Quiz
HEART CONTRACTION
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Perguntas do quiz (22)
1ACTION POTENTIALS IN PACEMAKER CELLS:
1) sodium enters the cell down a channel causing [blank_start]depolarisation[blank_end], this is initiated by the [blank_start]funny current[blank_end]
2) at the transmembrane potential of [blank_start]-55mV[blank_end], [blank_start]T-type Ca2+[blank_end] channels open and continue slow depolarisation
3) at the transmembrane potential of [blank_start]-40mV[blank_end] which is the threshold potential for pacemaker cells, [blank_start]L-type Ca2+[blank_end] channels open and depolarize the cell further
4) the voltage gated Ca2+ channels close and [blank_start]delayed rectifier potassium[blank_end] channels cause [blank_start]hyperpolarisation[blank_end] back to around [blank_start]-60mV[blank_end]- Adepolarisation
- Bfunny current
- C-55mV
- DT-type Ca2+
- ET-type Na+
- FT-type K+
- G-40mV
- HL-type Ca2+
- IL-type K+
- JL-type Na+
- Kdelayed rectifier potassium
- Ldelayed rectifier sodium
- Mdelayed rectifier calcium
- Nhyperpolarisation
- Orepolarisation
- P-60mV
2ACTION POTENTIALS IN MYOCYTES:
1) K+ [blank_start]passively[blank_end] diffuses out of the cell, at a resting potential of [blank_start]-90mV[blank_end]
2) Ca2+ and Na+ leak in through [blank_start]gap junctions[blank_end] from neighboring cells due to slight [blank_start]depolarisation[blank_end] in the neighboring cell
3) this increases membrane potential to around [blank_start]-70mV[blank_end] which causes [blank_start]Na+[blank_end] voltage gated ion channels to open, allowing the ion to enter the cell. it drives the membrane potential very quickly up to a positive value
4) the voltage gated Na+ channels close
5) new [blank_start]K+ channels[blank_end] voltage gated channels open, due to the depolarisation of the cell, this causes the ion to exit the cell and [blank_start]repolarise[blank_end] the cell
6) [blank_start]Ca2+[blank_end] begins leaking in through [blank_start]L-type[blank_end] voltage gated channels which results in a plateau, due to the fact that the concentrations of the ions entering and exiting the cell are very similar
7) Ca2+ channels [blank_start]close[blank_end] and K+ voltage gated channels [blank_start]open[blank_end] causing the membrane potential to decrease and get close to the initial resting potential- Apassively
- Bactively
- C-90mV
- Dgap junctions
- Etight junctions
- Fdesmosomes
- Gdepolarisation
- Hrepolarisation
- Ihyperpolarisation
- J-70mV
- KNa+
- LK+ transient channels
- MNa+ transient channels
- NCa2+ transient channels
- OCa2+
- PL-type
- QT-type
- Rrepolarise
- Sdepolarise
- Thyperpolarise
- Uclose
- Vopen
3what phase is described below:
baseline state that muscles are in during relaxation, until it reaches threshold. Na+, Ca2+ channels are closed and K+ rectifier channels are open keeping the transmembrane potential at its resting state- Aphase 1
- Bphase 0
- Cphase 2
- Dphase 3
- Ephase 4
4what phase is described below:
once threshold is reached there is a rapid influx through Na+ channels- Aphase 1
- Bphase 0
- Cphase 4
- Dphase 3
- Ephase 2
5what phase is described below:
only transient K+ channels open and the K+ efflux returns the transmembrane potential back to 0mV- Aphase 1
- Bphase 0
- Cphase 2
- Dphase 3
- Ephase 4
6what phase is described below:
influx of Ca2+ through L-type Ca2+ channels is electrically balanced by the efflux of K+ through delayed rectifier channels- Aphase 1
- Bphase 2
- Cphase 0
- Dphase 3
- Ephase 4
7what phase is described below:
Ca2+ channels close but delayed rectifier channels remain open and return the transmembrane potential back to the normal- Aphase 1
- Bphase 2
- Cphase 0
- Dphase 3
- Ephase 4
8what phases are seen in a myocyte action potential
- A0
- B1
- C2
- D3
- E4
9what phases are present in a pacemaker action potential
- A1
- B2
- C0
- D3
- E4
10pacemaker cells have automaticity and therefore can contract by themselves
- AVerdadeiro
- BFalso
11what are the locations of the paceamaker cells
- Asinoatrial node
- Batrioventricular node
- Cpurkine fibres
- Dright atrial wall
- Eleft atrial wall
- Fright ventricular wall
- Gleft ventricular wall
12funny currents cause K+ channels to be open as a result of hyperpolarisation to start the next contraction
- AVerdadeiro
- BFalso
13in the depolarisation of a pacemaker cell which of the following occurs
- Adecreased K+ movement out of the cell
- Bincreased K+ movement out of the cell
- Cincreased K+ movement into the cell
- Ddecreased K+ movement into the cell
- Eopening of transient Ca2+ channels
- Fclosing of transient Ca2+ channels
- Gopening of Na+ channels
- Hclosing of Na+ channels
14MYOCARDIAL INFARCTION:
cells become oxygen starved and produce lactic acid. As there is no ATP to pump [blank_start]Ca2+ out[blank_end] of the cytoplasm it results in the closure of [blank_start]gap junctions[blank_end] and electrical isolation- ACa2+ out
- BCa2+ in
- CNa+ out
- DNa+ in
- EK+ out
- FK+ in
- Ggap junctions
- Htight junctions
- Idesmosomes
15complete the diagram and label which cells action potential it is
- Aphase 4
- Bphase 0
- Cphase 1
- Dphase 2
- Ephase 3
- Fmyocyte action potential
- Gpacemaker action potential
16cardiac autorythmic cells have a resting potential
- AVerdadeiro
- BFalso
17which of the following characteristics are true for pacemaker cells
- Abig cells with contractile elements
- Bdo not have a resting potential
- Crespond to sympathetic stimulation but not parasympathetic
- Dresting potential is -55mV
- Esmall cells with contractile elements
18what ion is responsible for the depolarisation of pacemaker cells from -40mV
- ACa2+
- BCl-
- CNa+
- DK+
- EMg2+
19what ion is responsible for depolarisation of contractile myocytes
- ACa2+
- BNa+
- CMg2+
- DK+
- ECl-
20what happens in the plateau phase of cardiac action potential
- Aactivation of voltage gated K+ channels and an efflux of K+
- Bfast influx of Na+
- Copening funny current channels
- Dopening of L-type Ca2+ channels and decreased permeability to K+
- Eopening of transient channels for Ca2+
21a 66 year old man developed hyperkalaemia secondary to his metabolic acidosis. his serum potassium level is 6.7 mmol/L. How does cardiac action change in hyperkalemia
- Acells are hyperpolarised and therefore it is more difficult for them to trigger an action potential
- Bcardiac resting potential is less negative, initially cells fire easier, but later they are not fully able to repolarise fully
- Ccells fire more easily and therefore heart rate increases
- Dresting potential is more negative and some channels do not open
- Eresting potential is unchanged, but refractory periods are shortened
22what happens to the heart rate with the sympathetic stimulation of the pacemaker cells
- Adecrease
- Bdecreases at first then increases
- Cincreases at first then decreases
- Dincrease
- Eno change
Informações
- Descrição
- Adult 1 Quiz sobre HEART CONTRACTION , criado por David alibhai em 12-05-2019.
- Autor
- David alibhai
- Idioma
- English
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