31. The mammalian heart is myogenic and it is regulated by nerves. The hea

The mammalian heart is myogenic and it is regulated by nerves. The heartbeat originates from

sinoatrial node
QRS wave
T wave
hepatic portal system
This question was previously asked in
UPSC CDS-1 – 2017
The heartbeat originates from the sinoatrial node.
The sinoatrial (SA) node is a specialized group of cells located in the wall of the right atrium of the heart. It is the natural pacemaker of the heart, generating electrical impulses that initiate each heartbeat. The mammalian heart’s ability to generate its own impulse is referred to as its myogenic nature.
The SA node impulse spreads through the atria, causing them to contract, and then reaches the atrioventricular (AV) node, which conducts the impulse to the ventricles. The QRS wave and T wave are graphical representations of electrical activity in the ventricles during an electrocardiogram (ECG). The hepatic portal system is part of the circulatory system involved in blood transport from the digestive organs to the liver.

32. Which one of the following is considered as ‘good cholesterol’ with re

Which one of the following is considered as ‘good cholesterol’ with reference to individuals facing the risk of cardio-vascular diseases and hypertension ?

High Density Lipoprotein (HDL)
Low Density Lipoprotein (LDL)
Triglyceride
Fatty acids
This question was previously asked in
UPSC CDS-1 – 2016
The correct option is A) High Density Lipoprotein (HDL).
Lipoproteins are particles that transport cholesterol and other fats in the blood. HDL (High Density Lipoprotein) is often referred to as ‘good cholesterol’ because it helps remove excess cholesterol from arteries and transport it back to the liver, where it can be processed and removed from the body. This action helps prevent the buildup of plaque in arteries, reducing the risk of cardiovascular diseases.
LDL (Low Density Lipoprotein) is considered ‘bad cholesterol’ because it contributes to the buildup of plaque in the arteries. High levels of LDL increase the risk of heart disease and stroke. Triglycerides are another type of fat in the blood; high levels are also linked to increased risk of heart disease. Maintaining a healthy balance between HDL and LDL is important for cardiovascular health.