Skip to 0 minutes and 7 seconds Welcome to another of the “Home Practicals.” My name’s Dr Natasha Barrett, and I’ll be leading this practical. I hope you’ve already looked at the risks associated for this practical and how to minimise them. As before, if you haven’t already done so, please take a few minutes to look through them. We know that the purpose of practical work is to apply the theory to help deepen our knowledge. The aims of this practical are to investigate the effect of thrombosis. So by the end of this practical, you should have a better understanding of the effects of thrombosis and also how variable these effects can be. Let’s recap some of the theory.
Skip to 0 minutes and 45 seconds Haemostasis is the normal physiological response to prevent bleeding in the event of an injury. Haemostasis is triggered by injury exposing the subendothelial layer or the substances beneath the endothelium of the blood vessel, which triggers the blood to clot. Blood clotting is a multistep process, and it involves both the smallest cells in the blood - the platelets - and also the clotting factors, which travel around in the plasma. Thrombosis, on the other hand, is the pathological process that leads to blood clotting. It involves all the same steps and all the same processes, but it happens in the absence of injury inside a blood vessel. Today’s practical involves two parts.
Skip to 1 minute and 37 seconds In the first part, I’ll be giving you a demonstration of blood clotting using human blood. In the second part, we’ll be mimicking thrombosis to see what happens. Let’s run through the checklist of things that we’ll need for the practical. You’ll need your instruction sheet. Or perhaps you’ll be working from your mobile device. In which case, do protect it by placing it inside a clear plastic bag, as we will be working with water today. You’ll also need your worksheet or a piece of paper on which to write, and a pen to write with. I’m wearing my lab coat, as I’m in the laboratory, but at home, you can wear an apron to protect your clothes.
Skip to 2 minutes and 21 seconds Likewise, I’ll be wearing gloves and goggles, but at home, you won’t need to. You’ll need access to a sink and a tap. If you haven’t got access to that, then a tap and a bowl will do instead. It’s useful to have a tray or a plate to work on. And we’ll need a packet of jelly. We need several standard round balloons. A knife. We’ll need a stop clock with a second hand. If you have access to a sieve or a colander, this will be helpful.
Skip to 2 minutes and 55 seconds And then we need the usual equipment for clearing up at the end, so access to hot, soapy water; towels or paper towels; suitable disinfectant to wipe down the area; and a waste bag to put all your rubbish in. Run through the checklist once more, and when you’re ready, we can begin.
How blood clots: Home practical introduction
In this video Dr Natasha Barrett introduces the second of the home practicals.
First, we’ll look at blood in its complete state and separate it into each of its components – the three different types of blood cells suspended in plasma that we covered in Week 1’s step about Blood. We’ll then see what happens to whole blood when it is exposed to thrombin, an enzyme in the body that causes it to clot. Lastly, we’ll look more closely at the two components of blood that are responsible for clotting: the plasma and platelets.
A full list of the items needed for the practical will be available before the start of the exercise.
© University of Reading