1
Think about…
8.1 The transport system
8.2 The blood
8.3 The blood vessels
8.4 The heart
8.5 Blood circulation
8.6 Exchange of materials between
blood and body cells
8.7 Lymphatic system
Recall ‘Think about…’
Summary concept map
2
The patient has lost a
lot of blood.
He needs blood
transfusion.
3
donated blood
blood
donor
4
donated blood
5
artificial blood
bacteria
producing
haemoglobin
6
1
What are the
functions of blood
in our body
7
2
What is
haemoglobin
What is its role in
the body
8
3
Can artificial
blood totally replace
donated blood
Why
9
8.1 The transport system
In our city:
• transport system to carry goods and
people around
10
8.1 The transport system
How are substances
moved in organisms?
11
8.1 The transport system
In very small organisms:
O2
nutrients
waste
• by diffusion
12
8.1 The transport system
In multicellular organisms:
substances
need to move
long distance
• by a transport system
13
8.1 The transport system
human transport system
circulatory
system
(循環系統)
lymphatic
system
(淋巴系統)
14
8.1 The transport system
Human circulatory system
blood
• carries nutrients
and waste
15
8.1 The transport system
Human circulatory system
blood vessels
(血管)
• distributed
throughout
the body
16
8.1 The transport system
Human circulatory system
heart
• as a pump to
drive blood
17
8.1 The transport system
1 Humans are
multicellular
organisms. A transport system
is needed to carry substances from
one place to another over long
distances within the body.
18
8.1 The transport system
2 The human circulatory system
consists of:
blood
blood vessels
heart
19
8.2 The blood
What is the
composition?
20
8.2 The blood
Composition of blood
centrifugation
21
8.2 The blood
Composition of blood
plasma
blood cells
22
8.2 The blood
1 Plasma
• 90% water
• 10% soluble substances
23
8.2 The blood
1 Plasma
• 10% soluble substances
- plasma proteins
- nutrients
- waste
- respiratory gases
- hormones
24
8.2 The blood
2 Blood cells
25
8.2 The blood
2 Blood cells
blood platelet
red blood cell
white blood cell
26
8.2 The blood
2 Blood cells
Shape
Red
White
blood cells blood cells
Biconcave Irregular
disc
Blood
platelets
Small &
irregular
27
8.2 The blood
2 Blood cells
Red
White
blood cells blood cells
Nucleus
No
Large
Colour
Red
Blood
platelets
No
Colourless Colourless
due to haemoglobin
28
8.2 The blood
2 Blood cells
Size
Red
White
Blood
blood cells blood cells platelets
Small
Phagocyte: < red
(7-8 μm)*
large
blood cells
(10-29 μm)* (1-4 μm)*
Lymphocyte:
small
(6-10 μm)*
* Diameter
29
8.2 The blood
2 Blood cells
Red
White
blood cells blood cells
7000
Number 5.4 million
(/mm3)
Blood
platelets
250 000
Function
Blood
clotting
Carrying
oxygen
Killing
germs
by haemoglobin
30
8.2 The blood
2 Blood cells
Red
White
blood cells blood cells
Made in
Bone
Bone
marrow
marrow,
spleen
Life
span
Blood
platelets
Bone
marrow
120 days A few days A few days
31
8.2 The blood
2 Blood cells
Red
White
Blood
blood cells blood cells platelets
Break Liver and Killed by
Liver and
spleen
down in spleen
germs;
Passed out
in faeces
32
8.2 The blood
8.1
Examination of a blood smear
1 Examine a blood smear
with a microscope.
33
8.2 The blood
8.1
2 Identify different blood cells. Draw high
power diagrams of them.
red blood
cell
phagocyte
lymphocyte
34
8.2 The blood
8.1
3 Observe any differences between the blood
cells.
35
8.2 The blood
What are the
functions of blood?
36
8.2 The blood
Functions of blood
1 Transport of substances
Red blood cells
oxygen
37
8.2 The blood
Functions of blood
1 Transport of substances
Plasma
carbon dioxide
nutrients
urea
hormones
heat
antibodies
38
8.2 The blood
Functions of blood
2 Protection against diseases
Phagocyte
• engulfs and
digests germs
by phagoctosis
39
8.2 The blood
Functions of blood
2 Protection against diseases
Lymphocyte
• produces antibodies
kill germs or
neutralize toxins
40
8.2 The blood
Functions of blood
2 Protection against diseases
Blood platelets
• help in
blood clotting
prevents further blood
loss and entry of germs
through the wounds
41
8.2 The blood
1
blood
plasma
blood
platelet
blood cells
red
blood cell
white
blood cell
42
8.2 The blood
2 Functions of blood:
Plasma
carries heat and dissolved
substances
43
8.2 The blood
2 Functions of blood:
Red blood cells
contain haemoglobin
to carry oxygen
44
8.2 The blood
2 Functions of blood:
White blood cells
protect us against diseases
45
8.2 The blood
2 Functions of blood:
Blood platelets
help in blood clotting
46
8.3 The blood vessels
Three types of
heart
blood vessels
venae cavae
aorta
• arteries
• veins
arteries
veins
• capillaries
arterioles
venules
capillaries
47
8.3 The blood vessels
artery
(動脈)
arteriole
(小動脈)
venule
(小靜脈)
capillary network (微血管網)
vein
(靜脈)
48
8.3 The blood vessels
Arteries and veins
artery
vein
49
8.3 The blood vessels
Arteries and veins
thin layer of
fibrous tissue
thick layer of
muscles and
elastic tissue
thicker wall
artery
smaller lumen
50
8.3 The blood vessels
Arteries and veins
thick layer of
fibrous tissue
thin layer of
muscles and
elastic tissue
thinner wall
larger lumen
vein
51
8.3 The blood vessels
Arteries and veins
artery
vein
Why do arteries have a
thicker muscular wall?
52
8.3 The blood vessels
Arteries and veins
thick muscular wall
contracts and relaxes
diameter changed
regulates amount of blood flow
53
8.3 The blood vessels
Arteries and veins
artery
vein
Why do artery walls
contain more elastic fibres?
54
8.3 The blood vessels
Arteries and veins
when heart relaxes
arteries recoil (反衝)
continuous blood flow
55
8.3 The blood vessels
Arteries and veins
Direction of
blood flow
Vein
Artery
Towards the Away from
heart
the heart
vein
artery
56
8.3 The blood vessels
Arteries and veins
Vein
Nature of
blood
Artery
Deoxygenated Oxygenated
deoxygenated
blood
(not in
pulmonary vein
and umbilical vein)
oxygenated blood
(not in pulmonary
artery and
umbilical artery)
57
8.3 The blood vessels
Arteries and veins
Vein
Wall
vein
(fewer elastic
fibres)
Thinner
Artery
Thicker
artery
(more elastic
fibres)
58
8.3 The blood vessels
Arteries and veins
Vein
Lumen
large lumen
(resistance )
Large
Artery
Small
small lumen
59
8.3 The blood vessels
Arteries and veins
Vein
Blood
pressure
Low
due to resistance
in capillaries
Artery
High
due to pumping
of heart
60
8.3 The blood vessels
Arteries and veins
Vein
Force for
blood flow
Contraction
of muscles
Artery
Pumping of
heart
contraction
pumping
squeeze veins
blood flow
blood flow
61
8.3 The blood vessels
Arteries and veins
Vein
Presence of Present
valves
prevent
backflow of
blood
Artery
Absent
except at the
base of
pulmonary
artery and aorta
62
8.3 The blood vessels
Arteries and veins
to heart
vein
valve
muscle
1 Muscles
contract.
2 They press
against the
vein.
63
8.3 The blood vessels
Arteries and veins
to heart
3 The vein is
squeezed.
4 The blood is
forced to flow.
64
8.3 The blood vessels
Arteries and veins
to heart
5 Muscles
relax.
6 Valves
prevent
blood from
flowing back.
65
8.3 The blood vessels
Arteries and veins
Vein
Location
Artery
Close to
Deep inside
body surface the body
66
8.3 The blood vessels
8.2
Examination of the transverse sections
of an artery and a vein
1 Examine the
transverse sections
of an artery and a
vein with a
microscope.
artery
vein
67
8.3 The blood vessels
8.2
2 Draw labelled diagrams of the artery and
the vein.
3 Observe any structural differences
between them.
68
8.3 The blood vessels
artery
(動脈)
arteriole
(小動脈)
venule
(小靜脈)
capillary network (微血管網)
vein
(靜脈)
69
8.3 The blood vessels
Capillaries
small lumen
one-cell thick
capillary wall
differentially
permeable
70
8.3 The blood vessels
Capillaries
capillary wall
outside
inside
71
8.3 The blood vessels
Capillaries
outside
inside
• small substances, e.g. O2, glucose and
metabolic waste can pass through
72
8.3 The blood vessels
Capillaries

outside
inside
• blood cells and proteins are too large
to pass through
73
8.3 The blood vessels
Adaptations
1 Capillary bed (微血管床)
• large surface area for rapid exchange
capillary bed
74
8.3 The blood vessels
Adaptations
2 Large total cross-sectional area
75
8.3 The blood vessels
Adaptations
capillary (T.S.)
2 Large total cross-sectional area
76
8.3 The blood vessels
Adaptations
2 Large total cross-sectional area
• blood flows slowly to allow longer
period of time for exchange
77
8.3 The blood vessels
Adaptations
3 One-cell thick capillary wall
• short diffusion distance for rapid
exchange
one-cell thick
capillary wall
78
8.3 The blood vessels
8.3
Video
Examination of the capillary flow in a
fish tail fin
1 Wrap a small
living fish in moist
paper towels and
put it in a Petri
dish. Put a slide
over the tail fin.
79
8.3 The blood vessels
8.3
2 Using low power magnification of a
microscope or an image analysing device,
observe the movement of blood in the
capillary network in the tail fin.
red blood cell
80
8.3 The blood vessels
8.3
Results of observation
The blood flow in the capillary network is
quite slow. The direction of flow is one way.
Red blood cells have a similar diameter to
that of the capillaries.
red blood cell
81
8.3 The blood vessels
Blood pressure
blood pressure
pumping of heart:
• blood pressure
 high & changes
periodically
artery
arteriole
82
8.3 The blood vessels
Blood pressure
blood pressure
narrow diameter:
• high resistance
 blood pressure
drops
artery
capillary
arteriole
83
8.3 The blood vessels
Blood pressure
blood pressure
long distance from heart:
• great friction
 blood pressure
further drops
artery
capillary
vein
arteriole
venule
84
8.3 The blood vessels
1
aorta
branches into
arteries
pumps blood into
branch
into
heart
drain blood into
join to
form
join to form
85
8.3 The blood vessels
arterioles
branch into a
network of
capillaries
(exchange of materials)
venules
join to form
86
8.3 The blood vessels
1
aorta
branches into
arteries
pumps blood into
branch
into
heart
drain blood into
venae cavae
veins
join to
form
join to form
87
8.3 The blood vessels
2 Arteries:
• carries oxygenated blood
(except pulmonary artery
and umbilical artery)
88
8.3 The blood vessels
2 Arteries:
• wall contains thick layer of
muscles
muscles to regulate the
blood flow
• elastic
elastic fibres recoil to maintain
blood flow
89
8.3 The blood vessels
2 Veins:
• carries deoxygenated blood
(except pulmonary vein
and umbilical vein)
90
8.3 The blood vessels
2 Veins:
• large lumen to reduce
resistance to blood flow
• valves present to prevent
backflow
backflow of blood
blood flows in one direction
91
8.3 The blood vessels
2 Capillaries:
• allows exchange
exchange of materials
between blood and body cells
92
8.3 The blood vessels
2 Capillaries:
• branching increases surface
area
area for diffusion
cross-sectional area
• large total cross-sectional
blood flows slowly
more time for material
exchange
93
8.3 The blood vessels
2 Capillaries:
• one-cell thick capillary wall
provides short diffusion distance
94
8.3 The blood vessels
3 Movement of blood:
In arteries:
In veins:
pumping action
action of
pumping
the heart
contraction of
contraction
muscles lying next to
the veins
95
8.3 The blood vessels
4 Blood pressure:
In arteries:
In arterioles:
high
gradually drops
In capillaries: a great drop due to
narrow diameter
96
8.3 The blood vessels
4 Blood pressure:
In veins:
becomes even lower
as the blood has
overcome great
friction
friction and
travelled a long
distance
97
8.4 The heart
3D Model
• in the thoracic
cavity between
the two lungs
98
8.4 The heart
• about the size of
a fist (拳)
99
8.4 The heart
• weighs about
300 g
100
8.4 The heart
• surrounded by
pericardium
(圍心膜)
101
8.4 The heart
• mainly made up
of cardiac
muscles (心肌)
102
8.4 The heart
Structure of the heart
right
atrium
(右心房)
right
ventricle
(右心室)
left atrium
(左心房)
left ventricle
(左心室)
103
8.4 The heart
Structure of the heart
anterior
vena cava
posterior
vena cava
aorta
pulmonary
artery
pulmonary
veins
coronary
artery
coronary vein
104
8.4 The heart
Structure of the heart
• coronary arteries (冠狀動脈)
- receive blood from aorta
- supply oxygen and nutrients to
cardiac muscles
• coronary veins (冠狀靜脈)
- carry away carbon dioxide and
waste
105
8.4 The heart
Structure of the heart
106
8.4 The heart
Structure of the heart
right atrium
right
ventricle
left atrium
left ventricle
107
8.4 The heart
Structure of the heart
pulmonary
artery
anterior
vena cava
aorta
pulmonary
veins
posterior
vena cava
108
8.4 The heart
Structure of the heart
semilunar
valves
tricuspid
valve
bicuspid
valve
septum
109
8.4 The heart
Structure of the heart
• septum prevents mixing of blood
on the two sides
deoxygenated
blood
oxygenated
blood
110
8.4 The heart
Structure of the heart
right atrium
right
ventricle
left atrium
left ventricle
111
8.4 The heart
Atria
• thin muscular wall
112
8.4 The heart
Atria
deoxygenated
blood from
head & arms
anterior
vena cava
113
8.4 The heart
Atria
deoxygenated
blood from
head & arms
posterior
vena cava
deoxygenated
blood from legs
& abdomen
pulmonary
veins
oxygenated
blood from
lungs
114
8.4 The heart
Structure of the heart
right atrium
right
ventricle
left atrium
left ventricle
115
8.4 The heart
Ventricles
• thick muscular wall
116
8.4 The heart
Ventricles
• left ventricle has thicker muscular wall
right
left
117
8.4 The heart
Ventricles
Animation
right atrium
left atrium
right ventricle
left ventricle
pulmonary
artery
aorta
rest of body
lungs
118
8.4 The heart
Structure of the heart
semilunar
valves
tricuspid
valve
bicuspid
valve
septum
119
8.4 The heart
Heart valves
120
8.4 The heart
Heart valves
tricuspid
valve
(3 flaps)
aorta
semilunar
valves
bicuspid
valve
(2 flaps)
pulmonary
artery
121
8.4 The heart
Heart valves
Bicuspid valve and tricuspid valve
• prevent backflow of blood into atria
122
8.4 The heart
Heart valves
Bicuspid valve and tricuspid valve
• held by tough heart tendons (心腱索)
123
8.4 The heart
Heart valves
Bicuspid valve and tricuspid valve
• held by tough heart tendons (心腱索)
prevent valves
from turning
inside out
124
8.4 The heart
Heart valves
Semilunar valves
• prevent backflow of blood into ventricles
125
8.4 The heart
8.4
Video
Dissection and examination of a
pig heart
1 Identify the left and right sides, the
dorsal and ventral sides, and the major
blood vessels of a pig heart.
126
8.4 The heart
8.4
2 Run water slowly into each of the four
major blood vessels in turn. Observe
what happens.
127
8.4 The heart
8.4
3 Cut the ventricles from the bottom into
two halves horizontally. First along the
left side, then along the middle and lastly
along the right side. Remove the ventral
halves of the ventricles.
ventral side
128
8.4 The heart
8.4
4 Cut the atria into two halves to show the
valves. Remove the ventral halves of the
atria. Cut open the base of the pulmonary
artery and identify the semilunar valves
inside.
pulmonary artery
129
8.4 The heart
8.4
5 Move the pulmonary artery sideways to
the left. Then cut open the base of the
aorta and identify the semilunar valves
inside.
aorta
130
8.4 The heart
Adaptation of the heart as
an effective pumping organ
1 Cardiac muscles
can contract and
relax continuously
131
8.4 The heart
Adaptation of the heart as
an effective pumping organ
2 Ventricles have
thick muscular
wall
132
8.4 The heart
Adaptation of the heart as
an effective pumping organ
3 Bicuspid valve,
tricuspid valve
and semilunar
valves prevent
backflow of blood
133
8.4 The heart
Adaptation of the heart as
an effective pumping organ
4 Heart tendons
prevent bicuspid
and tricuspid
valves from
turning inside out
134
8.4 The heart
1 The
coronary arteries supply
oxygen and nutrients to the cardiac
muscles.
The coronary veins carry away
carbon dioxide and other waste
from the cardiac muscles.
135
8.4 The heart
2 The heart consists of four chambers:
right atrium
right ventricle
left atrium
left ventricle
136
8.4 The heart
2 Valves also present to prevent
backflow of blood:
semilunar
valves
tricuspid
valve
bicuspid
valve
137
8.4 The heart
3 Blood vessels that carry blood into
and out of the heart:
venae
cavae
carry
deoxygenated
blood into the
heart
138
8.4 The heart
3 Blood vessels that carry blood into
and out of the heart:
pulmonary
artery
carries
deoxygenated
blood to the
lungs
139
8.4 The heart
3 Blood vessels that carry blood into
and out of the heart:
carry
oxygenated
blood into
the heart
pulmonary
veins
140
8.4 The heart
3 Blood vessels that carry blood into
and out of the heart:
carries
oxygenated
blood to all
parts of body
aorta
141
8.5 Blood circulation
blood circulation
pulmonary
circulation
(肺循環)
systemic
circulation
(體循環)
142
8.5 Blood circulation
pulmonary artery
pulmonary
circulation
venae cavae
aorta
pulmonary
veins
right
left
143
8.5 Blood circulation
pulmonary artery
systemic
circulation
venae cavae
aorta
pulmonary
veins
right
left
all other parts of
the body
144
8.5 Blood circulation
blood circulation
pulmonary
circulation
(肺循環)
systemic
circulation
(體循環)
145
8.5 Blood circulation
1 Pulmonary circulation
1 Right ventricle
contracts.
146
8.5 Blood circulation
1 Pulmonary circulation
pulmonary
artery
2 Deoxygenated
blood is
pumped to the
lungs.
147
8.5 Blood circulation
1 Pulmonary circulation
3 Gas
exchange
takes place.
lungs
148
8.5 Blood circulation
1 Pulmonary circulation
4 Oxygenated
blood returns
to the left
atrium.
pulmonary
veins
149
8.5 Blood circulation
2 Systemic circulation
1 Oxygenated
blood flows
from left
atrium to left
ventricle.
body parts
(except lungs)
150
8.5 Blood circulation
2 Systemic circulation
2 Left ventricle
contracts.
body parts
(except lungs)
151
8.5 Blood circulation
2 Systemic circulation
3 Blood is
pumped to all
body parts
(except the
lungs).
aorta
body parts
(except lungs)
152
8.5 Blood circulation
2 Systemic circulation
4 Exchange of
materials
takes place,
the blood
becomes
deoxygenated.
body parts
(except lungs)
153
8.5 Blood circulation
2 Systemic circulation
venae cavae
5 Deoxygenated
blood returns
to the right
atrium through
veins.
body parts
(except lungs)
154
8.5 Blood circulation
2 Systemic circulation
aorta
155
8.5 Blood circulation
2 Systemic circulation
head, neck, arms
anterior vena cava
156
8.5 Blood circulation
2 Systemic circulation
posterior
vena cava
aorta
157
8.5 Blood circulation
2 Systemic circulation
hepatic vein
liver
hepatic artery
158
8.5 Blood circulation
2 Systemic circulation
liver
hepatic portal vein
(nutrient-rich blood)
small intestine
159
8.5 Blood circulation
2 Systemic circulation
posterior
vena cava
1 After digestion,
nutrient-rich
blood is
passed to liver
through
hepatic portal
vein.
aorta
160
8.5 Blood circulation
2 Systemic circulation
2 The blood then
flows through
hepatic vein
and posterior
vena cava to
the heart.
posterior
vena cava
aorta
161
8.5 Blood circulation
1a In the pulmonary circulation:
The right ventricle pumps
deoxygenated blood through
the pulmonary artery to the
lungs
lungs for gas exchange.
162
8.5 Blood circulation
1a In the pulmonary circulation:
The oxygenated blood flows
through pulmonary veins to
the left atrium .
163
8.5 Blood circulation
1b In the systemic circulation:
The oxygenated blood flows
from the left atrium to the
leftventricle
ventricle .
left
164
8.5 Blood circulation
1b In the systemic circulation:
The left ventricle then pumps
the blood through aorta to
all parts of the body except the
lungs
lungs .
165
8.5 Blood circulation
1b In the systemic circulation:
Exchange of materials takes
place in the capillary bed. The
blood becomes deoxygenated .
166
8.5 Blood circulation
1b In the systemic circulation:
The deoxygenated blood
returns to the right atrium
through the venae cavae .
167
8.6 Exchange of materials
between blood and body cells
• takes place at capillaries
168
8.6 Exchange of materials
between blood and body cells
• takes place at capillaries
How does it
take place?
169
8.6 Exchange of materials between blood and body cells
Exchange of materials
plasma
capillary
red blood cell
tissue
fluid
body cell
170
8.6 Exchange of materials between blood and body cells
Exchange of materials
O2
171
8.6 Exchange of materials between blood and body cells
Exchange of materials
nutrients,
O2 water
CO2
waste
172
8.6 Exchange of materials between blood and body cells
Exchange of materials
How is tissue fluid
formed?
173
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
blood flow
capillary
arteriole
lymph
capillaries
(淋巴微管)
tissue fluid
body cells
venule
174
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
Arteriole end
pressure of blood
higher than
pressure of fluid
surrounding the
body cells
175
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
some components
of plasma are
forced out to form
tissue fluid
176
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
some components
of plasma are
forced out to form
tissue fluid
outside
inside
H2O
minerals
sugars
fats
hormones
177
capillary wall
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
some components
of plasma are
forced out to form
tissue fluid
outside
inside
WBC
white blood cells
squeeze through
178
capillary wall
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
some components
of plasma are
forced out to form
tissue fluid
white blood cells
squeeze through
outside
inside

RBC
platelets
plasma
proteins
some are too large
→ remain in blood
179
capillary wall
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
Venule end
water potential of
tissue fluid
higher than
water potential of
blood
180
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
water in tissue fluid
is drawn into
capillaries by
osmosis
181
8.6 Exchange of materials between blood and body cells
Formation of tissue fluid
small amount of
tissue fluid drains
into lymph
capillaries
182
8.6 Exchange of materials between blood and body cells
Why are all body cells
bathed in tissue fluid?
183
8.6 Exchange of materials between blood and body cells
Importance of tissue fluid
1 Provides a constant environment for
the body cells
2 Serves as an important link for the
exchange of materials between
capillaries and body cells
184
8.6 Exchange of materials between blood and body cells
1a At the capillaries, useful materials
are forced out of the blood into
the tissue fluid and then diffuse
into the body cells.
185
8.6 Exchange of materials between blood and body cells
1b Waste products from the body
cells diffuse into the tissue fluid
and then diffuse through the
capillary wall into the blood .
186
8.6 Exchange of materials between blood and body cells
2 Blood pressure in the capillaries
is higher than the pressure of fluid
surrounding the body cells.
plasma
Some plasma except plasma
protein
protein is forced out of the
capillaries to form the tissue fluid.
187
8.6 Exchange of materials between blood and body cells
2
White blood cells can squeeze
through the capillary wall and enter
the tissue fluid.
188
8.7 Lymphatic system
capillary
What
are lymph capillaries?
arteriole
lymph
capillaries
(淋巴微管)
tissue fluid
body cells
venule
189
8.7 Lymphatic system
• part of lymphatic system capillary
• tissue
fluid inside is called
arteriole
tissue
fluid
lymph (淋巴)
body cells
lymph
capillaries
(淋巴微管)
venule
190
8.7 Lymphatic system
Components of lymphatic
system
lymph
vessel
(淋巴管)
lymph node
(淋巴結)
group of
lymph nodes
191
8.7 Lymphatic system
Components of lymphatic
system
lymph
vessels join
to two large
veins,
returning
lymph into
blood
192
8.7 Lymphatic system
1 Lymph capillaries and
vessels
• lymph capillaries are blind-ended
join to form
lymph vessels
193
8.7 Lymphatic system
1 Lymph capillaries and
vessels
flow of lymph in
lymph vessels
~ blood flow in veins
contraction
of muscles
presence of
valves
194
8.7 Lymphatic system
1 Lymph capillaries and
vessels
• to prevent backflow
of lymph
valve
presence of
valves
195
8.7 Lymphatic system
2 Lymph nodes
• at intervals along lymph vessels
196
8.7 Lymphatic system
2 Lymph nodes
space filled with
white blood cells
lymph vessel
197
8.7 Lymphatic system
2 Lymph nodes
space filled with
white blood cells
lymph vessel
198
8.7 Lymphatic system
Functions of lymphatic
system
1 Collects and returns excess tissue
fluid to the blood
199
8.7 Lymphatic system
Functions of lymphatic
system
2 Protects us against diseases by
white blood cells
white blood cells
200
8.7 Lymphatic system
Functions of lymphatic
system
3 Transports lipids
In the small intestine,
lipids are absorbed into
lacteals in the villi.
201
8.7 Lymphatic system
Functions of lymphatic
system
3 Transports lipids
In the small intestine,
lipids are absorbed into
lacteal in the villi.
lacteals
villus
202
8.7 Lymphatic system
1 Lymphatic system consists of:
lymph
capillary
collects excess
tissue fluid as lymph
lymph
vessels
formed by joining
lymph capillaries
lymph
nodes
found at intervals
along lymph vessels
203
8.7 Lymphatic system
2 Lymph is driven forwards inside
lymph vessels by contraction of
muscles
muscles surrounding the vessels.
Valves are also present in the
lymph vessels to prevent backflow
of lymph.
204
8.7 Lymphatic system
3 Functions of lymphatic system:
• transports tissue fluid
back to the blood
205
8.7 Lymphatic system
3 Functions of lymphatic system:
• filters out germs from lymph
at lymph nodes
206
8.7 Lymphatic system
3 Functions of lymphatic system:
• transports lipids from
lacteals in intestinal villi to
the blood
207
1
What are the functions of blood in
our body?
Blood is the transport medium in our
body. It is also important in protecting
us against diseases.
208
2
What is haemoglobin? What is its
role in the body?
Haemoglobin in red blood cells acts as
oxygen carriers.
209
3
Can artificial blood totally replace
donated blood? Why?
Artificial blood consisting mainly of
haemoglobin can carry oxygen to the
organs. However, it cannot serve for
other functions of blood, such as defence
against diseases and blood clotting.
210
Transport in humans
is provided by
circulatory
system
lymphatic
system
consists of
heart blood
blood
vessels
211
blood
made up of
plasma
blood cells
include
red
white
blood cells blood cells
blood
platelets
212
lymphatic system
consists of
lymph vessels
have swellings
called
lymph nodes
lymph
formed
from
tissue fluid
213