The Circulatory Systemof Humans

What is that ‘lub dub, lub, dub’ noise in my

chest?

The noise is the sound of your

heart as it pumps blood.

The heart

• Your heart pumps blood all the time to all parts of your body.

• Your heart is made of heart muscle.

• The heart muscle contracts and relaxes continuously.

• You cannot control your heart muscle.

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The heart

Blood vessels

• Blood vessels are tubes which carry blood to different parts of your body.

• There are 3 types of blood vessels:– artery– vein– capillary

Blood vessels

Artery

Vein

Capillaries

Veins carry blood– rich in carbon

dioxide – back to the heart

Arteries carry blood– rich in oxygen– from your heart to

all parts of your body

Blood vessels Capillaries

– have very thin walls

– allow oxygen, digested food, water, carbon dioxide and waste materials to pass through their walls

Artery

Vein

Capillaries

Circulatory system

• Your heart, blood vessels and blood form the parts of the circulatory system.

• The circulatory system circulates blood from your heart to all parts of your body and back again.

lungs

heart

upper body parts

lower body parts

flow of blood rich in oxygen, digestedfood and water

flow of blood rich in carbon dioxide andwaste materials

Blood circulationBlood circulation

The heart is an organ that is made of a special muscle called the heart muscle.

The heart muscle contracts and relaxes repeatedly without rest!

What is the Heart and what it does

What causes blood flow?

• By contracting, the heart muscle squeezes blood out of the heart into thick-walled blood vessels. This causes blood to flow to all parts of our body.

• By relaxing, heart muscle makes blood flow back into heart from thin-walled blood vessels.

thick-walled blood thick-walled blood vesselsvessels

thin-walled blood thin-walled blood vesselsvessels

Blood Circulation: Step 1

• Your heart pumps oxygen-rich blood to all cells of your body.

• Your body cells use the oxygen, digested food and water from the blood to produce energy.

Blood Circulation: Step 1from lungs

Your heart pumps oxygen-rich blood to all cells of your body.

Your body cells use the oxygen, digested food and water from the blood to produce energy.

Blood Circulation: Step 1

Your heart pumps oxygen-rich blood to all cells of your body.

Your body cells use the oxygen, digested food and water from the blood to produce energy.

Blood Circulation: Step 1 to the body

Your heart pumps oxygen-rich blood to all cells of your body.

Your body cells use the oxygen, digested food and water from the blood to produce energy.

Blood Circulation: Step 2

As blood goes around your body, it picks up carbon dioxide and waste materials.

I’ve passed the waste to the kidneys and

liver.

On its way back to your heart, blood passes the waste materials to the excretory organs like your kidneys and liver.

Blood Circulation: Step 2

As blood goes around your body, it picks up carbon dioxide and waste materials.

On its way back to your heart, blood passes the waste materials to the excretory organs like your kidneys and liver.

When blood reaches your heart again, it is sent to the lungs where carbon dioxide is removed.

Next, to remove the carbon

dioxide.

Blood Circulation: Step 2

As blood goes around your body, it picks up carbon dioxide and waste materials.

On its way back to your heart, blood passes the waste materials to the excretory organs like your kidneys and liver.

When blood reaches your heart again, it is sent to the lungs where carbon dioxide is removed.

Blood Circulation: Step 2

As blood goes around your body, it picks up carbon dioxide and waste materials.

On its way back to your heart, blood passes the waste materials to the excretory organs like your kidneys and liver.

When blood reaches your heart again, it is sent to the lungs where carbon dioxide is removed.

Blood Circulation: Step 2

As blood goes around your body, it picks up carbon dioxide and waste materials.

On its way back to your heart, blood passes the waste materials to the excretory organs like your kidneys and liver.

When blood reaches your heart again, it is sent to the lungs where carbon dioxide is removed.

Blood Circulation: Step 2

As blood goes around your body, it picks up carbon dioxide and waste materials.

On its way back to your heart, blood passes the waste materials to the excretory organs like your kidneys and liver.

When blood reaches your heart again, it is sent to the lungs where carbon dioxide is removed.

To the lungs

Heartbeat

• Each heartbeat is a cycle of Each heartbeat is a cycle of contractioncontraction and and relaxationrelaxation of our of our heart muscle.heart muscle.

• As heart muscle As heart muscle contractscontracts and and relaxesrelaxes, it produces repeated , it produces repeated sounds - "lub dub", "lub dub", sounds - "lub dub", "lub dub", "lub dub" ..."lub dub" ...

Blood is squeezed out Blood is squeezed out of the ventricles (that of the ventricles (that is, the lower chambers is, the lower chambers of the heart)of the heart)

““Lub” soundLub” sound

Blood flows into Blood flows into the ventricles the ventricles

““dub” sounddub” sound

• ContractionContraction and and relaxationrelaxation of heart of heart muscle causes pressure along our muscle causes pressure along our blood vessels to rise and fall - this is blood vessels to rise and fall - this is known as known as PulsePulse..

• After every heartbeat, a pressure wave After every heartbeat, a pressure wave passes along your blood vessels.passes along your blood vessels.

• By pressing your fingers against your By pressing your fingers against your wrist, you can feel your pulse.wrist, you can feel your pulse.

Press your fingers gently against your wrist.

Pulse, Pulse rate and how to measure it

• The The number of times pulse occurs number of times pulse occurs in one minutein one minute is known as is known as Pulse Pulse RateRate..

• You can obtain pulse rate by You can obtain pulse rate by counting the number of times counting the number of times pulse occurs in one minute.pulse occurs in one minute.

The rate of your heartbeat changes with:

BABYAbout 120 times

per minute

ADULTAbout 70 - 90 times

per minute

age health

SlowFast

The rate of your heartbeat changes with the type of activity you are doing

When you exercise, your heart rate increases.

The heart needs to supply more food and oxygen to various parts of the body to produce more energy.