5.4 HORMONES Flashcards
Define hormone
- Chemical signals released/transported in the bloodstream that act as messengers
State the *two** types of hormones
- peptide/protein hormones
- steriod (lipid) hormones
State the difference between endocrine and exocrine glands
- Endocrine glands release their hormones (protein or steriod) into the bloodstream
- Exocrine glands have a duct that carriers their hormones away
Define first messenger
- A protein hormone that binds to a receptor on plasma cell surface membrane and activates the second messenger
Define second messenger
- A signalling molecule which stimulates** a change in activity of a cell
State the first messenger in adrenaline release
- Adrenaline
State the second messenger in adrenaline release
- Cyclic AMP (cAMP)
Describe the route of protein/peptide hormones
- From adrenal medulla it attaches to complementary receptor of glycoprotein in plasma cell membrane of target cell
- G protein attached to receptor becomes activated
- Activated G protein now activates the enzyme adenyl cyclase
- Activated adenyl cylases converts ATP to cAMP
- cAMP acts directly on channel protein or initates a cascade of enzyme-controlled reactions
Describe the route of steriod (lipid) hormones
- From adrenal cortex through plasma cell membrane of target cell
- Steroid hormone binds with specific receptor in cytoplasm
- Receptor-steroid compex forms, enters nucleus
- Binds to promoter region of a gene which increases production of mRNA
State why protein hormones are unable to enter cells
- Not lipid soluble
- Polar
State why steriod hormones can enter cells
- Lipid soluble
- Nonpolar
Draw the two types of adrenal glands
- Adrenal cortex
- Adrenal medulla
State the type of hormone secreted by the adrenal medulla
- Protein/peptide hormones
State the type of hormone secreted by the adrenal cortex
- Steroid/lipid hormones
Draw the structure of the adrenal cortex
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
- (GFR)
State the molecule adrenal cortex uses to create steroid hormones
- Cholesterol
Which hormone does zona glomerulosa release?
- Mineralcorticoids
Which hormone does zona fasciculata release?
- Glucocorticoids
Which hormone does zona reticularis release?
- Precursor androgens
State the role of the mineralcorticoids hormones
- Maintains blood pressure by controlling concentrations of Na- and K+
State the role of the glucocorticoids hormones
- Regulates metabolism of carbohydrates, proteins and fats in the liver
State the role of the precursor androgens hormones
- Taken up by ovaries or testes to develop sexual characteristics
Which part of the adrenal glands release adrenaline
- Adrenal medulla
Describe the structure of adrenaline
- Amino acid derivative
- Polar
- Lipid insoluble
State the effects of adrenaline release in fight or flight response
- Increased heart rate
- Increased stroke rate
- Increased blood pressure (via vasoconstriction)
- Pupil dilation ( increases sensory information)
- Relaxed smooth muscle in bronchioles (increases ventilation)
- Mental alertness increased
- Decreased digestion function
- Glycogenolysis (glycogen to glucose in liver) to increase blood glucose concentration (more energy)
