BP REGISTRATION & REGULATION. PECULIARITIES OF REGIONAL BLOOD SUPPLY

Lecturer MD, Ph.D. Angelika V. Ivasenko

Laws of haemodynamics Pressure difference is the moving

force in blood flow Blood flows from high pressure to low

pressure Pressure is created by ventricles

contraction

P=Q·R Q is minute volume of blood flow, it is

determined by heart work Q= HR · SV, HR- heart rate, SV –

stroke volume R is resistance of the vessel to blood

flow R, depends mainly on vessel radius

Functional classification of blood vessels (by Folkov) Buffer (aorta) Precapillary resistance vessels

(arteries,arterioli) Exchange vessels (capillaries) Postcapillary resistance vessels

(venuli,small veins) Arterio-venous anastomosis Volume vessels (big veins)

Linea velocity of blood flow in different parts of circulatory system

Aorta arteries arterioli capillaries veins

Pressure changes in different parts of circulatory system

Aorta arteries arterioli capillaries venuli,veins vena cava

Methods of BP registration

DIRECT-registeringpressure in the vessel

INDIRECT-registering

pressure in the cuff of

sphygmomanometer

PALPATORY(RIVA-ROCCHI)

AUSCULTATORY (KOROTKOV)

Direct measuring of blood pressure allows to register waves of blood pressure

WAVES on BP curve Waves of the 1st type- pulse waves Waves of the 2nd type-respiratory

waves Waves of the 3rd type-changing in the

tone of vasomotor centre

Indirect methods of BP registration Pressure is measured in the cuff, not

in the vessel Based on the III law of Newton we

consider it to be same (or almost same as in the vessel)

Riva-Rocchi method allows to measure systolic BP only

Korotkov’s method allows to measure both systolic & diastolic BP

Continuous blood flow Volume of blood vessels & heart

chambers should correlate with the volume of blood flow

Left & right heart should work in correlation

REGULATED PARAMETERS P=QR

Heart Work Vascular Tone

Factors influencing vascular tone Nervous

Hormonal

Basilar tone of the vessels registered without any nervous

& hormonal influences Has 2 components:1. Myogenic2. Tonic impulses from vasomotor

centre (1-3 per sec)

Vasoconstriction influences Sympathetic fibres (alfa-adrenoreceptors) Humoral influences 1. Renin-angiotensin2. Adrenalin3. serotonin

Vasodilation influences Sympathetic fibres (beta-adrenoreceptors) Sympathetic fibres (cholinoreceptors) Paraympathetic fibres (n. pudendus, chordae

tympani) Humoral influences:1. Hystamine2. Bradikinin3. Prostaglandines Metabolic influences (lactate, adenosine, pH)

SCHEME OF DEPRESSOR REFLEX

SCHEME OF PRESSOR REFLEX

Scheme BP Regulation