PHYSIOLOGY OF VENOUS AND LYMPHATIC SYSTEM.

1
PHYSIOLOGY OF VENOUS AND LYMPHATIC SYSTEM.
2
Blood flow in veins

• Blood flows through the blood vessels, including
  the veins, primarily, because of the pumping
  action of the heart, although venous flow is
  aided by the heartbeat, the increase in the
  negative intrathoracic pressure during each
  inspiration, and contractions of skeletal muscles
  that compress the veins (muscle pump).

3
Morpho-functional properties of venous system

• Veins are the vessels, which are carry out blood
  from organs, tissues to heart in right atrium.
  Only pulmonary vein carry out blood from lungs in
  left atrium. There are superficial (skin) and
  deep veins. They are very stretching and have a
  low elasticity. Valves are present in veins.
  Plexus venosus are depo of blood. Blood moving in
  veins under gravity.

4
Mechanism of regulation

• Difference of pressure in venous system is a
  cause of blood moving. From the place of high
  pressure blood moving to the place of low
  pressure. Negative pressure in chest is a cause
  of blood moving. Contraction of skeletal muscles,
  diaphragm pump, peristaltic movement of veins
  walls are the causes of moving.

5
Venous pressure

• Venous pressure is pressure of blood, which are
  circulated in veins. Venous pressure in healthy
  person is from 50 to 100 mm H2O. Increase of
  venous pressure in physiological condition may be
  in the action of physical activity. Determine of
  venous pressure is called phlebotonometry and
  give for doctors information about activity of
  right atrium.

6
Speed of blood stream

• Speed of vein blood stream depend on diameter of
  vessels. In venuls speed of blood moving is
  lower. In veins of middle diameter it 7-14 cm/s,
  in big veins the speed is near 20 cm/s. In big
  veins speed of blood moving depend on breathing
  and heartbeat.

7
Venous pulse

• Venous pulse is a moving of walls of big veins,
  which are depend on heartbeat. The cause of it
  stop of blood flow from vein to heart during
  atrium systole. At these time pressure in it
  increase. Methods of investigation of venous
  pulse are phlebography.

8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
Transport of substances through capillary membrane

• Substances are transported through capillary
  membrane are lipid soluble as O2 or CO2 and
  water-soluble as ions or glucose. Substances of
  molecule size more than 6-7 nm cannot diffuse
  through intra-endothelial pores. The greater the
  concentration difference of a given substance on
  two sides of capillary membrane, the greater will
  bi net rate of diffusion. Forces that determine
  fluid movement through capillary membrane are
  capillary pressure, interstitial fluid pressure,
  plasma colloid osmotic pressure and interstitial
  fluid colloid osmotic pressure. At arterial end
  of capillary pressure is higher than interstitial
  fluid pressure, which causes filtration. At
  venous end of capillary plasma colloid osmotic
  pressure is lower than interstitial pressure,
  which cause reabsorbtion.

17
(No Transcript)
18
Lymph and lymphatic circulation

• Lymph vessels are present in all tissues, except
  bones, nervous and superficial layers of skin.

19
Lymphatic capillaries

• Lymphatic capillaries begin as one side closed
  capacities, which are drained by smallest
  lymphatic vessels. Lymphatic capillaries have
  valves, which prevent opposite movement of lymph.
  Connective tissue fibers fix outer surface of
  lymphatic capillary to surrounding intracellular
  substance and keep it voluminous shape. Pressure
  of lymph inside the capillary is lower than in
  intracellular space, which helps to lymph flow.
  Capillary wall has basal membrane and one layer
  of endotheliocytes.

20
(No Transcript)
21
Morpho-functional properties of lymphatic system

• Lymph system has capillaries, vessels, where
  present valves, lymphatic nodes. In lymphatic
  nodes are lymphopoiesis, depo of lymph, their
  function is barrier-filter. Lymph flow in vein
  system through the chest lymph ductus. Functions
  of lymph 1. support of constant level of volume
  and components of tissue fluid 2. transport of
  nutritive substances from digestive tract in
  venous system 3. barrier-filter function. 4.
  take place in immunology reactions.

22
(No Transcript)
23
Composition and properties of lymph

• Lymph is tissue fluid that enters the lymphatic
  vessels. It drains into the venous blood via the
  thoracic and right lymphatic ducts. It contains
  clotting factors and clots on standing in vitro.
  Its protein content is generally lower than that
  of plasma but varies with the region from which
  the lymph drains. It should be noted that, in
  most locations, interstitial fluid is not
  protein-free it contains proteins that traverse
  capillary walls and return to the blood via
  lymph. Water-insoluble fats are absorbed from the
  intestine into the lymphatic vessels, and the
  lymph in the thoracic duct after a meal is milky
  because of its high fat content Lymphocytes enter
  the circulation principally through the lymphatic
  vessels, and there are appreciable numbers of
  lymphocytes in thoracic duct lymph. Time of
  clotting 10-15 minutes. There are 3 kinds of
  lymph peripheral, transport, central. The
  difference between them in cell quantity level.

24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
Production of lymph

• Fluid efflux normally exceeds influx across the
  capillary walls, but the extra fluid enters the
  lymph and drains through them back into the
  blood. This keeps the interstitial fluid pressure
  from rising and promotes the turnover of tissue
  fluid. The normal 24-hour lymph flow is 2-4 L.
  Appreciable quantities of protein enter the
  interstitial fluid in the liver and intestine,
  and smaller quantities enter from the blood in
  other tissues. The walls of the lymphatic are
  permeable to macromolecules, and the proteins are
  returned to the bloodstream via the lymphatic.

29

• The amount of protein returned in this fashion in
  1 day is equal to 25-50 of the total
  circulating plasma protein. In the kidneys,
  formation of a maximally concentrated urine
  depends upon an intact lymphatic circulation
  removal of reabsorbed water from the medullar
  pyramids is essential for the efficient operation
  of the countercurrent mechanism and water enters
  the vasa recta only if an appreciable osmotic
  gradient is maintained between the medullar
  interstitial and the vasa recta blood by drainage
  of protein-containing interstitial fluid into the
  renal lymphatic. Some large enzymes notably
  histaminases and lipase may reach the
  circulation largely or even exclusively via the
  lymphatic vessels after their secretion from
  cells into the interstitial fluid. The transport
  of absorbed long-chain fatty, for example,
  cholesterol from the intestine via the lymphatic
  vessels.

30
Mechanism of lymph flow

• Lymph flow is due to movements of skeletal
  muscle, the negative intrathoracic pressure
  during inspiration, the suction effect of high
  velocity flow of blood in the veins in which the
  lymphatic vessels terminate, and rhythmic
  contractions of the walls of the large lymph
  ducts. Since lymph vessels have valves that
  prevent backflow, skeletal muscle contractions
  push the lymph toward the heart. Pulsations of
  arteries near lymphatic vessels may have a
  similar effect. However, the contractions of the
  walls of the lymphatic ducts are important, and
  the rate of these contractions increases in
  direct proportion to the volume of lymph in the
  vessels. There is evidence that the contractions
  are the principal factor propelling the lymph.

31
Blood supply of the spleen

• There are 1,5-2 of volume circulation in the
  human spleen. In our organism spleen has a small
  amount of smooth muscle in the capsule and in
  pulpe. Activity in the sympathetic nerves caused
  vasocontriction. Histamine, adenosine caused
  vasodilatation, adrenaline, serotonine,
  prostaglandine vasocontriction.

32
Lympathatic system

• The lymphatic system has three primary functions.
  First of all, it returns excess interstitial
  fluid to the blood. Of the fluid that leaves the
  capillary, about 90 percent is returned. The 10
  percent that does not return becomes part of the
  interstitial fluid that surrounds the tissue
  cells. Small protein molecules may "leak" through
  the capillary wall and increase the osmotic
  pressure of the interstitial fluid. This further
  inhibits the return of fluid into the
  capillaries, and fluid tends to accumulate in the
  tissue spaces. If this continues, blood volume
  and blood pressure decrease significantly and the
  volume of tissue fluid increases, which results
  in edema (swelling). Lymph capillaries pick up
  the excess interstitial fluid and proteins and
  return them to the venous blood. After the fluid
  enters the lymph capillaries, it is called lymph.

33

• The second function of the lymphatic system is
  the absorption of fats and fat-soluble vitamins
  from the digestive system and the subsequent
  transport of these substances to the venous
  circulation. The mucosa that lines the small
  intestine is covered with fingerlike projections
  called villi. There are blood capillaries and
  special lymph capillaries, called lacteals, in
  the center of each villus. The blood capillaries
  absorb most nutrients, but the fats and
  fat-soluble vitamins are absorbed by the
  lacteals. The lymph in the lacteals has a milky
  appearance due to its high fat content and is
  called chyle.
• The third and probably most well known function
  of the lymphatic system is defense against
  invading microorganisms and disease. Lymph nodes
  and other lymphatic organs filter the lymph to
  remove microorganisms and other foreign
  particles. Lymphatic organs contain lymphocytes
  that destroy invading organisms.

34

• The lymphatic system consists of a fluid (lymph),
  vessels that transport the lymph, and organs that
  contain lymphoid tissue.

35
Lymph

• Lymph is a fluid similar in composition to blood
  plasma. It is derived from blood plasma as fluids
  pass through capillary walls at the arterial end.
  As the interstitial fluid begins to accumulate,
  it is picked up and removed by tiny lymphatic
  vessels and returned to the blood. As soon as the
  interstitial fluid enters the lymph capillaries,
  it is called lymph. Returning the fluid to the
  blood prevents edema and helps to maintain normal
  blood volume and pressure.

36
Lymphatic Vessels

• Lymphatic vessels, unlike blood vessels, only
  carry fluid away from the tissues. The smallest
  lymphatic vessels are the lymph capillaries,
  which begin in the tissue spaces as blind-ended
  sacs. Lymph capillaries are found in all regions
  of the body except the bone marrow, central
  nervous system, and tissues, such as the
  epidermis, that lack blood vessels. The wall of
  the lymph capillary is composed of endothelium in
  which the simple squamous cells overlap to form a
  simple one-way valve. This arrangement permits
  fluid to enter the capillary but prevents lymph
  from leaving the vessel.

37
(No Transcript)
38

• The microscopic lymph capillaries merge to form
  lymphatic vessels. Small lymphatic vessels join
  to form larger tributaries, called lymphatic
  trunks, which drain large regions. Lymphatic
  trunks merge until the lymph enters the two
  lymphatic ducts. The right lymphatic duct drains
  lymph from the upper right quadrant of the body.
  The thoracic duct drains all the rest.
• Like veins, the lymphatic tributaries have thin
  walls and have valves to prevent backflow of
  blood. There is no pump in the lymphatic system
  like the heart in the cardiovascular system. The
  pressure gradients to move lymph through the
  vessels come from the skeletal muscle action,
  respiratory movement, and contraction of smooth
  muscle in vessel walls.

39
Lymphatic Organs

• Lymphatic organs are characterized by clusters of
  lymphocytes and other cells, such as macrophages,
  enmeshed in a framework of short, branching
  connective tissue fibers. The lymphocytes
  originate in the red bone marrow with other types
  of blood cells and are carried in the blood from
  the bone marrow to the lymphatic organs. When the
  body is exposed to microorganisms and other
  foreign substances, the lymphocytes proliferate
  within the lymphatic organs and are sent in the
  blood to the site of the invasion. This is part
  of the immune response that attempts to destroy
  the invading agent. The four types of lymphatic
  organs are described below.

40
Lymph Nodes

• Lymph nodes are small bean-shaped structures that
  are usually less than 2.5 cm in length. They are
  widely distributed throughout the body along the
  lymphatic pathways where they filter the lymph
  before it is returned to the blood. Lymph nodes
  are not present in the central nervous system.
  There are three superficial regions on each side
  of the body where lymph nodes tend to cluster.
  These areas are the inguinal nodes in the groin,
  the axillary nodes in the armpit, and the
  cervical nodes in the neck.
• The typical lymph node is surrounded by a
  connective tissue capsule and divided into
  compartments called lymph nodules. The lymph
  nodules are dense masses of lymphocytes and
  macrophages and are separated by spaces called
  lymph sinuses. Several afferent lymphatic
  vessels, which carry lymph into the node, enter
  the node on the convex side. The lymph moves
  through the lymph sinuses and enters an efferent
  lymphatic vessel, which carries the lymph away
  from the node. Because there are more afferent
  vessels than efferent vessels, the passage of
  lymph through the sinuses is slowed down, which
  allow time for the cleansing process. The
  efferent vessel leaves the node at an indented
  region called the hilum.

41
(No Transcript)
42
(No Transcript)
43
Tonsils

• Tonsils are clusters of lymphatic tissue just
  under the mucous membranes that line the nose,
  mouth, and throat (pharynx). There are three
  groups of tonsils. The pharyngeal tonsils are
  located near the opening of the nasal cavity into
  the pharynx. When these tonsils become enlarged
  they may interfere with breathing and are called
  adenoids. The palatine tonsils are the ones that
  are located near the opening of the oral cavity
  into the pharynx. Lingual tonsils are located on
  the posterior surface of the tongue, which also
  places them near the opening of the oral cavity
  into the pharynx. Lymphocytes and macrophages in
  the tonsils provide protection against harmful
  substances and pathogens that may enter the body
  through the nose or mouth.

44
(No Transcript)
45
Spleen

• The spleen is located in the upper left abdominal
  cavity, just beneath the diaphragm, and posterior
  to the stomach. It is similar to a lymph node in
  shape and structure but it is much larger. The
  spleen is the largest lymphatic organ in the
  body. Surrounded by a connective tissue capsule,
  which extends inward to divide the organ into
  lobules, the spleen consists of two types of
  tissue called white pulp and red pulp. The white
  pulp is lymphatic tissue consisting mainly of
  lymphocytes around arteries. The red pulp
  consists of venous sinuses filled with blood and
  cords of lymphatic cells, such as lymphocytes and
  macrophages. Blood enters the spleen through the
  splenic artery, moves through the sinuses where
  it is filtered, then leaves through the splenic
  vein.

46

• The spleen filters blood in much the way that the
  lymph nodes filter lymph. Lymphocytes in the
  spleen react to pathogens in the blood and
  attempt to destroy them. Macrophages then engulf
  the resulting debris, the damaged cells, and the
  otherlarge particles. The spleen, along with the
  liver, removes old and damaged erythrocytes from
  the circulating blood. Like other lymphatic
  tissue, it produces lymphocytes, especially in
  response to invading pathogens. The sinuses in
  the spleen are a reservoir for blood. In
  emergencies such as hemorrhage, smooth muscle in
  the vessel walls and in the capsule o

47
(No Transcript)
48
Thymus

• The thymus is a soft organ with two lobes that is
  located anterior to the ascending aorta and
  posterior to the sternum. It is relatively large
  in infants and children but after puberty it
  begins to decrease in size so that in older
  adults it is quite small.
• The primary function of the thymus is the
  processing and maturation of special lymphocytes
  called T-lymphocytes or T-cells. While in the
  thymus, the lymphocytes do not respond to
  pathogens and foreign agents. After the
  lymphocytes have matured, they enter the blood
  and go to other lymphatic organs where they help
  provide defense against disease. The thymus also
  produces a hormone, thymosin, which stimulates
  the maturation of lymphocytes in other lymphatic
  organs.

49
(No Transcript)
50

• THANCK YOU!