GRADE 9 BIOLOGY
TRANSPORT IN ANIMALS
OBJECTIVES:
ü Name the transport system in animals
ü List the functions of blood
ü List and describe components of blood and relate
their description to their individual roles
ü Describe the role of blood in defending the body
against diseases
TRANSPORT SYSTEM IN ANIMALS
q The transport system in animals is known
as the circulatory system
q This system is made up of:
q blood vessels that take blood to and
from the cells
q the heart that pumps the blood
FUNCTIONS OF BLOOD
q Transport of:
q oxygen and carbon dioxide
q nutrients and products of metabolism
q chemical substances such as hormones and enzymes
q metabolic waste such as urea ( to be excreted)
q Regulate: maintain body temperature (distribute heat)
q Protect: sealing wounds, by the formation of clots
q Defend: fight disease organisms
COMPONENTS OF BLOOD
q Blood consists of:
q Plasma
q Red Blood Cells
q White Blood Cells
q Platelets
COMPONENTS OF BLOOD
q Plasma
q Pale, straw-colored liquid made up of
q 90% water
q 10% dissolved substances
q Transport substances in solution to and from the
body cells
COMPONENTS OF BLOOD
q Red Blood Cells
q Flat and hollowed in the center
q Do not have a nucleus
q Has a lot of space for
haemoglobin
q Transports oxygen to body cells
COMPONENTS OF BLOOD
q White Blood Cells
q Larger than red blood cells
q Help the body fight against disease
organisms
q Two main types:
q Lymphocytes - make antibodies
and antitoxins
q Phagocytes – similar to
amoebae and surround and
digest germs
COMPONENTS OF BLOOD
q Platelets
q Small pieces of cells
q Help the blood clot and seal up
any small cuts
q A scab forms and the skin
repairs itself
ROLE OF BLOOD IN FIGHTING DISEASES
q Red Blood Cells
q Haemoglobin in red cells allows blood to carry 60 times more
oxygen than could be dissolved in the plasma
q Iron is a part of the haemoglobin molecule
q Iron deficiency results in less haemoglobin being made
q This causes anaemia
ROLE OF BLOOD IN FIGHTING DISEASES
q Chemicals and Platelets
q After getting a cut on the skin a clot is made to help stop
bleeding
q This clot is made from chemicals in the blood and platelets
q If left uncovered a scab then forms and dries on the skin
ROLE OF BLOOD IN FIGHTING DISEASES
q White Blood Cells
q If micro-organisms get into the blood they are attacked by
the immune system
q This is the system made up of the white cells in the
blood
White blood cell
Micro-organisms
(e.g. bacteria)
ROLE OF BLOOD IN FIGHTING DISEASES
q White Blood Cells
q Lymphocytes
q Have a clear cytoplasm and a large nucleus
q Some bacteria produce poisonous substances called
toxins
q Lymphocytes produce antitoxins to neutralize these
toxins preventing us from getting sick
q All viruses and some bacteria have chemicals on their
surfaces, called antigens
q The lymphocyte produces antibodies to help the body
fight off these viruses and bacteria
ROLE OF BLOOD IN FIGHTING DISEASES
q White Blood Cells
q Phagocytes
q White cells that resemble amoebae
q They can surround the micro-organisms and digest
them
Micro-organisms
(e.g. bacteria)
Phagocyte