Fisiologi Peredaran Darah

Tahun ajaran 2009-20010

Komponen Sistem Peredaran darah

1. Jantung2. Pembuluh Darah

3 Sel sel Darah3. Sel-sel Darah

The circulatory system keeps blood y y ppumping despite gravity’s pull

– Muscle contractions help bl d t l hill i thblood travel uphill in the veins of a giraffe’s long legslegs

– The wriggling of the corn snake squeezes its veinssnake squeezes its veins and increases circulation

Fungsi SPD

– It transports O2 and nutrients to cells – It takes away CO2 and other wastes

Kapiler merupakan bagian SPD yang berhubungan langsung p p g y g g g gdengan jaringan tubuh

Capillary

Redbloodcell

Keluar masuk substansi dari/ke jaringan yang jauh kapiler dibantu oleh cairan interstisial cairan interstisial

Capillary

INTERSTITIALFLUID

Diffusion ofmolecules

Tissuecell

Sistem Peredaran DarahSistem Peredaran DarahSistem Terbuka Pores

Tubular heart

Sistem tertutup ArterioleCapillary beds

Artery(O2-rich blood)

Venule

Vein

AtriumAtrium

VentricleHeartArtery

(O2-poor blood)Gillcapillaries

FISHES AMPHIBIANS REPTILES (EXCEPT BIRDS) MAMMALS AND BIRDS( )

Lung capillaries Lung capillariesLung and skin capillariesGill capillaries

P l t P lA t RightPulmocutaneouscircuit

Pulmonarycircuit

Pulmonarycircuit

Atrium (A)

Heart:ventricle (V)

Artery Gillcirculation

AV VV VV

A A A AALeft Systemicaorta

Right systemicaorta

Right Left Right Left Right Left Systemic

circuitSystemic

circuitSystemic

circulationVein

V VV

Systemic capillaries Systemic capillaries Systemic capillaries Systemic capillariesFigure 42.4

7Capillaries ofH d d

Superiorvena cava

Capillaries Capillaries

Head and armsvena cava

Pulmonaryartery

Pulmonaryartery

Capillariesof right lung

Capillariesof left lung

6

Aorta9

23 3

411

Pulmonaryvein

Pulmonaryi

RIGHT VENTRICLE

1 LEFT ATRIUM5

LEFT VENTRICLE10

RIGHT ATRIUM

veinvein

Capillaries of

Inferiorvena cava

Aorta

8

Capillaries ofabdominal organsand legsSPD Manusia

Struktur Jantung

Pulmonaryartery

Superior

Aorta

PulmonarySuperiorvena cava

RIGHTATRIUM

yartery

LEFTATRIUM

Pulmonaryveins Pulmonary

veins

Semilunarvalve

Atrioventricular

Semilunarvalve

Atrioventricularvalve

Inferiorvena cava

Atrioventricularvalve

vena cava

RIGHTVENTRICLE

LEFTVENTRICLE

The cardiac cycle

Semilunarvalvesclosed

Atrial systole; ventricular diastole

2

Semilunarvalvesopen

0.1 sec

0.3 sec

AV valvesopen

open0.4 sec

AV valvesclosedAtrial and

ventricular1

ventricular diastole Ventricular systole;

atrial diastole3

The control of heart rhythm

2 Signals are delayedat AV node.

1 Pacemaker generates wave of signals

3 Signals passto heart apex.

4 Signals spreadThroughout

to contract. ventricles.

SA node AV node Bundlebranches

(pacemaker)Heartapex

Purkinjefibers

Figure 42.8ECG

Ritmisitas Kontraksi-Relaksasi Jantung

DiastoleBlood flows from the veins into the heart chambers

Heart isrelaxed.AV valves

1 2 Atriacontract.

the heart chambers AV valvesare open.

SYSTOLE0.1 sec

• Systole– The atria briefly

3 Ventriclescontract.Semilunarvalvesare open.

0.4 sec0.3 sec

ycontract and fill the ventricles with bloodTh th t i l

p

DIASTOLE– Then the ventricles

contract and propel blood out

• Heart valves prevent backflowHeart valves prevent backflow

C di t t• Cardiac output – The amount of blood pumped into the aorta by

th l ft t i l i tthe left ventricle per minute

Blood pressure depends on •cardiac outputcardiac output

•resistance of vessels

The pacemaker sets the tempo of the heartbeat

The SA node (pacemaker) generates electrical signals that trigger the contraction of the atria

The AV node then relays these signals to the ventricles

Pacemaker AV nodeSpecialized

l fibPacemaker(SA node)

Rightatrium

AV node muscle fibers

1 2 3 4

Rightventricle

ECG

Blood pressure

Blood pressurereading: 120/70

A typical blood pressure reading for a 20-year-oldis 120/70. The units for these numbers are mm of mercury (Hg); a blood pressure of 120 is a force that can support a column of mercury 120 mm high.

1 The cuff is loosened further until the blood flows freelythrough the artery and the sounds below the cuff

disappear. The pressure at this point is the diastolic pressure remaining in the artery when the heart is relaxed.

4

Rubber cuffinflatedwith air

120 120

Pressurein cuff above 120

Pressurein cuff below 120

Pressurein cuff below 70

70

Artery

Sounds audible instethoscope

Sounds stop

ArteryArteryclosed

A sphygmomanometer, an inflatable cuff attached to apressure gauge, measures blood pressure in an artery.The cuff is wrapped around the upper arm and inflated until the pressure closes the artery, so that no blood

2 A stethoscope is used to listen for sounds of blood flow below the cuff. If the artery is closed, there is no pulse below the cuff. The cuff is gradually deflated until blood begins to flow into the forearm, and sounds from blood

3

Figure 42.12

flows past the cuff. When this occurs, the pressure exerted by the cuff exceeds the pressure in the artery.

pulsing into the artery below the cuff can be heard with the stethoscope. This occurs when the blood pressure is greater than the pressure exerted by the cuff. The pressure at this point is the systolic pressure.

Measuring blood pressure can reveal cardiovascular problemsp

Blood pressure is measured as systolic and diastolic pressures

Blood pressure120 systolic80 diastolic80 diastolic(to be measured)

Rubber cuff

Pressurein cuffbelow120

Pressurein cuffbelow 80

Pressurein cuffabove120

inflated with air

S d

Artery

Soundsaudible instethoscope

Soundsstop

Arteryclosed

1 2 3 4

Epithelium

Epithelium Basementmembrane

Valve

Smoothmuscle

ConnectiveCAPILLARY

Epithelium

Smoothmuscle

Connectivetissue

ARTERY

Connectivetissue

VEIN

ARTERIOLEVENULE

Pressure is highest in Systolicgthe arteries

Diastolicpressure

ypressure

– It drops to zero by the

Relative sizes andnumbersof blood zero by the

time the blood

vessels

blood reaches the veins

Three factors keep blood moving back to the heart

– muscle contractions– breathing– one-way valvesy

Direction ofblood flowin vein

Valve (closed)Skeletal muscle

Valve (open)

Hypertension is persistent systolic pressure higher than 140 mm Hg and/or diastolic pressure higher than 90 mm Hg

– It is a serious cardiovascular problem

e.g Heart Attack

What is a heart attack ?

A heart attack is damage that occurs when a coronary feeding the heart is blocked

Aorta

Rightcoronaryartery

Aorta

L ftartery Leftcoronaryartery

Blockage

Dead muscle tissue

Blood vessel blockage is usually due to blood clots

(see case of heart disease)

Connectivetissue

Smoothmuscle Epithelium Plaque

Smooth muscle controls the distribution of blood

Muscular constriction of arterioles and precapillary sphincters controls the flow through capillariesg p

Precapillary sphincters Thoroughfarechannel

Thoroughfarechannel

CapillariesArteriole Venule Arteriole Venule

1 Sphincters relaxed 2 Sphincters contracted

The transfer of materials between the blood and interstitial fluid can occur byoccur by

– leakage through clefts in the capillary wallsg g p y– diffusion through the wall– blood pressureblood pressure– osmotic pressure

Tissue cells

Arterialend of

ill

Tissue cells

Osmoticpressure

Osmoticpressure Venous

end ofillcapillary

Bloodpressure

Bloodpressure

capillary

INTERSTITIALFLUID NET PRESSURE

OUTNET PRESSURE

IN

Withdrawblood

Place in tubePLASMA 55%

CONSTITUENT MAJOR FUNCTIONS

Centrifuge

CELLULAR ELEMENTS 45%

WaterSolvent forcarrying othersubstances

Salts

CELL TYPE NUMBER(per mm3 of blood)

FUNCTIONS

Erythrocytes(red blood cells) 5–6 million Transport of

oxygenOsmotic balance,pH buffering, andregulation ofmembranepermeability

SodiumPotassiumCalciumMagnesiumChlorideBicarbonate

oxygen (and carbon dioxide)

Leukocytes(white blood cells) 5,000–10,000

Defense andimmunity

Plasma proteinsOsmotic balance,pH bufferingClottingImmunity

Albumin

FibrinogenImmunoglobins(antibodies)

, , immunity

BasophilEosinophil

Lymphocyte

( )

Substances transported by bloodNutrients (e.g., glucose, fatty acids, vitamins)Waste products of metabolismRespiratory gases (O2 and CO2)Hormones

Eosinophil

NeutrophilMonocyte

Platelets 250,000–400 000 Blood clotting400,000

• Red blood cells contain hemoglobin

White blood cells function both inside and outside the circulatory system

g– Hemoglobin enables the

transport of O2yThey fight infections and cancer

Basophil Eosinophil

Monocyte

Neutrophil Lymphocyte

When a blood vessel is damaged platelets responddamaged, platelets respond

They help trigger the formation of an insoluble fibrin clot that plugs the leak

Injury to lining of bloodvessel exposes connectivetissue; platelets adhere

1 2 3Platelet plug forms Fibrin clot trapsblood cells

Connectivetissue

Platelet releases chemicalsthat make nearby platelets sticky

Plateletplug

Clotting factors from:g

Platelets

Damaged cells

Calcium andother factorsin blood plasma

Prothrombin Thrombin

Fibrinogen FibrinFibrinogen Fibrin

All blood cells develop from stem cells in bone marrowcells in bone marrow

Such cells may prove valuable for treating certain blood disorders

Peran Darah sebagai Immun system