Circulatory system - Function, Definition - Human Anatomy | Kenhub

Summary

Matt from Kenhub presents an engaging tutorial on the circulatory system, highlighting its function, definition, and anatomy. The system, composed of the heart, blood vessels, and blood, operates through two circuits: the pulmonary and systemic. It delivers oxygen and nutrients to body tissues and facilitates waste removal. The heart, acting as a muscular pump, is detailed with its four chambers and valves, emphasizing the importance of cardiac output. Blood vessels—arteries, veins, and capillaries—are categorized by their structure and function. The video concludes with an invitation to explore more anatomy resources on Kenhub.

Takeaways

• 💓 The circulatory system, also known as the cardiovascular system, is composed of the heart, blood vessels, and blood.
• 🔄 It operates through two main circuits: the pulmonary circuit (heart to lungs) and the systemic circuit (heart to body tissues).
• 🌀 The system's primary function is to supply oxygen and nutrients to the body's tissues and remove waste products.
• 🏠 The pulmonary circuit facilitates the exchange of oxygen and carbon dioxide in the lungs.
• 🚀 The heart acts as the pump, driving blood circulation through electrostimulation and its muscular structure.
• 🏋️‍♂️ The heart has four chambers: two atria that collect blood and two ventricles that pump it out.
• 🚫 Heart valves prevent the backflow of blood, ensuring one-way flow through the heart.
• 🔄 The right side of the heart handles deoxygenated blood, while the left side manages oxygenated blood.
• 🏃‍♂️ Cardiac output, measured in liters per minute, varies with activity levels and is higher in males than in females.
• 🌐 Blood vessels are categorized into arteries, veins, and capillaries, each with distinct structures and functions.
• 🩸 Blood consists of plasma, red blood cells, white blood cells, and platelets, each playing a critical role in the body's functions.

Q & A

What are the main components of the circulatory system?

The main components of the circulatory system are the heart, blood vessels, and blood.

How many circuits does the circulatory system have and what are they?

The circulatory system has two circuits: the pulmonary circuit, which runs between the heart and lungs, and the systemic circuit, which runs between the heart and peripheral tissues.

What is the primary function of the pulmonary circuit?

The primary function of the pulmonary circuit is to carry deoxygenated blood to the lungs for the exchange of oxygen and carbon dioxide.

What does the systemic circuit deliver to the body's tissues?

The systemic circuit delivers oxygenated blood, along with nutrients, to the body's tissues.

How does the heart function as a pump in the circulatory system?

The heart functions as a pump by beating and pushing blood through the circulatory system via electrostimulation.

What are the four chambers of the heart and their functions?

The heart has four chambers: the left atrium, left ventricle, right atrium, and right ventricle. The atria collect blood returning to the heart, while the ventricles pump blood out.

What is the purpose of the valves in the heart?

The valves in the heart prevent the backflow of blood into the chambers, ensuring that blood flows in one direction.

What is the cardiac output and how is it calculated?

Cardiac output is the amount of blood, in liters, pumped out of the heart per minute. It is calculated by multiplying the heart rate by the stroke volume.

What are the three major classes of blood vessels and their functions?

The three major classes of blood vessels are arteries, veins, and capillaries. Arteries transport blood away from the heart, veins carry blood towards the heart, and capillaries facilitate the exchange of gases, nutrients, and waste products.

How do the walls of capillaries differ from those of arteries and veins?

Capillary walls are microscopic and have a one-cell layer thick endothelial lining, allowing for the exchange of gases, water, nutrients, and waste products. They can only tolerate very low blood pressure.

What are the four major components of blood and their roles?

The four major components of blood are plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Plasma carries carbon dioxide, hormones, and metabolic waste products; red blood cells transport oxygen; white blood cells are part of the immune system; and platelets help form blood clots to prevent bleeding.

Outlines

00:00

💓 Overview of the Cardiovascular System

Matt from Kenhub introduces the circulatory system, highlighting its components: the heart, blood vessels, and blood. The system comprises two circuits, the pulmonary and systemic, with the former facilitating gas exchange between the heart and lungs, and the latter distributing oxygenated blood to the body's tissues. The heart, acting as a muscular pump, is divided into four chambers with atria collecting blood and ventricles pumping it out. The cardiac output, which varies with activity, is calculated by multiplying heart rate and stroke volume. The video also discusses the three types of blood vessels: arteries, veins, and capillaries, each with distinct structures and functions. Blood itself consists of plasma, red blood cells, white blood cells, and platelets, each playing a crucial role in the body's functions.

05:02

📚 Interactive Learning with Kenhub

The script transitions to promoting Kenhub as an alternative to traditional textbooks for learning anatomy. It invites viewers to explore more videos, quizzes, articles, and an atlas on human anatomy by clicking the 'Take me to Kenhub' button. The video encourages a shift from old learning methods to a new, interactive approach, positioning Kenhub as a partner in anatomy education.

Keywords

💡Circulatory System

The circulatory system, also known as the cardiovascular system, is a vital biological system in vertebrates. It is responsible for pumping blood throughout the body, delivering oxygen and nutrients to the tissues and organs while removing metabolic waste products. In the video, the circulatory system is described as being composed of the heart, blood vessels, and blood, highlighting its critical role in maintaining life.

💡Pulmonary Circuit

The pulmonary circuit is one of the two circuits of the circulatory system, specifically designed for the exchange of gases. It carries deoxygenated blood from the heart to the lungs, where oxygen is picked up, and carbon dioxide is released. This process is crucial for respiration, as explained in the script where it mentions the pulmonary circuit carrying deoxygenated blood to the lungs for gas exchange.

💡Systemic Circuit

The systemic circuit is the larger of the two circuits in the circulatory system, responsible for distributing oxygenated blood from the heart to the body's tissues and organs. It plays a key role in the delivery of nutrients and the collection of deoxygenated blood, as described in the video script where it details the systemic circuit's function in transporting oxygenated blood to the tissues.

💡Cardiac Output

Cardiac output refers to the volume of blood pumped by the heart per minute, which is a measure of the heart's efficiency in circulating blood. It is calculated by multiplying the heart rate by the stroke volume. The script provides specific values for cardiac output in males and females, emphasizing its importance in understanding the heart's performance.

💡Heart

The heart is a muscular organ that acts as the pump of the circulatory system. It is composed of four chambers: two atria and two ventricles, each with specific functions in blood circulation. The video script explains that the heart's muscular septum divides it into left and right sides, with each side pumping different types of blood.

💡Blood Vessels

Blood vessels are the conduits through which blood travels in the circulatory system. They include arteries, veins, and capillaries, each with distinct structures and functions. The script describes the histological structure of these vessels, detailing how arteries have thick walls to withstand high pressure, while veins have thinner walls and larger lumens to carry blood at lower pressure.

💡Arteries

Arteries are blood vessels that carry oxygen-rich blood away from the heart to the body's tissues. They have thick, muscular walls to handle the high pressure of blood being pumped from the heart. The video script mentions that arteries have small internal lumina, which allows them to withstand the pressure of blood flow.

💡Veins

Veins are blood vessels that return oxygen-poor blood from the body's tissues back to the heart. They have thinner walls compared to arteries and larger internal lumens to accommodate the lower pressure of blood flow. The script explains that veins also have valves to prevent the backflow of blood, ensuring one-way flow towards the heart.

💡Capillaries

Capillaries are the smallest blood vessels in the body, serving as the site of exchange for gases, nutrients, and waste products between the blood and the body's tissues. They are described in the script as having very thin walls, consisting of a single layer of endothelial cells, which facilitates the exchange process due to their permeability.

💡Blood Components

Blood is composed of several components, including plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Each component has a specific function in the body, such as oxygen transport, immune response, and blood clotting. The video script outlines the roles of these components, emphasizing their importance in the overall functioning of the circulatory system.

💡Electrostimulation

Electrostimulation refers to the process by which electrical signals initiate muscle contractions, such as those in the heart. The heart's rhythmic beating is controlled by electrical impulses that coordinate its contractions, as mentioned in the script when discussing how the heart pumps blood throughout the body.

Highlights

The circulatory system is comprised of the heart, blood vessels, and blood.

There are two circuits: the pulmonary circuit and the systemic circuit.

The pulmonary circuit carries deoxygenated blood to the lungs for oxygenation.

The systemic circuit delivers oxygenated blood to the body's tissues.

The heart acts as a pump, distributing blood throughout the body.

The heart has four chambers: two atria and two ventricles.

Valves in the heart prevent backflow of blood.

The right side of the heart pumps deoxygenated blood, while the left pumps oxygenated blood.

Cardiac output is approximately 5.6 liters in males and 4.9 liters in females.

Cardiac output can be calculated by multiplying heart rate by stroke volume.

Arteries have thick walls to withstand high blood pressure.

Veins have thin walls and carry blood under low pressure back to the heart.

Capillaries are the site of gas and nutrient exchange due to their thin walls.

Blood is composed of plasma, red blood cells, white blood cells, and platelets.

Red blood cells, or erythrocytes, are the primary oxygen carriers in the blood.

White blood cells, or leukocytes, are part of the immune system and help fight infections.

Platelets help in blood clotting and prevent bleeding.

Kenhub offers interactive learning tools such as videos, quizzes, and an anatomy atlas.

Transcripts

Hello everyone!

It’s Matt from Kenhub, and this tutorial will provide a general overview of the function,

definition, and anatomy of the circulatory system or the cardiovascular system.

The circulatory system is comprised of the heart, the blood vessels, and the blood.

It consists of 2 circuits that carry blood around.

The smaller being the pulmonary circuit which runs between the heart and the lungs, and

the larger being the systemic circuit which runs between the heart and the peripheral

tissues.

The cardiac circulatory system functions by providing the tissues of the body with oxygen

and nutrients which are transported in the blood.

The pulmonary circuit carries the deoxygenated blood into the lungs where the exchange of

oxygen and carbon dioxide that the body has produced occurs before the blood returns back

to the heart.

The heart then pumps the newly oxygenated blood around the systemic circuit of the body

and delivers the oxygenated blood to the tissues before collecting the deoxygenated blood and

sending it back to the heart with unused nutrients and metabolic waste products.

These extra substances within the blood filter into the liver for processing.

The heart is a muscle that acts as a pump.

Through electrostimulation, it beats and pushes the blood around the entire body through the

circulatory system.

The heart is comprised of 4 chambers that consist of 2 pairs on the left and right sides

of the heart.

The atria collect blood returning to the heart while the ventricles pump blood out of the

heart.

The valves in the heart prevent the backflow of blood into the chambers of the heart.

The muscular septum divides up the 2 sections of the heart creating a left and right side

each containing one atrium and one ventricle.

The right side of the heart pumps deoxygenated blood and the left side pumps oxygenated blood.

The amount of blood in liters that is pumped out of the heart per minute is known as the

cardiac output, which is around 5.6 liters in males and 4.9 liters in females.

It can be calculated by multiplying the heart rate which is the number of beats per minute

by the stroke volume which is the amount of blood that collects in the ventricles when

they are at full capacity and about to contract.

The cardiac output varies depending on whether the person is exercising or resting.

There are 3 major classes of blood vessels namely arteries, veins, and capillaries and

they are categorized according to their histological structure.

Arteries transport blood between the tissues and away from the heart and have thick muscular

walls with small internal lumina or passageways that can withstand blood under high pressure.

Veins carry blood away from the tissues and towards the heart and have thin walls.

Their internal lumen is larger than that of the arteries due to the fact that they contain

blood under low pressure.

They also have valves that prevent the blood from flowing backwards.

Lastly, the capillaries, which are found in the muscles and the lungs, are microscopic

and have a one-cell layer thick endothelial lining.

In other words, the walls of the capillaries have the width of one single epithelial cell.

They can only tolerate blood under very low pressure due to the fact that it will move

slower and gas exchange has a chance to take place.

This is also where the exchange of gases, water, nutrients, and waste products takes

place because the capillary walls are thin and fenestrated.

After this, the capillaries collect into venules which are the equivalent to arterioles and

fenestrated.

Capillaries connect arterioles and venules.

The blood is made up of 4 major components.

The plasma is the fluid that surrounds the blood cells and helps transport carbon dioxide,

hormones, and the metabolic waste products.

Red blood cells which are also known as erythrocytes are formed in the bone marrow and function

mainly as oxygen carriers.

White blood cells or leukocytes make up the body’s immune system by producing antibodies

and helping destroy harmful microorganisms.

These cells are also created in the bone marrow.

Lastly, platelets are cells that clump together to form blood clots and help protect the body

by preventing bleeding.

This video is more fun than reading a textbook, right?

If you want more videos, interactive quizzes, articles, and an atlas of human anatomy, click

on the “Take me to Kenhub” button.

It is time to say goodbye to your old textbooks and say hello to your new anatomy learning

partner, Kenhub!

See you there!

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