Electrical activity of the heart

Question 1

What forms the physical connection between 2 cells?

Answer 1

desmosomes

Question 2

What forms the electrical connection between 2 cells?

Answer 2

Gap junction

Question 3

What name is given to the repeating alternate pattern of desmosomes and gap junctions in cardiac cells?

Answer 3

intercalated discs

Question 4

What ion is responsible for the contraction of muscle?

Answer 4

Calcium

Question 5

Does skeletal muscle or cardiac muscle demonstrate tetanus?

Answer 5

Skeletal muscle

Question 6

What is meant by the functional syncytium in cardiac muscle?

Answer 6

It acts as a syncytium would ie one massive cell but really all the cells still have their own nucleus and are just helped to contract as one

Question 7

Does cardiac muscle have a long or short action potential in comparison to skeletal muscle?

Answer 7

Long

Question 8

Why can cardiac muscle not exhibit tetanic contraction?

Answer 8

Long refractory period

Question 9

What can calcium entry regulate about the contraction?

Answer 9

strength

Question 10

What do cells with unstable resting membrane potential act as?

Answer 10

Pacemakers

Question 11

What is the initial depolarisation in non pacemaker cells due to?

Answer 11

Initial depolarisation due to sodium

Question 12

What is the plateu in non pacemaker cells due to?

Answer 12

Increase in calcium through voltage gated channels and also a decrease in the leaky potassium channels

Question 13

What is the repolarisation in non pacemaker cells due to?

Answer 13

Reversing the plateu eg reinstating the permeability of leaky potassium channels and a decrease in the permeability to calcium

Question 14

What is the action potential in packemaker cells due to?

Answer 14

Increase in permeability to calcium

Question 15

What is the pacemaker pre potential due to?

Answer 15

Not a simple story, basically anything that makes the cell more positive

Question 16

For every degree Celsius change in body temperature how much does the heart rate increase by?

Answer 16

10 beats per minute

Question 17

What drugs decrease the force of contraction?

Answer 17

calcium channel blockers

Question 18

What drugs increase the force of contraction?

Answer 18

cardiac glycosides

Question 19

How are hypo and hyper kalemia anomalous?

Answer 19

They both cause fibrillation and heart attack and are not opposites

Question 20

What is the sino atrial node also known as?

Answer 20

The pacemaker

Question 21

What is the main thing of importance about the annulus fibrosus?

Answer 21

It is non conducting

Question 22

Why is the AV node also known as the delay box?

Answer 22

As the annulus fibrosus is not conducting all blood travels through via this and so slows down emptying of the atria before the ventricles contract

Question 23

What is the function of the bundle of his and purkinje fibres?

Answer 23

Rapid conducting system and ensures the ventricles contract in unison

Question 24

What does ECG stand for?

Answer 24

electrocardiogram

Question 25

What does the p wave correspond to?

Answer 25

atrial depolarisation

Question 26

What does the QRS complex correspond to?

Answer 26

ventricular depolarisation

Question 27

What does the T wave correspond to?

Answer 27

ventricular repolarisation