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-G for food absorption and
  gaseous exchange to occur efficiently

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Transport Systems in Humans
Circulatory System
Lymphatic System
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Circulatory System
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Human Circulatory System
BLOOD
BLOOD VESSELS
HEART
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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

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Blood

• The various components in blood can be separated
  by a machine called a CENTRIFUGE

• After centrifugation, blood is divided into two
  portions

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

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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

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Transport of Oxygen
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Transport of Oxygen
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Transport of Oxygen
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Transport of Oxygen
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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

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Investigation 1 To
investigate the effects of oxygen and carbon
dioxide on chickens blood
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Procedure
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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

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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

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Phagocytes
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Bacteria
Phagocyte
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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

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When the lymphocyte encounters a matching
antigen, the antibody interlocks with
the antigen and marks it for
destruction
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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

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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

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Platelets
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After the clot is formed, bleeding is stopped.
The clot hardens to form a scab and the wound
gradually heals
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Blood Clotting
Blood vessel constricts to slow down blood loss
RBCs trapped in a network of fibrin threads
Platelet plug
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Blood Clotting
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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
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PLASMA
Dissolved Substances (10)
Water (90)
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Plasma Dissolved Substances

• Plasma proteins antibodies, fibrinogen
• Lipids
• Glucose
• Amino acids
• Hormones coordinate body activities
• Mineral salts
• Urea
• Carbon dioxide

Nutrients
Wastes
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Investigation 2
Detecting the presence of
glucose in a blood sample
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Procedure
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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
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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
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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

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Changes in blood pressure in different types of
blood vessels
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Blood pressure (kPa)
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With pulse
No pulse
Capillaries
Veins
Arteries
Arterioles
Venules
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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

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Arteries
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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

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Veins