KS3
Respiration
The process of respiration is a chemical reaction. Energy is released from glucose.
There are a couple of ways respiration occurs and health issues can make this harder for some.
The process of respiration
The process of respiration through ventilation (breathing) in humans is a chemical reaction that happens in all cells of the human body.
The body obtains and uses oxygen and eliminates carbon dioxide. Oxygen is needed to release energy from food as energy is needed for cellular respiration.
For plants, respiration occurs through the absorption of oxygen and the expulsion of carbon dioxide through the leaves.
Aerobic
Aerobic means in the presence of oxygen and aerobic respiration happens in a cells organelle called mitochondria.
Mitochondria are found in cells that need more energy like sperm cells or muscle cells.
This type of respiration takes the energy from glucose and slowly releases lots of it.
The equation for this type of respiration is:
glucose + oxygen → carbon dioxide + water
Anaerobic
If you were to do a short burst of high-intensity exercise, the cells in your body might lack the oxygen they need. In this case, anaerobic respiration happens.
Anaerobic is in the absence of oxygen.
With anaerobic respiration, the energy released from glucose is much less than aerobic but is released very quickly. So your cells receive a short burst of energy.
Lactic acid is the product of anaerobic respiration, which can cause a burning sensation in your muscles and even cramp.
The equation for anaerobic respiration looks like this:
glucose → lactic acid
Circulatory system
In order to get oxygen around your body, your heart pumps blood cells through arteries, veins and capillaries in a circular system. The circulatory system is your heart and the three different types of blood vessel.
Types of blood vessel
Each blood vessel has a job to do in helping the heart circulate oxygen and cells around your body.
Arteries
Arteries take the freshly pumped oxygen rich blood away from your heart. The pressure is high straight from the heart. Strong walls of thick muscle mean the arteries withstand the high blood pressure whilst remaining elastic enough to allow blood to pump through with each heart beat.
Veins
The job of the vein is to bring oxygen-depleted blood back into the heart. The structure of the vein is clever. The walls are thinner and less elastic than the artery. There are special one-way valves to stop the blood from going back the wrong way as the blood pressure is low. There are three types of veins.
Capillaries
In every tissue of your body you will find capillaries. Capillaries are delicate blood vessels and are the smallest blood vessels in your circulatory system. Their role is to deliver the glucose and nutrients your cells need for respiration and healthy function. Their walls are thin so that diffusion can take place.
The heart
Your heart is the most important organ of the circulatory system and vital in your body.
It's job is to pump blood to the lungs and then around the rest of the body. Did you know the heart pumps blood through 60,000 mile-long (97,000 km) network of blood vessels?
There are four chambers in the heart. At the top are the chambers called the right and left atria. At the bottom are the left and right ventricles.
Right Atria
The atria on the right collects the carbon dioxide-rich blood and pumps it down to the left ventricle.
Right Ventricle
The right ventricle pumps deoxygenated blood to the lungs to collect more oxygen and remove carbon dioxide.
Left Atria
The atria on the left collects oxygen-rich blood and pumps it down to the left ventricle.
Left Ventricle
The job of the left ventricle is to pump the oxygenated blood away from the heart to the rest of the body.
Smoking and Asthma
Tobacco smoke contains many harmful substances and carcinogens such as:
- Nicotine
- Tar
- Carbon Monoxide
Many chemicals in tobacco smoke and tar destroy cilia, which causes mucus to start to build up in the small airways making it harder for the smoker to breathe. This also increases the chance of getting bronchitis.
What is Smoking?
Smoking is the act of inhaling and exhaling the fumes of burning plant material, most commonly tobacco in a cigarettes.
Nicotine
Nicotine causes the blood vessels to become narrower, which increases blood pressure.
Narrower blood vessels can lead to heart conditions such as coronary heart disease as these blood vessels are more susceptible to becoming blocked with cholesterol.
Blocked vessels
The consequence of this blockage is that less red blood cells carrying oxygen will be able to travel to the heart. Therefore, less aerobic respiration can take place in important cells such as the cardiac muscle cells and can lead to a heart attack.
Tar
Tar forms a sticky layer inside the lungs and causes the breakdown of the walls of the alveoli causing them to merge together.
This reduces the surface area to volume ratio, which means less gas exchange takes place and can lead to emphysema. Tar also increases the chances of getting lung cancer.
Effects of carbon monoxide
Carbon monoxide binds irreversibly to haemoglobin found in red blood cells, reducing their ability to carry oxygen.
This means that the circulatory system has to work harder, increasing the risks of heart disease and strokes.
How does smoking affect the gas exchange system?
Goblet cells in the lining of the trachea, bronchi and bronchioles produce sticky mucus. This traps dirt and pathogens. Cells with tiny hair-like projections called cilia then move the mucus out of the lungs.
Asthma
Asthma is a very common condition that affects bronchioles - the small tubes that carry air in and out of your lungs. It is a chronic condition with two main components, constriction and inflammation.
Constriction
The tightening of the muscles surrounding the airways.
Inflammation
The swelling and irritation of the airways. This may lead to symptoms such as coughing, wheezing, chest tightness, or shortness of breath.
How does asthma affect the gas exchange system?
When a person with asthma is exposed to a trigger, the airways leading to the lungs become more inflamed or swollen than usual, making it harder to breathe. Finally, the airways can become congested due to a build-up of mucus, secreted goblet cells that line your trachea.
Airways
The airways also get smaller due to a tightening of the muscles surrounding the airways.
Symptoms
Symptoms such as coughing, wheezing, chest tightness, or shortness of breath can be treated using asthma relievers.
What is a reliever?
Relievers are drugs that relax and open up the airways, making it easier to breathe. Relievers are often administered using a device called an inhaler. This lets you breathe the medicine in through your mouth and directly into your lungs.
Glucose
Glucose comes from the Greek word "sweet" and is a type of sugar. Just like our bodies use glucose for fuel, plants use glucose for energy.
It is a product of photosynthesis and plants use it for respiration.
Glucose is a molecule that is used to make cellulose. Cellulose has strength and provides the structure of plant cell walls. For humans, cellulose also provides fibre for the digestive system.
Starch
Plants transform glucose into starch. Starchy vegetables like potatoes and grains keep their energy stored as starch. Plants convert stored starch back to glucose at night for respiration.
Photosynthesis equation
The word equation for photosynthesis looks like this: carbon dioxide + water -light → oxygen + glucose
Photosynthesis
Photosynthesis happens in the leaves of plants. It can only occur if there is energy from light and chlorophyll.
Chlorophyll is the name of the green pigment found in chloroplasts within a plant cell. Plants use photosynthesis to produce glucose which is an essential food source.
In addition to chlorophyll and light, plants also need carbon dioxide and water for photosynthesis to occur. Oxygen and glucose are the products of the process.
The importance of photosythesis
Photosynthesis is an incredibly important process, plants will die if they are unable to photosynthesise.
Oxygen produced by photosynthesis is needed for respiration.
If all the plants were to die our food chains would be drastically changed.
From the grass that farm animals graze on to the seaweed and algae in our rivers and seas, almost every food chain would lose a producer.
Our atmosphere
Products we get from trees like our flooring, house structures, doors and window frames, the pencil you use to draw with and many others require photosynthesis.
Even fossil fuels were formed from photosynthesis, so our fuel and transport would be affected if the process wasn't able to occur.
As you can see photosynthesis is vital to the world as we know it. It brings balance to the atmosphere with the levels of oxygen and carbon dioxide.
Lung capacity
The deepest breath you can breathe in is your vital lung capacity. It differs from person to person. Some people can inhale deeply, and others can only inhale half the amount.
If you have a large lung capacity, you can inhale large amounts of oxygen.
Lung capacity
One way to increase your lung capacity is to exercise regularly. As part of training, athletes exercise in order to increase their lung capacity. A bigger lung capacity helps to transport large amounts of oxygen around the body.
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