Chapter 28-29- The Heart and Blood Vessels

Atrioventricular node

A group of specialised muscle cells that’s reached by the pacemaker’s impulses and causes the ventricles to contract, pushing blood out of the heart (ventricular systole).

Located at the bottom of the right atrium near the septum.

Long muscle fibres that run from the A.V node down either side of the septum and spread out across the ventricle walls.

Causes the ventricles to contract, pushing blood out of the heart (ventricular systole).

The rhythmic expansion and contraction of the walls of the arteries as blood is forced through them.

A pulse can be easily detected ever an artery is close to the surface of the skin or passing over a bone (eg. wrist, temple, neck).

The force the blood exerts against the wall of a blood vessel.

Measured by a sphygmomanometer.

Blood pressure is highest in the arteries (causing them to expand -pulse).

Blood pressure is lowest in the veins.

Where blood is forced into the aorta by the contraction of the left ventricle (systolic pressure).

Where blood is forced into the aorta by the contraction of the left ventricle.

When the ventricles relax - diastolic pressure.

Low pressure when the ventricles relax.

120/80 mm of mercury

Someone suffering from high blood pressure.