Control and coordination Flashcards
Outline the differences between the endocrine system and the nervous system.
Nervous system communicates by electrical impulses whereas endocrine system communicates by hormones.
Mode of transmission for nervous system is neurones whereas for endocrine system is blood.
Transmission speed is faster in nervous system than endocrine system.
Location of effect is specific for nervous system whereas it can be widespread for endocrine system.
Duration of effect is shorter for nervous system than endocrine system.
Explain how auxin affects the growth of plant stems.
Auxin increases stem height.
Binds to receptors on cell surface membrane.
Allow H+ ions to be pumped into the cell.
H+ ions activates expansin and break bonds between cellulose.
Water enter cells by osmosis.
Cell elongate.
Describe how neurones maintain a resting potential.
Sodium potassium pump actively transports Na+ out of the cells and K+ into the cells.
Two K+ enter the cell for every three Na+ that leave the cell.
Inside of neurone is more negative than outside.
Outline the sequence of events occuring after stimulation of the sacroplasmic reticulum that results in the shortening of a sacromere.
Ca2+ ions leave sacroplasmic reticulum.
Calcium ions bind to troponin.
Tropomyosin moves.
Actin binding site exposed.
Myosin head forms cross bridge with actin.
Myosin head tilts and power stroke occurs.
Describe how the release of dopamine from the presynaptic neurone can lead to an action potential in the postsynaptic neurone.
Dopamine diffuse across synaptic cleft.
Dopamine binds to receptors on postsynaptic membrane.
This causes Na+ channels to open.
Influx of Na+ ions into the neurone causes depolarisation of postsynaptic membrane.
