycogen to glusoce
what is gluconeogenesis
production of new glucose from amino acids and fats
what happens if blood glucose is too high
detected by beta cells that then secrete insulin into blood
insulin targets hepatocytes, muscle cells and othe cells
insulin binds to receptors on plasma membrane of cells and activate an enzyme calles adenyl cyclase that converts ATP to cAMP
cAMP acts as secondary messenger inside the cell
what are hepatocytes
liver cells
what does insulin do tp target cell if glucose is too high
more glucose channels in membrane so more glucose enters
glycogenesis
glucose convert to fats
increase glucose used in respiration
what is glycogenesis
glucose converted to glycogen
how is insulin released from beta cell
cell membrane has pottasium and calcium ion channel
K+ channeks are normally open so K+ flow
when blood glucose concentration is high the glucose moves into the cell
glucose is metabolised to produce ATP
the ATP closes K+ channels
accumulate of K+ alters potential difference across membrane - inside = less negative
change in potential difference opens the Ca2+ channels
Ca2+ cause vesicle of insulin to fuse with cell surface membrane releasing insulin by exocytosis
