Why do organisms need a transport system? - PowerPoint PPT Presentation

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Why do organisms need a transport system?

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Why 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 ... – PowerPoint PPT presentation

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Title: Why do organisms need a transport system?


1
Why 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

2
Transport Systems in Humans
Circulatory System
Lymphatic System
3
Circulatory System
4
Human Circulatory System
BLOOD
BLOOD VESSELS
HEART
5
Blood
  • 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

6
Blood
  • The various components in blood can be separated
    by a machine called a CENTRIFUGE
  • After centrifugation, blood is divided into two
    portions

7
Blood
Plasma (55 by volume) (straw colour)
Blood Cells (45 by volume) (red colour)
8
What is blood made up of?
9
BLOOD CELLS
250 000/mm3
7 000/mm3
5 000 000/mm3
10
Blood Cells
White Blood Cell
Red Blood Cell
Platelet
11
Where are blood cells made?
12
Red Blood Cells (Erythrocytes )
13
Red 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

14
Red 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

15
Transport of Oxygen
16
Transport of Oxygen
17
Transport of Oxygen
18
Transport of Oxygen
19
Transport 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

20
Investigation 1 To
investigate the effects of oxygen and carbon
dioxide on chickens blood
21
Procedure
22
White 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

23
White 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

24
Phagocytes
25
Bacteria
Phagocyte
26
White 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

27
When the lymphocyte encounters a matching
antigen, the antibody interlocks with
the antigen and marks it for
destruction
28
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29
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30
Leukaemia
  • 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

31
Platelets (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

32
Platelets
33
After the clot is formed, bleeding is stopped.
The clot hardens to form a scab and the wound
gradually heals
34
Blood Clotting
Blood vessel constricts to slow down blood loss
RBCs trapped in a network of fibrin threads
Platelet plug
35
Blood Clotting
36
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37
A 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
38
PLASMA
Dissolved Substances (10)
Water (90)
39
Plasma Dissolved Substances
  • Plasma proteins antibodies, fibrinogen
  • Lipids
  • Glucose
  • Amino acids
  • Hormones coordinate body activities
  • Mineral salts
  • Urea
  • Carbon dioxide

Nutrients
Wastes
40
Investigation 2
Detecting the presence of
glucose in a blood sample
41
Procedure
42
Functions 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
43
Functions 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
44
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45
Blood 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

46
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47
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48
Changes in blood pressure in different types of
blood vessels
16
Blood pressure (kPa)
8
With pulse
No pulse
Capillaries
Veins
Arteries
Arterioles
Venules
49
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50
Arteries
  • 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

51
Arteries
52
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53
Veins
  • 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

54
Veins
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