Dynamics of blood and lymph flow

1. DYNAMICS OF BLOOD AND
LYMPH FLOW
DR. MITALI THAMKE
I MDS

2. Index
• INTRODUCTION
• CIRCULATORY SYSTEM
• FUNCTIONAL PART OF CIRCULATION
• ARTERIES
• ARTERIOLES
• Capillaries
• VENULE
• VEIN

3. • HEMODYNAMICS
• BLOOD FLOW
• FACTORS MAINTAINING BLOOD FLOW
• ARTERIAL PRESSURE
• HEMODYNAMIC DISORDER
• LYMPHATIC SYSTEM
• FORMATION OF LYMPH
• COMPONENTS OF LYMPHATIC SYSTEM
• LYMPHATIC ORGAN

4. • Lymphatic flow
• Lymphatic disorder
• Conclusion
• References

5. INTRODUCTION
• Dynamics means study of motion
• Identify the types of blood and lymphatic vessels that make up the circulatory
system and the regulation and function
• Describe how physical principles dictate the flow of blood and lymph around the
body.

6. • Understand the basis of methods used to measure blood flow and blood
pressure in various vascular segments.
• Understand the basis of disease states where components of the blood and
vasculature are abnormal, dysregulated, or both.

7. • Circulation is divided into:
I. Systemic circulation
II. Pulmonary circulation

8. I. Systemic circulation
 Supplies all the tissues of body except lungs
 Transport blood through most all body part from left ventricle
and back to right atrium
 84% of total circulation
II. Pulmonary circulation
 Transport blood from right ventricle through lungs and back to
left atrium
 9% of total circulation

9. • Function of Circulatory System
i. carry nutrients and hormones to tissues
ii. wastes products away from tissues
iii. to maintain an appropriate environment in all the tissue fluids of the body for
optimal survival and function of the cells

10. Functional Parts of the Circulation.
• ARTERIES
• ARTERIOLES
• CAPILLARIES
• VENULES
• VEINS

11. ARTERIES
• Arteries are vessels that carry blood from heart to tissue
• Arteries have 3 walls or tunics :
I. Tunica interna,composed of lining of endothelium, a basement membrane and a layer of elastic tissue
II. Tunica media; composed of elastic and smooth fibers
• Two important function of elasticity(vasodilation) and contractility (vasoconstriction)
III. Tunica externa;composed of elastic and collagen fiber
• Arteries are of two types
I. Elastic (conducting) arteries
II. Muscular (distributing) arteries

12. 12
Arteries
• Elastic- largest arteries near heart
• Low resistance
• More elastin interspersed
with the tunica media
• Can distend and recoil
back to pump blood
(maintain blood pressure)
• Muscular-
• Supply organs
• Can regulate diameter of
artery to control blood
supply to organ
• Thick tunica media with
more smooth muscle
• External and internal
elastic lamina.

13. Arterioles
• Smallest arteries- “resistance
arteries”
• THICK tunica media- little
compliance
• Diameter controlled by local factors
(intrinsic) and sympathetic division
(extrinsic) and long-term factors
(hormones)
• Metarterioles- just upstream of
capillary beds.
• Precapillary sphincters-controls
blood reaching capillary bed.
13

14. Capillaries
Smallest blood vessels
Single layer of endothelial
cells and basal lamina
Primary function is to
permit the exchange of
nutrient and wastes
between blood and tissue
cells
14

15. 15
Types of Capillaries
• Continuous
– Most common and least
permeable
– Intercellular clefts and
transcellular cytosis allows for
exchange of molecules
– Abundant in skin and muscle
• Fenestrated
– “Holes” in the endothelial
membrane
– Found in kidney
• Sinusoidal/ discontinuous
– Most permeable and least
common
– Big ‘holes” in endothelial
membranes
– Big clefts between cells
– Liver, spleen, and bone marrow
especially

17. VENULES
• Several capillaries unite to form vein called venules
• Venules collect blood from capillaries and drain into vein
• Venule closest to capillaries consist of a tunica interna of endothelium and tunica externa of
connective tissue.

18. VEINS
• Veins composed of essentially the same three coats as arteries but there are variations in their relative
thickness
• Tunica interna of vein is extremely thin as compared wih arteries
• Tunica media of vein is much thinner and tunica externa is thicker
• Many vein especially in limbs features valves, which are needed because venous blood pressure is low
• The pressure present in the vein is barely enough to overcome the force of gravity pulling back down
• Valves prevent the backflow and in this way aid the flow of blood to heart

20. Comparison of Veins and Arteries
Arteries: Veins:

21. vessel includes features
Elastic arteries Aorta, pulmonary artery and major
branches
Elastic recoil maintains continuous
blood flow and diastolic arterial
pressure(Windkessel effect)
Conducting(muscular)arteries Main arteries e.g. Cerebral coronary
,popliteal radial
Thicker muscle in tunica media
Resistance vessels Smallest terminal arteries and
arterioles
Single layer of muscle in tunica
media
Regulate local blood flow to match
local demand
Arteriovenous shunt Shunt vessels Connect arterioles to venule
bypassing capillaries
Present in skin nasal mucosa
Regulate temperature
Exchange vessels capillaries Largest cross section area
Provide O2 and nutrition to tissues
Capacitance vessels vein Store large volumes of blood

22. Dynamics of blood flow
• Hemodynamics is study of movement of blood and of forces
concerned

23. MEAN VOLUME OF BLOOD FLOW
• Mean volume of blood flow is the volume of blood, which flow into region of circulatory system in a
given unit of time
• It is the product of mean velocity and cross sectional area of the vascular bed
Q = V x A
Where,
Q = Quantity of blood
V = Velocity of blood flow
A = Cross sectional area of the blood vessel.

24. Methods for Measuring Blood Flow.
1. Electromagnetic Flowmeter.
2. Ultrasonic Doppler Flowmeter.
3. Plethysmograph
4. Venous Occlusion Plethysmography
5. By Flick’s Principle

25. TYPES OF BLOOD FLOW
• The blood flow through a blood vessel is of two types:
1. Streamline or Laminar flow
2. Turbulent flow

26. LAMINAR OR STREAMLINE FLOW TURBULENT FLOW
Blood flow in large no.of layers at steady rate. It
shows parabolic distribution of velocity i.e,velocity
being greater in center of stream.
Blood flow in all directions in vessel and continuously
within vessel
It is silent in nature It is noisy in nature
Within limit show linear relationship with pressure Turbulence is given by Reynold’s number(Re)=vpd/n
where, v =velocity of flow in cm/sec
p(Rho)=density of blood equal to 1
d= daimeter of vessel( in cm)
n(eta)= viscosity of blood in poise

27. FACTORS MAINTAINING VOLUME OF BLOOD
FLOW
• Blood flow is determined by five factors :
1. Pressure gradient
2. Resistance to blood flow
3. Viscosity of blood
4. Diameter of blood vessels
5. Velocity of blood flow

28. Pressure gradient
• It is the pressure difference between the two ends of blood vessel
• The volume of blood flowing through blood vessels is directly proportional to
pressure difference.
• Pressure gradient = P1— P2
Where,
P1 = Pressure at proximal end of the vessel
P2 = pressure at distal end of the vessel

29. • Maximum pressure gradient is seen between the aorta and the
inferior vena cava.
• The pressure in aorta is 120 mm Hg and pressure in inferior vena cava
is 0 mm Hg
• So, the pressure gradient is 120 - 0 = 120 mm Hg

30. Blood vessels P1 (mm Hg) P2 (mm Hg) Pressure gradient
(mm Hg)
Between aorta and
vena cava
120 0 120
two end of aorta 120 100 20
beginning of arteries
and end of arteriols
100 30 70
Arterial and venous
end of capilaries
30 15 15
Two end of venules 15 10 5
Two end of vein 10 0 10
Two end of vena cava 0 -2 2

31. Resistance to the blood flow
• It is the friction, tension or hindrance against which blood flow
• Peripheral resistance means the resistance offered to blood flow in peripheral
blood vessels
• Volume of blood flow ∝ 1
𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒
• Determinants of peripheral resistance :
i. Radius of blood vessels
ii. Pressure gradient
iii. Viscosity of blood

32. • Peripheral resistance∝
1
radius of the blood vessel
• lesser the radius, more will be the resistance
• Radius of the arterioles is very less.
• because the arterioles remain partially constricted all the time due to
sympathetic tone
• So, the resistance is more. Hence, the arterioles are called resistant vessels.

33. • Formula to determine resistance
Resistance =
Pressure gradient
Volume of blood flow
=
P1 – P2
𝑄

34. VISCOSITY OF BLOOD
• Viscosity is the friction of blood against the wall of the blood vessel.
• Viscosity in influences the blood flow through resistance.
• Volume of blood flow ∝
1
viscosity of blood.
• Viscosity in influences the blood flow through resistance

35. • Factors determining viscosity:
i. RBC count is the main factor
ii. viscosity is plasma protein, mainly albumin.
• When hemoconcentration occurs as in case of burns or in
polycythemia, the viscosity increases and the velocity of blood flow
decreases, so the volume of blood reaching the organ is decreased.

36. Diameter of blood vessels
• Volume of blood flow ∝ diameter of the blood vessels
• When the diameter of a segment of blood vessel is considered, the aorta
has the maximum diameter and capillary has got the minimum diameter.
• But, in circulation, the diameter of the vessel is considered in relation to
the cross-sectional area through which the blood flows.
• Cross-sectional area is progressively increased as the arteries ramify and as
the distance from the heart is increased

37. • Cross-sectional area of each branch is smaller, but the sum of the cross-sectional
areas of all the branches is always greater than that of the parent vessel.
• In this way , the aorta has got less cross sectional area of 4 cm2, compared to
that of capillaries which is 2500 cm2
• Diameter of the aorta depends upon the elasticity of the wall and its recoiling
tendency helps in maintaining the flow and pressure.
• Diameter of the arterioles depends upon the sympathetic tone.

38. Velocity of Blood Flow
• Velocity of blood flow is the rate at which blood flows through a
particular region
• Volume of blood flow ∝ velocity of blood flow

39. HAGEN-POISEUILLE EQUATION
• According to Hagen-Poiseuille equation, volume (Q) of any uid owing
through a rigid tube is:
1. Directly proportional to pressure gradient (P1- P2)
2. Directly proportional to the fourth power of radius ( r4)
3. Inversely proportional to length of tube (L)
Thus, Q = K
(P1 – P2) × r4
𝐿

40. Poiseuille’s Law

41. VELOCITY OF BLOOD FLOW
• DEFINITION
Velocity of blood flow is the rate at which blood flows through a
particular region of the body.
Volume of blood flow ∝ velocity of blood flow
it mainly depends upon the diameter or cross-sectional area of blood
vessel.

42. MEAN VELOCITY OF BLOOD FLOW IN
DIFFERENT VESSELS
• Mean velocity (cm/second) of blood flow in different blood vessels:
Large arteries : 50.00
Small arteries : 5.00
Arterioles : 0.50
Capillaries : 0.05
Venules : 0.10
Small veins : 1.00
Large veins : 2.00

43. • METHODS OF STUDY
1. By Using Flowmeters
2. By Hemodromography
• Hemodromography is a technique by which the velocity of blood is
continuously recorded .

44. FACTORS MAINTAINING VELOCITY
• Three factors are responsible for the maintenance of the
velocity of blood flow:
1. Cardiac output
2. Cross-sectional area of the blood vessel
3. Viscosity of the blood.

45. 1. Cardiac Output
o Velocity of blood flow ∝ cardiac output
o Increase in cardiac output leads to increase in the velocity of blood ow in all parts of the circulation.
2. Cross-sectional Area of Blood Vessels
o Velocity of blood flow ∝
1
total cross−sectional area of the vascular bed
• Cross-sectional area increases progressively as the arteries ramify
• Cross-sectional area of each branch is smaller, but the sum of the cross- sectional areas of
all the branches is always greater than that of the parent vessel.
• So, velocity of blood flow is decreased as the distance from the heart is increased.

46. 3. Viscosity of Blood
• Velocity of blood flow is inversely proportional to the viscosity of
blood.
• If viscosity is more, the velocity of blood flow is reduced
• It is because of the friction of blood against arterial wall, which is
more when viscosity of blood is increased.

47. CIRCULATION TIME
Definition:
• Circulation time is the time taken by blood to travel through a part or whole of the circulatory
system.
• If a substance is injected into a vein, the time taken by it to appear in the blood of the same
vein or in the corresponding vein on the opposite side shows the total circulation time.
• if the transit is from vein to the lungs, it shows the circulation time through pulmonary circuit
• if it is from vein to capillaries, it shows the time for fow through pulmonary circuit, left heart
and arteries to capillaries, i.e. the total circulation time minus the time for venous return.

48. MEASUREMENT OF CIRCULATION TIME
• Circulation time is measured by introducing some easily recognized
substance into bloodstream and determining the time when the
substance appears at a given point (end point) in the circulation.
• The injected substance must produce some characteristic response at
its end point, so that its appearance could be easily recognized.
• Introduction of the substance into circulation is done by injecting
through median cubital vein or directly into the heart

49. Substances used for Measuring Circulation Time
1. Histamine : Causes flushing of face due to vasodilatation
2. Dehydrocholine (20%): Gives a bitter taste when it reaches the tongue
3. Ether or acetone: Detectable in breath by smell
4. Sodium cyanide (small dose) : Causes hyperpnea when it reaches the carotid artery (by
acting on baroreceptors)
5. Dye fluorescein : Identified at the end point by yellow color; it is used for total circulation
time
6. Radioactive substances: Detected at various points of the body by using an ionization
chamber

50. TYPICAL CIRCULATION TIMES
1. Arm vein to arm vein (total circulation time): 25 seconds (22 to 28), determined by using dye
fluorescein
2. Arm vein to face: 24 seconds, determined by using histamine
3. Arm vein to tongue:11seconds(8to16),determined by using dehydrocholine
4. Arm vein to lung (pulmonary circulatory time): 6 seconds (4 to 6), determined by using ether or
acetone
5. Arm vein to heart (shortest circulation time): 4 seconds, determined by using radioactive substances
6. Arm vein to carotid artery: 14 seconds (12 to 15), determined by using sodium cyanide.

51. TOTAL CIRCULATION TIME AND HEARTBEAT
• Number of heartbeat/total circulation time, however, remains the
same for human beings and all the animals, i.e. about 30/total
circulation time.

52. CONDITIONS ALTERING CIRCULATION TIME
1. Circulation time is decreased when the velocity of blood ow is
increased
2. the circulation time is more when the velocity is less.

53. Conditions when Circulation Time is Prolonged
(Sluggish Blood Flow)
1. Myxedema: Due to decreased metabolic activity
2. Polycythemia: Due to increased viscosity of blood
3. Cardiac failure: Due to inability of the heart to pump blood.

54. Conditions when Circulation Time is Shortened
(Rapid Blood Flow)
1. Exercise: Due to increased cardiac activity and vasodilatation
2. Adrenaline administration: Due to increased cardiac activity
3. Hyperthyroidism: Due to increased metabolic activity
4. Anemia: Due to decreased blood volume and less viscosity
5. Decrease in peripheral resistance: Due to vasodilatation.

55. LOCAL REGULATION OF BLOOD FLOW –
AUTOREGULATION
• INTRODUCTION
• Autoregulation means the regulation of blood ow to an organ by the organ itself.
• It is de ned as the intrinsic ability of an organ to regulate a constant blood ow, in
spite of changes in the perfusion pressure (arterial pressure – venous pressure).
• Autoregulatory response is independent of neural and hormonal in uences. So, it is
the intrinsic capacity of the organ.

56. ROLE OF PRESSURES IN AUTOREGULATION
• Perfusion Pressure and Effective Perfusion Pressure
• perfusion pressure refers to balance between the pressure in blood
vessels on either side of the organ, i.e. arterial pressure minus venous
pressure (PA – PV) across the organ.
• Effective perfusion pressure is the perfusion pressure divided by
resistance in the blood vessels.
• Formula to determine effective perfusion pressure
EFP =
PA – PV
R

57. THEORIES OF AUTOREGULATION
• Autoregulation is explained by two theories:
1. Myogenic theory
2. Metabolic theory

58. • Two basic mechanisms that explain local
control of blood flow
1. Myogenic theory
Increase in blood flow

Stretches the vessel

Contraction of vascular smooth muscle

Decrease blood flow back to normal

60. 2. Metabolic theory
Increase in rate of metabolism

Accumulation of vasodilator substances in active tissues

Blood vessels dilate

Increase blood flow
Vasodilator metabolites
O2 tension, CO2 tension, Temperature, K+, lactate,
Adenosine, Histamine.

61. Arterial blood pressure
• Arterial blood pressure is defined as the lateral pressure exerted by the
column of blood on wall of arteries.
• The pressure is exerted when blood flows through the arteries.
• Arterial blood pressure is expressed in four different terms:
1. Systolic blood pressure
2. Diastolic blood pressure
3. Pulse pressure
4. Mean arterial blood pressure.

62. • Normal pulse pressure: 40 mm Hg (120 – 80 = 40).
1. MEAN ARTERIAL BLOOD PRESSURE
• Mean arterial blood pressure is the average pressure existing in the arteries. It is the diastolic pressure
plus one third of pulse pressure. To determine the mean pressure, diastolic pressure is considered than the
systolic pressure. It is because, the diastolic period of cardiac cycle is longer (0.53 second) than the
systolic period (0.27 second).
• Normal mean arterial pressure: 93 mm Hg (80 + 13 = 93).
• Formula to calculate mean arterial blood pressure:
• Mean arterial blood pressure
• = Diastolic pressure + 1/3 of pulse pressure
• = 80 + 40 = 93.3 mm Hg

63. • Blood pressure is altered in physiological and pathological conditions.
1. Physiological condition
I. Age
II. Sex
III. Body Built
IV. Diurnal Variation
V. After Meals
VI. During Sleep
VII. Emotional Conditions
VIII.After Exercise

64. Local factors determining arterial blood pressure

68. Hormones involved in regulation of arterial blood
pressure

69. Hemodynamic disorder
1. Hypotension
2. Hypertension
3. Stroke
4. Varicose vein
5. shock

70. Hypotension
• Hypotension is the low blood pressure. When the systolic pressure is
less than 90 mm Hg, it is considered as hypotension.
• Types
• Primary hypotension
• Secondary hypotension
• Orthostatic hypotension
unknown cause. It is also called essential hypotension. Frequent
fatigue and weakness are the common symptoms of this condition.
However, the persons with primary hypotension are not easily
susceptible to heart or renal disorders.
Orthostatic hypotension is the sudden fall in blood
pressure while standing for some time. It is due to
the effect of gravity.
Diseases, which cause hypotension are:
i. Myocardial infarction
ii. Hypoactivity of pituitary gland
iii. Hypoactivity of adrenal glands

71. Hypertension
• Hypertension is defined as the persistent high blood pressure.
• when the systolic pressure remains elevated above 150 mm Hg and
diastolic pressure remains elevated above 90 mm Hg
• If there is increase only in systolic pressure, it is called systolic
hypertension.

72. • Types of Hypertension
1. Primary hypertension or essential hypertension
2. Secondary hypertension.
3. Experimental Hypertension

73. Primary Hypertension or Essential Hypertension
• Primary hypertension is the elevated blood pressure in the absence of
any underlying disease.
• Primary hypertension is of two types:
• i. Benign hypertension
• ii. Malignant hypertension.

74. • Benign hypertension
• It is defined as the essential hypertension that runs a relatively long and
symptomless course.
• Malignant hypertension
• Malignant hypertension is a severe form of hypertension with a rapid course
leading to progressive cardiac and renal diseases
• Systolic pressure rises to about 250 mm Hg and diastolic pressure rises to 150
mm Hg.
• developed due to the combined effects of primary and secondary
hypertension

75. • Secondary hypertension is the high blood pressure due to some
underlying disorders.
• Types : 1.Cardiovascular hypertension
• Endocrine hypertension
• Renal hypertension
• Neurogenic hypertension
• Hypertension during pregnancy

76. VARICOSE VEIN
• Varicose vein is the vein that become irregularly swollen and enlarged
• Mostly superficial vein of leg are affected
• Cause is the permanent dialatation caused by incompetence of valve
of vein

77. Stroke
• Stroke is the sudden death of neurons in localized area of brain due to
inadequate blood supply.
• Causes
• Heart disease
• Hypertension
• High cholesterol
• High blood pressure
• Heavy smoking
• Heavy alcohol consumption
• Symptoms

78. Shock
• Shock is a clinical syndrome characterized by impairment of adequate
tissue perfusion primarily due to low cardiac output
Classification How low cardiac output develop Causes/ subdivision
Hypovolemic shock or cold shock Amout of fluid in the vascular
system is inadequate to fill
it,resulting in decrease in
circulating blood volume
A. Hemorrhage /hemorrhagic shock
B. Trauma/traumatic shock
C. Surgery/ surgical shock
D. Dehydration /dehydration shock
Disrtributive or low resistance shock Size of capacitance vessels is
increased by vasodilation causes
decrease cardiac output
A. fainting (syncope)/neurogenic
shock
B. Anaphylaxis/ anaphylatic shock
C. Sepsis/septic shock
Cardiogenic shock Inadequate pumping action of heart
as a result of myocardial
abnormalities
A. Myocardial infarction
B. Congenital heart failure
C. arrhythmias
Obstructive shock Obstruction of blood flow in lungs
or heart
A. tension pneumothorax
B. Pulmonary embolism

79. BLOOD SUPPLY OF PERIODONTIUM
• The gingiva receives its blood supply mainly through supraperiosteal
blood vessels which are terminal branches of
• sublingual artery (a.s.)
• the mental artery (a.m.)
• the buccal artery (a.b.)
• the facial artery (a.f.)
• the greater palatine artery (a.p.)
• the infra orbital artery (a.i.),
• and the posterior superior dental artery (a.ap.).

80. Blood supply of the periodontium
• The dental artery (a.d.), which is a branch of the superior or inferior
alveolar artery (a.a.i.), dismisses the intraseptal artery (a.i.) before it
enters the tooth socket
• The terminal branches of the intraseptal artery (rami perforantes, rr.p.)
penetrate the alveolar bone proper in canals at all levels of the socket
• They anastomose in the periodontal ligament space, together with blood
vessels originating from the apical portion of the periodontal ligament and
with other terminal branches, from the intraseptal artery (a.i.)

81. Lymphatic System
• Lymphatic system is a closed system of lymph channels or lymph
vessels, through which lymph flows.
• It is a one-way system and allows the lymph flow from tissue spaces
toward the blood.
• Lymphatic system develop by end of fifth week of intrauterine life

82. Functions of the Lymphatic System
• Reabsorbs excess interstitial fluid:
• returns it to the venous circulation
• maintain blood volume levels
• prevent interstitial fluid levels from rising out of control.
• Transport dietary lipids:
• transported through lacteals
• drain into larger lymphatic vessels
• eventually into the bloodstream.
• lymphocyte development, and the immune response.

83. SITUATION OF LYMPH VESSELS
• Lymph vessels are situated in the following regions:
1. Deeper layers of skin
2. Subcutaneous tissues
3. Diaphragm
4. Wall of abdominal cavity
5. Omentum
6. Linings of respiratory tract except alveoli
7. Linings of digestive tract
8. Linings of urinary tract
9. Liver
10. Heart.

84. • Lymph vessels are not present in the following structures:
1. Superficial layers of skin
2. Central nervous system
3. Cornea
4. Bones
5. Alveoli of lungs.

85. Components of the Lymphatic System
• Lymph
• Lymphatic Vessels
• Lymphatic Capillaries
• Lymphatic Vessels
• Lymphatic Trunks
• Lymphatic Ducts
• Lymphatic Organs
• Thymus
• Lymph Nodes
• Spleen
• Tonsils
• Lymphatic cells

86. FORMATION OF LYMPH
• Lymph is formed from interstitial fluid, due to the permeability of
lymph capillaries.
• blood passes via blood capillaries in the tissues, 9/10th of fluid
passes into venous end of capillaries from the arterial end
remaining 1/10th of the fluid passes into lymph capillaries.

88. Lymphatic Capillaries
Features of structure:
• Single layer of overlapping endothelial cells
• More permeable than that of blood capillary
• Absent from avascular structures, brain, spinal cord splenic pulp
and bone marrow

89. Lymphatic Capillaries – Lacteals
• The contains special types of lymphatic capillaries called lacteals.
pick up not only interstitial fluid, but also dietary lipids and lipid-soluble
vitamins.
• The lymph of this area has a milky color due to the lipid and is also called .

90. Lymphatic Vessels
Features of structure
 Three layered wall but thinner than vein,
 More numerous valves than in vein
 Interposed by lymph nodes at intervals
 Arranged in superficial and deep sets

91. LYMPH TRUNKS
 right and left jugular trunks
 right and left subclavian
trunks
 right and left
bronchomediastinal trunks
 right and left lumbar trunks

92. LYMPHATIC DUCTS
Right lymphatic duct
 Formed by union of
right jugular,
subclavian, and
bronchomediastinal
trunks
 Ends by entering the
right venous angle

93. THORACIC DUCT…..
• At the root of the neck, it
turns laterally
• arches forwards and
descends to enter the left
venous angle
• before termination, it
receives the left jugular,
Subclavian and broncho-
mediastinal trunk
93

94. DRAINAGE PATTERN
THORACIC DUCT -
Drains lymph from lower
limbs, pelvic cavity,
abdominal cavity, left
side of thorax, and left
side of the head, neck
RIGHT LYMPHATIC DUCT
-Receives lymph from
right half of head, neck,
thorax and right upper
limb, right lung, right side
of heart, right surface of
liver

95. Lymphatic system of the periodontium
• labial and lingual gingiva of the mandibular incisor region is drained to the
submental lymph nodes (sme)
• palatal gingiva of the maxilla is drained to the deep cervical lymph nodes (cp)
• The buccal gingiva of the maxilla and the buccal and lingual gingiva in the
mandibular premolar–molar region are drained to submandibular lymph nodes
(sma)
• The third molars are drained to the jugulodigastric lymph node (jd)

96. Lymphatic Cells
• Also called lymphoid cells.
• Located in both the lymphatic system and the cardiovascular system.
• Work together to elicit an immune response.
• Types of lymphatic cells are:
• macrophages
• epithelial cells
• dendritic cells
• lymphocytes

97. LYMPHATIC ORGANS
• Red bone marrow
• Thymus gland
• Lymph nodes
• Lymph nodules
• Spleen

98. Thymus Gland
• Location – behind the sternum in the mediastinum
• The capsule divides it into 2 lobes
• Development
• Infant – conspicuous
• Puberty – maximum size
• Maturity – decreases in size
• Function
• Differentiation and maturation of T cells

99. Lymph Nodes
• Oval structures located along lymphatics
• Enclosed by a fibrous capsule
• Cortex = outer portion
• Germinal centers produce lymphocytes
• Medulla = inner portion
• Medullary cords
• Lymph enters nodes through afferent lymphatics, flows through sinuses, exits
through efferent lymhpatic

101. • Functions of the lymph nodes are:
1. When lymph passes through the lymph nodes, it is filtered, i.e. the
water and electrolytes are removed. But, the proteins and lipids are
retained in the lymph.
2. Bacteria and other toxic substances are destroyed by macrophages of
lymph nodes. Because of this, lymph nodes are called defense
barriers.

102. Lymphatic Nodules
• Oval clusters of lymphatic cells with some extracellular matrix that are not
surrounded by a connective tissue capsule.
• Filter and attack antigens.
• In some areas of the body, many lymphatic nodules group together to form
larger structures.
• very prominent in the mucosa of the small intestine, primarily in the
ileum
• also present in the appendix

103. Spleen
• Largest lymphatic organ
• Located between the stomach & diaphragm
• Structure is similar to a node
• Capsule present
• But no afferent vessels or sinuses
• Histology
• Red pulp contains all the components of circulating blood
• White pulp is similar to lymphatic nodules
• Functions
• Filters blood
• Stores blood

104. Formation of Lymph
• Lymph is derived from interstitial fluid that flows into the lymphatics.
• lymph formed in the liver has a protein concentration as high as 6
g/dl, and lymph formed in the intestines has a protein concentration
as high as 3 to 4 g/dl.

105. RATE OF LYMPH FLOW
• About 120 mL of lymph flows into blood per hour.
• about 100 mL/hour flows through thoracic duct and 20 mL/ hour
flows through the right lymphatic duct.

106. • Factors Increasing the Flow of Lymph
1. Interstitial fluid pressure.
2. Blood capillary pressure.
3. Surface area of lymph capillary by means of dilatation.
4. Permeability of lymph capillaries.
5. Functional activities of tissues.

107. Lymphatic Pump Increases Lymph Flow
• when a collecting lymphatic or larger lymph
vessel becomes stretched with fluid, the
smooth muscle in the wall of the vessel
automatically contracts.
• each segment of the lymph vessel between
successive valves functions as a separate
automatic pump
• is, even slight filling of a segment causes it to
contract, and the fluid is pumped through the
next valve into the next lymphatic segment
• This fills the subsequent segment, and a few
seconds later it, too, contracts, the process
continuing all along the lymph vessel until the
fluid is finally emptied into the blood
circulation
• large lymph vessel such as the thoracic duct,
this lymphatic pump can generate pressures as
great as 50 to 100 mm Hg

108. Factors That Determine Lymph Flow.
• two primary factors that determine lymph flow are
1. the interstitial fluid pressure
2. the activity of the lymphatic pump
• Therefore, one can state that, roughly, the rate of lymph flow is
determined by the product of interstitial fluid pressure times the
activity of the lymphatic pump.

109. Lymphatic disorder
1. Lymphangitis
2. Lymphedema
3. Lymphadenopathy
4. Lymphomas
5. Tonsilitis
6. Splenomegaly

110. LYMPHANGITIS
• Inflammation of the lymph vessels
• Commonest cause bacteria called streptococcus pyogenes(most
common).
• Lymph vessels appear as red streaks through the skin accompanied
by painful enlargement of lymphnode

111. FILARIASIS

112. LYMPHEDEMA
• Occurs due to
accumulation of
lymphatic fluid in the
interstitial tissue
• Sometimes can be
appreciated after wearing
tight clothing or jewellary
on affected limb

113. LYMPHADENOPATHY
• Lymphadenopathy or
adenopathy is diseases of
lymph node in which they are
abnormal in size number and
consistency.
• Lymph nodes become
swollen/ enlarged and may
be painful to touch.
• Lymph node enlargement is
recognized as a common sign
of infectious, autoimmune, or
malignant disease

114. LYMPHOMAS
• Cancers originating either
from the lymphocytes in the
lymph nodes or the lymphatic
tissue in organs
• Risk factors

115. TONSILLITIS
• Infection of the pharyngeal
tonsils
• Tonsils are swollen,
• Fever and pain during
swallowing usually present
• Treatment – surgical removal
of tonsils (TONSILLECTOMY)

116. SPLENOMEGALY
• Enlarged Spleen
• Causes: increased blood flow
• Increased function
• infiltration
• Treatment : splenectomy

117. Conclusion
• Hemodynamic assessment is a key component of the evaluation of
the critically ill patients and has both diagnostic and prognostic
utility.
• Knowledge of lymph dynamics is necessary to understand their
transport. Moreover, knowledge about lymph dynamics is considered
to contribute to the control of immune functions and the designing of
diagnosis and treatment of lymph node metastasis of tumors.

118. REFERENCES
1. Guyton : Textbook of Medical Physiology,11th edition.
2. Ganong :Medical Physiology ,23rd edition.
3. Sembulingam: Essentials Of Medical Physiology,6th edition.
4. B D Chaurasia’s : Human Anatomy, 5TH Edition.

119. THANK YOU