Unknown For Now Flashcards
what is angina
fixed vessel narrowing and endothelial dysfunction
stable - episodic brought on by excersie
unstable - any time
Channels where is teh relaxation and restoring Ca2+
Utilises the Na2+ electrochemical gradient to pump Ca2+ out of the cell
Utilises ATP hydrolysis to actively pump Ca2+ out of the cell
Utilises ATP hydrolysis to actively pump Ca2+ into the SR
what is electromechical coupling
opening of plasma membrane voltage actiavtes L type ca cahnnels in response to depolarisation with or without potential generation
what is pharmacomechial coupling
agent that causes chnage in smooth muscle tone without a change in membrane potential (production of intracellular second messengers contract or relx) IP3 , cGMP
Flexion withdrawl reflex
Pain - flexors contracted extensors relax
Opposite - flexors relax extesnors contracted
golgi tendon reflex
muscle contracts
extrafusal shortens
stimualte golgi tendon organ
Ib firing frequey send information to inhibitory interneuons
synpase in a motorneurons
muscle relax firing frequency of group lb deccreasess
syngergists relax and antagonist contract
Stretch myotatic reflex
Muscle stretch
1a afferent fibres muscle firing
synapse on the a motorneuron
sensory information relay
cause contraction
decrease firing frequency
What does the tail region do
tail portions are a helices that intertwine
hinge region the molecule open to form 2 globular heads
the head region are the cross bridges between thick and thin filament
Elbow Joint
Synovial hinge joint only flex extent
lateral / medial collateral ligament
Knee Joint
Cruciate ligament collateral ligament do not fit properly and stabilise the joint
Intervertable joints
Longitnidal ligaments and ligamentum flvaum
largely stiff inelastic strictures
how do calcium channel blockers
Calcium channels blockers act as a l type calcium channel on vascular smooth muscle but also at l type calcium channels in cardiac myocytes
what are the main classes of calcium channel blockers
Dihydrropridines - nifedipine and amlodipine
Benzothiasepines - diltiazem
Phenyalkylamines - verapamil
KATP channels openers
Hypertension be used with beta blocker and dieutrics
Open channels in smooth muscle cell membrane hyperolarise smooth cells
~ minoxidil and nicorandil
a blockers
a 1 adrenoreceptors singalling cascade leads to smooth muscle contraction following activation of sympathetic
prevent signalling cascade therefore leads to vasodilation
~ prazonin
Pacemaker activity of cardiac autorhythmic cells
Pakcemaker potential - Na in through funny channels
Trasient type Ca open goes to threshold
Long lasting Ca open very fast depoalrisation
K+ out goes repolarises
Action potential in a cardiac contractile cell
Na+ in fast
K+ out fast
Ca2+ in slow
K+ out fast
what is the refractory peroid
action potential with then contractile response where no action potential
what is an ECG not
not direct recording of electrical acitvity
it is not recording of single action potential in a single cell at a single point in time
comparison in voltage detected but not actual potential
how does the pattern chnage
whether upward and downward deflection is recorded is determined electrodes with respect to current flow in heart
different waveforms same electrical activity activity recorded electrodes different body parts
ECG leads
6 from limbs
6 chest around the heart
Six limb leads
Leads I II III
difference in potentials between the two electrodes
one on left leg acts as a ground
are bipolar
Six Chest Leads
are also unipoalr
exploring electrode
electrical potential cardiac muscaulture immediately beneath the electrode in six different locations surrounding the heart
Einthoven’s triangle
voltage recording are made between points that form an equilateral tringable over the thorax and any single trace is a recording o the voltage difference measured between any two ventricles
What does QRS mask
No separate wave for atrial repoalrisation is visible the electrical activity associated with atrial repoalrisation occurs simultaneously with ventricular depoalrsation and is maksed by QRS
why is p wave smaller than QRS
atria have a much smaller muscle mass than ventricles
where is there no current flow
PR Segment
ST Segment
TP interval
strength of cardiac muscle contraction and accordingly SV
Varying the initial length of the cardiac muscle fibres, which in turn depends upon EDV (intrinsic control)
Varying the extent of sympathetic stimulation (extrinsic control)
Increase EDV increase SV
Intrinsic control of SV depends on the direct correlation between EDV and SV
this is length-tension relationship of cardiac muscle