6.2+The+transport+system

6 Physiology - 6.1 Digestion - 6.2 The transport system - 6.3 Defence against infectious disease - 6.4 Gas exchange - 6.5 Nerves, hormones and homeostasis - 6.6 Reproduction - Physiology Labs

6.2 The transport system

 * Assessment statements** (IBO notes added to some points to clearly indicate what needs to be understood and what does not)
 * 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. Care should be taken to show the relative wall thickness of the four chambers. Neither the coronary vessels nor the conductive system are required. ||
 * 6.2.2 || State that the 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. 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). Histology of the heart muscle, names of nerves or transmitter substances are not required. ||
 * 6.2.5 || Explain the relationship between the structure and function of arteries, capillaries and veins. ||
 * 6.2.6 || State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets. ||
 * 6.2.7 || State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat. ||

6.2.5 looks at the structure and function of blood vessels. When comparing arteries and veins students often say "arteries have thicker walls then veins", this is not true. Arteries and veins vary hugely in size from the Aorta and Vena Cava which join to the heart down to much smaller arterioles and venioles which can be found adjoining capillary beds in various tissues throughout the body. A large vein has a thicker wall than a small artery. It is more correct to say that __"compared to the size of lumen the walls of arteries are thicker than those of veins"__.
 * Key Points**

You remember recent news stories concerning exercise related cardiac incidents? [|Fabrice Muamba was "dead for 78 minutes"]
 * Starter**

Did you wonder what was causing this and similar incidents? Read more in this [|exhibit by the royal society].

This video outlines how the heart can be screened to detect potential problems media type="custom" key="23684558"

Draw, label and annotate the heart to show your understanding of it's structure. media type="custom" key="24866328"

Log in to the [|DCS Bridge]to obtain your workbooks and supporting resources. Word versions of workbooks available below for those unable to access the DCS Bridge. media type="custom" key="23684560"
 * Workbooks and Worksheets**

[|i-Biology] has produced an alternative notes [|Essential Biology 6.2: The Transport System (Core)]


 * Presentations and tutorials**

The khan academy has a video tutorial on the [|Circulatory System and the Heart]

You should be able to draw and label a good quality diagram of the heart. This diagram adapted from Draw to the core shows a good example an includes a helpful structural annotations: media type="custom" key="21040906"

Steven Taylor ([|i-Biology]) has a great presentation to view and take notes from before starting your notebook media type="custom" key="26595456"

Sunamas Inc. breaksdown the[| blood flow through the heart] into steps in this narrated animation

Biocoach has a good tutorials on [|Cardiovascular System I: The Beating Heart] and [|Cardiovascular System II: The Vascular Highway] plus quizzes to test your learning; both tutorials you will find useful.

[|Click4Biology] has a good set of notes on this topic, particularly useful if you need help to explain the steps in the cardiac cycle and/or how it is controlled

Can you label a heart diagram without your resources to hand? Use the Freeze animation to test yourself and help you develop your drawing and labelling skills media type="file" key="heart.swf" width="648" height="486"
 * Activities**

This is a [|youtube video] which does a nice job of showing a heart and lung dissection
 * Useful links**

Though not part of this topic MedMovie explains very nicely how [|atherosclerosis causes coronary heart disease] and 'heart attacks' (scroll down the topic list to atherosclerosis)