Title: Why do organisms need a transport system?
1Why do organisms need a transport
system?
- In large organisms, the distance over which
oxygen, carbon dioxide, nutrients and wastes have
to move is too L-O-N-G for food absorption and
gaseous exchange to occur efficiently
2Transport Systems in Humans
Circulatory System
Lymphatic System
3Circulatory System
4Human Circulatory System
BLOOD
BLOOD VESSELS
HEART
5Blood
- Blood is a LIQUID TISSUE consisting of blood
cells which float in a liquid
- Blood acts as a TRANSPORT MEDIUM to carry various
substances in the forms of solution and suspension
6Blood
- The various components in blood can be separated
by a machine called a CENTRIFUGE
- After centrifugation, blood is divided into two
portions
7Blood
Plasma (55 by volume) (straw colour)
Blood Cells (45 by volume) (red colour)
8What is blood made up of?
9BLOOD CELLS
250 000/mm3
7 000/mm3
5 000 000/mm3
10Blood Cells
White Blood Cell
Red Blood Cell
Platelet
11Where are blood cells made?
12Red Blood Cells (Erythrocytes )
13Red Blood Cells
- RBCs are formed in BONE MARROW
- They have a short life-span about 120 days only
- Old RBCs are destroyed in the liver and the
spleen
- Matured RBCs in mammals do not possess a nucleus
14Red Blood Cells
- They are shaped like biconcave discs in order to
provide a large surface area for diffusion of
gases
- Their red colour comes from haemoglobin which is
responsible for carrying oxygen from the lungs to
all parts of the body
15Transport of Oxygen
16Transport of Oxygen
17Transport of Oxygen
18Transport of Oxygen
19Transport of Carbon Dioxide
- Most of the carbon dioxide is carried in the
blood in the form of hydrogencarbonate ions
(HCO3-). An enzyme inside the RBC helps to
convert the CO2 into HCO3- and vice versa
20Investigation 1 To
investigate the effects of oxygen and carbon
dioxide on chickens blood
21Procedure
22White Blood Cells (Leukocytes)
- Irregularly-shaped
- Possess nucleus
- Kill pathogens
- Number of WBCs in body can vary
- Different WBCs have different lifespans ranging
from 10 hours to over 1 year
23White Blood Cells
- 1) Phagocytes
- They are made in the bone marrow
- They have a lobed nucleus
- They can move like an Amoeba out of blood
capillaries to engulf germs and dead cells
24Phagocytes
25Bacteria
Phagocyte
26White Blood Cells
- 2) Lymphocytes
- They have a large nucleus
- They are made in the bone marrow and then migrate
to lymph nodes - Some lymphocytes produce antibodies others kill
invading cells directly - They also produce antitoxins to neutralize toxins
produced by germs
27When the lymphocyte encounters a matching
antigen, the antibody interlocks with
the antigen and marks it for
destruction
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30Leukaemia
- Leukaemia is a cancer of the tissues which
produce blood - Large numbers of abnormal white cells are
produced, which are unable to carry out their
normal function of fighting infection - The abnormal cells also displace the normal
production of red cells and platelets - Can be treated with chemotherapy, radiotherapy or
bone marrow transplant
31Platelets (Thrombocytes)
- Tiny fragments formed from specialized cells in
the bone marrow - They have no nucleus
- They have a short life span less than 10 days
- They are involved in the process of blood clotting
32Platelets
33After the clot is formed, bleeding is stopped.
The clot hardens to form a scab and the wound
gradually heals
34Blood Clotting
Blood vessel constricts to slow down blood loss
RBCs trapped in a network of fibrin threads
Platelet plug
35Blood Clotting
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37A Comparison of RBCs, WBCs and Platelets
Red blood cells
White blood cells
Platelets
Bone marrow, lymph nodes
Bone marrow
Bone marrow
Site of production
5 000 000/mm3
7 000/mm3
250,000/mm3
Number
Lym8-10?m Phag12?m
Tiny cell fragments
8?m diameter
Size
Biconcave disc-shaped
Shape
Irregular
Irregular
No nucleus Haemogloblin
Nucleus No haemoglobin
No nucleus No haemoglobin
Structure
Function
Transport of oxygen
Blood clotting
Body defence
38PLASMA
Dissolved Substances (10)
Water (90)
39Plasma Dissolved Substances
- Plasma proteins antibodies, fibrinogen
- Lipids
- Glucose
- Amino acids
- Hormones coordinate body activities
- Mineral salts
- Urea
- Carbon dioxide
Nutrients
Wastes
40Investigation 2
Detecting the presence of
glucose in a blood sample
41Procedure
42Functions of Blood
Transportation of
1. Oxygen in the form of oxyhaemoglobin
2. Carbon dioxide in the form of HCO3-
3. Food from ileum to all parts of body
4. Urea from liver to kidneys
5. Hormones from endocrine glands
6. Antibodies to all parts of body
7. Heat to keep uniform temperature
43Functions of Blood
Defence against infection
1. Phagocytes engulf germs
2. Lymphocytes produce antibodies to destroy
germs or antitoxins to neutralize toxins
3. Blood clotting prevents excess blood loss
and entrance of bacteria
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45Blood Vessels
- A system of tubes for distributing blood around
the body - Artery carry blood AWAY from the heart
- Vein carry blood TOWARDS the heart
- Capillary narrow vessel connecting arteries and
veins - Arteries branch into smaller vessels called
arterioles - Small vessels called venules join into veins
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48Changes in blood pressure in different types of
blood vessels
16
Blood pressure (kPa)
8
With pulse
No pulse
Capillaries
Veins
Arteries
Arterioles
Venules
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50Arteries
- Carry blood AWAY from the heart
- Contain oxygenated blood (exception
pulmonary artery) - Thick walls of muscles
- Elastic fibres allow arterial wall to withstand
pressure - Lumen is small and appeared to be round
- No valves
- Need to withstand high pressure
- The muscles around the artery can contract or
relax to allow the vessel to constrict or dilate
51Arteries
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53Veins
- Carry blood TOWARDS the heart
- Contain deoxygenated blood (exception pulmonary
vein) - Thinner walls compared to those of arteries
- Walls are less elastic and muscular
- Lumen is larger and appeared flattened
- Contain valves that are surrounded by skeletal
muscles - Pressure of blood is low
54Veins