hormonal communication summary

Hormonal communication
Hormones
Chemical messengers that carry information and are released when the gland is
stimulated

● STEROID: non-polar & lipid-soluble
○ Bind to their receptors
○ →hormone-receptor complex acts as a TRANSCRIPTION FACTOR
that facilitates/inhibits transcription of a specific gene
● PROTEIN: hydrophilic = insoluble in lipids
- Can’t cross cell membrane
- Acts a FIRST MESSENGER : binds to their receptor on the cell surface
- Triggers SECOND MESSENGER cAMP that sets off a signal cascade to activate
enzymes



Glands
● ENDOCRINE
○ Secrete hormones directly into the bloodstream
● EXOCRINE
○ Release secretions via ducts

, 2

Adrenal glands

Adrenal cortex
Release steroid hormones vital to life

● MINERALOCORTICOIDS (eg. aldosterone)
○ Control blood pressure by regulating salt + water concentration in the
body
● GLUCOCORTICOIDS (eg. cortisol)
○ Regulate metabolism (how fast carbohydrates convert into energy)
○ Regulates blood pressure & cardiovascular function in response to stress



Adrenal medulla
Release non-essential hormones when sympathetic nervous system is stimulated by
stress

● ADRENALINE
- Increase heart rate, glycogenolysis
- Relax smooth muscles of bronchioles to increase air flow + O2
● NORADRENALINE
- Widens pupils + air passages in lungs
- Narrows blood vessels to non-essential organs (eg. digestive) to increase blood
pressure


Pancreas

Exocrine
Secrete digestive enzymes (eg. amylases, proteases, lipases) & pancreatic juice into the
pancreatic duct into top small intestine (duodenum) to aid digestion of large molecules
in food

● Darkly stained
- Acinar cells (berry-like structures)