KardiovaskularKardiovaskular

Oleh:Oleh:M. Rasjad IndraM. Rasjad Indra

Fungsi Umum Kardiovaskuler Fungsi Umum Kardiovaskuler

Melayani kebutuhan jaringan:Melayani kebutuhan jaringan:– Mengangkut nutrisi & oksigen ke jaringanMengangkut nutrisi & oksigen ke jaringan– Mengangkut sisa metabolisme dari jaringanMengangkut sisa metabolisme dari jaringan– Mengangkut hormon ke sel targetMengangkut hormon ke sel target

Memelihara lingkungan internal untuk Memelihara lingkungan internal untuk kehidupan & fungsi optimal sel.kehidupan & fungsi optimal sel.

Bagaimana pengendalian kerja Sistem Kardiovaskuler agar dapat melayani kebutuhan jaringan seluruh tubuh???

Aliran Darah

Tekanan Darah

Memenuhi Kebutuhan Perfusi Jaringan

Pompa Jantung

Tahanan Pembuluh Darah Lokal

Tahanan Pembuluh Darah Total

Kontraksi Otot jantung

Potensial Aksi

Sistem Konduksi & Otot Jantung

Ruang & Katub jantung

Kontraksi Otot Pembuluh Darah

Otot Pembuluh Darah

Siklus jantung

PengendalianParameter:

1. Curah jantung2. Tekanan darah [P]3. Aliran darah [Q]4. Tahanan pembuluh darah [R]

Curah jantung = Volume sekuncup x frekuensi jantung

RPQ

Hukum Ohm:l

Q

8

Pr 4Hukum Poiseuille:

r = jari-jari pembuluh darahŋ= viskositas darahl = panjang pembuluh darah

Fungsi Bagian KardiovaskulerFungsi Bagian KardiovaskulerJantungJantung: : – Memompa darahMemompa darahArteriArteri: : – Transpor darah di bawah tekanan tinggi ke jaringan.Transpor darah di bawah tekanan tinggi ke jaringan.AteriolAteriol: : – Mengatur aliran darah yg menuju kapilerMengatur aliran darah yg menuju kapilerKapilerKapiler: : – Pertukaran cairan, nutrisi elektrolit hormon antara Pertukaran cairan, nutrisi elektrolit hormon antara

darah dan cairan interstisialdarah dan cairan interstisialVenulaVenula: : – Mengalirkan darah dari kapiler ke vena sedangMengalirkan darah dari kapiler ke vena sedangVenaVena: : – Mengalirkan darah dari jaringan ke jantungMengalirkan darah dari jaringan ke jantung– Reservoir darah terkendaliReservoir darah terkendali..

Volume Darah di Sistem Volume Darah di Sistem KardiovaskularKardiovaskular

84 % di sirkulasi sistemik:84 % di sirkulasi sistemik:– 64 % di vena64 % di vena– 13 % di arteri13 % di arteri– 7 % di arteriole dan kapiler sistemik7 % di arteriole dan kapiler sistemik

16 % di sirkulasi paru dan jantung:16 % di sirkulasi paru dan jantung:– 7 % di jantung7 % di jantung– 9 % di paru9 % di paru

Penampang pembuluh darahPenampang pembuluh darah

Pembuluh darahPembuluh darah Penampang (cmPenampang (cm22))

AortaAorta 2,52,5Ateri kecilAteri kecil 2020

ArterioleArteriole 4040

KapilerKapiler 25002500

VenuleVenule 250250

Vena kecilVena kecil 8080

Vena cavaVena cava 88

Kecepatan Aliran DarahKecepatan Aliran Darah

Di aorta: 33 cm / detikDi aorta: 33 cm / detikDi kapiler: 0,3 mm / detikDi kapiler: 0,3 mm / detik

Oleh karena tekanan darah makin ke perifer makin turun, maka aliran darah:

• Panjang kapiler: 0,3 – 1 mm darah berada di kapiler 1 – 3 detik

• Waktu untuk pertukaran antara plasma dan interstisial sangat singkat!!!!

Tekanan DarahTekanan Darah

3 Prinsip Dasar Fungsi 3 Prinsip Dasar Fungsi KardiovaskulerKardiovaskuler

1.1. Aliran darah ke setiap jaringan Aliran darah ke setiap jaringan dikendalikan berdasarkan kebutuhan dikendalikan berdasarkan kebutuhan jaringan.jaringan.

2.2. Curah jantung dikontrol terutama oleh Curah jantung dikontrol terutama oleh keseluruhan kebutuhan jaringan.keseluruhan kebutuhan jaringan.

3.3. Tekanan darah dikontrol oleh pengendali Tekanan darah dikontrol oleh pengendali aliran darah lokal maupun oleh aliran darah lokal maupun oleh pengendali curah jantung.pengendali curah jantung.

ELEKTROKARDIOGRAFIELEKTROKARDIOGRAFI

BIPOLAR STANDARD LEADS

UNIPOLAR AUGMENTED EXTRIMITY LEADS

UNIPOLAR PRECORDIAL LEADS

KURVA EKG

Gelombang EKGGelombang EKG

P: dihasilkan dari depol atriumP: dihasilkan dari depol atriumQ (q): Defleksi negatif pertama, hasil dari depol Q (q): Defleksi negatif pertama, hasil dari depol ventrikelventrikelR (r): Defleksi positif pertama selama R (r): Defleksi positif pertama selama depolarisasi ventrikel.depolarisasi ventrikel.S (s): Defleksi negatif pertama setelah RS (s): Defleksi negatif pertama setelah RR’ (r’): Defleksi positif kedua setelah S (s)R’ (r’): Defleksi positif kedua setelah S (s)T: Defleksi hasil repolarisasi ventrikelT: Defleksi hasil repolarisasi ventrikelU: Defleksi positif setelah T hasil repolarisasi U: Defleksi positif setelah T hasil repolarisasi lambat septum interventrikularis.lambat septum interventrikularis.

Interval EKGInterval EKG

R-R: interval antara dua puncak RR-R: interval antara dua puncak RPP: interval antara dua permulaan PPP: interval antara dua permulaan PP-R: interval awal P sampai awal QRS (0,12-0,20)P-R: interval awal P sampai awal QRS (0,12-0,20)– Depolarisasi atriumDepolarisasi atrium– Keterlambatan di AV nodeKeterlambatan di AV node– Perjalanan impuls ke bundle of HisPerjalanan impuls ke bundle of His

QRS: interval dari awal Q sampai akhir S (<0,10)QRS: interval dari awal Q sampai akhir S (<0,10)VAT: interval dari awal Q sampai puncak R(<0,05)VAT: interval dari awal Q sampai puncak R(<0,05)Q-T: Interval dari awal Q sampai akhir T(<0,43)Q-T: Interval dari awal Q sampai akhir T(<0,43)

Segmen EKGSegmen EKG

PR segment: dari akhir P s/d awal QRSPR segment: dari akhir P s/d awal QRS– Keterlambatan impuls di AV NodeKeterlambatan impuls di AV Node

ST segment: akhir QRS (J point) s/d awal TST segment: akhir QRS (J point) s/d awal T– Keterlambatan repolarisasi ventrikel setelah Keterlambatan repolarisasi ventrikel setelah

depolarisasi ventrikel tuntasdepolarisasi ventrikel tuntas

Injury current: menyebabkan ST segemnt Injury current: menyebabkan ST segemnt elevasi atau depresielevasi atau depresi

Local Control of Blood Local Control of Blood FlowFlow

IntroductionIntroduction

The greater the metabolism The greater the metabolism the greater the greater its blood flowits blood flow– Liver: 95 ml/min/100 g of liver tissue.Liver: 95 ml/min/100 g of liver tissue.– Kidneys: 1100 ml/min Kidneys: 1100 ml/min cleansing the blood. cleansing the blood.

The importance of blood flow control The importance of blood flow control effective & efficienteffective & efficient– Serving metabolic needServing metabolic need– Efficient heart workload.Efficient heart workload.

Mechanism of Blood Flow ControlMechanism of Blood Flow ControlAcute control (rapid changes in local vasodilatation / Acute control (rapid changes in local vasodilatation / vasoconstriction):vasoconstriction):– Effect of tissue metabolismEffect of tissue metabolism– The availability of oxygen changes.The availability of oxygen changes.– Two basic theories:Two basic theories:

Vasodilator theory: Vasodilator theory: adenosine; COadenosine; CO22; histamine; K; histamine; K++ & H & H++

Oxygen lack theory: Oxygen lack theory: vasomotion in metarterioles & precapillary vasomotion in metarterioles & precapillary sphincters.sphincters.

– Other nutrients besides Oxygen:Other nutrients besides Oxygen:– Lack of glucose Lack of glucose vasodilatation vasodilatation– Vitamin B deficiency Vitamin B deficiency vasodilatation vasodilatation

The examples of acute metabolic The examples of acute metabolic control of local blood flowcontrol of local blood flow

1.1. Reactive hyperemiaReactive hyperemia• Blocked (seconds – hours) Blocked (seconds – hours) unblocked unblocked• Blood flow increases to 4 – 7 times normalBlood flow increases to 4 – 7 times normal• Depends on how long it is blocked.Depends on how long it is blocked.

2.2. Active hyperemiaActive hyperemia• Tissue activity Tissue activity lack of nutrient & release lack of nutrient & release

vasodilator substances.vasodilator substances.• Local blood flow increases 20 times in Local blood flow increases 20 times in

muscle during heavy exercise.muscle during heavy exercise.

Blood flow control & The arterial Blood flow control & The arterial pressure changespressure changes

Acute autoregulation theory:Acute autoregulation theory:1.1. The metabolic theoryThe metabolic theory2.2. The myogenic theory (still doubtful !!)The myogenic theory (still doubtful !!)

Endothelial-Derived Relaxing Factor Endothelial-Derived Relaxing Factor “EDRF” (NO):“EDRF” (NO):

– Rapid flow of blood Rapid flow of blood shear stress shear stress NO NO release release relaxes the local arterial wall. relaxes the local arterial wall.

Long Term Blood Flow RegulationLong Term Blood Flow Regulation

1.1. Change in Tissue VascularityChange in Tissue Vascularity– Reconstruction to meet the needs of the Reconstruction to meet the needs of the

tissuestissues– Role of Oxygen in Long-Term Regulation.Role of Oxygen in Long-Term Regulation.– Vascular Endothelial Growth Factors:Vascular Endothelial Growth Factors:

1.1. VEGFVEGF2.2. FGFFGF3.3. AngiogeninAngiogenin

2.2. Collateral Circulation:Collateral Circulation:

Humoral Regulation of The CirculationHumoral Regulation of The Circulation1.1. Vasoconstrictor Agents:Vasoconstrictor Agents:

1.1. Norepinephrine & EpinephrineNorepinephrine & Epinephrine2.2. AngiotensinAngiotensin3.3. VasopressinVasopressin4.4. EndothelinEndothelin

2.2. Vasodilator Agents:Vasodilator Agents:1.1. BradikyninBradikynin2.2. HistaminHistamin

3.3. Effects of Ion & Other Chemical FactorsEffects of Ion & Other Chemical Factors1.1. Calcium Calcium vasoconstriction vasoconstriction2.2. Potasium Potasium Vasodilatation Vasodilatation3.3. Magnesium Magnesium powerful vasodilatation powerful vasodilatation4.4. Hydrogen Hydrogen vasodilatation vasodilatation5.5. Acetate & Citrate Acetate & Citrate mild degree vasodilatation mild degree vasodilatation

Rapid Control of Arterial Rapid Control of Arterial Pressure by Nervous Pressure by Nervous

SystemSystem

Pengendalian sirkulasi oleh sistem Pengendalian sirkulasi oleh sistem sarafsaraf

Peran sistem saraf dalam pengendalian Peran sistem saraf dalam pengendalian aliran darah lokal aliran darah lokal sangat kecil.sangat kecil.Sistem saraf lebih berperan pada fungsi Sistem saraf lebih berperan pada fungsi global dalam hal:global dalam hal:

1.1. Pendistribusian darah ke area tubuh tertentuPendistribusian darah ke area tubuh tertentu2.2. Kekuatan pompa jantungKekuatan pompa jantung3.3. Pengendalian cepat tekanan darah Pengendalian cepat tekanan darah

Three Major Changes Three Major Changes If sympathetic nervous system are stimulatedIf sympathetic nervous system are stimulated1.1. Almost all arterioles are constrictedAlmost all arterioles are constricted

• Increases the total peripheral resistanceIncreases the total peripheral resistance2.2. The veins especially & other large vessels are The veins especially & other large vessels are

strongly constrictedstrongly constricted• Increases venous return Increases venous return increase cardiac out put increase cardiac out put

(Starling Law)(Starling Law)3.3. The heart enhancing cardiac pumpingThe heart enhancing cardiac pumping

• Increases heart rateIncreases heart rate• Increases cardiac contractilityIncreases cardiac contractility

Anestesi spinal menyebabkan penurunan tekanan darah akibat hilangnya tonus vasomotor

Reflex Mechanism for Maintaining Reflex Mechanism for Maintaining Normal Arterial PressureNormal Arterial Pressure

Baroreceptor Reflexes:Baroreceptor Reflexes:– The receptors: Baroreceptors or PressoreceptorsThe receptors: Baroreceptors or Pressoreceptors

Located in the wall of several of large systemic Located in the wall of several of large systemic arteriesarteriesSinus caroticus Sinus caroticus n. Hering n. Hering n. Glossopharyngeus n. Glossopharyngeus tr. Solitarius tr. Solitarius Med. Oblongata.Med. Oblongata.Arcus aortae Arcus aortae n. Vagusn. Vagus

– The Response: Feedback signals to reduce The Response: Feedback signals to reduce arterial pressurearterial pressure

Vasodilatation of the veins and arteriolesVasodilatation of the veins and arteriolesDecreased heart rate & the strength of heart Decreased heart rate & the strength of heart contractioncontraction

Function of Baroreceptor ReflexFunction of Baroreceptor Reflex

During changes in Body PostureDuring changes in Body Posture– To maintain relatively constant arterial To maintain relatively constant arterial

pressure in the upper bodypressure in the upper bodyPressure BufferPressure Buffer Function Function– Opposes either Opposes either increasesincreases or or decreasesdecreases in in

arterial pressure.arterial pressure.Unimportance of Baroreceptor System for Unimportance of Baroreceptor System for Long RegulationLong Regulation– The resetting of baroreceptor systemsThe resetting of baroreceptor systems

Pencatatan tekanan darah selama 2 jam pada kondisi NORMAL (gambar atas) dan pada beberapa minggu setelah DENERVASI sinus caroticus dan Sinus aorticus

Chemoreceptors Reflex:Chemoreceptors Reflex:– The receptors sensitive to:The receptors sensitive to:

Lack of oxygens; COLack of oxygens; CO22 excess and H excess and H++ excess. excess.

Located in the wall of small arteries; Carotid Bodies & Aortic Located in the wall of small arteries; Carotid Bodies & Aortic Bodies.Bodies.

– Not a powerful control in a normal arterial pressure Not a powerful control in a normal arterial pressure rangerange

Important in below 80 mmHgImportant in below 80 mmHg

Low-pressure Receptors:Low-pressure Receptors:– Stretch receptorsStretch receptors– Located in the wall of: Pulmonary arteries & AtriumLocated in the wall of: Pulmonary arteries & Atrium– Role: to minimize arterial pressure changes in Role: to minimize arterial pressure changes in

response to changes in blood volume.response to changes in blood volume.

Reflex Mechanism for Maintaining Normal Reflex Mechanism for Maintaining Normal Arterial Pressure (Cont.)Arterial Pressure (Cont.)

Volume Reflex (Volume Reflex (Atrial Reflex that Activate the KidneyAtrial Reflex that Activate the Kidney))– Stimulation: Stretch of the atriaStimulation: Stretch of the atria– Response: Response:

1.1. Dilatation of the afferent arteriole in the kidneyDilatation of the afferent arteriole in the kidney2.2. To Hypothalamus To Hypothalamus Decrease ADH secretion Decrease ADH secretion 3.3. Release of Atrial Natriuretic Peptide (ANP)Release of Atrial Natriuretic Peptide (ANP)

The Bainbridge ReflexThe Bainbridge Reflex– Stimulation: Stretch of the atriaStimulation: Stretch of the atria– Response: n. Vagus Response: n. Vagus Med. Oblongata Med. Oblongata Increase the Increase the

heart rate & strength of the heart contractionheart rate & strength of the heart contraction

Reflex Mechanism for Maintaining Reflex Mechanism for Maintaining Normal Arterial Pressure (Cont.)Normal Arterial Pressure (Cont.)

CACI

HIGHER CENTER

VASOMOTORCENTERCI CA

JANTUNG

SV Hr

C.O.PX

TPR

“Blood Pressure”O2

HCO2

PH

CHEMORECEPTOR

+

VCVD

+“Baroreceptor”

-

BARORESEPTORCONTROL “Blood Pressure”

Role of the Kidney in Long Term Role of the Kidney in Long Term Regulation of Arterial PressureRegulation of Arterial Pressure

Renal-Body Fluid System for Renal-Body Fluid System for Arterial Pressure ControlArterial Pressure Control

Too much extracellular fluid

The blood volume & arterial pressure rise

The kidneys excrete thr excess extracellular fluid

The arterial pressure back toward normal

Pressure diuresis: An increase in arterial pressure only a few mm Hg can double the renal output of water

Pressure natriuresis: An increase in arterial pressure only a few mm Hg can double the renal output of salt

How Does Increased Fluid Volume Elevate How Does Increased Fluid Volume Elevate the Arterial Pressure?the Arterial Pressure?

Extracellular fluid volume ↑

Blood Volume ↑

Mean circulatory Filling pressure ↑

Venous return ↑

Cardiac output ↑

Auto-regulation

Total peripheral resistance ↑

Arterial pressure ↑

Importance of Salt in the Renal-Body Fluid Importance of Salt in the Renal-Body Fluid Schema for Arterial Pressure RegulationSchema for Arterial Pressure Regulation

Excess salt in the body Excess salt in the body → The osmolality of the → The osmolality of the body fluid increases → Stimulate the thirst body fluid increases → Stimulate the thirst center → Drink extra amounts of water → center → Drink extra amounts of water → Increases the extra-cellular fluid volumeIncreases the extra-cellular fluid volumeThe increase in osmolality in the extracellular The increase in osmolality in the extracellular fluid → Stimulate hypothalamus to secrete ADH fluid → Stimulate hypothalamus to secrete ADH → The kidney reabsorb water from the renal → The kidney reabsorb water from the renal tubular fluid → Increasing the extracellular fluid tubular fluid → Increasing the extracellular fluid volume.volume.Increasing extracellular volume → Elevation of Increasing extracellular volume → Elevation of the arterial pressure.the arterial pressure.

Renin-Angiotensin SystemRenin-Angiotensin System

Renin:Renin:– Small protein EnzymeSmall protein Enzyme– Synthesized in the JG cellsSynthesized in the JG cells– Stored in an inactive form: Stored in an inactive form: ProreninProrenin– This secretion is stimulated by fall blood This secretion is stimulated by fall blood

pressurepressure– Catalyze reaction: Angiotensinogen Catalyze reaction: Angiotensinogen → →

Angiotensin I.Angiotensin I.– It persists in the blood for 30 – 60 minutes.It persists in the blood for 30 – 60 minutes.

Decreased arterial pressure

Kidney

Angiotensinogen

Renin

Angiotensin I

Liver

Converting enzyme

Lungs

Angiotensin II

Blood vessels

Vasoconstriction

Aldosteron secre.

Sodium reabsorption

H2O & Na reabsorption

ADH secretion

Renal retension H2O & Na

Normal effective arterial blood volume

Essential HypertensionEssential HypertensionAbout 90-95 % of hypertension casesAbout 90-95 % of hypertension casesUnknown origin & strong hereditary tendencyUnknown origin & strong hereditary tendencyCharacteristics of severe essential hypertension:Characteristics of severe essential hypertension:

1.1. MAP is increased 40 – 60 %.MAP is increased 40 – 60 %.2.2. In the late & more severe stages: RBF decreased 50 %In the late & more severe stages: RBF decreased 50 %3.3. The resistance to blood flow through the kidneys is The resistance to blood flow through the kidneys is

increased twofold to fourfold.increased twofold to fourfold.4.4. But, GFR is often near normal.But, GFR is often near normal.5.5. The cardiac output is about normal.The cardiac output is about normal.6.6. The TPR is increased about 40 – 60 % The TPR is increased about 40 – 60 % ~ elevation of ~ elevation of

arterial pressure.arterial pressure.7.7. The kidney will not excrete adequate amount of salt The kidney will not excrete adequate amount of salt

and water unless the arterial pressure is high.and water unless the arterial pressure is high.

Treatment of Essential HypertensionTreatment of Essential HypertensionTwo types of drugs:Two types of drugs:

1.1. Increase renal blood flow (vasodilator drug):Increase renal blood flow (vasodilator drug):1.1. Inhibiting sympathetic nervous signal to the Inhibiting sympathetic nervous signal to the

kidneys or blocking the action of the sympathetic kidneys or blocking the action of the sympathetic transmitter substance on the renal vasculaturetransmitter substance on the renal vasculature

2.2. Directly paralyzing the smooth muscle of the Directly paralyzing the smooth muscle of the renal vasculaturerenal vasculature

3.3. Blocking the action of the renin-angiotensin Blocking the action of the renin-angiotensin system on the renal vasculature or renal tubules.system on the renal vasculature or renal tubules.

2.2. Decrease tubular reabsorption of salt and Decrease tubular reabsorption of salt and water:water:

– NatriureticNatriuretic– DiureticDiuretic

0 30 1 2 4 8 16 32 1 2 4 8 16 1 2 4 8 16

Detik Menit Jam Hari

0

1

2

3

4

5

6

7

8

9

10

11

Baroreseptor

Kemoreseptor

CNS ischemic responseRenal-blood volume pressure control

Stress relaxation

Renin-angiotensin Capillary fluid shift

Aldosterone