Cardiovascular System

Assistants of PhysiologyPhysiology Department

Medical Faculty, Hasanuddin University

Circulatory System

The Distribution of Blood in Cardiovascular System

1. Heart (7%)

2. Systemic Arterial System (13%) : Aorta : 2% Elastic Arteries : 4% Muscular Arteries : 5% Arterioles : 2%

3. Pulmonary Circuit (9%) : Pulmonary Arteries : 3% Pulmonary Capillaries : 2% Pulmonary Veins : 4%

4. Systemic Capillaries (7%)

5. Systemic Venous System (64%) : Large Veins : 18% Large Venous networks

(liver, bone marrow, skin) : 21% Venules and medium-sized veins : 25%

Arterial System

AP = CO x TPRAP = Arterial Pressure

CO = Cardiac Output = SV X HR

TPR = Total Perifer Resistance

TPR is influenced by : Viscosity Vascular resistance

- Vessel Length - Vessel Diameter Turbulence

Circulatory Regulation

Short-term Regulation

Medium-term Regulation

Long-term Regulation

Medium-term Regulation

Increased blood volume extravasasi-Transudation- Exudation

Decreased blood volume intravasasi (transcapillary refill/ autotransfution)

Long-term Regulation

Venous System

Characteristic : larger diameter valves distensibility compliance capasitance vessel

Venous Pressure : Central Venous Pressure Peripheral Venous Pressure

Increase of CVP :

Valsalva’s Manouver

Decreased of CVP :

Hypovolemic Shock

Expiration

Central Venous Pulsation

a wave : Atrial kick c wave : ventricular contraction v wave : Tricuspid valve’s

closing x descent : Rapid Filling y descent : Atrial relaxation

VENOUS RETURN

Venous return influenced by : Body Position Muscle Pump Thoracic Pump CVP (central venous pressure) Stroke Volume (SV) etc

MICROCIRCULATION

AUTOREGULATION

Myogenic theory

- Transmurral pressure

- Longitudinal Pressure Metabolic theory

- Decrease of oxygen

- Increase of CO2

- Decrease of pH

- Vasodilators accumulation

AUTOREGULATION

Hyperemia :

- Active hyperemia

- Reactive hyperemia

STARLING’S FORCE

STARLING’S FORCE

Filtration Rate :

K {( Pc – Pi ) – ( c - i )}

K : Permeability coefficient

Pc : Capillary Hydrostatic pressure

Pi : Interstitial Hydrostatic pressure

c : Capillary Oncotic Pressure i : Interstitial Oncotic Pressure

OEDEMA

Oedema consist of : Interstitial oedema Intercelluler oedema

Mechanism of Interstitial Oedema : Hydrostatic Pressure Oncotic Pressure Obstruction of Lymphatic System

HYPOVOLEMIC SHOCK