CHAPTER 9
TRANSPORT IN ANIMALS
Y9 BIOLOGY
LEARNING OBJECTIVES
DOUBLE CIRCULATION OF MAMMALS
ADVANTAGES OF DOUBLE CIRCULATION
• More efficient
• High blood pressure for sufficient blood supply.
• Allow different pressure in each loop.
• Prevent mixing of oxygenated and deoxygenated
blood.
• Allows animals to have high metabolic rate.
LEARNING OBJECTIVES
HEA
RT
PATHWAY OF BLOOD THROUGH THE HEART
• Deoxygenated blood coming from the body flows into the right atrium via
the vena cava
• Once the right atrium has filled with blood the heart gives a little beat and the
blood is pushed through the tricuspid (atrioventricular) valve into the right
ventricle
• The walls of the ventricle contract and the blood is pushed into the pulmonary
artery through the semilunar valve which prevents blood flowing backwards into
the heart
• The blood travels to the lungs and moves through the capillaries past the alveoli
where gas exchange takes place (this is why there has to be low pressure on this
side of the heart – blood is going directly to capillaries which would burst under
higher pressure)
PATHWAY OF BLOOD THROUGH THE HEART
• Oxygen-rich blood returns to the left atrium via the pulmonary vein
• It passes through the bicuspid (atrioventricular) valve into the left
ventricle
• The thicker muscle walls of the ventricle contract strongly to push the
blood forcefully into the aorta and all the way around the body
• The semilunar valve in the aorta prevents the blood flowing back down
into the heart
CONTROL OF BLOOD FLOW
THROUGH THE HEART
METHODS FOR MEASURING HEART ACTIVITY
➢ Pulse Rate
➢ Heart sounds
➢ Electrocardiograms (ECGs)
PULSE RATE
PULSE RATE MEASUREMENT
MANUAL METHOD
PULSE RATE MEASUREMENT
ELECTRONIC METHOD
HEART SOUNDS
HEARD BY USING
STETHOSCOPE
ELECTROCARDIOGRAMS
(ECGS)
EFFECT OF PHYSICAL ACTIVITY ON HEART
RATE
• A heartbeat is a contraction. Each contraction squeezes blood to
the lungs and body.
• The pulse is a pressure wave passing through the arteries as a
result of the heartbeat.
• At rest, the heart beats about 70 times a minute, but this varies
according to a person’s age, sex and fitness. It is higher if you are
younger and/or female, and lower if you are fit.
• An increase in physical activity increases the pulse rate, which
can rise to 200 beats per minute.
WHY PHYSICAL ACTIVITY AFFECTS THE
HEART RATE
• This is because during exercise the muscles
need more energy, so the heart has to
deliver more oxygen and glucose for
respiration.
• After exercise has stopped, the pulse rate
gradually drops to its resting state.
• If the individual is fit, this happens quickly,
but an unfit person’s pulse rate will take
longer to return to normal.
CORONARY HEART DISEASE
CORONARY ARTERY
ANGINA
POSSIBLE CAUSES OF CORONARY HEART DISEASES
➢Diet
➢Stress
➢Smoking
➢Genetic predisposition
➢Age & Gender
➢Lack of exercise
LEARNING OBJECTIVES
LEARNING OBJECTIVES
COMPOSITION OF BLOOD
• Blood transports materials through out
the body inside blood vessels.
•
PLASMA
Straw colored, nonliving part of blood.
• 90% Water
• Helps to regulate body temperature
• Contains Electrolytes
• Plasma transports blood cells, products of
digestion and hormones throughout the
body.
✓ Tiny, disc like, biconcave cells
RED CELLS
✓ Do not have nuclei
✓ Spongy cytoplasm enclosed in an elastic cell membrane
✓ Cytoplasm contains a red pigment Haemoglobin.
✓ One RBC live for about 4 months
✓ 200 000 million red cell (1 % of the total) wear out and replaced each day
✓ Red cells are made by the red bone marrow of certain bones
HAEMOGLOBIN & OXYHAEMOGLOBIN
WHITE BLOOD CELLS
• White blood cells are involved with phagocytosis and antibody
production.
• The two most numerous types of white blood cells are
phagocytes and lymphocytes.
• The phagocytes can move about by a flowing action of their
cytoplasm and can escape from the blood capillaries into the
tissues by squeezing between the cells of the capillary walls.
• They collect at the site of an infection, engulfing and digesting
harmful bacteria and cell debris – a process called
phagocytosis . In this way they prevent the spread of infection
through the body. One of the functions of lymphocytes is to
produce antibodies.
PLATELETS
• Pieces of blood cells
• No nucleus
• Live 2-4 days
• Involved in clotting of blood
• Produced in red bone marrow