The skin is the largest organ in the human body, covering the entire surface and acting as the first line of defense against environmental factors. It also helps regulate body temperature and prevents water loss.
The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart. This is an exception to the usual rule that veins carry deoxygenated blood.
A normal resting heart rate for adults ranges from 60 to 100 beats per minute. Rates above or below this range may indicate a medical condition that requires attention.
The autonomic nervous system controls involuntary actions like heart rate, blood pressure, digestion, and breathing. It has two main divisions: the sympathetic and parasympathetic systems.
The systolic pressure is the top number in a blood pressure reading and represents the pressure in the arteries when the heart contracts and pumps blood. It is typically higher than the diastolic pressure.
