The sympathetic nerve increases the heart rate and the parasympathetic nerve decreases the heart rate.

The parasympathetic nerve increases the heart rate and the sympathetic nerve decreases the heart rate.

Adrenalin and the sympathetic nerve work together to decrease your heart rate in an emergency situation.

Adrenalin and the parasympathetic nerve work together to increase your heart rate in an emergency situation.

tricuspid valve.

semilunar valve.

mitral valve.

septum.

Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body

Right atrium → Left atrium → Right ventricle → Left ventricle → Lungs → Body

Left atrium → Left ventricle → Lungs → Right atrium → Right ventricle → Body

Body → Left atrium → Right atrium → Lungs → Left ventricle → Right ventricle

Arteries have a thick middle layer and veins have a large lumen.

Arteries have a thin middle layer and veins have a large lumen.

Arteries have a thick middle layer and veins have a small lumen.

Arteries have a thin middle layer and veins have a small lumen.

away from the heart.

towards the heart.

around the heart.

through the heart.

Arteries are situated deeper in tissues, whereas veins enable heat loss from the blood to the environment.

Capillaries are situated at tissue level, whereas veins help maintain core body temperature.

Capillaries and veins are located close to the skin surface to enable heat loss from the blood to the environment.

Veins are situated deeper in tissues, whereas arteries help maintain core body temperature.

Oxygenated blood flows from the right ventricle into the pulmonary artery.

Deoxygenated blood flows from the left atrium into the left ventricle.

Oxygenated blood flows from the right atrium into the right ventricle.

Oxygenated blood flows from the left ventricle into the aorta.

away from the heart.

towards the heart.

around the heart.

through the heart.

The SA node is the natural pacemaker of the heart and stimulates cardiac muscle contraction in the septum.

The AV node is the natural pacemaker of the heart and stimulates cardiac muscle contraction in the ventricle.

The SA node is the natural pacemaker of the heart and stimulates cardiac muscle contraction in the atria.

The AV node is the natural pacemaker of the heart and stimulates cardiac muscle contraction in the atria.