introduction - lms.ipb.ac.id bahan ajar fisiologi veteriner 2 (kardiovaskuler) 1 2/28/2017 bahan...

2/28/2017

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D I V IS ION O F P H Y S IOLOGY

D E PARTEMEN T O F A N ATOYI , P H Y S IOLOGY A N D

P H A RMACOLOGY

FA C ULTY O F V E TERINARY M E DICINE

2/28/2017 BAHAN AJAR FISIOLOGI VETERINER 2 (KARDIOVASKULER) 1 2/28/2017 BAHAN AJAR FISIOLOGI VETERINER 2 (KARDIOVASKULER) 2

INTRODUCTION

The cardiovascular system is a transportsystem of the body (blood flow anddiffusion) It comprises blood, heart and blood vessels.The system supplies nutrients to and remove

waste products from various tissue of body.The conveying media is liquid in form of

blood which flows in close tubular system.

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FUNCTION OF CARDIOVASCULAR SYSTEM

Transport nutrients, hormonesRemove waste productsGaseous exchange ImmunityThermoregulation Blood vessels transport blood◦Carries oxygen and carbon dioxide◦Also carries nutrients and wastes

Heart pumps blood through blood vessels


COMPONENTS OF CARDIOVASCULAR SYSTEM

BLOOD

HEART

BLOOD VESSELS

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Sumber: Cunningham’s Textbook of Veterinary Physiology 5th ed pp:173-174

Transport via body surface


Open Circulation System


Sumber: Eckert Animal Physiology: Mechanism and Adaptation 4th ed pp:476


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Duke’s Physiology of Domestic Animals 13th ed pp:289

Overview of the

Cardiovascular System

Sumber: Cunningham’s Textbook of Veterinary Physiology 5th ed pp:160


The Heart

• Location

– Thorax between the lungs

– Pointed apex directed toward left hip

• About the size of your fist

• Covering by pericardium

• The walls: picardium, myocardium,

endocardium that contains the Purkinje fibers.

• Four chambers: atria and ventricles (right and

left)


The Heart: Valves

• Allow blood to flow in only one direction

• Four valves

– Atrioventricular valves – between atria and

ventricles

• Bicuspid valve (left)

• Tricuspid valve (right)

– Semilunar valves between ventricle and artery

• Pulmonary semilunar valve

• Aortic semilunar valve

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The Heart: Valves

• Valves open as blood is pumped through

• Held in place by chordae tendineae (“heart

strings”)

• Close to prevent backflow


Blood

Circulation


Co

ntran

ction

of th

e V

entricle

Relaxatio

n o

f the

ventricle

Sumber: Dee Unglaub Silverthorn Human Physiology An Integrated Approach 6th ed pp 476

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CARDIAC MUSCLE FIBREa. Contractile muscle fibre

• Same as sceletal muscle fibre (myocardium)

• Using ATP as a energy for contranction

• Contains lots of mitochondria

• Extensive capillary network to supply O2

• Having a specialized plasma membrane called desmosome linking between cells

• Contains gap junctions between cells which are areas with a low detention (areas of low resistance) allows the action potential conduction from one cell to the adjacentb

b. Excitating and conductive muscle fibre


Characteristic of Electrical Conduction

-The resting membrane potential of heart muscle cells depends on:

At the time of cardiac muscle cells depolarized, there will be action potential

The highest frequency of action potential produced by the SA node (ganglion Remark on amphibians and reptiles) = trigger pulse (pacemaker)

Cardiac muscle action potential lasts longer than the action potential in skeletal muscle (100-250 msec vs. 1-2 msec)



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Characteristic of Cardiac Muscle

Chronotropic (automaticity, rythmicity)

Bathmotropic (excitability)

Dromotropic (conductivity)

Inotropic (contractility)

Potential Action of the Cardiac Muscle

Potential action of the heart muscle has:

1 Fast depolarization phase

2 Partial initial rapid repolarization phase

3 Plateau or long period of slow repolarization (Prolonged

period of slow repolarization) phase

4 Fast repolarization phase




Conduction System• Intrinsic conduction system

(nodal system)

– Cardiac muscle cells contract, without nerve impulses, in a regular, continuous way

• Special tissue sets the pace• Sinoatrial node (SA) - Pacemaker

• Atrioventricular node (AV)

• Atrioventricular bundle

• Bundle branches

• Purkinje fibers

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Cardiac Conduction System• Group of structures that send electrical impulses through

the heart

• Sinoatrial node (SA node)– Wall of right atrium

– Generates impulse

– Natural pacemaker

– Sends impulse to AV node

• Atrioventricular node (AVnode)– Between atria just above ventricles

– Atria contract

– Sends impulse to the bundle of His

• Bundle of His

– Between ventricles

– Two branches

– Sends impulse to Purkinje fibers

• Purkinje fibers

– Lateral walls of ventricles

– Ventricles contract


Conduction SystemFAST FIBERS

- Regular cardiac muscle

- Bundle of His and Purkinye fibres

SLOW FIBERS

- Pacemaker

Sumber: Duke’s Physiology of Domestic Animals 13th ed pp:309


Sinoatrial (SA) node:• Located on the back wall of the right atrium trigger heartbeats

(cardiac pacemaker) AP spreads throughout the atria atrium contraction

• Potential action is also delivered to the AV node with a higher velocity so the action potential will reach the AV node before the whole atrial muscle is excitated

• This impulse burst of speed is affected by the sympathetic and parasympathetic nerves rhythmic pulsations can be brought forward or slowed

SA Node



Atrioventricular (A-V) node:

Slow conduction (50 -150 msec) electrical impulses slowed down its speed when achieve the A-V node before delivering overall to the A-V bundle and Purkinje fibers delay between contraction of the atria and ventricles

AV Node


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A-V Bundle (of His):

• After the impulse passing through the AV node, the conduction velocity will increase

• The relationship between A-V node and the A-V Bundle is only connect the electrical impulses from the atria to the ventricles. Once the impulse to stimulate the A-V Bundle, these impulses are delivered directly to the interventricular septum and Bundle Branches entered into left and right and finally stimulate Purkinje fibers to spontaneously occur ventricular contraction.

AV Bundle (Bundle of His)


Purkinje Fibers

Specialized muscle fibers that can conduct electrical impulses to five times faster than ordinary muscle fibers.





Myo

cardiu

m

Pacemaker


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Automation Nature of the Heart

Some cardiac muscle cells were able to induce a spontaneous action potential ectopic focus

Ectopic foci can occur if:

SA node is not working properly

Disturbance in the conduction system

Refractory Period

Absolute refractory period

Relative refractory period

The plateau phase and repolarization period longer refractory period will be longer


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Elektrocardiograph (ECG)

Potential action that occurs in the heart muscle electric current can be detected on the surface of the body

Electric current electrodes on the body surface to produce an electrocardiogram (ECG)

Electrocardiograph – is the instrument that records the electrical activity of the heart

Electrocardiogram (ECG) is the record of that activity


Elektrocardiogram (ECG)

ECG is a diagnostic tool to determine:

Abnormalities of heart rate or rhythm

Conduction system abnormalities

Hypertrophy / atrophy of the heart

Physiological aspects of the heart


Elektrocardiogram (ECG)

Normal ECG P wave, QRS complex and the T wave

PR interval time starting from the beginning of the P wave and the beginning of the QRS complex

QT interval time starting at the beginning of the QRS complex and the end of the T wave


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• P wave

- Atrial depolarization

• QRS complex

- Ventricular

depolarization

• T wave

- Ventricular

repolarization


LIMB LEADS

Bipolar leadsI II III

Augment leadsaVR aVL aVF


Standard ECG’s

• To determine the mean electrical axis it is necessary to run the 3

standard bipolar leads as well a the 3 augmented unipolar limb

leads.

• Lead I- right arm (+) compared to left arm (-).

• Lead II- right arm (-) compared to left leg (+),

• Lead III- left arm (-) compared to left leg (+)

• aVR-right arm (+) compared to point halfway between right arm

• and left leg (-)

• aVL- left arm (+) compared to a point halfway between left arm

• and right arm.

• left leg (+) compared to a point halfway between left arm and

• right arm (-).

• Only lead II is needed to assess arrhythmias and lead I is the

• most important lead

Type of electrodes:RA, right forelegLA, left forelegRL, right hind legLL, left hind legV1 - V6 chest leads

ECG Electrodes and Leads

There are 12 leads routinely used:3 pieces of raw sandapan bipolar (I, II and

III).3 pieces sandapan limb unipolar (aVR, aVL

and aVF).6 pieces sandapan unipolar chest (V1 - V6)


Lead I: Describing the potential difference between the right foreleg (RA) and left foreleg (LA)Lead II: Describing the potential difference between the right foreleg (RA) and left hind leg (LL)Lead III: Describing the potential difference between the left foreleg (LA) and the left hind leg (LL)aVR lead :unipolar lead right foreleg compared to neutralaVL lead : unipolar lead left foreleg compared to neutralAVF lead: unipolar lead hind legs compared to neutralLead (V1 - V6): Recording the potential of a point on the surface of the chest.

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CHEST LEADS

6 UNIPOLAR LEADSV1V2 V3V4 V5V6




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Normal ECG, One cardiac cycle

ECG Paper

ECG Measurement



Arrythmia CordisArrhythmia is abnormal heart rhythms Cause:

Cardiac pacemaker naturally cause abnormal in rhythm or

frequency

Conduction system is interrupted

Another part of the heart takes over the function of the pacemaker

Bradycardia a decrease in pulse frequency

Can lead to weakness, headache, intolerance to light, fainting, dizziness

Tachycardia increase in pulse frequency

Can result in the same thing with bradycardia condition except weakness

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Fibrilation

Atrial Fibrillation:

Atria do not contract normally vibrate

Blood can not be normally pumped

Blood will be stuck and will form clots if clog into brain stroke


VentricularFibrillation :

◦ Ventricle contraction is faster, irreguler and incoordinated

◦ Only a small amount or no blood is pump out of the heart

Heart Block

Impulse conduction from the atria to the ventricles disrupted

Classifed based on the degree of damage:◦ First degree (first-degree) impulses are conducted through

the AV node is slower than normal

◦ Second degree (Second-degree) Not all of impulses reach the ventricles (dropped beats)

◦ Third degree (Third-degree) AV node being blockaded in total ventricular leads its own rhythm


Penggunaan EKG sebagai alat bantu diagnostik

• Abnormality of ECG coronary heart disease

• Depression of ST segment myocardial

ischemia


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CARDIAC CYCLE

The heart is a pump (two pumps, right and left)Cardiac cycle: the period starting from the beginning of a contraction and ends at the beginning of the next contractionNormal cardiac cycle lasts about 0.7 - 0.8 secondsSystole = contractionDiastole = relaxation


There are five phases in the cardiac cycle:

Systole: isovolumetric ventricular contraction

Systole: ventricular ejection

Diastole: isovolumetric ventricular relaxation

Diastole: passive ventricular filling

Diastole: active ventricular filling


CARDIAC CYCLE

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Isovolumetric Ventricular Contraction

Ventricular contraction

Increased ventricular pressure rapidly

The entire valve remains closed no blood is pumped out of the heart

Ventricular volume remains constant


Ventricular EjectionVentricular contraction continues

Pressure continues to rise

Ventricular pressure> pressure in the aorta and in the pulmonary artery

Aortic and pulmonary valves open

Blood pumping occurs


Isovolumetric Ventricular Relaxation

Ventricular relaxation

Ventricular pressure decreased rapidly

Aortic and pulmonary valve closes

Ventricular volume remains constant


Passive Ventricular FillingAtrial pressure is greater than the ventricular pressure

AV valve opens

Blood flows from the atria to the ventricles

Play in role in about 70% ventricular filling

The actual filling occurs during 1/3 of diastole


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Active Ventricular FillingSA node depolarization cause action potential that spreads throughout the atria

Atrium contracts during 1/3 of final diastole

The final volume of blood from the atria to fill the ventricles during atrial contraction

Produce a final volume/final ventricle vplume (End Diastolic Volume = EDV)



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Heart SoundLUBB-DUPP (heart sound I dan II)

LUBB = AV valve closure (early systole).

DUPP = aortic and pulmonary valves closure

Phonograph

Heart sound III and IV

Heart sound III passive ventricular filling (1/3 end of diastole)

Heart sound IV active ventricular filling

Abnormal sound

Murmur (valve leakage or imperfect closure)



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Mean Arterial Blood PressureMAP the average blood pressure between systolic pressure and diastolic pressure in the aorta

MAP Q x PR

Q = Cardiac output = HR x SV

SV = Stroke volume EDV – ESV


Arterial Blood Pressure

• A systolic/diastolic pressure – Normal : 120/80 mmHg

– High : 140/90 mmHg

• Systolic pressure (value at the top)– The pressure arising at the time of ventricular

contraction

Diastolic pressure (value at the bottom

– The pressure arising at the time ventricle relaxation



Blood Pressure• Pulse Pressure (PP)

– The difference between systolic and diastolic

pressure

– PP = systolic - diastolic

• Mean Arterial Pressure (MAP)

– The average of pressure in the aorta

– MAP = diastolic + 1/3 (systolic – diastolic)


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Stroke Volume

SV increases when EDV increased or ESV decreased during exercise

Increased in EDV occurs due to the increased blood flow in the veins (venous return)

ESV decreased due to the increase of heart contractions


Cardiac Output (Q)

• Q = HR x SV or Q = (FH) (Vs)

• Where:

• Q = the volume of blood pumped by the left ventricle per minute (L/min)

• FH = frequency of cardiac pulse (pulse/min)

• Vs = stroke volume (the average volume of blood pumped per contraction = L/pulse)


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Cardiac Output (Q)

• During aerobic activity,the increase of cardiac

output equivalent to intensity

• Factors: body size, heredity and

circumstances


Regulation of Cardiac FunctionIntrinsic versus Extrinsic Regulation

◦ Intrinsic

◦ Preload

◦ Starling’s law of the heart

◦ Afterload

◦ Extrinsic

◦ Parasympathetic

◦ Sympathetic

◦ Hormonal


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The dynamics of blood circulation1. Laminar and turbulent flow

2. Blood Flow

3. Poiseuille’s Law

4. Viscosity

5. Compliance


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1. Laminar & Turbulent Flow

Laminar flow produces the smallest resistance

Turbulent flow occurs when the laminar flow disrupted


LAMINER FLOW


TURBULENT FLOW


2. Blood Pressure

Measuring the power generated by the blood that suppress the wall of blood vessel

Unit: mmHg

Often carried out at the laboratory level


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3. Blood Flow

Measuring the rate of blood flow throughout the vessel.

Unit: Liter or milliliter per minute


3. Blood FlowThe blood flow is directly proportional to the difference in pressure in the blood vessel

Inversely proportional to the resistance in the blood vessels

Blood Flow = (P1 – P2) / R


4. Poiseuille’s Law

Describes factors that affect the resistance to blood flow

Flow = π (P1 – P2) / 8vl / r4

Flow = (P1 – P2) / r4


5. ViscosityDescribing the resistance of a liquid to flow

The higher the viscosity, the greater the pressure needed to drain the fluid

Blood viscosity is strongly influenced by the hematocrit value


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6. Compliance

Compliance = “stretchability”.

The vein compliance is about 24 times greaterthan the arterial’s

Veins act as reservoir (64% of the total blood volume)



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Distensibility/Windkessel Effect◦ Against the pressure

l Elastic Recoi◦ Back into original shape, save the pressure (reservoir

of pressure)

ARTERY



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Vein• Drain from the peripheral to the heart

• Slow in flow

• Contains lots of CO2

• Low-pressure

• Thin-walled

• Branching from two to one



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Regulation of Blood Flow to the Tissue

In most tissues, blood flow is proportional to the metabolic needs

The blood flow is determined by dilatation of metarteriol and precapillary sphincter relaxation

The blood flow can be increased 7-8 times



Vasodilator substances produced when the metabolism increases:

CO2

Lactic acid

Hydrogen ions

Etc2/28/2017 BAHAN AJAR FISIOLOGI VETERINER 2 (KARDIOVASKULER) 114



Pengaturan Saraf & Hormonal untuk Sirkulasi Lokal

◦ Area di pons, otak tengah, dan diencephalon berperan dalam stimulasi dan inhibisi pusat vasomotor


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Regulation of Blood Flow to the Tissue Nerves & Hormonal control for the local circulation

Autonomous control functions quickly

Sympathetic motor fibers innervate all EXCEPT capillary blood vessels, pre-capillary sphincter and metarteriole

Center of the regulation is located at the vasomotor area in the lower pons and upper medulla oblongata.


Pengaturan Aliran Darah ke Jaringan

Nerves & Hormonal control for the local circulation

◦ Neurotransmitter = norepinephrine

◦ Binding to the α-adrenergic receptor

vasoconstriction


Nerves & Hormonal control for the local circulation

Epinephrine and norepinephrine from the adrenal medulla give the same effect

This hormone generally causes vasoconstriction, but in other tissues such as skeletal muscle, epinephrine binds to β-receptors and causes dilation of blood vessels


Regulation of Mean Arterial Pressure

MAP = diastolic + 1/3 (pulse pressure)

MAP = Q X PR

MAP = HR X SV X PR


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Regulation of Mean Arterial PressureShort-term regulation:

Baroreceptor reflex

Baroreceptor is a receptor that is

sensitive to stretching

Located in the carotid artery and the

arcus aorticus2/28/2017 BAHAN AJAR FISIOLOGI VETERINER 2 (KARDIOVASKULER) 122



Short-term Regulation◦ Chemoreceptor reflex

◦ Carotis body and dan aortic body

◦ Stimulated by the decrease of O2 pressure and the increase of CO2 and hydrogen ions concentrationCause vasocontriction s


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Long-term regulation ◦ Renin-Angiotensin-Aldosterone System


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Organization: supplied by coronary arteries

Blood Flow: representing 5% of the cardiac output

Factors affecting blood flow:

Physical work

Adenosine (coronary vasodilation on

hypoxia)

The autonomic nervous system

Coronary Circulation


Coronary Circulation

Arteria

ExtracoronerArteria coroner

ArterioleArteriole

Capillary

Vein

Sinus coroner and

Vena Kardia anterior

Cardiac Chamber

Arteriosinusoidal

vessel

Arterioluminalvessel

Vena Thebesian

Left and right coronary artery that is located in the base of

the aorta supplies blood to heart

The flow of blood back to the heart through the coronary

sinus and v. cardia anterior, into the right atrium (cardiac

chamber)

Some of the vessels that can drain

blood supply to the heart chambers:

Arteriosinusoidal

Vena Thebesian

Arterioluminal vessel



Splanchnic Circulation:

Blood from the intestine, pancreas, and spleen flows through v. portal hepatik

to the liver and from the liver through v. hepatik to the inferior vena cava

The liver receives +

1000 ml / min of v.

portal and + 500 ml /

min from the hepatic

artery


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Fetal CirculationPlacenta = Lung fetus.

From maternal, O2

taken by fetal, CO2

released from the fetus

to the maternal

circulation pass-through

the villi villi resembling

cellular lung function

In Sheep / Human:

O2 saturation in v.

Umbilical = 80%

O2 saturation in a.

Umbilical = 55%

O2 saturation in adult

humans in systemic

arterial = 98%


Out of systemic aterial and venous system

Function: to return the remaining fluid due to the capillary filtration

Open ends, leading to heart

Lymph Vessel


Consists of:

1. Organ that produce and store lymphocytes cells

(lymph nodes).

2. Lymphatic vessel that returns the lymph fluid to the

circulatory system.


Function::• Returning the excess of tissue fluid that comes out of the

capillary.• Returns plasma protein out of the capillaries, and reabsorp again

through the lymph vessels.• Helps transport nutrients that are absorbed, especially

fat from the digestive system into the blood.• Disposing of toxic substances and cellular impurities from the tissue

after infection or tissue damage. Control the quality of the excess flow of tissue fluid by filtering

through lymph nodes organ before back into circulation.


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Water and substrate that are dissolved in the blood plasma (except blood cells and large protein molecules) an freely pass through the thin capillary walls (pores, D: 8 nm).

Every day an estimated of 20 liters of fluid is filtered and enter to the interstitial tissue (nonrenal). 18 l / day of it is reabsorped into the blood capillaries while 2 l / day returning to the bloodstream via the lymphatic system.

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introduction - lms.ipb.ac.id bahan ajar fisiologi veteriner 2 (kardiovaskuler) 1 2/28/2017 bahan...

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