This unit uses the theme of personal health to revise work on the human organ systems, and diet. These ideas are built on further by considering the locomotor system, the benefits of exercise and the dangers of poor diet, alcohol, smoking and drugs. Sexual reproduction is revised and a section on contraception and STDs has been included. While many of the health problems are common throughout the western world, I have chosen to focus closer to home and use data about Bermuda.
(Image - The island's world champion triathlete, Flora Duffy, training along Harbour Road.)
(Image - The island's world champion triathlete, Flora Duffy, training along Harbour Road.)
Exercise
Objectives:
- Describe how exercise affects the pulse rate and breathing rate
- Describe ways in which fitness can be assessed
- Understand the process of aerobic respiration
In order to live our bodies require energy to be released from respiration. Respiration is a fundamental chemical reaction that occurs continuously in EVERY LIVING CELL in EVERY LIVING ORGANISM.
\[glucose\; + oxygen\; \rightarrow\; carbon\;dioxide\;+\;water\]
\[glucose\; + oxygen\; \rightarrow\; carbon\;dioxide\;+\;water\]
In order for the raw materials for respiration to reach every cell and the products removed we need to have three major SYSTEMS:
One of the key measures of fitness is how quickly they both return back to their resting values after you have finished exercising. The fitter you are, the less the heart needs to work to provide the materials for respiration. Fitter muscles have less fat surrounding the muscle fibres. The heavier you are, the more effort is required for movement, so more load on the heart. Heart disease occurs when fats in the form of cholesterol build up in the blood vessels that supply oxygen and glucose to the heart muscle itself and the heart stops pumping. There are two forms of heart disease: heart attack (due to a plumbing problem), heart arrest (due to an electrical problem).
Best recommendation for preventing heart disease and maintaining fitness - exercise at least 30 minutes every day and avoid foods high in sugar and saturated fats.
The four Ss of fitness:
The Benefits of Exercise are:
LAB - Measuring how quickly your pulse returns to normal after exercise.
- Digestive System to absorb water and nutrients from our food into our blood (Mouth, esophagus, stomach and intestines)
- Respiratory (Breathing) System to absorb oxygen from the air into our blood and remove the carbon dioxide (lungs, windpipe and diaphragm)
- Circulatory System to transport the materials around the body (heart and blood vessels)
One of the key measures of fitness is how quickly they both return back to their resting values after you have finished exercising. The fitter you are, the less the heart needs to work to provide the materials for respiration. Fitter muscles have less fat surrounding the muscle fibres. The heavier you are, the more effort is required for movement, so more load on the heart. Heart disease occurs when fats in the form of cholesterol build up in the blood vessels that supply oxygen and glucose to the heart muscle itself and the heart stops pumping. There are two forms of heart disease: heart attack (due to a plumbing problem), heart arrest (due to an electrical problem).
Best recommendation for preventing heart disease and maintaining fitness - exercise at least 30 minutes every day and avoid foods high in sugar and saturated fats.
The four Ss of fitness:
- Stamina - how long that you can move for
- Suppleness - how flexible you are
- Strength - how strong you are
- Speed - how fast you can move
The Benefits of Exercise are:
- improved muscle tone and fitness
- weight loss
- increased confidence
- feel-good factor due to released endorphins
- improved heart muscle tone
LAB - Measuring how quickly your pulse returns to normal after exercise.
Muscles and Bones
- Recall the functions of the skeleton
- Identify some common joints
- Describe how muscles work
- Explain how antagonistic pairs of muscles move bones in some joints
The body is supported and able to move because the muscles and bones. The bones are stiff, mostly tubular structures made from calcium carbonate. The muscles are bundles of muscle cells that can contract and relax. It is important to note that muscles can only pull - they can never push. Think of muscles being like a rope. Therefore, in order to have controlled motion every moving part need to have pairs of muscles that can work against each other. These are called ANTAGONISTIC PAIRS. The classic example are the biceps and triceps muscles that control the forearm.
To lift the forearm the biceps contracts and the triceps relax and are allowed to stretch. To lower the forearm under control, the biceps relaxes and the triceps contracts.
The names for these muscles comes from the number of TENDONS that attach the muscle to the shoulder bones. Tendons are tough, fibrous strands that hold the muscles to the bones. In locations where the muscle has to be located away from the joint (back of the knees and hands/wrists), the tendons lie in a tube and work in a similar manner to the bicycle brake cable.
It is possible for tendons in these tubes to become inflamed and painful - this is a common repetitive strain injury due to (say) excessive time working on a computer!
The names for these muscles comes from the number of TENDONS that attach the muscle to the shoulder bones. Tendons are tough, fibrous strands that hold the muscles to the bones. In locations where the muscle has to be located away from the joint (back of the knees and hands/wrists), the tendons lie in a tube and work in a similar manner to the bicycle brake cable.
It is possible for tendons in these tubes to become inflamed and painful - this is a common repetitive strain injury due to (say) excessive time working on a computer!
Many joints have to have a bearing surface (cartilage) and a lubricant (synovial fluid) to reduce the friction and erosion that would occur if the bones were to simply rub against each other. The bones themselves are held together by tough fibrous bands called LIGAMENTS.
Common injuries include inflammation of the fluid, damaged cartilage and torn ligaments. These can take a long time to heal and may even require surgery. (both images from Google Images) |
The other jobs of the skeleton are:
- protection, particularly the skull and rib cage, which protect the brain and the vital organs of the heart and lungs.
- red blood cell production, which occurs in the marrow that exists inside the tubular sections of the larger bones. The bones are hollow to reduce weight and the insides are a fleshy material that makes blood. Red blood cells are unusual as they don't have a nucleus. This increases the available volume, so they can carry more oxygen, but means that the cells cannot undergo cell division.
- The movement of the ribcage aids breathing.
The main types of joint in the human body. For this course the important ones are: knee and elbow (hinge), neck to skull (pivot), shoulder and hip (ball and socket)
Image from www.exploringnature.org |
Diet
- Recall the basic food groups and a balanced diet
- Know the short term effects of excessive sugar consumption
- Know the long term effects of a poor diet
The old adage "you are what you eat" is still true after all these years. The source for the elements that you need to survive and grow come from the food and drink that you ingest. If you consume junk, don't be surprised if that is reflected in how you look, feel and function. A balanced diet is key to a healthy lifestyle. No amount of exercise can cure a bad diet. Probably the best advice that I have ever seen on this is a phrase from a documentary called In Defence of Food.
"EAT FOOD, NOT TOO MUCH, MOSTLY PLANTS." (it should be clarified that food means proper food and not boxed junk)
"EAT FOOD, NOT TOO MUCH, MOSTLY PLANTS." (it should be clarified that food means proper food and not boxed junk)
Food Group |
Function(s) |
Examples |
Carbohydrate (starch) |
Source of energy - insoluble, made from long chains that must be digested first |
Bread, pasta, potatoes, rice. |
Carbohydrate (sugars) |
Source of energy - soluble and therefore quick absorbing |
Sodas, chocolate, candy, processed foods, fruit, honey |
Protein |
Growth and repair of cells - made from amino acids |
Meats, dairy products, legumes (beans etc), nuts |
Fats |
Source of energy, insulation that lies under the skin, insoluble and made from fatty acids |
meats, dairy, nuts |
Fibre |
Keeps the digestive system moving - made from the indigestible plant cellulose from the cell walls of plant cells. |
Unprocessed plant material (e.g. wholewheat, bran flakes, brown rice) |
Vitamin A |
Helps to maintain healthy eyesight |
carrots! |
Vitamin C |
Prevents scurvy |
Most fruits and vegetables |
Iron |
Required for healthy red blood cells to be able to carry oxygen, prevents anemia |
red meat, some leafy vegetables (e.g. spinach) |
Calcium |
Builds bones and teeth |
Dairy products, fish. |
Sugar - the BIG PROBLEM
Before the rise of refined sugars, humans consumed limited amounts of soluble sugars in fruits and honey. Since the 1600s refined sugars have formed an increasingly large percentage of our calorific intake. This has caused and is causing major lifestyle related problems - the most critical are obesity and diabetes (type II). To understand why, we need to find out what happens to sugar when we eat it:
The other problem is that refined sugars are not always obvious. The vast majority of processed foods are laden with them, especially breakfast cereals and candy.
Before the rise of refined sugars, humans consumed limited amounts of soluble sugars in fruits and honey. Since the 1600s refined sugars have formed an increasingly large percentage of our calorific intake. This has caused and is causing major lifestyle related problems - the most critical are obesity and diabetes (type II). To understand why, we need to find out what happens to sugar when we eat it:
- Sugar is soluble and so it dissolves quickly and passes through the walls of the intestine and is absorbed rapidly into the blood.
- This leads to a rapid increase of the blood sugar level - short term energy boost and 'feel good' effect.
- The main function of the pancreas is to control the blood sugar level between certain limits. If the blood sugar level exceeds those limits, it secretes a chemical called INSULIN.
- Insulin converts blood sugar to FAT, which is stored in fat cells, which swell up. Originally this was required as food was not always available. If the blood sugar level is too low, the pancreas converts the stored fat back into blood sugar.
- If the fat cells are full to capacity, more are made by cell division. This is the start of obesity.
- If the insulin is added too fast, then this can cause a large drop in blood sugar, leading to low energy and feeling down - called a sugar crash.
- If sugar intake > energy output, then there is a net gain of fat.
- Long term, the pancreas eventually gets worn out and 'fed up' of maintaining the blood sugar levels and stops producing insulin --> diabetes (type II)
The other problem is that refined sugars are not always obvious. The vast majority of processed foods are laden with them, especially breakfast cereals and candy.
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Lungs and Smoking
- Describe how ventilation occurs and explain how it works using a model lung
- Describe some effects of smoking on the body
The purpose of the respiratory system is to get oxygen from the air into the blood and carbon dioxide out of the blood and into the air. The efficiency of this GAS EXCHANGE is hampered by the fact that 78% of the air going in is made of nitrogen and only 21% is oxygen. The process of air going in and out of the lungs is called breathing and is controlled by 2 sets of muscles; the diaphragm and the interstitial muscles between the ribs. When these muscles contract, the chest cavity expands and air is drawn in. It is hard to hold your breath for a long time as these muscles eventually get tired of contracting. Exhaling the air happens when the muscles relax.
Mucus and cilia in the lining of the pipes (airways) help to ensure that pollutants do not damage the inner surfaces of the lungs.
Mucus and cilia in the lining of the pipes (airways) help to ensure that pollutants do not damage the inner surfaces of the lungs.
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The lungs are made from millions and millions of tiny balloons called ALVEOLI. This increases the surface area to increase the rate of gas exchange with the blood. They are connected to the mouth and nose by a branching series of pipes called trachea (windpipe), bronchi and bronchioles.
I imagine the lungs sort of like trees, with the trunk (trachea) dividing into smaller branches (bronchi) and twigs (bronchioles) until the end up at the leaves (alveoli). |
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Terrible sound track, but riveting video. The biggest error in this experiment is that there is some degree of self-cleaning via the mucus membranes which does reduce the filth somewhat in the lungs.
However, autotopsies clearly show that the lungs of a committed smoker are foul and black with tar as well as frequently being diseased. |
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And here is another video showing the nasty stuff that collects in the lungs and trachea from smoke. I haven't included a video of the autopsies of smoker's lungs, but if you are interested look on YouTube!
Note: this occurs for all forms of smoking, cigarettes, roll ups, pipes and cigars. (Cigars are particularly foul smelling - why do people think that others ever want to be near them when they are smoking?) |
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Very old comedy clip from the BBC series from the 1980s, when it seemed that tackling the smoking crisis was impossible. Tobacco advertising used to be everywhere and smoking was still allowed in the workplace. Staff rooms used to be scary and smelly places to go. It was only banned on school campuses in the mid-90s!
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COVID 19 - Science of ventilators
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Alcohol and Drugs
- Explain what addiction is and recall some addictive drugs
- Classify drugs as medicinal/recreational, legal/illegal
- Recall some of the effects and side-effects of different drugs
- Explain what stimulants and depressants are
A drug is a chemical that changes how the mind and/or body works.
There are four main groups of drugs:
There are four main groups of drugs:
- medicinal drugs - painkillers, anti inflammatories, beta-blockers etc etc
- recreational drugs (legal) - nicotine, caffeine and alcohol
- recreational drugs (illegal) - opioids, hallucinogenics, cannabis and many others
- performance enhancing drugs - steriods
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This graph illustrates how the blood alcohol concentration (BAC) changes with time. There are two curves.
BLUE - 4 measures of spirits, whiskey or rum, were drunk within a few minutes on an empty stomach. The BAC rockets up as spirits are concentrated and with nothing in the stomach the ethanol was rapidly absorbed into the blood. Over time the liver metabolises the alcohol. This person was below the drink-drive limit after about 4 hrs. RED - 4 measures of spirits were drunk on a full stomach over a period of about 4 hrs. The peak level of alcohol in the blood is less (the person is less drunk), but from start to being under the limit is about 5 - 6 hrs. |
A graph of the relative risk of having a vehicle accident as a function of the blood alcohol levels. I am unsure of the origin of the data. It maybe based on accident statistical data or reaction time. Hard to tell, however the point is that the probability of an accident drastically increases as the blood alcohol level increases. The legal limit in Bermuda is 80 mg/100 ml (0.08 g/dL on the graph) |
Sexual Health
- Recall the basic concepts of sexual reproduction in humans
- Understand the various methods of contraception and the advantages/disadvantage of each
- Understand the concept of STDs and how to prevent them