Sub 1.2 - Circulatory System_2009c

8/9/2019 Sub 1.2 - Circulatory System_2009c

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PREPARED BY :EN. MUHD FAZLI B. DOLLAH

BIOLOGY TEACHERSBP INTEGRASI GOPENG

BIOLOGY FORM 5


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THE HUMAN

HEART


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LEARNING

OUTCOMES Explain how blood is propelled through thehuman circulatory system,

Explain briefy how blood pressure isregulated,

Compare & contrast the circulatory systems in

the ollowing humans, sh & amphibians.

Conceptualise the circulatory system in

humans.


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The Structure & Functionof the Humn Hert

The rdcomponent!"#$"% o circulatorysystem

ituated between the two lungsin the

thoracic ca'ityThe organ responsible or generating the

pressureto pump blood through the networ(o blood 'essels

) *ar( red, cone+shaped, muscular organ eight - /+0/ gramsin an adult

$ade up o our chambers1 two upper thin+walled atria, two lower thic(+walled 'entricles


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SU!ER "ENA #A"ASU!ER "ENA #A"A

RIGHT ATRIUMRIGHT ATRIUM

TRICUS!I$ "AL"ETRICUS!I$ "AL"E

RIGHT "ENTRICLERIGHT "ENTRICLE LEFT "ENTRICLELEFT "ENTRICLE

LEFT ATRIUMLEFT ATRIUM

!ULMONARY "EIN!ULMONARY "EIN

!ULMONARY ARTER!ULMONARY ARTER

AORTAAORTA

SEMI%LUNAR "AL"ESEMI%LUNAR "AL"E

!ULMONARY "EIN!ULMONARY "EIN


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TRICUS!I$ "AL"ETRICUS!I$ "AL"E

SEMI%LUNAR "AL"ESEMI%LUNAR "AL"E

BICUS!I$ "AL"EBICUS!I$ "AL"E


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The 'al'es in the heart ensure thatblood fows only in one direction

Tricu'i( )*)e1 right atrium & right'entricle

Bicu'i( )*)e1 let atrium & let

'entricle Semi%*unr )*)e1 at the base o

aorta & pulmonary artery

The heart is made up o cardiac musclewhich is myogenic!it contracts &relaxes automatically throughout lie%


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The rhythmic contractions are generatedwithin the cardiac muscle itself & are not

initiated by nerves. The heart functions like two pumpswithdifferent pressure systems.

Right pump deoxygenated blood lungs

Left pumpoxygenated blood body

Sinoatrial (SA no!"(specialised cardiacmuscle cell located in the right atrial wall!

near the entrance of the superior vena cava. "unction li#" a $a%"&a#"rcausing the

atria to contract simultaneouslyforce

blood into ventricles


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Atrio)entricu*r +A", no(e!lying atthe base o the right atrium%

The excitatory wa'es stimulate the )2node generates its own electricalimpulses which are conducted byspecialised muscle bres called bundle o

Hi -.re & !ur/in0e -.reto thewalls o 'entricles contractsimultaneously & blood is pumped out o

the heart. 3ight 'entricles which is less muscular

pumps the blood into the pulmonaryartery lungs
http://c1f5%20-%20biovideo/SA%20&%20AV%20-%20cardiac_conduction.movhttp://c1f5%20-%20biovideo/SA%20&%20AV%20-%20cardiac_conduction.movhttp://c1f5%20-%20biovideo/SA%20&%20AV%20-%20cardiac_conduction.movhttp://c1f5%20-%20biovideo/SA%20&%20AV%20-%20cardiac_conduction.mov


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14et 'entricle is thic(er & moremuscularthan the right'entricles generate a greaterpressureto pump blood throughaorta & to other arteries in thebody.


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Ho' !o" t)" *loo! in t)" +"in,lo' *a%# to t)" )"art-

1 5ormal mo'ement contraction o s(eletalmuscles s6uee7esthe 'eins, increasedpressure pushes open the 'al'es in the 'einsto orce the fow o blood towards the heart.

1The 'al'esin the 'eins pre'ent bac( fow othe blood

1The residualheart pressure1 8nhalationthe inspiratory mo'ements

lower the thoracic pressure & helps to drawthe blood along the main 'eins towards theheart.

1 9ra'ityhelps to return blood in those 'einsabo'e the heart.


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FACTORS MO$IFYING THEHEART RATE

1) node can initiate heartbeatonits own. The heart rate may bemodied by certain other actors.

1!a% the sympathetic ner'ecarryingimpulses to the heart can increasethe heart rate

!b% the parasympathetic ner'ecarrying impulses to the heart slowsdown the heart rate.


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hen excitedan increasedsecretion o the hormoneadrenaline

: epinephrine which causes theheart to beat aster

!a% an increase in the partial pressureo C;< in the blood or a decrease inp= increase the heart rate

!b% a all in partial pressure o C;< inblood decreases the heart rate.


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1=eart rate also increase when

body temperature is ele'ated:when there is a decrease inblood pressure


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Re2u*tor3 Mechnim of.*oo( 'reure

Blood pressure1 the orce o the bloodexerted by the pumping heart on the walls othe arterial blood 'essels.

)rterial blood pressure is highest duringcontraction o the 'entricles!'entricular systole%& lowest duringdiastole.

5ormal human blood pressure1 >


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tretch+sensiti'e receptors :baroreceptors1located in the arch walls o theaorta &carotid arteries !supply blood to the brain%.

$onitor the pressure o bloodfowing to thebrain & to the body.

)nincreasein blood pressure stretches the

baroreceptorsimpulses are sent to thecardiovascular centrein medulla oblongatato help regulate blood pressure.

8mpulses sent 'iaparasymphatetic nerve

to the heart slow down the heartbeatsmooth muscles o arteries relax, decreasethe resistance o blood fow in the blood'essels blood pressure decrease


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The widening o blood 'essels B vasodilation

The wea(er cardiac muscle contraction &

lower resistance o blood fowin blood 'esselsblood pressure , bac( to normal 'alue

8 blood pressure low!in a state o shoc(% baroreceptors less stimulated send ner'e

impulses at a slower rate to the cardio'ascularcentre stimulation o ) node by thesympathetic nervestronger cardiacmuscle contraction as well as the smooth

muscles in the walls o arteries increase theresistance o blood fow in the blood 'essels.

5arrowing o blood 'essel vasoconstriction

CIRCULATORY SYSTEM IN


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CIRCULATORY SYSTEM INFISH4 AM!HIBIANS &

HUMANS

CIRCULATORY SYSTEM

CLOSED OPENED

SINGLE DOUBLEINSECTS &

MOLLUSCS

COMPLETE :-

HUMANS

INCOMPLETE :-

REPTILESAMPHIBIANS

FISH

CIRCULATORY IN HUMANS


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CIRCULATORY IN HUMANS4FISH &AM!HIBIANS

CIRCULATORY SYSTEM IN FISH

1 ingle circulatory system1 blood fowsthrough the heart only onceor each

circulation.1 =eart *eoxygenated blood gillsoxygenated blood body heart

1 Alood pressure drops collected insinuses!large spaces% atrium


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CIRCULATORY SYSTEM IN HUMANS

1 *ouble circulatory system1 blood

fows through the heart only twiceoreach circulation.

1The pulmonary circulation & systemic

circulation.1 "ulmonary circulation1 right 'entricledeoxygenated blood lungs !'ia

pulmonary arteries% pulmonary'eins let atrium


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CIRCULATORY SYSTEM IN HUMANS

1 ystemic circulation1 let 'entricle

oxygenated blood

body !'ia aorta%

superior & inerior 'ena ca'a rightatrium.

1 Complete double circulatory systemheart being di'ided into two right pump!to lungs% & let pump !to body parts%.

1 )d'antages - oxygenated blood returns to

heart to be pumped again increasesthe pressure o the blood speeding upthe deli'ery.


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CIRCULATORY SYSTEM IN AM!HIBIANS

1 *ouble circulatory system1 blood fows

through the heart only twiceor eachcirculation.

1The pulmonary circulation & systemiccirculation.

1Three+chambered hearttwo atria & one'entricle.

1 ome mixing o oxygenated &

deoxygenated blood in 'entricle enterthe systemic circulation !incompletedouble circulatory system% less ecient.


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CIRCULATORY SYSTEMSORGANISMS CIRCULATORY

SYSTEMCHARACTERISTICS

HUMANS COMPLETE DOUBLECLOSED

CIRCULATORY

SYSTEM

The blood enters the heart twiceduring one complete cycle.

The oxygenated & deoxygenatedblood not mixing together

!SH SINGLE CLOSEDCIRCULATORY

SYSTEM

An atrium & a "entricle

The deoxygenated blood enters theatrium & then the "entricle

The blood enters the heart once

AM#H!$!ANS INCOMPLETEDOUBLE CLOSED

CIRCULATORY

SYSTEM

Two atria% one "entricle

Mixing o oxygenated blood &deoxygenated blood in the single"entricle.

!NS'(TS OPENEDCIRCULATORY

SYSTEM

$lood low in haemocoel


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EERCISE 678

1. The walls of the left side of theheart are generally thicker thanthose of the right side of the

heart, and the wall of theventricles are thicker than thoseof the atria. Suggest reasonsforthese differences.

2. Describe the similaritiesanddifferencesbetween the arteriesand veins.


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Documents

Sub 1.2 - Circulatory System_2009c