Download 6.2 Pulverman

6.2
The Transport System
by Joe Pulverman
June 2008
6.2.1: Draw and label a diagram of the heart showing the four chambers,
associated blood vessels, valves and the route of blood through the heart.
Teacher’s note: Care should be taken to show the relative thickness of the
four chambers. Neither the coronary vessels nor the conductive system are
required.
6.2.2: State that coronary arteries supply heart muscle
with oxygen and nutrients
Coronary arteries supply heart muscle with
oxygen and nutrients.
6.2.3: Explain the action of the heart in terms of
collecting blood,pumping blood,and opening
and closing of valves.
The atria are the collecting chambers – they collect blood from the veins.
The ventricles are the pumping chambers – they pump blood out into the
arteries at high pressure. The valves ensure that the blood always flows in
the correct direction. (Pg.48 blue book)
Teacher’s note: A basic understanding is required, limited to the collection
of blood by the atria, which is then pumped out by the ventricles into the
arteries. The direction of flow is controlled by atrio-ventricular and
semilunar valves.
6.2.4: Outline the control of the heartbeat in terms of myogenic muscle
contraction, the role of the pacemaker, nerves, the medulla of the brain
and epinephrine (adrenaline).
Heart muscle tissue has a special property – it can contract on its own without being stimulated by a
nerve. One region is responsible for initiating each contraction. The region is called the pacemaker
and is located in the wall of the right atrium. Each time the pacemaker sends out a signal the heart
carries out a contraction or beat. Nerves and hormones can transmit messages to the pacemaker.
(Pg. 48 Blue book)
Adrenalin, carried to the pacemaker by the bloodstream tell the pacemaker to speed up the
beating of the heart.
Histology of the heart muscle, names of nerves or transmitter substances are NOT required.
Aim 7: Simulation and data logging involving heart rate monitors, or data logging involving an EKG
sensor to measure electrical signals produced during muscle contractions, can be used.
6.2.5: Explain the relationship between the structure
and function of arteries, capillaries and veins.
Arteries: 1) Thick outer layer of longitudinal collagen and elastic fibres to avoid bulges and leaks. 2) Thick wall to withstand the
high pressure. 3) Thick layers of circular elastic and muscle fibres to help pump the blood on after each heart beat. 4) Narrow
lumen to help maintain the high pressure.
Veins: !) This layers with a few circular elastic and muscle fibres because blood does not flow in pulses so the veins wall cannot
help pump it. 2) Wide lumen is needed to accommodate the slower flowing blood. 3) Thin wall allows the vein to be pressed flat
by adjacent muscles, helping to move the blood. 4) Thin outer layer of longitudinal collagen and elastic fibres because there is
little danger of bursting.
Capillaries: 1) Wall consists of a single layer of thin cells so the distance for diffusion in or out is small. 2) Pores between cells in
the wall allow some of the plasma to leak out and form tissue fluid. Phagocytes can also squeeze out. 3) Very narrow lumen only
about 10µm across so that capillaries fit into small spaces. Many small capillaries have a larger surface area than fewer wider
ones.
6.2.6: State that blood is composed of plasma,
erythrocytes, leucocytes (phagocytes and
lymphocytes) and platelets.
Blood is composed of plasma, erythrocytes,
leucocytes (phagocytes and lymphocytes) and
platelets.
Erythrocytes = red blood cells
Leucocytes = white blood cells (used in body
defense system)
Campbell Ch. 42 pg. 882
6.2.7: State that the following are transported by the
blood: nutrients, oxygen, carbon dioxide,
hormones, antibodies, urea and heat.
Nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat
are all transported by the blood.
See Ch. 41 pgs. 854-855 in Campbell book
Teacher’s note: No chemical details are required