Question

Human heart is myogenic and it is supplied with sympathetic and vagus nerve branches that are acceleratory and inhibitory in nature respectively.Which one of the following statement is incorrect w.r.t the heart beat?

• A. In foetal heart the heart rate is $140-130$ beats per minutes
• B. Mental status such as depression and grief decrease heart rate
• C. An excess of $C{a}^{++}$ ion decreases heart beat rate
• D. High levels of $N{a}^{+}$ and $K^{+}$ decreases the strength of contraction

Answer 1

The correct option is B Mental status such as depression and grief decrease heart rate

Heartbeat rate is the number of the beating of the heart per minute.

• It is found that in normal humans, the rate of heartbeat is about 70 - 72 times per minute but in feotus or babies it is found much higher about 140 - 130 times per minute or may even up to 160 per minute.
  
• At the time of mental disorders like depression, grief or sadness body releases stress hormone, these stress hormone tightens the blood vessels, thus increases the heart rate.
• Calcium ions play a major role in cardiac activity as well in muscle contraction when they are present in high amount then causes a lower heartbeat.
• Sodium-potassium pumps are the ion channels or proton pumps that regulate the activity of contraction in the heart muscles. Excess of these ions dilates the blood vessels, thus lowers the heart rate and strength of the contraction of the heart muscles.

So, the correct option is 'Mental status such as depression and grief decrease heart rate'.