Topic 6.2 The Transport System

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Topic 6.2 The Transport System
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What is the Circulatory System?

• Circulatory System is a system of internal
  transport that transports
• (i) Oxygen and Carbon dioxide
• (ii) Nutrients to body cells
• (iii) Waste products to specific sites for
  disposal.

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Basic Mammal Blood Flow
Closed Circulatory System
What is an open circulatory system? How do simple
organisms circulate?
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Simple Diffusion

• Open Circulation

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6.2 (U1) Arteries convey blood at high pressure
from the ventricles to the tissues of the body.

• Arteries are one of three types of blood vessels.
  They carry oxygen rich blood away from the heart
  to the tissues of the body.
• The lumen is the opening in a blood vessel
  through which the blood flows. The lumen in
  arteries is narrow to help maintain blood
  pressure.
• Arteries receive blood from the ventricles, very
  thick muscular chambers in the heart.

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6.2 (U1) Arteries convey blood at high pressure
from the ventricles to the tissues of the body.

• The artery walls contain elastic tissues and
  smooth muscles which allow them to stretch and
  contract in response to increased blood volume.
  The contractions propel blood through the
  arteries.
• The walls of the arteries are designed to
  withstand the fluctuating pressure without
  bulging (aneurysm) or rupturing.
• Arteries supply blood to each organ in the body.

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6.2 (U2) Arteries have muscle and elastic fibres
in their walls

• Arteries are very thick walled blood vessels.
  They have a strong outer covering called the
  tunica externa (adventitia) which is made of
  collagen and elastic fibres (connective tissue).
  This allows the walls of the arteries to expand
  in response to pressure created by blood flow.
• The middle layer, tunica media consists of smooth
  muscle and elastic tissue composed of the protein
  elastin which allow the arteries to help pump the
  blood through the body.
• The inner layer of the arteries is known as the
  tunica intima and it is composed of an elastic
  membrane lining and smooth tissues covered by
  elastic tissues.

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6.2 (U3) The muscle and elastic fibres assist in
maintaining blood pressure between pump cycles.

• Blood pressure is measured when the ventricles
  contract and relax.
• Pressure is highest (systolic pressure) when the
  ventricles contract and push blood into the
  arteries.
• Pressure is lowest (diastolic pressure) when the
  ventricles relax and fill with blood.
• When the lumen stretches and the walls of the
  artery push outward there is potential energy
  stored. Pressure decreases at the end of the
  heartbeat and the arteries squeeze propelling
  blood forward.

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6.2 (U3) The muscle and elastic fibres assist in
maintaining blood pressure between pump cycles.

• Blood vessels will experience vasoconstriction
  (lumen decreases) and vasodilation (lumen
  increases) when the circular muscles in the wall
  contract and relax.
• These processes increase and decrease blood flow
  and blood pressure. It controls blood flow
  through smaller branching arteries known as
  arterioles.

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6.2 (U4) Blood flows through tissues in
capillaries with permeable walls that allow
exchange of materials between cells in the tissue
and the blood in the capillary

• Capillaries are the smallest and thinnest (10 µm)
  blood vessels. They are designed this way to
  allow them to fit into tiny spaces and so that
  exchange of materials between the blood and all
  body cells can be efficient.
• They are composed of one thin layer of
  endothelium cells with spaces between the cells
  and are coated in a protein gel.
• Blood plasma (liquid portion of blood) can leak
  out through spaces and form tissue fluid which
  provides an exchange medium for gases and
  nutrients.

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• The permeability of the capillary walls are
  different depending on the surrounding tissues
  and what particles it needs to be permeable to.
  Capillaries also have the ability to adapt to new
  roles over time in response to the needs of the
  tissues.

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6.1 (U5) Veins collect blood at low pressure from
the tissues of the body and return it to the
atria of the heart.

• Veins carry blood towards the heart and into the
  atria.
• Pressure is much lower/walls are thinner.
• Less muscle and elastic fibres so they can dilate
  more.
• At rest 80 of blood volume is in veins
• Blood flow assisted by muscle contractions and
  gravity.
• Veins are found all over the body and like
  arteries serve each organ.

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Major Arteries Veins
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6.2 U6 Valves in veins and the heart ensure
circulation of blood by preventing backflow
Valves in the heart work in a similar
mannerpressure inside the chambers causes the
valves to close
http//www.youtube.com/watch?vHNuPWdfjDoc
Take notes on animation
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6.2 (S1) Identification of blood vessels as
arteries, capillaries or veins from the structure
of their walls.

• Complete handout given in class

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6.2 (U7) There is a separate circulation for the
lungs.

• Two main pathways
• Pulmonary includes the right side of the heart
  and to from the lungs. Blood is pumped under
  low pressure, is deoxygenated on the way to the
  lungs and oxygenated on the way back to the
  heart.
• Systemic includes the left side of the heart and
  to from all other organs tissues. Blood is
  under higher pressure, oxygenated on the way out
  and deoxygenated on the way back.
• Valves in the heart and veins ensure blood flows
  in one direction only (arteries to capillaries to
  veins).

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6.2 (S2) Recognition of the chambers and valves
of the heart and the blood vessels connected to
it in dissected hearts or in diagrams of heart
structure.
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Chambers in the Human Heart

• Right Atrium
• Left Atrium
• Right Ventricle
• Left Ventricle
• Atria collect blood from veins and pass it to the
  ventricles.
• Ventricles collect blood from the atria and pump
  it to the arteries.

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Valves in the Human Heart

• Atrioventricular (bicuspid) Valve
• Aortic Valve

• Atrioventricular (tricuspid) Valve
• Pulmonary Valve

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Blood Vessels of the Human Heart

• Pulmonary Artery
• Aorta

• Inferior Vena Cava
• Superior Vena Cava
• Pulmonary Vein

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Coronary Arteries

• The coronary arteries branch off the aorta, the
  largest artery in the human body.
• Coronary arteries branch out and into the muscle
  tissue of the heart and they supply the heart
  with much needed oxygen and nutrients.