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Cardiovascular and Circulatory System intro

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Cardiovascular and Circulatory System part 2

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Cardiovascular and Circulatory System pt 3

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British Heart Foundation - How does a healthy heart work?

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Blood Pressure Animation | Heart disease risk factors

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BBC Bitesize - GCSE Biology (Single Science) - Blood - Revision 1

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Learn about blood, a complex liquid tissue, and how it transports oxygen, dissolved substances and heat around the body.

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How does our circulatory system keeps us alive? | BBC Teach

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The capillaries connect the two types of blood vessel and molecules are exchanged between the blood and the cells across their walls.

Carry oxygenated blood, except for the pulmonary artery

Always carry deoxygenated blood, except for the pulmonary vein

Carry blood under high pressure

Carry blood under low or negative pressure

Have thick muscular and elastic walls to pump and accommodate blood

Have thin walls - have less muscular tissue than arteries

A type of supporting tissue called connective tissue provides strength

Have less connective tissue than arteries

The channel in the blood vessel that carries blood - the - is narrow

Have a wide lumen

Capillaries

Capillaries connect the smallest branches of arteries and veins

The walls of capillaries are just one cell thick. Capillaries therefore allow the exchange of molecules between the blood and the body's cells - molecules can across their walls. This exchange of molecules is not possible across the walls of other types of blood vessel.

Looking at blood cells

You may be given some prepared slides of blood to examine with the microscope.

Many types of blood cell are 10 μm in diameter or less. You will need high magnification to examine them in detail.

The slides will have been stained to show the cells, and cell features. This picture shows many red blood cells and three white blood cells.

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BBC Bitesize - GCSE Combined Science - Cellular respiration and transport - Edexcel - Revision 2

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Revise cellular respiration and transport with BBC Bitesize for GCSE Combined Science, Edexcel.

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Top 10 healthy heart tips
A healthy lifestyle will make your heart healthier. Here are 10 things you can do to look after your heart.

Give up smoking

If you're a smoker, quit. It's the single best thing you can do for your heart health.

Smoking is one of the main causes of coronary heart disease. A year after giving up, your risk of a heart attack falls to about half that of a smoker.

You're more likely to stop smoking for good if you use NHS stop smoking services. Visit the Smokefree website or ask your GP for help with quitting.

Get active

Getting - and staying - active can reduce your risk of developing heart disease. It can also be a great mood booster and stress buster.

Do 150 minutes of moderate-intensity aerobic activity every week. One way to achieve this target is by doing 30 minutes of activity on 5 days a week. Fit it in where you can, such as by cycling to work.

Manage your weight

Being overweight can increase your risk of heart disease. Stick to a healthy, balanced diet low in fat and sugar, with plenty of fruit and vegetables, combined with regular physical activity.

Find out if you're a healthy weight with the BMI calculator. If you're overweight, try our 12-week NHS weight loss plan.

Eat more fibre

Eat plenty of fibre to help lower your risk of heart disease - aim for at least 30g a day.

Eat fibre from a variety of sources, such as wholemeal bread, bran, oats and wholegrain cereals, potatoes with their skins on, and plenty of fruit and veg.

Cut down on saturated fat

Eating too many foods that are high in saturated fat can raise the level of cholesterol in your blood. This increases your risk of heart disease.

Choose leaner cuts of meat and lower fat dairy products like 1% fat milk over full-fat (or whole) milk.

Read the facts about fat.

Get your 5 A Day

Eat at least 5 portions of a variety of fruit and vegetables a day. They're a good source of fibre, vitamins and minerals.

There are lots of tasty ways to get your 5 A Day, like adding chopped fruit to cereal or including vegetables in your pasta sauces and curries.

Get more 5 A Day fruit and veg tips.

Cut down on salt

To maintain healthy blood pressure, avoid using salt at the table and try adding less to your cooking.

Once you get used to the taste of food without added salt, you can cut it out completely.

Watch out for high salt levels in ready-made foods. Most of the salt we eat is already in the foods we buy.

Check the food labels - a food is high in salt if it has more than 1.5g salt (or 0.6g sodium) per 100g.

Adults should eat less than 6g of salt a day in total - that's about 1 teaspoon.

Eat fish

Eat fish at least twice a week, including a portion of oily fish. Fish such as pilchards, sardines and salmon are a source of omega-3 fats, which may help protect against heart disease.

Pregnant or breastfeeding women should not have more than 2 portions of oily fish a week.

Drink less alcohol

Do not forget that alcohol contains calories. Regularly drinking more than the NHS recommends can have a noticeable impact on your waistline.

Try to keep to the recommended daily alcohol limits to reduce the risk of serious problems with your health, including risks to your heart health.

Read the food label

When shopping, it's a good idea to look at the label on food and drink packaging to see how many calories and how much fat, salt and sugar the product contains.

Understanding what's in food and how it fits in with the rest of your diet will help you make healthier choices.

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A healthy lifestyle will make your heart healthier. Here are 10 things you can do to look after your heart. If you're a smoker, quit. It's the single best thing you can do for your heart health. Smoking is one of the main causes of coronary heart disease.

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Overview of the Cardiovascular System

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It's a muscle, about the size of your fist, in the middle of your chest tilted slightly to the left.

What is the function of the human heart?

Each day, your heart beats around 100,000 times. This continuously pumps about five litres (eight pints) of blood around your body through a network of blood vessels called your circulatory system. This blood delivers oxygen and nutrients to all parts of your body to help your organs and muscles work properly. Your blood also carries away unwanted carbon dioxide and waste products.

What is the structure of the human heart?

Your heart has a left side and a right side, they are separated by a thin muscular wall called the Septum. Both sides of your heart have an upper chamber and a lower chamber.

the upper chambers are called the left atrium and the right atrium (or the atria)

the lower chambers are called the left ventricle and the right ventricle.

The right side of your heart receives the de-oxygenated blood that has just travelled round your body. It pumps the blood to your lungs to collect a fresh supply of oxygen. The left side of your heart pumps the re-oxygenated blood round your body again.

Your heart muscle is made up of three layers of tissue:

Pericardium - a thin, outer lining that protects and surrounds your heart.

Myocardium - a thick, muscular middle layer that contracts and relaxes to pump blood around of your heart.

Endocardium - a thin, inner layer that makes up the lining of the four chambers and the valves in your heart.

What does the heart's electrical system do?

Your heart's electrical system tells your heart when to contract and when to relax to keep your blood pumping regularly. The instructions to contract and relax are carried by electrical signals.

The electrical signals are sent from the sinus node which is known as your heart's natural pacemaker. Usually, the sinus node will send the electrical signals at a steady pace, but the pace can change depending on your emotions and if you are active or resting - this is your heart rate.

How does blood flow around the heart and the body?

Your heart is linked to the rest of the circulatory system with blood vessels called arteries and veins.

your arteries deliver oxygen-rich blood from the heart to other areas of your body

your veins return the de-oxygenated blood from your organs back to your heart

your arteries and veins are connected by even smaller blood vessels called capillaries.

Your blood flows around your heart and the rest of your body in one direction, like a one-way traffic system. Your heart valves control the direction of your blood flow, they act like doors that open and close with every heartbeat. There are four valves in your heart, they are:

the tricuspid valve and the pulmonary valve on the right side of the heart

the mitral valve and the aortic valve on the left side of your heart.

Like the rest of your body, your heart needs to be supplied with oxygen-rich blood to work properly too. The coronary arteries are the arteries responsible for supplying the heart with oxygenated blood. The coronary arteries are spread across the outside of the heart to deliver the blood.

How do your heart and lungs add oxygen to your blood?

Your blood flows through your heart and your lungs to become re-oxygenated before being pumped to the rest of your body. Oxygen is added to your blood in four main steps, they are:

The right atrium receives the low-oxygen blood that has just travelled round the body. The right atrium pumps the blood to the right ventricle.

The right ventricle pumps the low-oxygen blood to the lungs to pick up a fresh supply of oxygen.

The left atrium receives to high-oxygen blood from the lungs and pumps it to the left ventricle.

The left ventricle pumps the high-oxygen blood to the rest of the body.

What are heart and circulatory diseases?

Sometimes the heart and circulatory system don't work like they should, this can cause heart and circulatory diseases (also called cardiovascular diseases). We fund research into these conditions and their risk factors, including:

What causes your heart and circulatory system to go wrong?

Problems with your heart and circulatory system, including heart attack or a stroke, are usually caused by a gradual build-up of fatty material (called atheroma) in the arteries around the heart and in the arteries that supply blood to your brain.

The fatty material lines the walls of heart's coronary arteries making the space for blood to flow narrower. When the arteries become narrowed and the blood flow is restricted, the arteries can't deliver enough blood to the heart and the brain, which can cause heart and circulatory diseases.

What puts me at risk of heart and circulatory disease?

Many heart and circulatory diseases share the same risk factors including:

Heart and circulatory diseases can be worrying but the good news is that there are lots of things you can do to reduce your risk of developing heart and circulatory diseases now.

Check your heart age

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We've followed an eight-step process to make sure this content is reliable, accurate and trustworthy. Learn how we make our health information reliable and easy to understand.
Page last reviewed: August 2021
Next review due: August 2024
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Find out how a healthy heart works and its role pumping blood around your body. Watch our short animated guide to your heart.