Cardio-Vascular System — the first-year Physiology chapter on the heart and the blood’s journey

Put two fingers on the inside of your wrist, below the thumb. You can feel a beat. That beat is where this chapter ends up, on its tenth topic. Before it gets there, it asks how the heart makes that beat, and how the blood travels around the body.

The NCH syllabus gives “Cardio-Vascular System” chapter six of Physiology and Biochemistry (HomUG-PB). “Cardio” means heart. “Vascular” means the blood vessels. So the chapter is about the heart and the vessels working together.

The sheet lists thirteen topics. That is a lot to hold. This piece sorts them into four groups, so you can see the shape of the chapter.

Group one: the heart as a pump

• Introduction to cardiovascular system
• Properties of cardiac muscle
• Cardiac cycle
• Heart sounds

Cardiac muscle is the muscle of the heart. You met it in chapter five, Nerve Muscle Physiology, as “Physiology of Cardiac muscle”. Here the sheet asks for its “properties”: the special things it can do that let the heart beat on its own, again and again.

The cardiac cycle is one full heartbeat, from start to finish. The heart fills, then squeezes, then relaxes to fill again. Your textbook breaks the cycle into phases. Learn them in order. A timeline drawing helps.

Heart sounds are the sounds a doctor hears through a stethoscope. Each one is linked to a moment in the cardiac cycle. So learn the cycle first, and the sounds will make sense.

Group two: the blood’s journey

• General principles of circulation
• Regional circulation – Cerebral, Splanchnic, Capillary, Cutaneous & skeletal muscle circulation

“Circulation” means the blood’s movement around the body. The general principles are the rules that apply everywhere: what makes blood flow, and what slows it.

“Regional” means one part of the body at a time. The sheet names five. Some of the words need a gloss. Cerebral means the brain. Splanchnic means the organs of the abdomen, such as the gut. Capillary means the tiniest blood vessels. Cutaneous means the skin. Skeletal muscle circulation is the blood supply of the muscles you move. Each region has its own needs, and its blood flow is handled a little differently. A five-row table keeps this tidy.

Group three: measuring the heart

• Normal and abnormal Electrocardiogram (ECG)
• Cardiac output
• Heart rate
• Arterial blood pressure
• Radial Pulse

These are the ways the heart’s work is measured and recorded.

An electrocardiogram, or ECG, records the heart’s electrical activity as a wave on paper. The sheet says “normal and abnormal”, so you need to know what a normal tracing looks like and what changes can appear.

Cardiac output is how much blood the heart pumps out in a given time. Heart rate is how many times it beats in a minute. Arterial blood pressure is the pressure of blood inside the arteries, the vessels that carry blood away from the heart. The radial pulse is the beat you felt at your wrist. It is named after the radial artery there.

Your textbook will give the normal values and the formulas. This piece does not, because the sheet does not. Learn them from your book, exactly.

Group four: control and change

• Regulation of cardiovascular system
• Cardiovascular adjustments during exercise

“Regulation” means control. The heart and vessels do not work at one fixed speed. The body adjusts them to meet its needs. Exercise is the example the sheet chooses. When you run, what changes in your heart and vessels, and why? That question pulls the whole chapter together.

How the chapter sits in the year

This is chapter six. It follows Nerve Muscle Physiology, which gave you cardiac muscle. It comes just before the Respiratory System, and the two chapters work as a pair. The heart moves the blood. The lungs load it with oxygen. Both chapters end with exercise, which is a good sign that they are meant to be read together.

The Anatomy side matters too. The Thorax chapter of Anatomy shows where the heart sits and how it is built. Here you learn how it works.

What to take from it

1. Explain the properties of cardiac muscle.
2. Draw the cardiac cycle as a timeline, with the heart sounds marked on it.
3. Know the five regional circulations and what each word means.
4. Know what ECG, cardiac output, heart rate, blood pressure and the radial pulse each measure.
5. Explain what the body adjusts during exercise.

The sheet gives thirteen names and no numbers. Every value you will be asked to learn comes from your textbook and your teachers.

Where to go next on the platform

This piece sits in the first-year Physiology and Biochemistry room. “Nerve Muscle Physiology — the first-year Physiology chapter on signals and movement” comes just before it. “Thorax — the first-year Anatomy chapter on the chest, the heart and the lungs” gives the structure behind this chapter.