blood circulation

1. Chapter 9
Transport in Animals
Ong Yee Sing
2017

2. Objectives
• To know the circulation of substances and the circulatory system in lower animals.
• To understand closed circulatory system and open circulatory system.
• To know the circulatory system in each kind of vertebrates.
• To understand the circulatory pathway of blood (including pulmonary circulation and systematic
circulation) in human body.
• To master the knowledge on structure, physiology and functions of heart.
• To comprehend the relationship between the structures and functions of artery, vein and blood
capillary.
• To compare the differences among artery, vein and blood capillary.
• To comprehend the composition of blood and the functions, as well as the source of origin, of
each constituent.
• To comprehend the functions of blood.
• To master the mechanism of transport of gases in blood.
• To comprehend the lymphatic system in human body and its functions.

3. 9.1 Transport in animals

4. Importance of circulatory system

5. Circulatory system
• The circulatory system is an organ system
that permits blood to circulate and transport
nutrients (such as amino acids, mineral
salts), oxygen, carbon dioxide, hormones,
and blood cells to and from the cells
Includes
• cardiovascular system, which distributes blood,
• lymphatic system, which circulates lymph

6. Function of circulatory system
• Provide nourishment
• Remove waste
• Transport hormone
• Help in fighting diseases
• Stabilize body temperature
and pH
• Maintain homeostasis

7. Types of circulatory system
• Open-circulatory system
• 分成：
• E.g. insect
• Closed-circulatory system
• E.g. earthworm, fish, reptiles,
birds, mammals

8. Comparison
Open circulatory system Closed circulatory system
Definition
Haemolymph leaves the heart in short,
branched arteries that open up into
large spaces.
The blood is contained within a
completely closed system of vessels
with a pumping organ like a heart or
contractile vessels. Blood does not
enter body cavity.
Contact
with cells
Haemolymph percolates around
organs, directly bathing the cells.
Vessels branch into smaller and smaller
tubes that penetrate among the cells of
tissues.
Example
• more inactive animals.
• Insects (tracheal system for oxygen
supply).
• Animals having a fast metabolism
and larger bodies.
• Warm blooded animal

9. Advantages and disadvantages
Open circulatory system Closed circulatory system
Advantages • Exchange of materials is direct
between the hemolymph and
tissues.
• There is no diffusion barrier.
• Fine-scale control over the
distribution of blood to different
body regions is possible.
• Muscular walls of vessels can
constrict and dilate to vary the
amount of flow through specific
vessels.
• Blood pressures are fairly high and
the circulation can be vigorous.
Disadvantages • Little fine control over distribution
of the hemolymph to body
regions.
• No mechanism for reducing flow
to a specific part of an organ.
• It is a more complex system.
• It requires more energy for blood
distribution.

10. 9.1.2 Circulation of substances in
lower animals

11. Tree of life

13. Lower animals
• Animals of relatively simple or
primitive characteristics as
contrasted with humans or with
more advanced animals such as
mammals or vertebrates, e.g.
Hydra水螅 and Turbellaria涡虫
• Small size permits nutrients
and other substances to reach
all the body parts by simple
diffusion.
Pseudoceros dimidiatusHydra

14. • https://http://end0skeletal.tumblr.com/post/167031883969/basket-
stars-are-a-taxon-of-brittle-stars-which
• en.wikipedia.org/wiki/Basket_star

15. Unicellular organisms
• Unicellular organisms such as
Paramecium and Amoeba
• Small size with Large surface
area to volume ratio allows
exchange of waste and
nutrients through diffusion.
• Cytoplasmic streaming细胞质流
also assists in the distribution
of food to the whole cell.
Paramecium and Amoeba

16. Annelids环节动物
• The annelids (Latin anellus, "little
ring"), also known as the ringed
worms or segmented worms, consists
of multiple segments with the same
sets of organs.
• The transport system in annelids such
as earthworm is a closed-circulatory
system.
• The arterial arches of an earthworm
pulsate搏动 to pump blood from the
dorsal blood vessel背血管into the
ventral blood vessel腹血管.
• The ventral blood vessels blood
transports nutrients and oxygen to
other parts of the body.
• The blood contains haemoglobin to
enhance efficiency of oxygen
transport.
Dorsal
blood
vessel
Arterial
arches
Ventral
blood
vessel
Body
vessel

17. Anatomical axes

18. Insect heart
• An insect such as
grasshopper has an
open circulatory
system.
• The dorsal part of the
body of grasshopper has
a thin, long, segmented,
tubular sac-like heart
which can pump blood
to the head through the
only blood vessel.
haemocolom
心室小孔

19. Insect circulation
• The blood flows out of this blood
vessel and enters the
haemocoelom血腔 - spaces
between the tissues found in the
body cavity/sinuses.
• The blood in these spaces flows to
the posterior part and returns to
the heart through the tiny
openings (ostia心室小孔) of the
heart chambers.
ostia
heartaeota
haemocoelom

20. 9.1.2
Circulatory
system in
vertebrates

21. Vertebrate circulatory system
• Fish, birds, amphibians, reptiles, mammals
• A type of closed circulatory system.
• Includes
• Heart
• Blood vessels (artery, vein, blood capillaries)
• Blood.

24. Heart chambers
• atrium心房
• from Latin atrium "central court or first main
room of an ancient Roman house
• ventricle心室
• from Latin ventriculus, diminutive
of venter ‘belly.’
• Blood enters the
heart at the
atrium and exit
from the
ventricle.

25. Fish heart
• Two–chambered heart:
• an atrium心房
• a ventricle心室.

26. Fish circulatory system
• It is a single circulation system.
• The blood only flows one round and in one
direction in every complete circulation.
• The ventricle pumps blood from the artery to
the gills.
• Oxygenated blood flows from the blood
capillaries (in the gills) to artery.
• The blood then flows to blood capillaries in
every part of the body
• The blood return to the heart through the
vein.

27. Amphibians and reptiles heart
• The heart of amphibians and
reptiles (except the crocodile)
consists of two atria and one
ventricle.
• Crocodile have a complete septum
that separate the ventricle into
two, but a hole outside the
ventricles, called the foramen of
Panizza, allows blood to move
from one side of the heart to the
other.

28. Crocodile circulation
• Because of little or no
lung use under the
water, a big portion of
the blood stream is
diverted away from
lungs; therefore oxygen
poor blood is pumped
back to the body.
• The blood circulation of
crocodiles is similar to
birds, mammals, and
humans while they are
active on land. Oxygen-
deprived blood is sent to
lungs for gas exchange.
Not in textbook

29. Amphibians and reptiles circulation
• It is an incomplete double circulation or a semi-
double circulation.
• There are two pathways after the blood flows out
of the heart, i.e. lung circulation and body
circulation.
• Although there is only one ventricle, there is a
muscular projection which separates the
oxygenated blood and deoxygenated blood that
blood cannot comes from the left and right part of
ventricle.
• However, the oxygenated blood and the
deoxygenated blood cannot be separated
completely.

30. Birds and mammalian heart
• The heart of birds and mammals is
divided into four complete chambers:
two atria and two ventricles.

31. Birds and mammalian circulation
• It is a double circulation.
• The right atrium and ventricle contain
deoxygenated blood, while the left
atrium and ventricle contain oxygenated
blood.
• The bloods do not mix with each other.

32. Advantages of double circulation
• higher blood pressure
• greater flow of blood to the tissues.

33. Summary
semi-double circulation double circulationsemi-double circulationSingle circulation

34. 9.2.1 Human circulatory system

35. • Cardiovascular system consists of the heart,
blood vessel and blood.
• double circulation = blood flows through the
heart two times in a complete circulation
• Circulations includes:
• Pulmonary circulation
• The blood circulation between the heart and
lung
• Systemic circulation
• The blood circulation between the heart and
other parts of the body
• includes the hepatic portal circulation and the
coronary circulation.
Human circulatory system

36. Pulmonary circulation
• Deoxygenated blood is carried to the lungs
by the pulmonary artery.
• The blood undergoes gaseous exchange at
the alveoli.
• Oxygenated blood is carried back to the
heart by the pulmonary vein.
Left Atrium
Pulmonary veins
Pulmonary venule
Blood capillaries on the surface of alveoli
Pulmonary arteriole
Pulmonary arteries
Pulmonary trunk
Right ventricle
Right atrium

37. Systemic circulation
• Oxygenated blood is pumped by
the heart into aorta.
• The blood is carried to every
organ and tissue (except lungs)
to undergo exchange of
substances.
• The deoxygenated blood is
transported back to the heart
through anterior (or superior)
and posterior (or inferior) vena
cava.
Right Atrium
Veins
Venule
Blood capillaries
Arteriole
Arteries
Aorta
Left ventricle
Left atrium

39. Hepatic portal circulation
• The hepatic portal vein
collects water-soluble
nutrients (monosaccharides,
amino acids, vitamins B & C,
minerals) which absorbed by
the villi of the small intestine
and transports it to the
capillaries of the liver.
• These nutrients will be
processed, utilized or
detoxified by the liver cells.
• The blood flows into the
hepatic portal vein and will
return to the heart via the
posterior vena cava.
Right ventricle
Inferior vena cava
Hepatic vein
Liver
Hepatic portal vein
Villi capillaries

40. Coronary circulation
Right atrium
Coronary vein
Coronary venule
Blood capillaries
Coronary arteriole
Coronary artery
Aorta
Left ventricle
• Provide oxygen and
nutrients for the
myocardium (heart
muscle).
• For this circulation, the
blood pressure is high,
the speed of blood flow is
fast, and the circuit
length is short.

41. Summary

42. 9.2.2 The heart

43. 9.2.2.1 Structure of the heart

44. Heart
• The heart is a blood pump which drives
the circulation of blood.
• The contraction of the ventricles pumps
blood to the whole body including the
lungs.
• The heart contains four cavities:
• Two atrium
• Two ventricles
• Mainly constructed with myocardium
(heart muscle).
• The ventricles are separated by a
septum.

45. Unidirectional blood flow
• A heart valve normally allows
blood to flow in only one direction
through the heart.
• Two atrioventricular valves:
• Tricuspid valve is between the right
ventricle and the right atrium.
• Bicuspid / mitral valve is between
the left ventricle and the left atrium.
• Two semilunar valves:
• Pulmonary valve is between the left
pulmonary artery and right ventricle.
• Aortic valve is between the aorta
and the left ventricle.
• The chordae tendineae (tendinous
chords) are tendons that connect
the papillary muscles to the
tricuspid valve and the mitral valve
in the heart.

46. The heart valves

47. • chordae tendinae =
fibrous cords that keep
the AV valve cusps from
swinging into the atria &
prevent regurgitation of
blood.
• papillary muscles =
muscles in the ventricles
connected to the
chordae tendinae. These
muscles help stabilize
the AV valves during
ventricular contraction.
Attachment of the valves

48. How the Heart Works Video
• Chapter 9 How the Heart Works 3D Video.flv

49. 9.2.2.2 How the heart works

50. Heart Beats
• The pumping action of the heart (heartbeat) is controlled by the heart’s
electrical system or the cardiac conduction system.
• The beating of the heart is involuntary.
• Heart beat is rhythmic and consistent though the heart.
• The cardiac muscle cells are closely connected to each other by
intercalated discs闰盘.

51. Heart nodes
• Heart nodes are specialized
muscle tissues that behave
as both muscle and nervous
tissue.
1. Sinoatrial node（S-A node)
窦房结
2. Atrioventricular node（A-
V node)房室结
3. Atrioventricular bundle /
Bundle of His房室束
4. Purkinje fibers柏金氏纤维

52. Signal transmission in the heart
1. The SA node generate
wave of contraction
signals.
2. Signals are delayed at
the AV node.
3. Signal are passed to the
AV / His bundle.
4. Signal are spread
throughout ventricles
through the Purkinje
fibres.

53. Pacemaker电子心脏起博器
• A pacemaker can replace
the function of sinoatrial
node when needed.
• Modern pacemakers have
two parts
• the pulse generator
• one or more leads (small
wires that run from the
pulse generator to the
sinoatrial node)

55. Electrical signal and contraction of the heart
• The electrical signal generated by
the Sinoatrial node causes
excitation of the myocardia.
• The atria contract, follow by the
ventricles.
• Systole收缩期 is the the period which
the heart chamber contracts.
• from Greek σύν (syn, "together") +
στέλλειν (stellein, "send").
• Diastole舒张期 is the period which
the hear chamber relaxes and
refills with blood following systole
(contraction).
• Greek word διαστολη “dilation”

57. Four stages of a cardiac cycle
心房收缩期 心室收缩期 心房舒张期 心室舒张期

58. The cardiac cycle takes about 8 seconds

59. Atrial systole
• Blood flows from pulmonary vein and
anterior, posterior vena cava into the
left and right atria.
• The Sinoatrial node generate
electrical signal.
• The atria contract.
• The pressure in the atria increases.
• The blood flows into the left and right
ventricles respectively.
• Both the mitral valve (bicuspid valve)
and the tricuspid valve open to allow
the entry of blood into the ventricles.
• The semilunar valves are closed.
• This process takes about 0.1 second.

60. Ventricular systole
• The left and right ventricles are filled with
blood.
• The electrical signal generated by the
Sinoatrial node is passed to Atrioventricular
node, Atrioventricular bundle / Bundle of His
and finally the Purkinje fibers.
• The ventricles contract.
• The high blood pressure of the ventricles
inside increases push open the semilunar
valves.
• The blood is pumped into aorta and
pulmonary artery.
• At the same time, the increasing blood
pressure causes the mitral valve and tricuspid
valves close to prevent the back flow of blood
into the atria.
• The closure of mitral valve and tricuspid valve
produces the first heart sound (“lub”).
• This process takes about 0.3 second.

61. Atrial diastole
• After the atrial contraction (atrial
systole) is completed, atria begin
to dilate immediately after
(about 0.1 second).
• This process occurs at the same
time with ventricular systole.
• The pressure in atria decreases.
• Blood from the pulmonary vein,
anterior and posterior vena cava
to flow into the left and right
atria respectively.
• This process takes about 0.7
second.

62. Ventricular diastole
• The ventricles relax and dilate after
pumping blood into aorta and
pulmonary artery.
• This causes the mitral valve and
tricuspid valve to open, then blood flow
into the ventricles.
• The semilunar valves is closed,
producing the “dup” second heart
sound.
• The “dup” sound indicates the
beginning of ventricular diastole. It has
a higher pitch and it lasts for a shorter
time.

63. “dup”“lub”

65. Blood pressure in the heart
3
a small backflow of blood into the ventricles
The atrioventricular
valves are bulged
backward into the
atria because of
increasing pressure
in the ventricles
Blood continues
to fill atria and
ventricles.Blood fill the
atria.

66. Blood pressure in the body
• Blood pressure is the pressure of
circulating blood on the walls of
blood vessels.
• Blood pressure is highest in the left
ventricle, and lowest in the right
atrium, to create a pressure
gradient to encourage blood flow.
Left ventricle > aorta > arteries >
aterioles > capillaries > venules >
veins > venae cavae > right atrium
• Blood pressure can be controlled by
the autonomic nervous system and
hormones such as adrenaline.

67. Measuring blood pressure
• Blood pressure is generally
measured from the brachial
artery上肢肱动脉.
• Blood pressure is highest
when the ventricles contract
= systolic pressure收缩压.
• Blood pressure is the lowest
when the ventricles relax =
diastolic pressure舒张压.
• Blood pressure is higher in
men compare to women (<50
years old).

69. Electrocardiogram, ECG
• The beating of the heart is controlled by
electrical impulses generated by the
sinoatrial node.
• Impulses are transmitted by
depolarising the surface of a cardiac
muscle cell.
• After depolarizing, the cell surface must
return to the original status through
repolarizing.
• The changes in electrical potential can
be measure on the body surface using
electrodes from a voltmeter.
• The graph illustrating regular changes in
electrical potential in each cardiac cycle
is known as electrocardiogram.

71. Components of ECG
• P wave
• The left and right atria are excited.
• The atria contracts.
• QRS complex
• Left and right ventricles are excited.
• The ventricles contract.
• A much stronger electrical signal
because of the larger size of the
ventricular cardiac muscle.
• The recovery of the atria occurs
here but masked by the QRS
complex.
• T wave
• The recovery of the ventricles.

72. Atria repolarizing simultaneously

74. Importance of ECG
• ECG can help us understand the activities of the
heart and it can also be used to diagnose heart
diseases.

75. 9.2.3 Blood vessel

76. Type of blood vessels
• Artery动脉
• from Greek artēria, probably from
airein ‘raise’.
• The blood vessel which carries blood
away from the heart.
• Vein静脉
• from Latin vena ‘blood vessel’ and
‘small natural underground channel of
water
• The blood vessel which carries blood
from tissue cells back to the heart.
• Blood capillary微血管
• The finest blood vessels which
connect arterioles小动脉 with venules小
静脉.

77. • Red blood cell escaping
from a raptured venule.
• SEM, x2300

78. Subtypes of blood vessels

79. Structure of the blood vessels
• The wall of artery and vein is practically
the same. It is mainly divided into three
layers:
• Capillaries only have a layer of squamous
epithelium as the endothelium.
Layer Tissue type
endothelium squamous epithelium
mesothelium smooth muscle tissue
adventitious layer connective tissue

80. Comparison among the blood vessels
Artery Capillary Vein
Thickness of vessel
wall
Thickest Thinnest Thinner than the arteries
Diameter Smaller than the veins Smallest Largest
Total area Smallest Largest Larger than the arteries
Blood volume About 20%
Least (varies
with activities)
Most about 70%
Speed of blood Fastest Slowest Slower than the arteries
Smooth muscle More ✖ Less
Elastic fibre More ✖ Less
Valve ✖ ✖
Yes, to avoid backflow of
blood
Exchange of materials ✖ Free diffusion ✖
Penetration of WBC ✖ Yes ✖

81. Mechanisms of blood flow
Artery Capillary Vein
 Contraction of the heart
 Contraction of
the heart
 Contraction of the skeletal
muscle
 Elasticity of the artery
wall
 Negative pressure created
when the atria relax
 Contraction of the
smooth muscle
 Negative pressure created
when the thoracic cavity
expands during inhalation
 Increases of blood
volume
 Gravity

82. 9.2.4 Blood

83. Formed elements of blood
• Human body contains about
5 litres of blood.
• Blood is a fluid tissue, which
circulates through the whole
body.
• Fractioning of whole blood
can be done by
centrifugation离心分离法.
• Blood consists mainly of
• blood corpuscles血球(45%)
• blood plasma血浆(55%)

84. Centrifugation离心分离法
• By spinning laboratory samples at very
high speeds, the components of a given
mixture are subjected to centrifugal force
离心力, which causes more dense particles
to migrate away from the axis of rotation
and lighter ones to move toward it.
Supernatant
Pallet

85. Types of blood corpuscles
lymphocyte
platelet
leucocyte

86. 9.2.4.1 Blood corpulses

87. Production of blood corpuscles
• Blood corpuscles are generally produced
by the red bone marrow红骨髓 but not all
of them mature in the bone marrow.

88. Erythrocyte红血球
• Greek eruthros ‘red’ + from New Latin -
cyta ‘cell’
• The mammalian erythrocytes are
biconcave双凹, circular disc圆盘in shape
and without nuclei.
• Their cytoplasm is filled with
haemoglobin which combines readily
with oxygen or carbon dioxide and
releases oxygen or carbon dioxide
readily.
• Function is to carry oxygen to every
part of the body.
Top:
TEM
Left:
SEM

89. Birth of erythrocyte
• Maturing erythrocytes have a nucleus.
• The nucleus is lost in mammals to increase volume available for
haemoglobin.

90. Death of erythrocyte
• The life span of red blood
cells is about 120 days.
• Old red blood cells are
carried to spleen脾 or liver
to be destroyed by
phagocytosis.
• The heme group of the
haemoglobin is recycle.
• Iron ion is stored in the liver.
• The rest of heme is secreted
in the bile as bilirubin.

92. Structure of haemoglobin
• From Ancient Greek αἷμα
(haîma, “blood”) + Latin
globus (“ball, sphere”)
• A protein with quaternary
structure with four protein
subunits, i. e.
• 2 α polypeptide chain
• 2 β polypeptide chain
• The alpha and beta
chains have different
sequences of amino acids,
but fold up to form similar
three-dimensional
structures.
Globin - heme-
containing
globular proteins

93. Heme group
• Each polypeptide chain consists of a
heme groups – a total of 4 heme
groups.
• The heme groups give the red
appearance of erythrocyte.
• The centre of each heme group
contains an Fe2+ ion, which is the site
for oxygen binding.
• Each haemoglobin can bind to four
oxygen atoms

94. Leucocyte白血球
• Greek leukos ‘white’ + kytos ‘cell’
• Leucocytes are colourless and with
nuclei.
• They are larger than red blood cells.
• They can perform amoeboid
movement变形运动.
• Based on the granules in the
cytoplasm, leucocytes can be divided
into two groups, granulocyte颗粒白血球
and agranulocyte无颗粒白血球.
• The life span of leucocytes ranges from
a few hours to about 100 days.

95. Function of leucocytes
• Form the internal defense in our immune
system (see chapter 10).
• The leucocytes protect our body from the
assault of bacteria and other pathogens.
• When a body suffers from illness, there will
be a change in the total number of white
blood cells as well as the ratio of each type of
white blood cells depending on the pathogen
type.

96. According to the difference in staining properties of the cells, granulocytes can
be divided into neutrophil, eosinophil and basophil. Agranulocyte include
lymphocyte and monocyte.

97. Granulocytes
• Latin granulum ‘granule’ + -cyte ‘cell’
• a circulating white blood cell having prominent granules
in the cytoplasm and a nucleus of two or more lobes.
• Eosinophil嗜酸性白血球
• eosin (a red, acidic dye) + -o- + -phil ‘like’
• combating multicellular parasites by releasing toxic proteins and
oxidizing agents.
• control mechanisms associated with allergy and asthma 
inflammation
• Basophil嗜硷性白血球
• baso- ‘basic’ + -phil ‘like’
• responsible for inflammatory and allergy by producing
histamine组织胺
• producing heparin to prevent blood clotting
• Can undergo phagocytosis
• Neutrophil嗜中性白血球
• neutro- ‘neutral’ + -phil ‘like’
• Use phagocytosis to digest pathogens
pink red blue

98. Agranulocytes
• a- ‘without’ + granulocyte
• Agranulocytes are white blood cells
with a one-lobed nucleus and no
granules in their cytoplasm.
• Lymphocyte淋巴细胞
• lympho- ‘lymph’ + -cyte.
• produce antibodies (B cells)
• cell-mediated immune response (T cells)
• Monocyte单核细胞
• mono ‘one’ + -cyte
• phagocytosis

99. Platelets血小板
• Platelets do not have nucleus.
• They are fragments of cytoplasm
separated from megakaryocyte (cell
with large nucleus) in bone marrow.
• Their shapes are irregular.
• The life span of platelets is about 7 –
14 days.
• Old or dead platelets are engulfed by
the reticuloendothelial cells (a.k.a. the
mononuclear phagocytic system,
which consists of phagocytic cells such
as monocytes) in liver, spleen and
bone marrow.
• Platelets cause blood to clot.

100. 9.2.4.2 Blood plasma

101. Blood plasma
• The liquid portion of blood.
• Blood plasma contains water,
protein, mineral salts, glucose,
waste (urea, carbon dioxide),
hormones etc.

102. Composition of blood plasma
Component Function Origin
Water (90%)
• Maintain the volume of blood
• transport substances
Liver
Plasma protein (7-8%)
 Albumin白蛋白
 Fibrinogen纤维蛋白原
 Immunoglobulin免疫球蛋白
 Maintain the osmotic pressure and
pH value of blood
 Clotting of blood
 Fight against pathogen
Mineral salts
Maintain the osmotic pressure and
pH value of blood
Absorbed from
alimentary canal
Nutrients (glucose, amino acids,
fats)
Nutrient needed by cells
Absorbed from
alimentary canal
Waste (Urea, CO2, etc.) To be excreted Liver
Hormone Regulate metabolism Relevant organs

103. 9.2.4.3 Function of blood

104. Transport
• Gases (oxygen, carbon dioxide)
• Nutrients (glucose, amino acids, mineral
salts)
• Metabolic waste products (urea, bilirubin)
• Heat
• Hormone (endocrine gland hormones)

105. Defense
• Leucocyte
• engulf pathogens, bacteria and foreign bodies
• produce antibody
• Platelet
• Lead to blood clotting
• Prevent blood lost
• Prevent entrance of foreign bodies and pathogens

106. Regulation of body temperature
• Blood transport heat.
• Heat can be lost through the epidermis.
• When blood capillaries under the epidermis dilate舒张, more blood
will flow through the epidermis and more heat will be lost.
• When the blood capillaries constrict, less blood will flow through the
epidermis and less heat will be lost.

107. • Luminol is a chemical that can be
used to show trace amounts of blood
by creating a light producing chemical
reaction when mixed with
hemoglobin.
• Luminol powder is mixed into a liquid
containing hydrogen peroxide and
other chemicals. This mixture will
then be sprayed over the area that is
being examined.
• The reaction of the Luminol spray
mixing with the iron in blood will
then produce a blue glow that can be
seen in a dark room.
• Other substances that can
accidentally have the same reaction
with Luminol are: bleach, urine,
faeces & horseradish.
• Unfortunately Luminol can destroy
other crime scene evidence so it is
usually used after other options have
been explored.

108. 9.2.4.3.1 The transportation of
oxygen

109. Haemoglobin
• Red blood cells contain haemoglobin, which can
binds to oxygen atoms with their Fe(II).
• A total of four oxygen molecules (4 O2) can be
carried by a haemoglobin.
• When oxygen is bind, a conformation change is
triggered.
• The iron is not oxidized, but merely changes its
position of electron shells.
• This conformation
change induces
binding of other
three oxygen
atoms.

111. Variation in oxygen transport proteins
• Fetal haemoglobin has higher affinity to oxygen to ensure sufficient
oxygen can be obtained from the placenta.
• Myoglobin肌红素, found only in the skeletal muscle tissue, has highest
affinity to oxygen to store oxygen for stannous activities or prolong
holding of breath such as in the case of diving.
Myoglobin only has
one heme group.

112. Loading and unloading of oxygen
• Deoxyhaemoglobin combines with oxygen to form oxyhaemoglobin.
• Oxyhaemoglobin is an unstable compound.
• Hence the combination of haemoglobin with oxygen is reversible.

113. Factors affecting formation of
oxyhaemoglobin
• The concentration of oxygen
• The concentration of carbon
dioxide
• The pH of blood
• The concentration of carbon
monoxide

114. O2 concentration
• pO2 ↑ (lung alveoli)
• haemoglobin
combines with
oxygen to form
oxyhaemoglobin.
• pO2 ↓ (body tissue)
• oxyhaemoglobin
releases oxygen into
the tissue cells.

115. CO2 concentration
• pCO2 carbon dioxide ↑ (tissues)
• the affinity of haemoglobin for
oxygen ↓
• oxygen is released to the tissues ↑
• blood saturated with oxygen ↓
• pCO2 carbon dioxide ↓ (lung
alveoli)
• the affinity of haemoglobin for
oxygen ↑
• blood saturated with oxygen ↑

116. Quiz
• Based on the graph, when CO2 is
presence in the blood,
________.
A. nothing change to the affinity
of haemoglobin to oxygen
B. the affinity of haemoglobin to
oxygen increases
C. the affinity of haemoglobin to
oxygen decreases

117. The pH of blood
• [CO2] ↑
• pH ↓
• oxygen is released to the tissues ↑
• blood saturated with oxygen ↓
• In tissues with high metabolic rate and
high activity, more carbon dioxide and
hydrogen ions are produced and this
promotes the oxyhaemoglobin in
blood capillaries to release oxygen.

118. CO concentration
• Carbon monoxide is an
odourless gas.
• It has an extremely high
affinity to haemoglobin.
• CO + Hb  HbCO
(carboxyhaemoglobin)
• It is a competitive inhibitor to
oxygen for haemoglobin.
• It can inhibit the transport of
oxygen when presence in the
blood.

119. • CO is a colorless, tasteless and
odorless compound produced
by incomplete combustion of
carbon-containing materials.
• A carbon monoxide detector
can detect the presence of the
carbon monoxide gas in order to
prevent carbon monoxide
poisoning.
• CO detectors can be placed near
the ceiling or near the floor
because CO is very close to the
same density as air.

120. The Bohr effect
• The hemoglobin's oxygen binding affinity is
inversely related both to acidity and to the
concentration of carbon dioxide.
• CO2 + H2O ⇌ H2CO3 ⇌ HCO3
- + H+ (pH ↓)
• Hb + H+ ⇌ HHb
• The lower pH changes the conformation of
haemoglobin and promotes dissociation of
oxygen.
• The haemoglobin then binds to proton to
form haemoglobinic acid (HHb).
• The Bohr Effect is importance for enhanced
unloading of oxygen in metabolically active
peripheral tissues such as exercising
skeletal muscle.
• The Bohr effects also occurs when when
carbon monoxide is present and binds to
haemoglobin to form carboxyhaemoglobin.

121. Shifting of curve
• Left shift
• Haemoglobin affinity
to oxygen ↑
• blood saturated with
oxygen ↑
• Right shift
• Haemoglobin affinity
to oxygen ↓
• blood saturated with
oxygen ↓

122. Conclusion

123. 9.2.4.3.2 Transportation of
carbon dioxide

124. Transportation of CO2
• CO2 by the cells enters the blood
by diffusion.
CO2 is transported to the alveoli
by:
• CO2 + H2O ⇌ H2CO3 (carbonic
acid)
• CO2 + Hb ⇌ HbCO2
(carbaminohaemoglobin)
• CO2 + H2O ⇌ H2CO3 ⇌ H+ +
HCO3
- (hydrogen carbonate
/bicarbonate)

126. carbaminohaemoglobin
bicarbonate
as
carbonic acid
as

127. Direct dissolve in blood plasma
• About 5% of the carbon dioxide dissolves directly in water to form
carbonic acid (H2CO3).
• This carbonic acid is transported by the blood plasma.
• This process is very slow because there is no suitable catalytic
enzyme carbonic anhydrase in the plasma.
CO2 + H2O ⇌ H2CO3

128. As carbaminohaemoglobin
• When the partial pressure of carbon dioxide is high, carbon dioxide
can bind to haemoglobin to form carbaminohaemoglobin.
CO2 + Hb ⇌ HbCO2

129. As bicarbonate
• The carbon dioxide enters the red blood cells
where it combines with water to form carbonic
acid (H2CO3) under the action of the enzyme
carbonic anhydrase quickly.
• The carbonic acid dissociates into hydrogen ions
(H+) and hydrogen carbonate ions (HCO3
-).
CO2 + H2O ⇌ H2CO3
carbonic anhydrase
H2CO3 ⇌ H+ + HCO3
-

130. The fate of carbonic acid
• The proton (H+) will bind to the haemoglobin in
the red blood cell to form haemoglobinic acid
(HHb).
• To prevent acidification of blood by influx of H+
• To induce dissociation of oxygen from haemoglobin
• The hydrogen carbonate ions (HCO3
-) move from
the red blood cell into blood plasma.
• The concentration of HCO3
- in blood plasma in the
vein will be higher than that of the artery.
• The chloride ions (Cl-) in the plasma move into the
red blood cells to maintain the charge balance. This
is called chloride shift.
H+ + Hb ⇌ HHb

131. Conclusion
H2CO3

132. Releasing of CO2 in the alveoli
• pO2 is high and pCO2 is low in the alveoli.
• The hydrogen carbonate ions (HCO3
-) in the
plasma return to the red blood cells and
combine with hydrogen ions (H+) forming
carbonic acid.
• Carbonic acid converts into water and carbon
dioxide.
• This process occurs faster in RBC than plasma due
to the presence of carbonic anhydrase in RBC.
• Carbon dioxide diffuse into the alveoli and into
the atmosphere.
H+ + HCO3
- ⇌ H2CO3
carbonic anhydrase
H2CO3 ⇌ CO2 + H2O

133. pH Buffers
• Organisms must stabilize the blood-pH within a narrow range
of between 7.36 and 7.44 so that chemical reactions within the
body can occurs smoothly.
• Acid-base buffers confer resistance to a change in the pH of a
solution when hydrogen ions (protons) or hydroxide ions are
added or removed.
• An acid-base buffer typically consists of a weak acid, and
its conjugate base (salt).
• The concentrations of the weak acid and its salt are large
compared to the amount of protons or hydroxide ions added or
removed.
• When protons are added to the solution, it will be removed by
reacting with the base component of the buffer is converted to
the weak-acid.
• When hydroxide ions are added to the solution, protons are
dissociated from the weak-acid molecules of the buffer,
converting them to the base of the buffer (and thus
replenishing most of the protons removed).
• The ratio of acid to base changes only slightly.
• Thus, the effect on the pH of the solution is small, within
certain limitations on the amount of H+ or OH- added or
removed.

134. Haemoglobin as a pH buffer in the blood
• Haemoglobin helps to maintain the pH of the blood within a suitable
range and at the same time it maintains an equilibrium of ions of the
blood.
• Avoid major pH change when pCO2 is rising or falling.
• Maintain charge balance and participate in the chlorine switch.

135. 9.2.5 Lymphatic system

136. The lymphatic system
• Latin lympha "water"
• The lymphatic system is part
of the circulatory system.
• The lymphatic system is an
open circulatory system.
• Lymphatic system is mainly
made up of lymph淋巴, lymph
nodes淋巴结, lymphatic
vessels淋巴管and lymphatic
organs淋巴器官

137. Function of the lymphatic system
• Remove of interstitial fluid from
tissues
• Maintain the composition of
blood plasma
• Immune system
• Produce lymphatic cells and
antibodies
• Filter the interstitial fluid
• Absorb and transport fatty acids
and fats from the digestive
system.

138. Lymph
• Lymph is the fluid flows in the
lymphatic vessels.
• When blood flows through the
blood capillaries, part of the
blood plasma diffuses through
the capillary walls into the
intercellular/extracellular space
and form the tissue fluid /
interstitial fluid组织液.
• Some tissue fluid flows into the
lymphatic capillaries to form
lymph.
• The composition of lymph is
similar to the blood plasma, but
with less proteins.
• Lymph contains lymphocyte,
but no red blood cells and
platelets. Human
lymph

139. Lymphatic vessel
• The lymph capillaries are blind
tubes (closed at the end).
• The edges of adjacent endothelial
cells内皮细胞 (a type of squamous
epithelial cells) overlap to form
"flaplike minivalves".
• The permeability of lymph
capillaries is larger than that of the
blood capillaries.
• Macromolecules in the tissue fluid
such as proteins, lipids and
bacteria can enter lymph
capillaries easily.

140. Structure of lymphatic vessel
• Lymphatic vessels have thin walls.
• Lymphatic vessels have valves to
prevent the backflow of lymph.

141. Lymphatic drainage
• Lymphatic system drainage is
organized into two separate
drainage areas.
• The right drainage area clears
the right arm and chest.
• The lymph is drained into the right
lymphatic duct.
• The lymph enters the blood
through the right subclavian vein.
• The left drainage area clears all
of the other areas of the body
including both legs, the lower
trunk upper left of the chest, and
the left arm.
• The lymph is drained into the
thoracic duct.
• The lymph enters the blood
through the left subclavian vein.

142. superior vena cava
Movement of lymph
right
subclavian
vein
right
lymphatic
duct
the right
arm and
chest
left
subclavian
vein
thoracic
duct
both legs, the
lower trunk
upper left of
the chest, and
the left arm

143. Mechanisms of lymph flow
• During inspiration (inhalation), the
thoracic cavity expands producing a
negative suction force.
• This suction force and the
contraction of the skeleton muscles
around the lymphatic vessels cause
lymph to flow towards the two
largest lymphatic ducts (the thoracic
duct and the right lymphatic duct)
against the force of gravity.
• Also move by the rhythmic
contraction of lymphatic vessel
(smooth muscle) and skeletal
muscle.
• The valve also ensure unidirectional
movement of lymph.

144. Lymph nodes
• At definite points along the lymphatic
ducts are numerous small swellings called
lymph nodes (lymph glands).
• Many lymph nodes can be found in the
neck颈部, the mesenteries肠系膜, the
armpits腋窝and the groin腹股沟 are the
most numerous.

145. Function of lymph nodes
• Lymph nodes manufacture
lymphocytes which produce antibodies
抗体.
• The lymph nodes also filter out the
microorganisms that invade the body
and other structures such as cancer
cells from the lymph.
• The flow of lymph through the lymph
nodes is very slow.
• The phagocytes are given sufficient
time to engulf pathogens.
• Inflammation, swelling and pain of the
lymph node when infection occurs.

146. Lymphatic organs
• Some organs in human
body are closely related
to lymphatic system, e.g.
spleen脾脏, thymus胸腺
and tonsil gland扁桃腺.
• These organs possess
structures similar to the
lymph nodes and these
structures can produce
lymphocytes.

147. Spleen脾脏
• Largest lymphatic organ in the body.
Red pulp红髓区
• filtering blood
• removes old red blood cells by phagocytes
• metabolizes hemoglobin to iron and
bilirubin (from heme)
• recycles iron
• store blood
White pulp白髓区
• grow white blood cells
• contain white blood cells, especially
monocytes

148. Thymus胸腺
• Greek θυμός (thumos) "anger" or "heart,
soul, desire, life"
• maturation of T-lymphocytes
• secretes hormones and cytokines that
regulate the maturation of T cells

149. Size of thymus
• largest in childhood but shrinking
and degenerating into fatty tissue
with age
• the immune system produces
most of its T cells during childhood
and requires very few new T cells
after puberty

150. Tonsil gland扁桃腺
• Tonsils are collections of lymphoid tissue
facing into the aerodigestive tract includes
the adenoid tonsil腺样体, two tubal tonsils咽鼓管
扁桃体, two palatine tonsils腭扁桃体, and the
lingual tonsil舌扁桃体.
• most commonly refers specifically to the
palatine tonsils.
• The immune system's first line of defense
against ingested or inhaled foreign
pathogens.
• Infection may cause swelling of the tonsils,
which may obstruct the airway or interfere
with swallowing.
palatine tonsils

151. Conclusion
Lymphatic organs