№4_The main indicators and patterns of hemodynamics. Classification and functional characteristics of blood..ppt

№
№4
4 The main indicators and patterns of
The main indicators and patterns of
hemodynamics. Classification and
hemodynamics. Classification and
functional characteristics of blood.
functional characteristics of blood.
Questions:
The main indicators and patterns of hemodynamics.
Classification and functional characteristics of blood
vessels. The movement of blood through the
arteries. The movement of blood through the
capillaries. The movement of blood through the
veins. Features of blood flow in individual organs.
Blood circulation during physical and emotional
stress. Regulation of vascular tone.
Physiology of lymph circulation. The composition
and properties of lymph. Lymph formation. The
movement of lymph through the vessels.
Рhysiology-1
Рhysiology-1

Hemodynamics
Hemodynamics ("hemo" – blood, "dynamics" – movement) is a branch
of physiology that studies the patterns of blood movement through the
vascular system. Blood vessels are a closed system in which blood
continuously circulates from the heart to the tissues and back to the heart.
The large (systemic) and small (pulmonary) circulatory circles ensure the
performance of all blood transport functions: respiratory, trophic, excretory,
participation in humoral regulation, maintenance of temperature balance in
the body.
The most widespread is the functional classification of the
cardiovascular system, proposed in 1960 by the Swedish scientist B.
Folkov. In accordance with this classification, all components of the
cardiovascular system, including vessels, are classified according to
functional characteristics:
1. The heart is a pump that rhythmically releases blood into the vessels and
sucks it to the heart.
2. Boiler vessels, or buffer vessels – aorta and large elastic-type arteries with
high extensibility and 8 converting intermittent blood flow from the heart into
continuous through the vessels.

3. Resistive vessels, or resistance vessels, are small arteries and arterioles that contain
smooth muscle fibers and have a high internal (myogenic) basal tone. These vessels
ensure the continuity of blood flow through the cardiovascular system, because they
create a high overall resistance to blood flow, preventing the complete outflow of blood
from large vessels to small ones. I.M. Sechenov called them "taps" of the vascular
system, because they participate in the redistribution of blood flow to various organs and
tissues. Resistive vessels, changing their lumen, provide increased blood flow to the
"working" organ and significantly reduce its flow to the resting organ.
4. Precapillary sphincters are muscle rings located in front of the capillaries; they
regulate blood flow into the capillaries.
5. Capillaries, or exchange vessels – provide transcapillary metabolism of substances
and gases between blood and tissues.
6. Postcapillary resistance vessels – venules and small veins – ultimately determine the
hydrostatic pressure in the capillaries, on which transcapillary exchange depends.
7. Shunting vessels or arteriol-venular anastomoses provide a direct flow of arterial
blood into the venous 9 part of the channel, bypassing the capillaries. They do not
perform an exchange function, are localized in certain areas of the skin (fingers, toes,
ear) and participate in thermoregulation.
8. Capacitive vessels (veins) – in which 75-80% of all circulating blood is located. A
slight change in their lumen can significantly affect the venous return of blood to the
heart.
Hemodynamics

BASIC LAWS OF HEMODYNAMICS
Hemodynamics is based on the laws of hydrodynamics. According to the latest laws of
hydrodynamics, the movement of fluid through the tubes is determined by the pressure
difference at the beginning and at the end of the tube, the resistance experienced by the
flowing fluid, and the velocity of the fluid.
Thus, the main parameters of hemodynamics include ¾ blood pressure; ¾ peripheral
vascular resistance; ¾ volumetric and linear blood flow rates.
Pressure Blood pressure is the force with which moving blood presses on the vessel
wall. According to the Poiseuille formula, the pressure value is: ∆P = Q × R, where P is
the blood pressure; Q is the amount (volume) of blood; R is the resistance in the
vascular system.
Physiological factors are superimposed on the physical patterns of blood flow
through the vessels: the work of the heart, changes in vascular tone, the volume of
circulating blood and its viscosity.
The blood pressure in the arteries is directly proportional to the volume of blood (Q) coming
from the heart and the resistance to blood outflow created by peripheral vessels (R). The
driving force of blood flow is the pressure gradient, which is created by the work of the heart
and peripheral resistance. The heart provides the blood with the energy of movement. The
measure of this energy is blood pressure. When the blood moves, all the energy splits into
two types: potential and kinetic. The lateral pressure 10 (hydrostatic) reflects the potential
energy – this is the force with which the blood presses on the walls of the vessels.
Hydrostatic pressure is measured using vertical piezometers placed in the vascular bed: to
what height the blood will rise in such a piezometer, this is the value of lateral pressure.

When using piezometers with a bent knee positioned against the fluid flow, the total
pressure is measured, which is equal to the sum of the lateral and dynamic pressure
P total = P hydrostatic (lateral) + P is dynamic. Dynamic pressure reflects the kinetic
energy of blood. Most of the blood energy transmitted by the heart goes to the lateral
pressure, less – to the dynamic. As you move away from the heart, blood pressure
decreases, as energy is spent on overcoming the resistance of the vascular system.
Swedish scientist Folkov divided the cardiovascular system into two areas
according to the magnitude of blood pressure:
¾ area of high blood pressure; ¾ area of low blood pressure. In the area of high
blood pressure, the P value is above 40 mm Hg. This zone includes the left
ventricle, aorta, arteries and arterioles of the large circulatory circle.
In the low pressure area, the P value is below 40 mmHg. These are the
capillaries, venules and veins of the great circle of blood circulation, the right
atrium, the right ventricle, the entire small circle of blood circulation and the left
atrium.
Resistance in the vascular system Resistance is a force that prevents the flow of blood.
According to the Poiseuille formula, the blood resistance in the vascular system
is equal, where L is the length of the vessel; p and 8 are constants; r is the radius
of the vessel; h is the viscosity of the blood. The resistance is created by the flowing
liquid due to the friction of the liquid particles against the vessel walls, as well as due to
the presence of internal friction between different layers of the liquid. Distinguish
between external and internal resistance; specific and total resistance.

The external resistance depends on the radius (r) and length (L) of the vessel. In narrow and
long vessels, the external resistance is high. Internal resistance is the force of internal friction
between cells and layers of moving blood. The internal resistance depends on the viscosity of
the blood (h): the greater the viscosity of the blood, the greater the internal resistance. The
viscosity is determined by the number of cells and proteins in the blood plasma. In humans,
the viscosity of blood is 4-5 times greater than the viscosity of distilled water. There is a
distinction between the concept of static viscosity (viscosity of blood in vitro) and dynamic
(viscosity of moving blood). The dynamic viscosity is influenced by the speed and nature of
blood flow: the higher the blood flow rate, the lower the dynamic viscosity and the lower the
internal resistance. In most large, medium and even small vessels, the diameter of which is
noticeably larger than the diameter of red blood cells, the nature of the blood flow is laminar
(layered). With laminar blood flow, erythrocytes move at the highest speed in the center of the
vessel (they have the highest specific gravity), leukocytes move to the periphery of the
erythrocytes at a lower 13 speed, and platelets and blood plasma move very slowly closer to
the wall. The layers slide relative to each other, which creates resistance (friction) for the flow
of blood as a heterogeneous fluid. Thus, in most vessels, the internal resistance is
determined by the internal friction force of these layers of blood and does not differ
significantly. Small arteries and arterioles are narrow, long, with numerous branches, vessels.
In the places of branches and bends of these vessels, the laminar nature of the blood flow is
disrupted and turns into turbulent (vortex). Vortices formed perpendicular to the blood flow
significantly increase the internal friction of the blood, and much more pressure is required for
its advancement. In capillaries, the nature of blood flow becomes chain-like, since their
diameter is equal to or even slightly smaller than the diameter of red blood cells. Red blood
cells move one after another in a chain, deforming according to the size of the capillary.

The blood flow has a single-layer character, which should lead to a noticeable
decrease in internal resistance. However, this does not happen due to the low blood flow
rate in the capillaries. Thus, the internal resistance in most vessels is the same and increases
only in small arteries and arterioles due to the predominance of the turbulent nature of the
blood flow in them. The external and internal resistance form the specific and total resistance
of the vessels. Resistivity is the resistance to blood flow in a given area of the vascular
system. In the aorta, the resistivity to blood flow is the lowest, since the aorta is a wide vessel
with a large radius. In the arteries, the resistivity increases, but not significantly, since the
arteries are quite large vessels and have a large radius. Small arteries and arterioles due to
contractions of a well-developed muscle membrane can dramatically reduce their lumen.
Arterioles are longer than capillaries, they are branched and convoluted vessels with
turbulent blood flow. Arterioles have the greatest resistivity, so they are called resistive
vessels. In capillaries, the resistivity is somewhat lower than in arterioles, since capillaries are
narrow, but very short vessels. The chain nature of the blood- 14 current causes a low
internal resistance. In the venous bed, the resistivity decreases, as the lumen of the vessels
increases. The low resistivity of blood in large veins facilitates the return of blood to the heart.
The movement of blood through low-pressure vessels (veins). Venous pulse. Veins
are capacitive vessels. They contain 70-80% of blood. The pressure in the venules is 12
-18 mmHg.
In the veins outside the thoracic cavity – 5-9 mm Hg. When flowing into the right atrium, it
fluctuates depending on the phases of respiration: on inspiration – below atmospheric, on
exhalation – higher by 2 – 5 mm Hg.

Additional factors that ensure blood flow in the veins:
1. Suction action of the chest. When inhaling, the pressure in the chest cavity decreases,
this contributes to the expansion of the veins, the effect of sucking blood from neighboring
vessels is triggered. The diaphragm, going down, increases intra-abdominal pressure, which
promotes venous flow to the heart from the vessels of the abdominal cavity.
2. Skeletal muscle contractions ("muscle pump"). Skeletal muscles, contracting,
squeeze the veins, which pushes blood to the heart. The presence of valves on the inner
surface of some veins counteracts the reverse blood flow.
3. The sucking action of the heart. The atrioventricular septum with ventricular systole,
shifting downwards, creates a sucking effect of blood to the heart from the veins.
4. Peristaltic contractions of the walls of some veins — 2-3 per minute.
5. Pulsation of nearby arteries. Venous pulse Microcirculation.
Capillary blood flow and its features. Microcirculation is the movement of blood
through the vessels of the microcirculatory bed, which include:
1. arterioles
2. metaarteriols
3. precapillary sphincter
4. precapillaries
5. capillaries
6. postcapillary venules
7. venules

Capillaries belong to the exchange vessels. They provide: - gas exchange, -
supply of cells with nutrients - excretion of metabolic products.
The exchange also occurs in the venules. At rest, blood circulates only in 25-
35% of all capillaries. The density of capillaries is greatest in the myocardium,
brain, liver, kidneys, lungs - up to 2500-3000 capillaries per 1 mm2. The
smallest is in bone, adipose, connective tissue. The diameter of the capillaries is
from 5 to 30 microns. The length of one capillary is 0.5–1.1 mm. The total surface of
all capillaries is 1000 m2. The total cross–sectional area of all capillaries of a large
circle is from 8000 to 11000 cm2.
Somatic type – has continuous endothelial and basal membranes, has a large
number of minute pores (4-5nm). Easily pass water and minerals. They are found in
skeletal and smooth muscles, adipose and connective tissue, lungs, and the
cerebral cortex. Visceral type – has "windows" (fenestra) with a diameter of 0.1
microns. Capillaries are covered with the thinnest membrane, permeable to water,
dissolved salts, macromolecules. They are found in the kidneys, gastrointestinal
tract, endocrine glands.
Sinusoidal type – the basement membrane is partially absent, the endothelial
membrane is intermittent, with large interstitial lumen.
Fluids and blood cells pass through them. Localized in the bone marrow,
liver, spleen. Diffusion osmosis, pinocytosis, Filtration and reabsorption
 

Diffusion occurs due to the concentration gradient of substances. Diffusion
has a two-way character; the speed is very high. Passing through the capillary
plasma fluid 40 times, it is completely exchanged with the intercellular fluid.
Through the total exchange surface of the body, the diffusion rate is
approximately 60 l/ min, an average of 85,000 liters per day. Nonpolar (fat-
soluble) substances and small uncharged molecules (O2, CO2, NH3 and
water) can diffuse directly through the capillary wall, without the need for
movement through the pores).
The rate of their diffusion through the capillary wall is many times higher than
the rate of transport of polar molecules. Polar substances (for example, Na+,
K+, Cl–, Ca2+ ions; various small but polar metabolites, as well as sugars,
nucleotides, protein and nucleic acid macromolecules) do not penetrate
membranes by themselves, carriers and ion channels (pores) are necessary for
their transport. Transfer through membranes. The permeability of the capillary
endothelium is not the same in different body tissues (liver capillaries are
permeable to albumin, the brain is not). The venous sections of the capillaries
are more permeable than the arterial ones.
Hydrostatic pressure in capillaries is the main filtration force. The main
force of reverse suction into the capillary is the colloidal osmotic
(oncotic) plasma pressure.

Regulation of vascular tone.
1. Local, regulating blood flow in individual organs and tissues;
2. Central, determining the value of blood pressure and systemic circulation.
The smooth muscles of the vessels constantly retain some tension — muscle
tone. The tone persists even in the complete absence of nervous and humoral
influences and is called basal or peripheral. Some smooth myocytes are able to
spontaneously excite, the excitation is transmitted to other cells and as a result
there are rhythmic fluctuations in tone — endogenous vasomotor. In
maintaining it, the leading role belongs to myogenic regulation.
Myogenic regulation is manifested by: - a change in the tone of the
vessels, characteristic of the condition of relative rest, in response to a change
in blood pressure in them (local mechanical stretching). - metabolic regulation.
the ability of metabolites (O2, CO2, H+ ions, ATP, AMP, adenosine (ATP
cleavage product), lactic acid and others) to have an expanding effect on blood
vessels supplying tissue.
Neurohumoral mechanisms of blood flow regulation
1. Afferent (receptor) link.
2. The central link.
3. The efferent link. https://www.youtube.com/watch?v=tG9dR8NOBQQ

There are several types of receptors located in the vessels (angioreceptors):
Baroreceptors (presso-) react to the rate and degree of stretching of the vessel
walls. According to the mechanism of action, they are mechanoreceptors.
Chemoreceptors are sensitive to the chemical composition of blood.
Angioreceptors are located in the vessels of the entire circulatory system, forming
a single receptive field, it includes reflexogenic zones. Of these, the most significant
are: aortic, sinocarotid, vascular zone of the pulmonary circle and others.
The vasomotor center of the medulla oblongata consists of 2 zones:
1. Depressive zone. It helps to reduce the activity of the sympathetic nervous
system, vasodilation, reduction of peripheral resistance, activates parasympathetic
mechanisms.
2. Pressor zone. Helps to increase blood pressure by increasing cardiac output
and peripheral resistance. There are reciprocal relationships between the first and
second zones: if the depressor zone is excited, then this leads to inhibition of the
pressor zone, and vice versa. The central link is the medulla oblongata
Vasomotor nerves
Sympathetic nerves, through:
 - adrenoreceptors - constriction and tone
 - adrenoreceptors - dilation m - cholinoreceptors - dilation

• Parasympathetic nerves, through:
acetylcholine - m-cholinoreceptors - NO - dilation of brain vessels, in the submandibular gland
(chord of the tympani) and organs
pelvic bradykinin and histamine - dilation of the vessels of the skin, gastrointestinal tract
Humoral regulation of the vascular bed
Vasoconstrictors
• Angiotensin - substances produced by the vascular endothelium (endothelins, thromboxanes,
• Endothelial vasoconstrictor (EDCF))
• Norepinephrine
• Vasopressin
Vasodilators
• Histamine
• Natriuretic hormone (atriopeptide)–
• Acetylcholine
• Kallikrein is a kinin system.
• Substance P
• Endothelial regulators (nitric oxide — NO)
Substances with a dual effect on blood vessels
• Adrenaline
• Serotonin (5-hydroxytryptamine)
• Prostaglandins

Physiology of lymph circulation
• Physiology of lymph circulation. The composition
and properties of lymph. Lymph formation. The
movement of lymph through the vessels.
Thoracic duct, its formation, drainage areas. Large
lymphatic trunks carrying lymph into the thoracic duct
(left bronchoconstrictor trunk, left subclavian trunk, left
jugular trunk) and their drainage areas.
The right lymphatic duct, its formation, topography,
drainage areas.
The main regional lymph nodes are: head, neck, upper
limb, thoracic cavity, abdominal cavity, lower limb, pelvis.
Ways of lymph outflow from the mammary gland. The
value of regional lymph nodes in normal and pathological
conditions.
Lymphoid organs: Bone marrow (red and yellow),
function, topography, structure. Thymus, its function,
topography, structure (lobes, parenchyma of thymus:
cortical substance, medulla), age features. Lymph
nodes, their structure (capsule, capsular trabeculae,
gates, reticular stroma, parenchyma of the lymph node:
cortical substance, medulla), topography. Spleen:
function, topography, structure. Lymphoid formations of
the digestive tract.

• GENERAL OUTLINE OF THE STRUCTURE OF THE LYMPHATIC SYSTEM The LYMPHATIC
SYSTEM, systema lymphaticum is an integral part of the vascular system.
It begins with blind capillaries in the tissues. It flows into the venous system. The functions of the
lymphatic system Drainage – drainage from the interstitial space of fluid and proteins (released
from the bloodstream), lipids, metabolic products, foreign particles, bacteria, cell debris, etc.
Transport – what is drained is transported through the lymphatic vessels. Immune – lymph
passes through the lymphatic vessels through the lymph nodes, which act as an immunological and
biological filter, carrying out immunological supervision, which contributes to the formation of the
body's resistance (the formation of immunity).
Hematopoietic – in the lymphoid organs, the formation and differentiation of lymphoid
elements (lymphopoiesis) occurs.
Cells of malignant tumors (cancer) spread along the lymphatic pathways, which is of great
clinical importance.

The lymphatic system is divided into two divisions:
Lymph transport routes lymphatic capillaries (endothelium only, without valves),
 postcapillaries (endothelium, with valves),
 lymphatic vessels (endothelium, smooth muscle cells, adventitia, valves), o lymphatic trunks, o
lymphatic ducts.
Lymphoid organs
Central organs of the immune system: red bone marrow, thymus gland. Peripheral organs of the
immune system: lymph nodes, spleen, lymphoid formations of the digestive tract, formation of
lymphoid tissue in the form of tonsils, tonsillae.

LYMPH TRANSPORT ROUTES
• Lymphatic capillaries (lymphocapillary vessels), vasa
lymphocappillaria: are the initial link, the "roots" of the
lymphatic system,
 have a wall consisting only of endothelial cells. With the
accumulation of fluid around the capillary, endothelial cells can
shift (this is facilitated by actin-like microfilaments),
the gaps between the cells increase, and the intercellular fluid
passes into the lumen of the capillary), are present in all tissues
and organs of the body, with the exception of the central
nervous system, eyeball, inner ear, epithelial skin and mucous
membranes, cartilage, parenchyma of the spleen, bone marrow
and placenta.
 Postcapillaries have:
  a wall of endothelial cells,
  valves.
 Lymphatic vessels, vasa lymphatica, are formed by the
fusion of lymphatic capillaries, there is a layer of smooth muscle
cells in the wall in addition to endothelial cells, they form intra-
and extra-organ plexuses, they have valves, valvulae
lymphaticae, which determine the direction of lymph flow
through lymphatic vessels, they have lymph nodes along the
way. In relation to the superficial fascia, lymphatic vessels can
be: o superficial (subcutaneous, lying in fatty tissue), o deep
(accompanying blood vessels and nerves). In relation to the
lymph node, there may be: o bringers (lymph flows through
them to the lymph node), o carrying out (lymph flows from the

LYMPH TRANSPORT ROUTES
• Lymphatic trunks, trunci lymphatici, are formed by connecting lymphatic vessels after the
passage of lymph through the lymph nodes (that is, lymphatic trunks are vessels in the path of
which there are no lymph nodes).
 Lymphatic trunks can be:
  paired (right and left):
 lumbar trunks (collectors from the lower extremities, pelvis and abdominal cavity), o jugular trunks
(from the head and neck), o subclavian trunks (from the upper extremities), o bronchoconstrictive
trunks (in the thoracic cavity);
 unpaired – only one, besides unstable – o intestinal (abdominal cavity). Diagram of the location
and drainage area of lymphatic ducts
 Lymphatic ducts, ductus lymphaticus
 All lymphatic trunks are collected into two ducts: • the thoracic duct, ductus thoracicus, collects 2/3
of all lymph, 10 • the right lymphatic duct, ductus lymphaticus dexter, collects 1/3 of all lymph. The
thoracic duct, ductus thoracicus, is the largest and main collector of lymph: it is formed at the level
of the XII thoracic – II lumbar vertebrae from trunks: o right lumbar lymph trunk, truncus lumbales
dexter, o left lumbar lymph trunk, truncus lumbales sinister. The thoracic duct flows into the left
venous angle or into the terminal part of the veins forming it (internal jugular and subclavian).
 Through the thoracic duct, lymph flows from: the lower extremities, the walls and organs of
 
the pelvis, the walls and organs of the abdominal cavity, the left half of the thoracic cavity. The
 
right lymphatic duct, ductus lymphaticus dexter, is formed from the trunks: o right jugular, o right
subclavian, o right bronchomediastinal, flows into the right venous angle (into the internal jugular

or subclavian vein at the place of their confluence with each other), drains the right side of the

head, neck and chest, the right upper a limb.

№4_The main indicators and patterns of hemodynamics. Classification and functional characteristics of blood..ppt

More Related Content

Similar to №4_The main indicators and patterns of hemodynamics. Classification and functional characteristics of blood..ppt (20)

More from kokane1st (8)

Recently uploaded (20)

№4_The main indicators and patterns of hemodynamics. Classification and functional characteristics of blood..ppt