Skip to 0 minutes and 4 secondsWelcome to the first of the home practicals. My name's Dr Natasha Barrett, and I'll be leading today's practical. Hopefully you've already read the information on the risks associated with this practical and how to minimise them. If you haven't, then do take a few minutes to read through it. It won't take long. Before we start, I'll run through the aims of the practical, I'll recap the theory, and go through the checklist of items that you'll need. The purpose of practical work is to apply the theory we've already covered. This helps us to deepen our understanding.
Skip to 0 minutes and 41 secondsThe aims of today's practical are to investigate the structure of the heart, so by the end of the session, you should be able to identify the left and the right sizes of the heart, the four chambers, the major and minor blood vessels as they enter and exit the heart, the valves, and the myocardium, or heart muscle wall. Let's recap some of the theory. I've got a model of the heart here. We can see we've got the left side of the heart and the right side of the heart. If we look at the bottom, we have the two ventricles, and above them, we have the two atria. Blood enters the heart through the atria, travelling into the ventricles before exiting.
Skip to 1 minute and 31 secondsWe can also see the major blood vessels that sit at the top of the heart.
Skip to 1 minute and 38 secondsBlood exits the left ventricle via the aorta. The aorta is the major artery of the body. It takes the blood away from the heart and off around the body. The right ventricle exits via the pulmonary artery. This artery divides into two and travels to the lungs so that the blood can become oxygenated. If we look around the back, we can see the vena cava. We can see it above and below. This is the main vein of the body. Blood returns to the heart. This is deoxygenated blood, returns to the heart to the right atrium, and there it travels into that right ventricle. On the other side, we can see the pulmonary veins.
Skip to 2 minutes and 26 secondsThese return oxygenated blood to the left atrium, which then travels into the left ventricle to be distributed via the aorta around the body. Between the ventricles and the atria, we have two valves, one on each site. These are known as the atrioventricular valves, and they prevent the back flow of blood. There are two more valves that sit between the ventricles and the major blood vessels, and these are the semilunar valves. If we put this back together, we can see the blood vessels on the surface of the heart. These are the coronary arteries, and these are the arteries that supply the vital blood and oxygen to the heart muscle itself, enabling it to contract.
Skip to 3 minutes and 17 secondsBefore we start the practical, let's recap the checklist of all the items we're going to need for the practical. First on the list is, of course, your instruction worksheet. Now you might be working from your mobile device, in which case, do protect it by popping it inside a plastic bag. You'll also need a worksheet or a piece of paper on which to make your notes and a pen to write with. I'm wearing a lab coat as I'm in the laboratory, but if you're working at home, I'd recommend that you wear an apron to protect your clothes. Also, today I'll be wearing gloves and goggles because I'm in the laboratory.
Skip to 3 minutes and 56 secondsHowever, if I was preparing raw meat at home in the kitchen, I wouldn't need to use these. But they are optional if you prefer to. We're going to need some specific equipment. The first thing we need is, of course, a tray or a plate on which to work. I've got this dissection tray, but you can use a plate. If you use a chopping board, then make sure it's one that's used only for raw meat. We're going to need some sort of heart, of course, and I'd recommend that you obtain a lamb's heart. Lamb's hearts are fairly easy to obtain, either from your local butcher or from your local supermarket.
Skip to 4 minutes and 33 secondsWe're going to use some weighing scales in order to weigh the hearts. And then we've got some specific equipment that we'll also need as well. We'll need some sort of blunt instrument to probe the heart. I have a probe here. But alternatively, you can just use an old ballpoint pen as long as you're happy to throw it away at the end. We're going to need to knife with which to cut the heart, so I'm going to be using a scalpel. But again, a kitchen knife is perfectly adequate. We're also going to need to use a ruler to take some measurements. And last but not least, we need the things to clear away at the end.
Skip to 5 minutes and 10 secondsSo we need access to hot, soapy water for both washing our utensils and for cleaning our hands. Do make sure you've got plenty of paper towels to hand, as this practical can get messy, and a suitable disinfectant with which to clean the surface with afterwards. Last but not least, it is useful to have a waste bag to put all the waste in. So run through the checklist once more and check that you have everything. And then when you're ready, let's begin.
Preparing for the heart dissection practical
In the next few steps you’ll have the opportunity to do a heart dissection at home. This is an optional exercise, so if you aren’t able to do the practical, or would rather not that’s fine. However, you should watch the videos of the practical (Part 1: Investigating the external structure of the heart, Part 2: Investigating the internal structure of the heart).
The benefits of doing the practical experiments
There is more to understanding a topic than just remembering facts. To really understand a topic we first learn the theory then we learn how to apply the theory through practical work.
Do I have to do the practical?
All of the practicals in this course are optional. Watching the following videos will provide enough information for you to take part in the discussions after the practical, and complete the quiz at the end of the week.
The aim of the first home practical is to investigate the structure of the heart. We will do this by taking a lamb’s heart (which you can buy at the butcher’s or many supermarkets) and dissecting it in stages to expose the anatomy.
The health and safety information is in the next step.
You will need the following items on trays or large plates ready to use:
- Instruction sheet or mobile device protected appropriately by placing it in a bag
- Pen / pencil to write with
- Gloves (optional)
- Tray, plate or suitable working surface (chopping board used only for raw meat)
- Animal heart, for example from a lamb or a chicken. These can be purchased from some supermarkets or butchers. Store it as directed on the packaging until you are ready to carry out the practical (usually in a refrigerator for a few days, or freeze if for longer and then defrost before use)
- Blunt instrument to probe the heart (eg an old ball point pen for lamb heart, or a paper clip for chicken heart)
- Access to hot soapy water
- Paper towels
- Suitable disinfectant
- Waste bag
Download a printable version of the Week 1 home practical guide: Investigating the structure of the heart.
You might like to share photos or even videos of your home lab or your heart dissection, in which case you’ll also need a camera or other suitable device. If you’re taking the photos or video yourself, remember to wash your hands well after touching the heart using hot soapy water. You might find it easier to ask a friend or family member to take photos or video for you. You can share your images and films on the Heart Health Padlet wall. If you’d prefer to use a different photo or video sharing service you can include a link in the discussion at the end of the exercise.
How to use Padlet
Find out how to use Padlet by reading the guide in the FutureLearn FAQ.
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