•

Updated May 8, 2026

•

1 page

Step-by-Step Blood Flow Through the Heart | Heart Diagram and Pacemaker Info

Leah Strawbridge

@leahstrawbridge_kjnx

The heart is a vital organ responsible for pumping blood... Show more

# The Heart

The heart is the organ that pumps blood around your
body. It is made from cardiac muscle tissue, which
is supplied with oxygen

The Heart: Structure and Function

The heart is a crucial organ in the human body, responsible for pumping blood throughout the circulatory system. It is composed of specialized cardiac muscle tissue, which receives its oxygen supply from the coronary artery. The heart's structure and function are intricately designed to ensure efficient blood flow through the heart | step by step.

Vocabulary: Cardiac muscle tissue - A type of involuntary striated muscle found in the walls and histological foundation of the heart.

The heart consists of four main chambers that work together to circulate blood. The right atrium and right ventricle handle deoxygenated blood, while the left atrium and left ventricle manage oxygenated blood. These chambers are connected to major blood vessels that play specific roles in the circulatory process.

Definition: The pumping of heart is called the cardiac cycle, which involves the contraction (systole) and relaxation (diastole) of the heart muscles.

The 12 steps of blood flow through the heart involve a complex sequence of events:

Deoxygenated blood enters the right atrium through the vena cava.
The right atrium contracts, pushing blood into the right ventricle.
The right ventricle pumps blood to the lungs via the pulmonary artery.
Blood becomes oxygenated in the lungs.
Oxygenated blood returns to the heart through the pulmonary vein.
The left atrium receives the oxygenated blood.
The left atrium contracts, pushing blood into the left ventricle.
The left ventricle contracts forcefully.
Oxygenated blood is pumped into the aorta.
The aorta distributes blood to the body's tissues.
Blood becomes deoxygenated as it supplies oxygen to tissues.
Deoxygenated blood returns to the right atrium, completing the cycle.

Highlight: The left ventricle is the part of the heart that pumps blood to the body, making it the most muscular chamber of the heart.

The heart's rhythm is controlled by a group of specialized cells located in the right atrium, known as the sinoatrial (SA) node. This natural pacemaker generates electrical impulses that regulate the heart rate.

Vocabulary: Sinoatrial (SA) node - The natural pacemaker of the heart is called the SA node, and its location is in the upper wall of the right atrium.

In cases of irregular heartbeats or other cardiac issues, artificial pacemakers can be used to provide electrical stimulation and maintain a proper heart rhythm. These devices are particularly useful for patients with certain heart conditions that require a pacemaker, such as bradycardia or heart block.

Example: Types of pacemaker for heart block include single-chamber, dual-chamber, and biventricular pacemakers, each designed to address specific cardiac conduction abnormalities.

Understanding the heart's structure and function is essential for maintaining cardiovascular health and recognizing potential issues. Regular check-ups and a healthy lifestyle can help ensure that this vital organ continues to perform its crucial role in sustaining life.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.

Where can I download the Knowunity app?

You can download the app from Google Play Store and Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content in Biology

AQA Biology: Key Concepts

Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.

Biology

Cell Biology and Cell structure

cell structures

Biology

A-Level Biology Year 1 Overview

Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.

Biology

Biology paper 1 Summary

Notes for Biology paper 1 contains the full course for AQA higher combined!

Biology

1.cells Gcse biology question cards

combined science higher biology

Biology

The functions of subcellular structures - B1 Biology

Flashcards on the different functions of subcellular structures: cell membrane, nucleus, mitochondria, ribosomes, cytoplasm, permant vacuole, chloroplasts and cell wall.

Biology

Biology Paper 1 quiz

this is a simple quiz on key knowledge needed for paper 1

Biology

Types of cells

biology

Biology

Cells part 1 function of cells.

About cells and function of cells etc.

Biology

Most popular content

Sociology of Education Overview

Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.

Sociology

Sociology of Families: Comprehensive Revision

Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.

Sociology

Criminology: Crime & Punishment Overview

Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.

Criminology

An Inspector Calls: Character Insights

Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.

English Literature

Criminology Theories Overview

Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.

Criminology

Romeo and Juliet: Key themes

Key Romeo and Juliet themes and analysed quotes

English Literature

WJEC Unit 4 Criminology

Criminology unit 4 detailed revision note

Criminology

Macbeth: Guilt and Ambition

Explore the complex themes of guilt and ambition in Shakespeare's 'Macbeth'. This analysis covers key characters, including Macbeth and Lady Macbeth, their moral dilemmas, and the tragic consequences of their ambition. Ideal for students studying character motivations, thematic elements, and the psychological impact of power. Includes insights on the natural order, manipulation, and the descent into madness.

English Literature

AQA Biology: Key Concepts

Biology

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.6/5

App Store

4.7/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

iOS user

Stefan S

iOS user

Samantha Klich

Android user

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Basil

Android user

David K

iOS user

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

Rohan U

Android user

Xander S

iOS user

Elisha

iOS user

Paul T

iOS user

Biology

•

271

•

Updated May 8, 2026

•

1 page

Step-by-Step Blood Flow Through the Heart | Heart Diagram and Pacemaker Info

Leah Strawbridge

@leahstrawbridge_kjnx

The heart is a vital organ responsible for pumping blood throughout the body. It consists of four chambers and various blood vessels that work together to circulate oxygenated and deoxygenated blood. The heart's natural pacemaker controls its rhythm, while artificial... Show more

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

The Heart: Structure and Function

Vocabulary: Cardiac muscle tissue - A type of involuntary striated muscle found in the walls and histological foundation of the heart.

Definition: The pumping of heart is called the cardiac cycle, which involves the contraction (systole) and relaxation (diastole) of the heart muscles.

The 12 steps of blood flow through the heart involve a complex sequence of events:

Deoxygenated blood enters the right atrium through the vena cava.
The right atrium contracts, pushing blood into the right ventricle.
The right ventricle pumps blood to the lungs via the pulmonary artery.
Blood becomes oxygenated in the lungs.
Oxygenated blood returns to the heart through the pulmonary vein.
The left atrium receives the oxygenated blood.
The left atrium contracts, pushing blood into the left ventricle.
The left ventricle contracts forcefully.
Oxygenated blood is pumped into the aorta.
The aorta distributes blood to the body's tissues.
Blood becomes deoxygenated as it supplies oxygen to tissues.
Deoxygenated blood returns to the right atrium, completing the cycle.

Highlight: The left ventricle is the part of the heart that pumps blood to the body, making it the most muscular chamber of the heart.

Vocabulary: Sinoatrial (SA) node - The natural pacemaker of the heart is called the SA node, and its location is in the upper wall of the right atrium.

Example: Types of pacemaker for heart block include single-chamber, dual-chamber, and biventricular pacemakers, each designed to address specific cardiac conduction abnormalities.