Video: Infectious disease

﻿So take a minute just to write down the date and the title so that you can keep all of your notes organised. Hello, I'm Miss Todd, this lesson is going to be all about infectious diseases. So for this lesson, you're going to need a pen, pencil, and some paper. If you don't have those things can you go and get them now. Excellent, so now you've got what you need for the lesson. you need to make sure that you're working in a quiet space where you won't be distracted. And can you turn off the notifications on your devices if you know how so they won't distract you during the lesson. Take a look at the images on the screen. These are all of jobs that require knowledge of infection, shut them out to me. Well done, so we've got a doctor, cleaner, PPE manufacturer, and pharmacist. This topic has gone to focus on infection. This lesson is going to look at the following things so can you please just have a read of those. I'm going to start by looking at infectious diseases. Infectious diseases are ones that can be caught. They can be spread because they are caused by microorganisms that can be spread from person to person. This is why we call them communicable diseases. They are different to noncommunicable diseases that could not be passed from person to person, for example, heart disease and cancer which you may have studied before. Read the question and point to the correct option when you think you've got it. Well done Read this question and shout the answer when you think you know. Well done, a disease that can be caught. Read the question and shout out your answer. Fantastic, infectious diseases are caused by microorganisms that are passed from person to person. The microorganisms that cause infectious disease are fungi, protist, bacteria, and viruses. So not all microorganisms cause disease, for example you might have looked at bacteria in the gut in key stage three. They are involved in making some essential vitamins and help digest fibre. Microorganisms that cause illness, we call them pathogens. Say it with me pathogens. You might know pathogens as germs, you can no longer use this term you must call them pathogens. Or you can prefer to the pathogen specifically whether it's a virus, bacteria, protist, or fungi. Read the question and shout your answer. Well done, virus, bacteria, protist and fungi. Now we're going to look at how these pathogens spread. So they can be spread through airborne droplets. So when an infected person coughs or sneezes, the droplets that come from their body are airborne they travel through the air. They then land on things or on host and transfer those microorganisms the pathogens. A touch, this could be when you shake hands with an infected person or touch a surface that an infected person has also touched. Food and water, so under cooked or reheated food can cause bacterial infections, dirty water can also transmit diseases. Animal or insect bites. If an animal is carrying a disease, this can be transmitted to humans for example rabies through a bite or a scratch. You may also get an infection if a noninfected animal bites you as the cut in your skin can let bacteria into your body Infected needles. Using the same needle with an infected person could also transmit disease, this is why all needles need to be sterile and are only used once. Unprotected sex. Having unprotected sex puts you at risk of catching chlamydia, gonorrhoea, HIV, and many other sexually transmitted diseases. You look at the photo here, this man is infected with a common cold when he coughs and sneezes these droplets become airborne and he is transferring those pathogens into the air where they can be transferred to somebody else. What I would like you to do is have a think of some ways that we can reduce the spread of pathogens. You can write these down or you can shout them out to me. Great. I would like you to do this part here and read how we can reduce the spread of pathogens. You need a bit more time, we pause, if not we'll go on. So to reduce the spread of pathogens free food and water we can make sure that we cook our food properly to ensure that any harmful microorganisms have been killed. We can not use food after use by date. If water hasn't been treated we can boil it, so water that comes out of the tap has already been treated. However, if you want to drink water from a river, it would be advised to boil it first to get rid of those harmful pathogens. And we also need to store food properly. For example, when you buy meat it goes into the fridge to prevent these microorganisms from growing. However, if you're not wanting to eat your meat for awhile, it will need to go in the freezer to prevent these microorganisms from growing for even longer. Now what I would like you to do on your own is for each method of transmission suggest at least one way that we can reduce the chances of spread. As an example, I've done food and water. So transmission through food and water could be reduced by cooking food thoroughly, not eating food past the use by date, and if water hasn't been treated we can boil it. I would like you to do the same for the other methods of transmission, and you might want to use the sentence starters to help you. So pause now and answer this question. If you need more time re-pause and have another go, if not we can move on. So as you can see here, some ways of reducing the spread they should be included in your sentences. If you haven't included these, can you please add them in now. Well done. So now we're going to look at how pathogens cause illness. So pathogens can cause illness in two ways, one way is by releasing toxins. Toxins are harmful substances produced by bacteria that poison the body's tissues and enzymes causing damage. There is also reproduction. So a rise in the number of pathogens when they reproduce can damage your cell even causing it to burst. Some pathogens hijack resources that the cell needs to survive. So they hijack the resources to reproduce themselves. When the cell becomes full it will burst damaging the cell. Your answer to me when you think you know. Excellent, releasing toxins and reproduction. So we'll start by looking at bacterial reproduction. Bacteria divide asexually once every 20 minutes or so. The colony grows and grows and causes damage by crowding and damaging the healthy cells around it. So a colony is a visible massive microorganisms in this example bacteria. So now we're going to take a look at virus reproduction. So virus reproduction is different to how bacterial cells reproduce. The virus so if we imagine this here is our virus, the virus needs a host cell to reproduce inside. The host cell is just one of our cells in animal cells. So this could be a cell in your throat for example. The virus injects the genetic material into the host cell. Once this genetic material is inside the host cell it will reproduce creating lots of new viruses. When the cell is full, the cell will burst open then these viruses are released into the blood. Each one of these viruses will then go into another host cell, reproduce, and burst the cell. When a cell bust it causes damage and that is what makes you feel ill. What I would like you to do now is have a go at this question on your own. Write your answer onto your piece of paper. The question is worth three marks as you can see in the brackets at the end, that means that you need to make three points. Pause here and have a go. If you need a bit longer just repause if not we're going to carry on. So pathogens make us ill by releasing toxins, toxins are poisons that cause cell and tissue damage while interfering with enzymes. Bacteria cause cell and tissue damage by reproducing rapidly. They overcrowd the healthy cells. Viruses cause cell and tissue damage by reproducing inside host cells. When the cell is full it bursts open damaging the cell. Make any changes to your answer if you need to. So we're now going to look at the body's defence mechanisms. First, we need to look at how these microorganisms, so the pathogens actually get into our body. So they come in through our eyes, nose, mouth, cuts in our skin, and the genitals. Now all of these parts of the body are defended to try and prevent the pathogens coming in. So your eyes have tears which are antiseptic, your nose and your windpipe have lots of mucus that can trap these pathogens. Once the pathogens are trapped in the mucus cilia waft the mucus to the mouth where it can be swallowed and the pathogens will be killed by the stomach acid, or it can be spat out and got rid of. Cuts in our skin are healed really quickly. The blood starts to clot immediately forming a physical barrier over the clot, so the pathogens cannot enter. We also have skin all over our body to make sure the pathogens can not get in. I read the question and shout out your answer to me. Well done eyes, mouth, nose, cuts and genitals. What I want you to do now is on your piece of paper answer the following question. It's worth two marks, so you need to make two points pause now and have a go. If you need more time, just re-pause, if not we'll move on. So make sure to correct your answer if need be. The nose and trachea have mucus to trap the tuberculosis bacteria when it enters the body. They also have cilia which wafts this mucus to the mouth. We can then get rid of the bacteria by swallowing the mucus and the stomach acid will kill it. Or we can blow our nose. Make any changes if you need to. Pause here and how the read of the summary slide that sums up the main points of the lesson. That brings us to the end of today's lesson. A really big well done, on all of the learning that you have achieved today. I've just got two final things that I'd like you to do now. First, have a look back at your notes from today and identify the three most important things that you've learned, it's totally up to you what they are. Then I would like you to go and complete the exit quiz, which will test you on what you've learned today and any prior knowledge that is also relevant. All that's left for me to say is thank you very much for listening to this lesson. Take care and enjoy the rest of your learning for today.

Worksheet: Infectious disease

Exit Quiz: Infectious disease

Completed: Infectious disease

This lesson we will look at infectious disease. We will learn how disease is spread and how we can prevent the spread from person to person. We will also look at how pathogens make us ill when they get inside our bodies, and what mechanisms our bodies have to defend us against pathogens.

Combined Science

Infectious disease

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