unit 5 - nervous system, the heart, muscles Flashcards
which nervous systems speeds up the heart?
sympathetic nervous system
which nervous systems slows down the heart?
parasympathetic nervous system
what des the parasympathetic nervous system release to slow down the heart?
acetylcholine (neurotransmitter)
what does the sympathetic nervous system release to speed up heart
noradrenaline (neurotransmitter)
ECG: what does part P represent?
atrial depolarisation (atrial systole)
ECG: what does part R represent?
ventricular depolarisation (ventricular systole)
ECG: what does part T represent?
repolarisation (atria + ventricular diastole)
does myoglobin do cooperative binding?
no
what curve is myoglobin’s affinity represented in?
hyperbolic curve
what are slow twitch muscles used for
maintain body posture
do slow twitch muscles contain myoglobin?
yes
how do slow twitch muscles respire?
mainly aerobically
what do slow twitch muscles use for fuel?
glucose mainly
what do slow twitch muscles contain a lot of?
mitochondria
what are fast twitch muscles used for?
sudden rapid activity
how do fast twitch muscles respire mainly?
anaerobicallly
what colour are the 2 types of muscles
fast - pale
slow- red (myoglobin)
what do fast twitch muscles have high levels of?
creatine
how are the myofibrils packed in fast twitch?
close together
what are the 3 types of muscle?
cardiac
skeletal
smooth
how do skeletal muscles appear under miscoscope?
striped
what is a myofibril?
several muscle cells
what do u call a muscle cell?
sarcomere
what does myogenic mean? example?
contract by itself w/o external stimuli
e.g. cardiac muscle
what is released from sarcoplasmic reticulum? what do they bind to? causing what?
calcium ions bind to troponin, this causes troponin to change shape and pull of the tropomyosin
what does the movement of tropomyosin do?
exposes the myosin binding site
what is released from myosin head once bonded to myosin binding site>
ADP + Pi
what does release of ADP + Pi cause?
causes myosin to change shape, and head bends forwards pushing actin along 10nm
what does free ATP do? what does it cause?
ATP bind to myosin head, cause change in shape, cross bridge between myosin + binding site broken
what does the presence of calcium ions activate?
ATPase enzyme, ATP is hydrolysed and energy is released, this is used to return myosin to original position
