SLAC Circulatory System

8/9/2019 SLAC Circulatory System

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© Boardworks Ltd 20061 of 36

The Circulatory System


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Functions of the circulatory system

The circulatory system has three functions:

1 Transporting su!stances around the !ody

These include o"y#en$ #lucose$ car!on

dio"ide$ nutrients$ water and waste %roducts

The circulatory system is descri!ed as a double

system !ecause it has two loo%s

3 Protecting the !ody Blood contains

cells and anti&!odies that fi#ht infectionand clottin# a#ents to sto% !leedin#

2 Controlling !ody tem%erature


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The double circulatory system

o"y#enated !lood to the rest ofthe !ody throu#h the arteries

deo"y#enated !lood !ack to the

heart throu#h the 'eins

The pulmonary circulation carries:

deo"y#enated !lood from theheart to the lun#s

o"y#enated !lood !ack from the

lun#s to the heart$ ready to !e

%um%ed out to the !ody

The systemic circulation carries:

lungs

body’scells


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© Boardworks Ltd 2006( of 36

The circulatory system

body’scells

lungs)eo"y#enated!lood is

%um%ed from

the heart to the

lun#s throu#h

the pulmonary

artery

*"y#enated!lood returns

to the heart

throu#h the

pulmonary

vein

*"y#enated

!lood is %um%ed

at hi#h %ressure

from the heart to

the !ody throu#h

the aorta

)eo"y#enated

!lood returns tothe heart

throu#h the

vena cava


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© Boardworks Ltd 2006+ of 36

The circulatory system


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Blood vessels

There are three types of blood vessels$ as shown in this

ma#nified %art of the circulatory system

,hy are there different ty%es of !lood 'essels-

blood from

the heart

blood to theheart

arterycarries !lood

!ack intothe heart

carries !loodaway fromthe heart

carries !lood toand from the!ody.s cells

vein


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Blood vessels

thic outer wall

thic inner layer of muscleand elastic fi!res

narrow central tu!e

lumen

thin outer wall

thin inner layer of muscle

and elastic fi!res

wide central tu!e

lumen

wall only one cell thick

!"T#"$

%#&NC!P&''!"$


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Blood vessels( valves

,hen !lood is flowin# a#ainst #ra'ity$ or when a 'ein is

suee4ed !y muscle action$ there is a risk that !lood will flowin the wron# direction %eins ha'e valves to %re'ent !ackflow

bloodto the

heart

bacflow

prevented vein valve open

vein valve closed

The 'al'es allow

!lood to flow in the

correct direction5

5!ut close if !lood

starts to flow in the

wron# direction


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Blood vessels



Cardiac system

The four cham!ers of the heart ha'e s%ecial names:

7 lower cham!er is called a ventricle

7n upper cham!er is called an atrium %lural: atria

rightatrium

rightventricle

left

atrium

left

ventricle



Cardiac system

8ere are some other im%ortant %arts of the heart:

The wallsare made of

cardiacmuscle

The walldi'idin# the

left and

ri#ht sidesof the heartis called the

septum

The semi)lunarvalves %re'ente"%elled !lood

flowin# !ack into

the heart

These two valves %re'ent !lood flowin#

!ack into the atria

from the 'entricles

Bicuspid

mitral 'al'e

Tricuspid

'al'e



The heart as a pump



The heart during e*ercise

+eart rate or pulse rate is

the num!er of times yourheart !eats e'ery minute

9t is e"%ressed in beats per

minute !%m

estin# heart rate 'aries fromindi'idual to indi'idual and is

affected !y fitness

The fitter you are$ the lower

your restin# heart rate will !eThe a'era#e restin# heart

rate is a!out /0;/+ !%m


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=ach indi'idual has a ma*imum heart rate ; the fastest

that their heart is a!le to !eat Testin# it %ro%erly is difficultand un%leasant$ as it in'ol'es %ushin# your !ody to its

a!solute limit

8owe'er$ ma"imum heart rate can !e estimated usin# a

sim%le formula:

,hat would your ma"imum heart rate !e-

a*imum +eart "ate -+" / 001 2 age

So$ a 2+ year&old would ha'e a ma"imum heart rate of

220 ; 2+ > 1+ !%m


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cardiac output / stroe volume 3 heart rate

+eart rate, stroe volume and cardiac output

The %ulse rate is not the only way of measurin# the heart

Cardiac output is the amount of !lood %um%ed

out of the left 'entricle of the heart %er minute

4troe volume is the amount of !lood %um%edout of the left 'entricle %er !eat

Cardiac out%ut can !e calculated !y multi%lyin# the

stroke 'olume !y the heart rate:

,hat is the cardiac out%ut of someone with a heart

rate of 60 !%m and stroke 'olume of 0 ml-




)urin# e"ercise$ the !ody uses u% o"y#en and nutrients at a

much faster rate To kee% the !ody su%%lied with what itneeds$ the heart !eats faster and with greater force

This means that the heart rate and stroe volume increase

,hat do you think ha%%ens to the cardiac out%ut-

e#ular e"ercise causes chan#es to the heart

The heart #ets lar#er

The muscular wall !ecome thicker

and stron#er

Stroke 'olume at rest increases$

leadin# to a lower restin# heart rate


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Blood pressure



Blood pressure

Blood %ressure de%ends on the s%eed of the !lood comin#

into a 'essel and the width of the 'essel itself

Arteries

4peed( high

5idth( medium

Pressure( high

Capillaries

4peed( medium

5idth( narrow

Pressure( medium

Veins

4peed( low

5idth( wide

Pressure( low



Blood pressure

7n indi'idual.s !lood %ressure is affected !y a num!er of

factors!ge ; it increases as you #et older

6ender ; men tend to ha'e hi#her !lood

%ressure than women

4tress can cause increased !lood %ressure

7iet ; salt and saturated fats can increase

!lood %ressure

#*ercise ; the fitter you are the lower your

!lood %ressure is likely to !e

8a'in# hi#h !lood %ressure %uts stress on your heart

9t can lead to angina$ heart attacs and stroes



#ffects of e*ercise on blood pressure

The immediate effect of e"ercise is to raise the !lood

%ressure as the heart !eats faster and more %owerfully

8owe'er$ in the long)term$

re#ular e"ercise reduces !lood

%ressure The fitter you are$ the

lower your !lood %ressure islikely to !e

)urin# intense e"ercise$ !lood flow to the muscles can

increase to 3+ times its normal 'olume 8i#her !lood

%ressure is necessary in order to #et this e"tra !lood to

the muscles



Blood flow and body temperature

The circulatory system %lays an im%ortant role in

re#ulatin# !ody tem%erature

9f the !ody #ets too hot$ ca%illaries near the surface of the

skin widen Blood is di'erted to the skin where the heat can

easily radiate away This is called vasodilation

,ater from the !lood is e"creted as sweat to cool the !ody

Ca%illariesSweat

#land



Blood flow and body temperature

9f the !ody #ets too cold$ ca%illaries near the surface of the

skin #et narrower Blood is di'erted away from the skin to

limit heat loss This is called vasoconstriction

Sweatin# sto%s

Ca%illariesSweat

#land


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Blood

Blood is the !ody.s means of transporting

su!stances around 9t trans%orts:

o*ygen from the lun#s to the heart and then to the

!ody.s tissues

carbon dio*ide from the tissues to the heart and then

to the lun#s to !e e"%ired

materials like hormones from one or#an to another

nutrients es%ecially glucose and minerals from the

intestines to the tissues

waste products to the kidneys



"ed blood cells

7lso called erythrocytes

7isc)shaped

?ade in the bone marrow

Contain a red&coloured

com%ound called haemoglobin

which !onds with o"y#en to form

o*yhaemoglobin

Trans%ort o"y#en to the tissues

Blood is made u% of a num!er of different elements

The most common cell in !lood is the red blood cell


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5hite blood cells

7lso called leucocytes

They are !i##er than red

!lood cells and ha'e lar#e

nuclei

7ct as the !ody.s defencesystem

Blood also contains white blood cells

Some white !lood cells surround and consume

harmful micro!es

Some %roduce chemicals called antibodies that fi#ht

infection


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Platelets

@ormed in red !one marrow

Aroduce thromboinase ;

a chemical needed for !lood

clottin#

Alatelets hel% to re%air tissues

and close wounds !oth

internally and e"ternally

,hen needed$ they #row into

irre#ular sha%es and stick to#ether

to form a plug o'er the wound

Platelets are also carried in the !lood


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Plasma

0 water

inor#anic salts

#lucose

anti!odies

urea and other waste %roducts

%lasma %roteins

The !lood cells and %latelets are sus%ended in a su!stance

called plasma Alasma is made u% of:

Plasma can be separated

from the other components

of blood using a centrifuge.

%lasma

Bl d ll


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Blood cells

" l f bl d i hi i t t ti l


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"ole of blood in achieving sports potential

Because red blood cells carry o"y#en$ which is 'ital to

muscle action$ it is ad'anta#eous for a %erformer to ha'e ahi#h red !lood cell count$ es%ecially in endurance e'ents

,hen athletes train and li'e at

altitude$ where there is less

o"y#en in the air$ their !odiescom%ensate !y %roducin# e"tra

red !lood cells

This means that they can

%erform at a hi#her intensity thanother athletes when %erformin#

at sea le'el

© EMPICS Ltd

Bl d d i


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Blood doping

7n athlete.s red !lood cell count can !e

illegally !oosted throu#h blood dopingSe'eral months !efore a com%etition$

!lood is remo'ed from a %erformer

Their !ody %roduces more !lood to re%lace

the !lood that has !een remo'edThe red !lood cells are se%arated out

from the remo'ed !lood and stored ust !efore the

com%etition$ they are re)in8ected into the com%etitor$ #i'in#

them an artificially hi#h red !lood cell countBlood do%in# can im%ro'e %erformance !y 019$ howe'er$ the

e"tra !lood can lead to dan#erous blood clots and all the

heart %ro!lems associated with high blood pressure

: i


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:ui;

C b ll th d


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Can you remember all these eywords<

Stroke 'olume

Cardiac out%utBlood %ressure

Dasodilation

Dasoconstriction

ed !lood cells

,hite cells

Alatelets

AlasmaBlood do%in#

7orta

Dena ca'aAulmonary

artery

Aulmonary 'ein

Aulmonarycirculation

Systemic

circulation

*"y#enated

)eo"y#enated

7rteries

Deins

Ca%illariesLumen

7tria

Dentricles

Se%tum

Tricus%id 'al'e

Bicus%id mitral

'al'e

Semi&lunar

'al'e

8eart rate

SLAC Circulatory System

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