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Option 9.7 - Pharmaceuticals: 2. The circulatory system transports
pharmaceuticals
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Syllabus reference (October 2002 version) |
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| 2. The circulatory system can be used to transport many pharmaceutical substances. |
Students learn to:
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Students: |
Extract from Senior Science
Stage 6 Syllabus (Amended October 2002). Board of Studies, NSW.
[Edit: 16 Sep 08]
Prior learning: Science Stages 4-5 Syllabus: Outcome 4.8 (content 4.8.5a).
Background: In order to reach sites of disease in the body, an efficient method of transporting pharmaceuticals is required. The circulatory system is one method of delivering pharmaceuticals to these sites.
gather and process information from first-hand or secondary sources to describe differences in veins, arteries and capillaries
- To gather first-hand information you would need to do a dissection
of an animal such as a rat or a rabbit. The larger arteries are easier to see
so look for the aorta coming from the left side of the heart and for a vein
look at the vena cava (caval vein) that goes to the right atrium of the heart.
- Look at the thickness of the walls of each blood vessel and record the
differences in a table. Record any other observations you have made.
Why can't you see any capillaries?
- Gather information from junior and senior science texts and from
the Internet. Also look in journals and popular magazines. A good web site is
The Heart: An Online
Exploration.
The Franklin Institute Science Museum, Philadelphia,
Pennsylvania, USA.
- Process the information you have learned by organising it under the headings Arteries, Veins, Capillaries. Within those headings have sub headings, Structure and Function.
describe the role of the circulatory system in transporting material around the body
- The circulatory system transports:
- nutrients from the digestive system to all the cells of the body, via the heart.
- metabolic wastes, including carbon dioxide away from the cells to excretory organs to be excreted.
- oxygen from the lungs to all cells of the body.
- hormones to target organs.
- These substances are transported in the blood stream.
identify the three main types of blood vessels in the body and discuss the differences in their blood-carrying capacity
- The three main types of blood vessels in the body are veins,
capillaries and arteries.
- Arteries are thick walled vessels that receive blood from the heart and
carry it away at high pressure to the parts of the body.
- Arteries terminate at a network of fine vessels called capillaries
that deliver substances to the cells. These vessels have walls that are only
one cell thick so that substances such as food and oxygen can pass across
them. They are so tiny that only one cell at a time can pass along them.
- Veins carry blood at lower pressure back to the heart. The excretory system and the lungs remove cellular wastes that travel in venous blood.
perform a first-hand investigation to observe blood in prepared slides to identify white blood cells using a microscope
- The teacher will provide slides of blood so that you can identify the
white blood cells with the aid of diagrams showing each of the cell types.
- White blood cells can be distinguished from red blood cells because white
blood cells have a nucleus that can be demonstrated by nuclear staining and
microscopy.
- Draw diagrams of the white blood cells. Make them as accurate as possible with as much detail as you can see. Use the diagrams in the text book to help you where it is not clear. Label the diagrams.
identify that the blood is a mixture of different substances, one of which is white blood cells
- Blood consists of two main fractions, the cells and the plasma.
- The plasma is the liquid fraction of the blood consisting of water and
dissolved substances.
- The cellular fraction consists of red blood cells (RBC), white
blood cells (WBC) and platelets.
- Red blood cells contain the red substance haemoglobin that carries oxygen
to all body cells.
- White blood cells are so called because they lack haemoglobin.
- Platelets are cell fragments that assist in blood clotting.
describe the role of white blood cells as including the identification of tissue damage
- White blood cells (WBC) are part of the defence system of the body that
protects it against invasion by microorganisms such as bacteria, parasites and
other foreign bodies.
- There are several types of white blood cells that perform different
functions.
- Some WBC destroy particles such as microorganisms by engulfing them and
digesting them.
- The accumulation of pus, which consists of liquid and dead white cells,
identifies sites where tissue has been infected and defended by
bacteria-engulfing WBC's.
- Another type of WBC is activated when tissue is invaded by foreign substances, to release chemicals that produce the redness and swelling of inflammation.
account for the advantage of using the circulatory system to transport pharmaceuticals around the body
- The circulatory system transports natural substances necessary for
cellular function and therefore body function.
- Because the circulatory system reaches all parts of the body it can be
used to transport foreign substances to the body, such as pharmaceuticals, to
diseased sites.
- Pharmaceuticals reach the circulatory system whether taken orally, administered intravenously (by vein), absorbed through the skin, or inhaled.
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