Download 14.3 The heart

14 The human circulatory system
•
14.1 Why do we need a circulatory system?
•
14.2 Blood vessels
•
14.3 The heart
•
14.4 Blood circulation in man
•
14.5 What is blood?
•
14.6 The functions of mammalian blood
•
14.7 What is the lymphatic system? (Extension)
•
Mind Map
14.1 Why do we need a circulatory system?
14.1 Why do we need a circulatory system?
Unicellular organism
O2
O2
O2
Cell
Absorb materials
from
surroundings
through cell
surface
14.1 Why do we need a circulatory system?
Multicellular organism
Absorb materials
from
surroundings
through body
surface
O2
O2
O2
14.1 Why do we need a circulatory system?
1
Surface area
Volume
Surface area to
volume ratio
size
2
= (1 x 1) x 6
=6
= (2 x 2) x 6
= 24
=1x1x1
=1
=2x2x2
=8
6/1 = 6
24/8 = 3
14.1 Why do we need a circulatory system?
1
Surface area for
Surface area
material exchange
The amount of
Volume
materials needed
Surface area to
volume ratio
size
2
= (1 x 1) x 6
=6
4 times
= (2 x 2) x 6
= 24
=1x1x1
=1
8 times
=2x2x2
=8
6/1 = 6
24/8 = 3
14.1 Why do we need a circulatory system?
If the body size increases, the surface
area per volume ratio
Thus, it is not enough to absorb materials
through the body surface
Surface area for
material exchange
The amount of
materials needed
Surface area to
volume ratio
= (1 x 1) x 6
=6
4 times
= (2 x 2) x 6
= 24
=1x1x1
=1
8 times
=2x2x2
=8
6/1 = 6
24/8 = 3
14.1 Why do we need a circulatory system?
For smaller animals
Larger surface area to volume ratio
Surface area is large
enough for gaseous
exchange of the whole
organism
ONLY
simple
diffusion
is enough
14.1 Why do we need a circulatory system?
For smaller animals
Larger surface area to volume ratio
Surface area is large
enough for gaseous
exchange of the whole
organism
No Transport
system is
needed
14.1 Why do we need a circulatory system?
Larger organism
14.1 Why do we need a circulatory system?
Material exchange
Organ
Transport
system
Larger organism
14.1 Why do we need a circulatory system?
For larger animals
Surface area to volume ratio
Smaller surface area to
volume ratio
Transport
system
Simple diffusion
through body surface
is not enough
Specialised organs
such as lungs are required for
effective material exchange
14.1 Why do we need a circulatory system?
1
Three
components
Heart
Blood vessel
2
Blood
3
14.2 Blood vessels
14.2 Blood vessels
Capillary
Vein
Artery
14.2 Blood vessels
From the heart
Vessel transports blood
away from the heart
Artery
Arteriole
Smaller artery
Blood
flow
14.2 Blood vessels
To the heart
Vessel transports blood
to the heart
Venule
Vein
Smaller vein
14.2 Blood vessels
2 Highly branched
Capillary
Artery
Vein
1
Carries blood from
arteriole to venule
14.2 Blood vessels
Blood pressure
Blood pressure / kPa
Low blood
pressure
High blood
pressure
Artery
arteries
arterioles capillaries venules
vein
Relative rate of blood flow
Vein
14.2 Blood vessels
Vein
No pulse
With pulse
Artery
arteries
arterioles capillaries venules
vein
Relative rate of blood flow
Blood pressure / kPa
Rhythmic change
of pressure
pulse
14.2 Blood vessels
Adaptation
of artery
Capillary
Vein
Artery
14.2 Blood vessels
Adaptation
of artery
Wall of
blood vessel
1
Muscles
Elastic
fibres
Lumen
2
14.2 Blood vessels
Adaptation
of artery
1
Thick Wall
A continuous
blood flow is
maintained by
High proportion
of elastic fibers
in artery
Withstand high blood
pressure
2
14.2 Blood vessels
Adaptation
of artery
Constriction
of arteriole
Dilation
of arteriole
14.2 Blood vessels
3 High proportion of
Adaptation
muscle
of artery
Regulates
the
Constriction
amount of blood
of arteriole
flowing through
14.2 Blood vessels
Adaptation
of artery
Thick Wall
High proportion of
elastic fibers
High proportion of
muscle
Summary
Withstand high
blood pressure
Maintain continuous
blood flow
Regulates the
amount of blood
flowing through
14.2 Blood vessels
Adaptation
of vein
Capillary
Vein
Artery
14.2 Blood vessels
Adaptation
of vein
Thin Thin
or thick ?
Wall
1
SmallLarge
or Large ?
Lumen
14.2 Blood vessels
Adaptation
Less resistant for
of vein
blood with
Thin lower
pressure to flow
Wall
1
through
Large
Lumen
14.2 Blood vessels
Adaptation
of vein
Valve
Blood can only flow in
one direction
2
Prevent backflow
of blood
14.2 Blood vessels
Squeeze the blood flowing
back to the heart
Adaptation
of vein
Valves
close
Skeletal
muscle
Vein
Skeletal
muscle
contracts
14.2 Blood vessels
Capillary
Vein
Deoxygenated
or Oxygenated
blood?
Artery
14.2 Blood vessels
Deoxygenated
blood
Vein
Except
pulmonary vein
Capillary
Oxygenated
blood
Artery
Except
pulmonary artery
14.2 Blood vessels
Capillary
Vein
Artery
Site for exchange of materials
between blood and tissue cells
14.2 Blood vessels
capillary
Can squeeze out between the
cells in the capillary wall
1
One cell thick
O2
nutrients
CO2
waste
White blood cell
2
tissue cells
Shorten the distance
for diffusion
Faster material
exchange
14.2 Blood vessels
Highly branched
3
B
Greater total crosssectional
Cell area
Slow down the
blood flow rate
Longer time for
Cell
diffusion
Cell
A
Increase surface
area for diffusion
Cell
14.2 Blood vessels
Arteries
Direction
Away from the
of blood
heart
flow
Wall
Thick
Comparison
Veins
Capillaries
To the heart
Link up
arteries &
veins
Thin
Very thin, only
one cell thick
Lumen
Small
Large
About the same
diameter as a
red blood cell
Valves
Absent
Present
Absent
14.2 Blood vessels
Arteries
Comparison
Veins
Capillaries
Blood
pressure
High
Low
Falls as blood
passes along
Pulse
With pulse
No pulse
No pulse
Oxygenation
of blood
Oxygenated
(except pulmonary
artery)
Deoxygenated
(except
pulmonary vein)
Blood becomes
deoxygenated as
it passes along
Deep inside Close to the Everywhere
Location
the body
surface
in the body
14.2 Blood vessels
Experiment 14.1
To examine the capillary blood flow in a fish's tail fin
small fish
glass slide
on the tail fin
petri dish
wet cotton wool
14.2 Blood vessels
Experiment 14.1
To examine the capillary blood flow in a fish's tail fin
1. Wrap a small living fish in wet
cotton wool and put it in a petri
dish.
2. Cover the tail fin with a glass slide.
3. Keep the cotton wool wet all the
time.
14.2 Blood vessels
Experiment 14.1
To examine the capillary blood flow in a fish's tail fin
4. Put the petri dish on the stage of a
microscope.
5. Observe the tail fin under the low
power of a microscope. Can you
see blood flowing in a network of
capillaries inside the tail fin? How
small are the capillaries compared
with that of a red blood cell?
14.3 The heart
14.3 The heart
Blood vessels A
Blood vessels B
Heart muscle
14.3 The heart
Blood vessels B
14.3 The heart
Coronary
artery
Supplies O2 and nutrients to
the heart muscle
to release
energy
Glucose
O2
for
muscle
contraction
14.3 The heart
Remove the wastes from the
heart muscles
Coronary
vein
Wastes
Wastes
14.3 The heart
Blood vessels A
Blood vessels B
Heart muscle
14.3 The heart
Blood vessels A
Coronary artery
Coronary vein
Heart muscle
14.3 The heart
The route
of blood flow
through the heart
14.3 The heart
Left
Right
14.3 The heart
Pulmonary artery
4
1
Superior vena cava
Right atrium
Semilunar valve
2
Tricuspid valve
Right ventricle
3
Inferior vena cava
1
14.3 The heart
A
Chambers
B
Vessels
Right atrium
Right ventricle
Pulmonary
artery
Vena cava
C
Valves
Semilunar valve
Tricuspid valve
14.3 The heart
Left
Right
14.3 The heart
4
Aorta
1
2
Pulmonary vein
Left atrium
Bicuspid valve
Semilunar valve
Left ventricle
3
14.3 The heart
Left atrium
Left ventricle
A
Chambers
Pulmonary vein
Aorta
Semilunar valve
Bicuspid valve
Vessels
Valves
B
C
14.3 The heart
Lungs
Pulmonary vein
Pulmonary artery
Aorta
Vena cava
Body
14.3 The heart
Atria
Receive blood from
Right atrium
Receives
deoxygenated
blood
Vena cava
Veins
Pulmonary vein
Left atrium
Receives
oxygenated
blood
14.3 The heart
Ventricles
Pump blood out of
the heart
Right ventricle
pump
deoxygenated
blood
to lungs
To other
parts of the
Lungs
body
The
body
Left ventricle
pump
oxygenated
blood
to the rest of
the body
14.3 The heart
Which chamber, ventricle
or atrium, has a thicker
heart muscle? Why?
The ventricle
because it pumps the blood to
a longer distance than the atrium
14.3 The heart
The left ventricle
Which chamber, left or right
ventricle, has a thicker heart
muscle? Why?
Because it creates a
greater force to pump the
blood around the body
which travels
longer than that to
the lungs
14.3 The heart
Valves
Semilunar
3
valves
Tricuspid
1
valves
Bicuspid
2
valves
14.3 The heart
Location
At the entrances of
the aorta and the
pulmonary artery
Semilunar
Between
atrium and ventricle
Bicuspid & Tricuspid
14.3 The heart
Heart
tendon
Not present
Semilunar
Prevent the valves from
being turned inside out
Present
Bicuspid & Tricuspid
14.3 The heart
Semilunar valve
The valves have no tendon but
they are pocket-shaped
14.3 The heart
Prevent backflow
of blood
Prevent backflow
of blood into
ventricle when the
ventricle relaxes
Semilunar
Prevent backflow of
blood into the
atrium when the
ventricle contracts
Bicuspid & Tricuspid
14.3 The heart
semilunar
valve
bicuspid
valve
pulmonary
artery
aorta
tricuspid
valve
Summary
14.3 The heart
Experiment 14.2
To dissect and examine the heart of a pig
1. Obtain a pig's heart from the
butcher.
2. Wash it with tap water.
14.3 The heart
Experiment 14.2
To dissect and examine the heart of a pig
3. Identify the followings:
a. the ventral and dorsal sides,
b. the left and right atria,
c. the left and right ventricles,
d. the aorta,
e. the pulmonary artery, and
f. the coronary vessels.
14.3 The heart
Experiment 14.2
To dissect and examine the heart of a pig
first cut
pulmonary artery
right atrium
right ventricle
aorta
left atrium
left ventricle
14.3 The heart
Experiment 14.2
To dissect and examine the heart of a pig
4. Locate the aorta, and cut into
it with a pair of scissors (first
cut). Open up the aorta and
the left ventricle. Make a cut
in the wall of the left atrium
(second cut). Now you are
going to display the left side
of the heart.
second
cut
pulmonary
artery
14.3 The heart
Experiment 14.2
To dissect and examine the heart of a pig
5. Make a third cut into
the pulmonary artery.
This will open up the
right side of the heart.
left atrium
open
heart tendon
6. Study the internal
structure of the heart.
third cut
14.3 The heart
Heart beats as the heart muscle contracts & relaxes
Blood is squeezed out
of the heart
Contracts
Systole
Blood flows back into
the heart
Relaxes
Diastole
Diastole 3
ventricular
systole
2
14.3 The heart
The cardiac
cycle
atrial
systole
1
Diastole 3
ventricular
systole
2
14.3 The heart
The cardiac
cycle
atrial
systole
1
14.3 The heart
The cardiac cycle
atrial systole
Bicuspid and tricuspid valves open
1
and larger than that in ventricles
Pressure in atria
increases
Atria
contract
Squeeze blood into
2
ventricles
Diastole 3
ventricular
systole
2
14.3 The heart
The cardiac
cycle
atrial
systole
1
14.3 The heart
The cardiac cycle
ventricular systole
1
Semilunar valves open
and larger than that in arteries
Pressure in ventricles
increases
Ventricles
Ventricles
contract
contract
2
Squeeze blood into
arteries
14.3 The heart
Ventricles
contract
The cardiac cycle
ventricular systole
Blood pressure in
ventricles is higher than
that in atria
3
Forces the bicuspid and
tricuspid valves to close
First Heart Sound
Diastole 3
ventricular
systole
2
14.3 The heart
The cardiac
cycle
atrial
systole
1
Both Ventricles &
Atria relax
14.3 The heart
The cardiac cycle
Diastole
Bicuspid and tricuspid
valves open
1
Blood flowing into
atria and ventricles
Both Ventricles &
Atria relax
14.3 The heart
The cardiac cycle
Diastole
Pressure in ventricles
decreases
and smaller than that
in arteries
2
Semilunar valves close
Second Heart Sound
14.3 The heart
3
The cardiac
cycle
O.4s
2
O.3s
O.1s
0.8s per one cardiac cycle
1
14.3 The heart The cardiac cycle
Systole
Diastole
14.3 The heart Pressure change
Pressure / kPa
?
Aorta
3
Ventricle
2
Atrium
1
Time / s
14.4 Blood circulation in man
Blood vessels and
double circulation
14.4 Blood circulation in man
Lung
Heart
The rest of
the body
Circulation
between the
heart & lungs
Circulation
between the
heart & the
rest of the
body
14.4 Blood circulation in man
Lung
Heart
The rest of
the body
Circulation
Pulmonary
between the
circulation
heart & lungs
Circulation
between
the
Systemic
heart
&
the
circulation
rest of the
body
14.4 Blood circulation in man
14.4 Blood circulation in man
Gaseous exchange
CO2
O2
Lungs
2
Pulmonary
artery
3
Pulmonary 4
vein
Left atrium 5
1 Right
ventricle
Pulmonary
circulatio
14.4 Blood circulation in man
14.4 Blood circulation in man
7 Right atrium
Inferior vena
6
cava
3c
Hepatic vein
3b Liver
Hepatic portal
4b vein
Renal vein
5c
Systemic
circulatio
Aorta
2
Left ventricle
1
3a
Hepatic artery
Gut
Renal artery
4a
5a
Kidney 5b
14.5 What is blood?
14.5 What is blood?
Our blood is composed of…
14.5 What is blood?
Plasma
Blood
55% by
volume
+
Blood
cells
45% by
volume
14.5 What is blood?
Blood
= Blood cells
+
Plasma
14.5 What is blood?
Blood cells
Red
blood
cells
Phagocytes
White
blood
cells
Blood
platelets
Lymphocytes
14.5 What is blood?
Blood
= Blood cells
+
Plasma (liquid)
14.5 What is blood?
10% dissolved
substances
90% Water
14.5 What is blood?
10% dissolved
substances
Gases
Metabolic
wastes
Proteins
Nutrients
Mineral
salts
Antibodies
Hormones
14.5 What is blood?
Blood cells
Blood
Red blood
platelets
cells
Red
blood
cells
White
blood
cells
Phagocytes
Lymphocytes
14.5 What is blood?
1
Where are they
produced?
Hollow
Bone
marrow
Bone
Produces blood
cells
14.5 What is blood?
3
are destroyed in
Liver
Life-span is
about 120 days
2
14.5 What is blood?
4
Shape
?
Biconcave
6
No nucleus
space for carrying
more haemoglobin
oxygen carrying
capacity of blood
Surface area for
diffusion of gases
5
Red pigment
Haemoglobin
which binds with
oxygen
Purplish Red
Haemoglobin
Oxyhaemoglobin
red blood cells
O2
O2
O2
O2
Bright Red
red blood cells
O2
O2
O2
O2
Oxyhaemoglobin
Bright Red
O2
O2
red blood cells
O2
O2
Oxyhaemoglobin
Bright Red
Haemoglobin
Purplish Red
O2
O2
red blood cells
O2
O2
Oxyhaemoglobin
Bright Red
14.5 What is blood?
Transport of oxygen
O2 + haemoglobin
Purplish red
in lungs
oxyhaemoglobin
in tissues
Bright red
Transport of carbon dioxide
in tissues
H++ HCO3-
CO2 + water
in lungs
14.5 What is blood?
alveolus in lung
CO2
O2
Deoxygenated blood
Oxygenated blood
heart
CO2
O2
tissue cells
14.5 What is blood?
Blood cells
Blood
White blood
platelets
cells
Red
blood
cells
White
blood
cells
Phagocytes
Lymphocytes
14.5 What is blood?
Size ?
Larger than
RBC
2WBC
1RBC
14.5 What is blood?
Shape?
Irregular
shape
2WBC
1RBC
14.5 What is blood?
Is there any nucleus?
Yes
2WBC
1RBC
14.5 What is blood?
Is there any
haemoglobin?
No
2WBC
1RBC
14.5 What is blood?
Where are they
produced ?
In bone
marrow
2WBC
1RBC
14.5 What is blood?
Function ?
Kill
germs
2WBC
1RBC
14.5 What is blood?
Which two types?
1
2
Phagocyte
Lymphocyte
14.5 What is blood?
1
Capillary
squeeze out
through the capillary
Phagocyte
It performs
amoeboid
movement
14.5 What is blood?
Its function is to
1
engulf
Germs
Phagocyte
14.5 What is blood?
Germs
2
Remove
Antibodies
Produces
Lymphocyte
14.5 What is blood?
Blood cells
Red
blood
cells
White
blood
cells
Blood
platelets
Blood Platelet
Phagocytes
Lymphocytes
14.5 What is blood?
Blood platelets
1
2
are
tiny fragments
are produced in red bone marrow
3
for
blood clotting
14.5 What is blood?
Comparison of RBC, WBC & Platelets
red blood cells
Site of
production
white blood cells
blood platelets
Bone marrow Bone marrow Bone marrow
Number
5,000,000/mm3
7,000/mm3
250,000/mm3
Size
8 µm
8 –12 µm
Very small
Shape
Biconcave
Irregular
Irregular
Structure
* No nucleus
* With haemoglobin
* With nucleus
* No haemoglobin
* No nucleus
* No haemoglobin
Function
O2 carrier
Kill germs
Blood clotting
14.5 What is blood?
Experiment 14.3
To detect the presence of glucose in plasma
1. Collect blood from a freshly killed
chicken in a bottle containing some
anticoagulant such as 10% sodium
oxalate solution or sodium citrate
solution.
2. Centrifuge the blood sample at about
3,000 revolutions per minute for 2
minutes.
14.5 What is blood?
Experiment 14.3
To detect the presence of glucose in plasma
3. Using a dropper, carefully
transfer about 2cm3 of the
supernatant from the
centrifuge tube to a test tube.
4. Test the supernatant for
glucose by using Clinistix
paper.
supernatant
14.5 What is blood?
Experiment 14.3
To detect the presence of glucose in plasma
Question 1:
Name the supernatant obtained
after centrifugation.
Answer 1: Plasma.
supernatant
14.5 What is blood?
Experiment 14.3
To detect the presence of glucose in plasma
Question 2:
What does the precipitate in the
centrifuge tube consist of?
Answer 2:
It consists of red blood cells, white
blood cells and blood platelets.
supernatant
14.5 What is blood?
Experiment 14.3
To detect the presence of glucose in plasma
Question 3:
What do you observe when the supernatant is tested by
using Clinistix paper? What does it indicate?
Answer 3:
The Clinistix paper changes from pink to blue (or purple),
indicating that glucose is present in the plasma.
14.5 What is blood?
Experiment 14.4
To investigate the effects of oxygen and carbon
dioxide on citrated chicken blood (For demonstration)
1. Collect some chicken blood. You can obtain
it from the market.
2. Blood clotting can be prevented by adding a
little anti-coagulant such as 10% sodium
oxalate solution or sodium citrate solution to
the blood sample. These solutions remove
calcium ions so that blood will not clot.
14.5 What is blood?
Experiment 14.4
To investigate the effects of oxygen and carbon
dioxide on citrated chicken blood (For demonstration)
hydrogen peroxide
MnO2
3. Bubble oxygen through
the blood. Oxygen can
be produced by adding
hydrogen peroxide to
manganese dioxide.
Observe the colour of
the blood.
20cm3
blood
14.5 What is blood?
Experiment 14.4
To investigate the effects of oxygen and carbon
dioxide on citrated chicken blood (For demonstration)
Question 1: What do you observe
when oxygen is bubbled through
the blood? Explain.
Answer 1: The blood turns bright
red when oxygen is bubbled
through it because
oxyhaemoglobin is formed in red
blood cells.
14.5 What is blood?
Experiment 14.4
To investigate the effects of oxygen and carbon
dioxide on citrated chicken blood (For demonstration)
4. Bubble carbon dioxide
through the oxygenated
blood. Carbon dioxide can
be produced by adding
dilute hydrochloric acid to
marble chips. Observe the
colour of the blood again.
dilute HCl
marble
chips
20cm3
blood
14.5 What is blood?
Experiment 14.4
To investigate the effects of oxygen and carbon
dioxide on citrated chicken blood (For demonstration)
Question 2: What do you observe when carbon dioxide is
bubbled through the blood? Explain.
Answer 2:
The blood turns purplish red when carbon dioxide is
bubbled through it because oxyhaemoglobin gives up
oxygen and is changed back into haemoglobin when the
carbon dioxide concentrations is high.
14.6 The functions of mammalian blood
14.6 The functions of mammalian blood
Functions of blood
Transport
Body defence
Temperature regulation
14.6 The functions of mammalian blood
Functions of blood
Transport
Gases
Food
Wastes
Hormone
Antibody
Heat
14.6 The functions of mammalian blood
Functions of blood
Body defence
Phagocytes
Engulf germs
Lymphocyte
Blood clotting
Produce antibodies to
remove germs
Germs are prevented
from entering
14.6 The functions of mammalian blood
Functions of blood
Temperature regulation
Distributing heat
evenly throughout the
body
Help to keep body
temperature
constant
14.7 What is the lymphatic system?
14.7 What is the lymphatic system?
Arteriole
end
Capillary
(one-cell thick)
Blood
Blood
Cell
Venule
end
14.7 What is the lymphatic system?
In arteriole end of
Forces all the blood composition
capillaries
except RBC, plantlets
Higher hydrostatic
& large protein
pressure than outside
Arteriole
end
Blood
Capillary
(one-cell thick)
Tissue fluid formation
Blood
Cell
Venule
end
Out
through
the
capillar
y wall
Tissue
14.7 What is the lymphatic system?
Importance of tissue fluid:
Bathes the cells and provides a
suitable environment for the cells
Medium for exchange of materials
between blood and cells
14.7 What is the lymphatic system?
Some tissue fluid returns
into venule end of
capillaries by osmosis
Tissue fluid
14.7 What is the lymphatic system?
Back to blood vessel
Heart
Tissue fluid
Excess tissue fluid
Circulatory
system
drains into lymph
capillaries
which carry lymph
back to circulatory
system
1
Lymphatic system
Lymph capillary
2
3
Lymph node
Lymph
vessel
14.7 What is the lymphatic system?
Back to blood vessel
How does the lymphHeart
move
without pumping organ?
Circulatory system
Tissue*fluid
By valves
1
Preventing backflow
of lymph
* By surrounding
skeletal muscle
Lymph capillary
contraction
2
To squeeze the
Lymphatic
system
lymph flowing
forward
3
Lymph node
Lymph
vessel
14.7 What is the lymphatic system?
Back to blood vessel
Heart
Kill germs
Circulatory system
Tissue fluid
Produce
antibodies
Lymphocytes can
be
Lymphatic
system
Lymph capillary
found inside the lymph
node
3
Lymph
2
vessel
Lymph node
1
14.7 What is the lymphatic system?
Villus
in small
intestine
A kind of lymph
vessels
Lacteal
carries fat
14.7 What is the lymphatic system?
Functions of the
lymphatic system
Carries excess tissue fluid
back to circulation
Lymph nodes filter the
lymph to destroy the
bacteria inside
Summary
As a medium for
material exchange
between blood & cell
Transports fat
Lymph nodes produce and store
lymphocytes. Lymphocytes are very
important in formation of antibodies
Mind Map
Circulatory system
double circulation
consists of
1. pulmonary
circulation
blood vessels
heart
blood
2. systemic
circulation
include
1. arteries
divided
into
2. veins
1. 2 atria
3. capillaries
2. 2 ventricles
cardiac
cycle
auricular
systole
ventricular
systole
diastole
consists
of
functions
are
1. plasma
1. transport
2. blood cells
2. body
defence
include
1. red blood
cells
2. white blood
cells
3. platelets
3. body
temperature
regulation
Mind Map
Lymphatic system
consists of
1. lymph vessels
2. lymph nodes
3. lymph
flows by
1. contraction of
skeletal muscles
2. pressure from
the tissues