MBCHB phase 2c Test With
Complete Solution
Say it to get the mark, what gases are being transported? - ANSWER co2
from tissues to lungs
o2 from lungs to tissues
movement of gas is based on what?
what type of movement? - ANSWER bulk movement from high to low
pressure.
via diffusion
what is tidal volume? - ANSWER volume of air moved into and out of lungs
during each ventilation cycle
what are 4 examples of properties that respiratory and circulatory systems
contain to facilitate gas diffusion - ANSWER large surface area for gas
exchange
large partial pressure gradients
gases w advantageous diffusion properties
specialised mechanisms for transporting O2 and CO2 bt lungs and tissues
explain partial pressure - ANSWER sum of partial pressures of a gas equal
total pressure.
partial pressure of gas=fraction of gas (fgas) in gas mixture x barometric
,pressure
so what is the partial pressure of oxygen? - ANSWER 21% o2 in the air
po2=0.21 x 760mmHg
=159mmHg
what happens in the airways to air? - ANSWER warmed and humidified,
saturated with water vapour.
skip to the heart.
the mitral valve (bicuspid) is on what side? - ANSWER LEFT! atrioventricular
the semilunar valves of the heart are what?
where? - ANSWER outflow- pulmonary valve of p. artery and aortic valve of
aorta.
bt ventricles and those vessels
explain isovolumetric contraction of the ventricles of the heart - ANSWER
interval bt closing of AV valves and opening of semilunar valves. *all valves
closed so no change in volume*
When does isovolumetric contraction take place? - ANSWER During QRS
after closure of mitral valve but before the aortic valve opens
early ventricular systole.
equation for cardiac output - ANSWER CO = HR x SV
equation for blood pressure - ANSWER BP = CO x PVR
the layers of heart tissue in the heart include the endocardium, myocardium
,(cardiac muscle), epicardium, pericardial cavity and parietal pericardium, with
a dense fibrous outer layer.
what do the endocardium, epicardium and parietal epi contain? - ANSWER
areolar tissue (loose connective collagen) and endothelium or epithelium
Which ventricle has a thicker wall? - ANSWER left
what is the resting membrane potential of the heart?
depolarisation vs repolarisation charges - ANSWER -80mV
depol= less (-) inside
repol= more (-) inside
currents of what ions in what direction are depolarising for the heart? -
ANSWER na and ca inwards.
currents of what ions in what direction are repolarising? - ANSWER k
outwards
k and na, where are they greater inside or outside of cell? - ANSWER K+
greater inside
Na+ outside
action potential is basically sequential activation and inactivation of inward
ca and na and outward k currents
at the resting potential, what is the relationship bt electrical and
concentration gradients? - ANSWER they are equal
so during an action potential, there is depolarisation. explain why - ANSWER
opening of VGSCs, allow inward Na+ so positive influx, inside becomes less
, negative.
what is phase 0 of the AP? - ANSWER the opening of VGSCs and influx of Na
what is phase 1 (notch) of AP? - ANSWER repolarisation- K+ leaves, so inside
becomes more - again.
inactivation of VGSC
next phase of AP? - ANSWER plateau phase 2.
balance of inward Ca2+ and outward K+.
so depol=repol
what is phase 3 of the AP? - ANSWER repolarisation, inward currents
inactivated and outward K+ predominate.
more - inside
final phase of AP - ANSWER resting -80mV
what APs mediate normal rhythm? (7)
combine their profiles to get what? - ANSWER specialised APs- SAN, atrial
muscle, AVN, common bundle, bundle branches and Purkinje fibres,
ventricular muscle
PQRSTU wave
there is a hierarchy of pacemakers. explain giving the bpm rates for three
main
in a normal healthy heart, which will predominate? - ANSWER SAN 70bpm
AVN 50bpm
Complete Solution
Say it to get the mark, what gases are being transported? - ANSWER co2
from tissues to lungs
o2 from lungs to tissues
movement of gas is based on what?
what type of movement? - ANSWER bulk movement from high to low
pressure.
via diffusion
what is tidal volume? - ANSWER volume of air moved into and out of lungs
during each ventilation cycle
what are 4 examples of properties that respiratory and circulatory systems
contain to facilitate gas diffusion - ANSWER large surface area for gas
exchange
large partial pressure gradients
gases w advantageous diffusion properties
specialised mechanisms for transporting O2 and CO2 bt lungs and tissues
explain partial pressure - ANSWER sum of partial pressures of a gas equal
total pressure.
partial pressure of gas=fraction of gas (fgas) in gas mixture x barometric
,pressure
so what is the partial pressure of oxygen? - ANSWER 21% o2 in the air
po2=0.21 x 760mmHg
=159mmHg
what happens in the airways to air? - ANSWER warmed and humidified,
saturated with water vapour.
skip to the heart.
the mitral valve (bicuspid) is on what side? - ANSWER LEFT! atrioventricular
the semilunar valves of the heart are what?
where? - ANSWER outflow- pulmonary valve of p. artery and aortic valve of
aorta.
bt ventricles and those vessels
explain isovolumetric contraction of the ventricles of the heart - ANSWER
interval bt closing of AV valves and opening of semilunar valves. *all valves
closed so no change in volume*
When does isovolumetric contraction take place? - ANSWER During QRS
after closure of mitral valve but before the aortic valve opens
early ventricular systole.
equation for cardiac output - ANSWER CO = HR x SV
equation for blood pressure - ANSWER BP = CO x PVR
the layers of heart tissue in the heart include the endocardium, myocardium
,(cardiac muscle), epicardium, pericardial cavity and parietal pericardium, with
a dense fibrous outer layer.
what do the endocardium, epicardium and parietal epi contain? - ANSWER
areolar tissue (loose connective collagen) and endothelium or epithelium
Which ventricle has a thicker wall? - ANSWER left
what is the resting membrane potential of the heart?
depolarisation vs repolarisation charges - ANSWER -80mV
depol= less (-) inside
repol= more (-) inside
currents of what ions in what direction are depolarising for the heart? -
ANSWER na and ca inwards.
currents of what ions in what direction are repolarising? - ANSWER k
outwards
k and na, where are they greater inside or outside of cell? - ANSWER K+
greater inside
Na+ outside
action potential is basically sequential activation and inactivation of inward
ca and na and outward k currents
at the resting potential, what is the relationship bt electrical and
concentration gradients? - ANSWER they are equal
so during an action potential, there is depolarisation. explain why - ANSWER
opening of VGSCs, allow inward Na+ so positive influx, inside becomes less
, negative.
what is phase 0 of the AP? - ANSWER the opening of VGSCs and influx of Na
what is phase 1 (notch) of AP? - ANSWER repolarisation- K+ leaves, so inside
becomes more - again.
inactivation of VGSC
next phase of AP? - ANSWER plateau phase 2.
balance of inward Ca2+ and outward K+.
so depol=repol
what is phase 3 of the AP? - ANSWER repolarisation, inward currents
inactivated and outward K+ predominate.
more - inside
final phase of AP - ANSWER resting -80mV
what APs mediate normal rhythm? (7)
combine their profiles to get what? - ANSWER specialised APs- SAN, atrial
muscle, AVN, common bundle, bundle branches and Purkinje fibres,
ventricular muscle
PQRSTU wave
there is a hierarchy of pacemakers. explain giving the bpm rates for three
main
in a normal healthy heart, which will predominate? - ANSWER SAN 70bpm
AVN 50bpm
