The Circulatory The Circulatory System.System.

The Circulatory SystemThe Circulatory System

The circulatory system is made of:The circulatory system is made of: The HeartThe Heart Arteries and ArteriolesArteries and Arterioles Veins and VenulesVeins and Venules CapillariesCapillaries BloodBlood

Functions Functions Circulate blood to all Circulate blood to all

parts of the bodyparts of the body Transport water, Transport water,

oxygen and nutrients oxygen and nutrients to cellsto cells

Remove wastes, Remove wastes, including carbon including carbon dioxide, from cellsdioxide, from cells

Maintain body Maintain body temperaturetemperature

The HeartThe Heart

Composed of Composed of four chambersfour chambers Two AtriaTwo Atria (upper chambers) & (upper chambers) & twotwo

VentriclesVentricles (lower chambers). (lower chambers). The Atria receive blood from the The Atria receive blood from the

body, the ventricles pump blood body, the ventricles pump blood back out into the body.back out into the body.

The HeartThe Heart The The SeptumSeptum divides divides

the the heartheart into into two two pumpspumps..

The The left pumpleft pump is the is the left atriumleft atrium and and left left ventricleventricle – full of – full of oxygen rich bloodoxygen rich blood from the lungs which from the lungs which gets pumped gets pumped around the body.around the body.

The HeartThe Heart The The right pumpright pump is is

the the right atriumright atrium and and right right ventricleventricle – full of – full of de-oxygenated de-oxygenated bloodblood from the from the body, body, gets sent to gets sent to lungslungs to get rid of to get rid of carbon dioxide and carbon dioxide and pick up oxygen.pick up oxygen.

Anatomy of the HeartAnatomy of the Heart

Heart Function Heart Function

The blood from the left pump The blood from the left pump (oxygen rich) does not mix with that (oxygen rich) does not mix with that of the right pump (oxygen poor), the of the right pump (oxygen poor), the septum of the heart keeps them septum of the heart keeps them separate.separate.

For blood to make a complete circuit For blood to make a complete circuit around the body it passes through around the body it passes through the heart two times.the heart two times.

Features of the heartFeatures of the heart Located Located slightly left of the sternumslightly left of the sternum The adult heart is about the The adult heart is about the size of a size of a

large fistlarge fist At rest, the At rest, the average heart-rate is 72 average heart-rate is 72

beats per minutebeats per minute Maximum Heart-rate = 220 – ageMaximum Heart-rate = 220 – age At rest the heart pumps 5 litres of blood At rest the heart pumps 5 litres of blood

per minuteper minute During maximum work it can pump over During maximum work it can pump over

30 litres per minute.30 litres per minute.

The Circulatory The Circulatory SystemSystem

PART BPART B

Blood VesselsBlood Vessels Arteries – Arterioles Arteries – Arterioles

– Capillaries – – Capillaries – Venules – Veins.Venules – Veins.

ArteriesArteries The aorta is the The aorta is the

largest artery in the largest artery in the body. The left body. The left ventricle pushes the ventricle pushes the blood into the aorta blood into the aorta and onto the rest of and onto the rest of the body.the body.

ArteriesArteries

The artery walls are The artery walls are elastic so they are elastic so they are able to expand with able to expand with each heartbeat to each heartbeat to accommodate blood.accommodate blood.

When you take your When you take your heart rate, you are heart rate, you are feeling the pressure feeling the pressure of the blood being of the blood being pushed into the pushed into the arterial system.arterial system.

ArteriesArteries

Arteries further reduce in size to Arteries further reduce in size to become arterioles as the network of become arterioles as the network of blood vessels work their way into the blood vessels work their way into the depths of the body.depths of the body.

Bleeding from an artery can be Bleeding from an artery can be recognised by the blood spurting out recognised by the blood spurting out with each heart beat and by its with each heart beat and by its bright red (oxygen rich) colour. bright red (oxygen rich) colour.

ArteriesArteries

Coronary Artery – supplies the Coronary Artery – supplies the hearts chambers with oxygen and hearts chambers with oxygen and nutrients.nutrients.

Heart attacks are often caused by a Heart attacks are often caused by a blockage of the coronary artery.blockage of the coronary artery.

Smoking, drinking, eating fatty foods Smoking, drinking, eating fatty foods and lack of exercise contribute to and lack of exercise contribute to coronary artery blockages.coronary artery blockages.

CapillariesCapillaries The exchange of The exchange of

nutrients and nutrients and waste between the waste between the body and blood body and blood cells occurs in the cells occurs in the capillaries.capillaries.

Heat from cells is Heat from cells is also absorbed into also absorbed into blood through the blood through the capillariescapillaries

Exchange of materials Exchange of materials is easy as capillaries is easy as capillaries are only one cell are only one cell thick.thick.

When you begin to When you begin to exercise capillaries exercise capillaries dilate to allow dilate to allow increased blood flow.increased blood flow.

Other capillaries Other capillaries come into use through come into use through the opening of pre-the opening of pre-capillary sphincters.capillary sphincters.

CapillariesCapillaries

A long term exercise program may A long term exercise program may increase the number of capillaries increase the number of capillaries supplying blood to muscles, allowing supplying blood to muscles, allowing an increased oxygen supply to an increased oxygen supply to muscle and removal of wastes.muscle and removal of wastes.

VeinsVeins

Veins carry blood back to the heart.Veins carry blood back to the heart. Veins have no pulse, blood flow is Veins have no pulse, blood flow is

steady and constant.steady and constant. The walls of veins are thin and not The walls of veins are thin and not

as elastic as artery walls.as elastic as artery walls.

Veins.Veins. The return of blood The return of blood

to the heart depends to the heart depends on contraction of on contraction of skeletal muscle.skeletal muscle.

Veins are squeezed Veins are squeezed by muscle as they by muscle as they contract.contract.

One way valves One way valves working against working against gravity and prevent gravity and prevent backflow of blood to backflow of blood to organs and muscles.organs and muscles.

Veins.Veins.

BloodBlood PoolingPooling after exercise is a after exercise is a problem if you don’t cool down.problem if you don’t cool down.

During a warm down, the muscle During a warm down, the muscle pump system continues to move the pump system continues to move the gradually diminishing excess blood gradually diminishing excess blood flow around the body until it has flow around the body until it has reached a resting level.reached a resting level.

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Complete “Circulatory System Complete “Circulatory System Homework Sheet 2”Homework Sheet 2”

The Circulatory The Circulatory SystemSystem

PART CPART C

BloodBlood Red Blood cells:Red Blood cells: Make up 99% of all Make up 99% of all

blood cellsblood cells Carry oxygen to, Carry oxygen to,

and carbon dioxide and carbon dioxide from, the cells and from, the cells and muscles.muscles.

Have a life span of Have a life span of four monthsfour months

BloodBlood White Blood Cells:White Blood Cells: Exist in the body in a Exist in the body in a

ratio of 1:700 red ratio of 1:700 red blood cells.blood cells.

Have a role in Have a role in immune functionimmune function

Have a life span of a Have a life span of a few days.few days.

Platelets:Platelets: Cause blood to clot Cause blood to clot

when blood vessels when blood vessels are damaged.are damaged.

Path of Blood Around the Path of Blood Around the BodyBody

Oxygenated blood travels from the lungs Oxygenated blood travels from the lungs to the left atria..to the left atria..

It goes down into the left ventricle which It goes down into the left ventricle which then squeezes it out the then squeezes it out the Aorta Aorta intointo arteries arteries andand to the muscles, organs, to the muscles, organs, brain etc..brain etc..

Oxygen,water and nutrients are dropped Oxygen,water and nutrients are dropped off, Carbon dioxide and wastes are picked off, Carbon dioxide and wastes are picked up at the up at the capillariescapillaries….….

Path of Blood Around the Path of Blood Around the BodyBody

De – oxygenated blood travels back to the De – oxygenated blood travels back to the right atriaright atria via the veins.. via the veins..

Deoxygenated blood moves from the atria Deoxygenated blood moves from the atria into the into the right ventricleright ventricle....

Deoxygenated blood is pumped from the Deoxygenated blood is pumped from the right ventricle to the right ventricle to the lungs, lungs, where it where it drops off carbon dioxidedrops off carbon dioxide (plus water (plus water plus heat) and plus heat) and picks up oxygenpicks up oxygen....

The cycle then continues..The cycle then continues..

In short…In short…

Oxygenated bloodOxygenated blood lungs lungs left left atria atria left ventricle left ventricle arteries arteries arterioles arterioles capillaries (drop off O capillaries (drop off O22, , pick up COpick up CO22)… )…

Deoxygenated bloodDeoxygenated blood capillaries capillaries venules venules veins veins right atria right atria right ventricle right ventricle lungs(drop off CO lungs(drop off CO22, , pick up Opick up O2)2).. ..

Blood pressureBlood pressure Blood pressure is caused Blood pressure is caused

by the ventricles by the ventricles contracting.contracting.

In arteries it fluctuates In arteries it fluctuates with each heart beat.with each heart beat.

The higher pressure The higher pressure (systolic) occurs when the (systolic) occurs when the ventricles contract.ventricles contract.

The lower pressure The lower pressure (diastolic) occurs when the (diastolic) occurs when the ventricles relax.ventricles relax.

Blood pressure is usually Blood pressure is usually described by these two described by these two limitslimits

Average blood pressure is Average blood pressure is 120/80mmHg 120/80mmHg

Blood pressureBlood pressure

In mammals, the chambers of the In mammals, the chambers of the heart contract rhythmically and heart contract rhythmically and spontaneously under the control of spontaneously under the control of certain group of heart muscle cells certain group of heart muscle cells called nodes.called nodes.

Sinoatrial and Atrioventricular.Sinoatrial and Atrioventricular.

Exercise & the Exercise & the Circulatory System Circulatory System

The benefits of a long term exercise The benefits of a long term exercise program on the circulatory system are:program on the circulatory system are:

Greater efficiency of the heartGreater efficiency of the heart Lower resting heart rateLower resting heart rate Increase in left ventricle sizeIncrease in left ventricle size Lower blood pressureLower blood pressure Greater blood volumeGreater blood volume Increase in haemoglobin count.Increase in haemoglobin count.

Important TermsImportant Terms

Stroke Volume –Stroke Volume – the amount of the amount of blood pumped into the systemic blood pumped into the systemic circuit with one heart beat. circuit with one heart beat. Avg. Adult female = 60mlAvg. Adult female = 60mlAvg. Adult Male = 80mlAvg. Adult Male = 80ml

In an endurance trained male under In an endurance trained male under maximal conditions it could reach maximal conditions it could reach 160ml! 160ml!

Important TermsImportant Terms

Cardiac OutputCardiac Output – the amount of – the amount of blood the body pumps in one minute. blood the body pumps in one minute. Around 5 litres at rest, up to 30 Around 5 litres at rest, up to 30 litres under maximum effort.litres under maximum effort.

Cardiac output = QCardiac output = Q Stroke Volume = SVStroke Volume = SV Heart Rate = HRHeart Rate = HR Q= SV x HRQ= SV x HR

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Complete Circulatory System Complete Circulatory System Homework Sheet 3Homework Sheet 3