FISIOLOGIA CARDIOVASCULAR
Robson A. S. Santos
HEMODINÂMICA DA CIRCULAÇÃO
PERIFÉRICA
In 1627, William Harvey was able to confirm his observation that the blood circulates
throughout the body, which he inferred from the structure of the venal valves. The following
year, in Exercitatio Anatomica, he published these conclusions as well as a description of
the heart as a mechanical pump
In 1651, Harvey published the concept that all living things originate from eggs. Harvey
believed that in principle organisms could be spontaneously generated, and that the
process was one of the self-generation of a complicated machine.
In 1661, Marcello Malpighi, in De pulmonibus, reported his observation of blood movement
through the capillaries. He is also noted for his studied of the glands.
In 1733, Hales measured blood pressure.
In 1738, Daniel Bernoulli, in Hydrodynamica, asserted the principle that as the speed of a
moving fluid increases, the pressure within the fluid decreases. In the process of
determining this, he invented the 'molecular theory of gases,' now known as the 'kinetic
theory of gases,' which introduced the notion that the gas particles were moving around
rapidly and that a gas's temperature is a function of the average speed of its particles.
PRINCIPAIS FUNÇÕES DO
SISTEMA CIRCULATÓRIO
Transporte e distribuição de substâncias
essenciais para os tecidos.
 Remoção de produtos do metabolismo.
 Ajustar o suprimento de oxigênio e
nutrientes em diferentes estados fisiológicos
 Regulação da temperatura corporal
 Comunicação humoral

O CIRCUÍTO
TÚBULOS
BOMBA
TÚBULOS
DISTRIBUIDORES
COLETORES
VASOS
DE TROCA
Pressure Drop in the Vascular
System
ELASTIC TISSUE
MUSCLE
LARGE ARTERIES
SMALL ARTERIES
ARTERIOLES
CAPILLARIES
VENULES &VEINS
LARGE
SMALL
INSIDE DIAMETER
LARGE
Distribuição do Sangue no
Sistema Circulatorio
67% VEIAS SIST. /VENULAS
 5% CAPILARES SISTÊMICOS
 11% ARTÉRIAS SISTÊMICAS
 5% VEIAS PULMONARES
 3% ARTÉRIAS PULMONARES
 4% CAPILARES PULMONARES
 5% ÁTRIOS/VENTRICULOS

Organização do Sistema
Circulatório
CIRCUITOS EM SÉRIE
E EM PARALELO
HEMODINÂMICA
VELOCIDADE,FLUXO,PRESSÃO
 FLUXO LAMINAR
 LEI DE POISEUILLE
 RESISTÊNCIA(SERIE-PARALELO)
 FLUXO TURBILHONAR E NÚMERO
DE REYNOLD

PRESSÃO HIDROSTÁTICA
136cm
0
100
200
0
100
200
P=pxgxh
0
100mmHg
P = Pressão mmHg
p = densidade
g = gravidade
h = altura
136cm
0
100
200
0
0
100
200
CONCEITOS IMPORTANTES
VELOCIDADE = DISTÂNCIA / TEMPO
V
=
D
/ T
FLUXO = VOLUME / TEMPO
Q =
VL
/ T
VELOCIDADE -FLUXO- ÁREA
V
=
Q
/ A
ENERGIA DE UM FLUÍDO ESTÁTICO VS
EM MOVIMENTO
ENERGIA TOTAL= POTENTIAL + CINÉTICA
ET
=
EP
+
EC
FLUÍDO EM REPOUSO (HIDROSTÁTICA )
FLUÍDO EM MOVIMENTO (HYDROSTÁTICA
+ HIDRODINÂMICA)
VELOCIDADE E PRESSÃO
0
0
100
200
ÁREA DE SECÇÃO TRANSVERSAL
E VELOCIDADE
A= 2cm2
Q=10ml/s
a
V= 5cm/s
10cm2
b
1cm/s
V=Q/A
1cm2
c
10cm/s
LEI DE POISEUILLE
Fluxo em Tubos Cilíndricos Rigídos
4
(FLUXO)Q =
DIFERENÇA
DE PRESSÃO
(Pi - Po) r
8ηL
VISCOSIDADE COMPRIMENTO
RAIO
POISEUILLE’S LAW GOVERNING FLUID
FLOW(Q) THROUGH CYLINDRIC TUBES
RESISTÊNCIA AO FLUXO NO
SISTEMA CARDIOVASCULAR
CONCEITOS BÁSICOS
Rt = R1 + R2 + R3…………. RESISTÊNCIAS EM SÉRIE
1/Rt = 1/R1 + 1/R2 + 1/R3…. RESISTÊNCIAS EM PARALELO
R1
PARALELO
SÉRIE
R1
R2
R3
R2
R3
RESISTÊNCIA AO FLUXO NO
SISTEMA CARDIOVASCULAR
O QUE REALMENTE OCORRE NO SCV?
BAIXA R
ALTA R
BAIXA R
ARTÉRIAS
ARTERÍOLAS
CAPILARES
Teorema de Bernoulli
para um fluxo constante em um leito fechado.
A soma da Energia de Pressão, Energia Cinética e Energia
Potencial em um determinado ponto do leito vascular é igual
a soma dessas Energias em um outro ponto do mesmo leito
vascular.
FLUXO LAMINAR VS FLUXO TURBILHONAR
O Número de REYNOLD
FLUXO
LAMINAR
Nr = pDv/ n
laminar = 2000 ou inferior
FLUXO
TURBILHONAR
p =
D=
v =
n =
densidade
diâmetro
velocidade
viscosidade
SISTEMA ARTERIAL

COMPLACÊNCIA

PRESSÃO ARTERIAL

PRESSÃO DE PULSO

MEDIDA DE PRESSÃO
THE END
THE CONCEPT OF THE HYDRAULIC
FILTER
SYSTOLE
DIASTOLE
COMPLIANT
RIGID
O2 CONSUMPTION (mlO2/100g/beat)
EFFECTS OF PUMPING THROUGH A
RIGID VS A COMPLIANT DUCT
0.1
PLASTIC TUBING
NATIVE AORTA
0
5
STROKE VOLUME (ml)
15
% INCREASE IN VOLUME
STATIC P-V RELATIONSHIP
IN THE AORTA
PRESSURE (mmHg)
ELASTIC MODULUS OR
ELASTANCE
Ep = P / D/D
ELASTANCE
P
V
Ep= ELASTIC MODULUS
D= MAX. CHANGE IN
AORTIC DIAMETER.
D= MEAN AORTIC DIAM.
COMPLIANCE
V
P
EP IS INVERSELY PROPORTIONAL TO C
MEAN ARTERIAL PRESSURE (MAP)
REMEMBER OHMS LAW?
CARDIAC OUTPUT
PERIPHERAL RESISTANCE
INSTANTANEOUS
INCREASE
STEADY STATE
INCREASE
ARTERIAL PRESSURE (mmHg)
EFFECT OF COMPLIANCE ON MAP
Pa = Qh - Qr / Ca
SMALL Ca
LARGE Ca
INCREASE CARDIAC OUTPUT
TIME
Qh- inflow (CO)
Qr- outflow
Ca- Compliance
Pa- MAP
PULSE PRESSURE
STROKE VOLUME
COMPLIANCE
V4
VB
VOLUME V3
V2
VA
V1
P1 PA P2
P3
PB
P4
PRESSURE
PULSE PRESSURE
EFFECTS OF:
COMPLIANCE
TOTAL PERIPHERAL RESISTANCE
TPR
COUPLING OF THE HEART AND BLOOD VESSELS
VASCULAR FUNCTION CURVE
HOW CARDIAC OUTPUT REGULATES
CENTRAL VENOUS PRESSURE
CARDIAC FUNCTION CURVE
HOW CENTRAL VENOUS PRESSURE (PRELOAD)
REGULATES CARDIAC OUTPUT
VASCULAR FUNCTION CURVE
CENTRAL VENOUR PRESSURE (mmHg)
HOW CHANGES IN CARDIAC OUTPUT INDUCE
CHANGES IN CENTRAL VENOUS PRESSURE?
8
Pmc
B
VASCULAR FUNCTION
CURVE
A
-1
0
8
CARDIAC OUTPUT (L/min)
CENTRAL VENOUR PRESSURE (mmHg)
HOW BLOOD VOLUME AND VENOMOTOR
TONE CHANGE THE VASCULAR FUNCTION
CURVE?
8
VASCULAR FUNCTION
CURVE
-1
0
8
CARDIAC OUTPUT (L/min)
CENTRAL VENOUR PRESSURE (mmHg)
TOTAL PERIPHERAL RESISTANCE
AND THE VASCULAR FUNCTION
CURVE.
8
VASCULAR FUNCTION
CURVE
-1
0
8
CARDIAC OUTPUT (L/min)
CARDIAC OUTPUT (L/min)
THE CARDIAC FUNCTION CURVE
CENTRAL VENOUS PRESSURE (mmHg)
CARDIAC OUTPUT (L/min)
EFFECTS OF SYMPATHETIC STIMULATION
ON THE CARDIAC FUNCTION CURVE
CENTRAL VENOUS PRESSURE (mmHg)
HOW BLOOD VOLUME AND PERIPHERAL
RESISTANCE CHANGE THE CARDIAC
FUNCTION CURVE?
CARDIAC OUTPUT (L/min)
VOLUME
CENTRAL VENOUS PRESSURE (mmHg)
RESISTANCE
CARDIAC OUTPUT (L/min)
THE CARDIAC FUNCTION CURVE IN
HEART FAILURE
CENTRAL VENOUS PRESSURE (mmHg)
HEART - BLOOD VESSELS
COUPLING
MORMAL FUNCTION
PUMP
VEINS
ARTERIES
Qh
5L/min
Pa
CPV=2mmHg=Pv
5L/min
COMPLIANCES
Cv = 19Ca
Cv>>>>Ca
Qr
PERIPHERAL R= Pa - Pv / Qr
R = 20mmHg/L/min
MPA=102mmHg
CARDIAC ARREST!
INMEDIATE EFFECT
FLOW STOPS HERE
PUMP
VEINS
ARTERIES
Qh
0L/min
Pa
CPV=2mmHg=Pv
5L/min
FLOW CONTINUES HRE
TRANSFER ART-->VEINS
Qr
R = 20mmHg/L/min
Qr= Pa - Pv/20
Qr CONTINUES AS LONG AS
A PRESSURE GRADIENT
IS SUSTAINED
CARDIAC ARREST
STEADY STATE
FLOW STOPPED
PUMP
VEINS
ARTERIES
Qh
0L/min
Pa = 7mmHg
Pv = 7mmHg = MEAN CIRCULATORY PRESSURE OR Pmc
95mmHg
5mmHg
FLOW STOPPED
0L/min
Qr
Qr = 0 ( NO Pa - Pv DIFFERENCE)
WE START PUMPING!
INMEDIATE EFFECT
FLOW STARTS
SOME VENOUS BLOOD
PUMP
VEINS
ARTERIES
Qh
1L/min
Pa = 7mmHg
Pv = 7mmHg
NO FLOW HERE YET
0L/min
Qr
FLOW RETURNS AT Qr AT
THE NEW Qh
PUMP
VEINS
ARTERIES
Qh
1L/min
Pa = 26mmHg
Pv = 6mmHg
FLOW STARTS
1L/min
Qr
R = 20mmHg
Qr = Pa - Pv / 20 = 1L/min