B1 Human Biology and some on environment. Flashcards
How can metabolic rate change from person to person.
The metabolism is the rate of reactions in the body.
People with a higher proportion of muscle in their bod will have a higher metabolism.
Physically bigger people also have a higher metabolism.
Men tend to have a higher metabolism as they are bigger and have a larger proportion of muscle.
Regular exercise boosts the resting metabolic rate as it build up muscle.
Age can also affect it.
Name the different food groups needed and what they are used for.
Carbohydrates release energy.
Fat keeps you warm and releases energy.
Protein is used for cell repair, cell growth and cell replacement.
Fibre is used to make sure everything runs smoothly for the body.
Vitamins and minerals keep the skin,bones, blood and everything else healthy.
How do activity levels affect energy intake?
When you exercise more energy is needed. The metabolic rate goes up and stays up for some time afterwards.
People with more active jobs need more energy on a daily basis.
This means if you aren’t very active, you should take in less energy.
What does malnourished mean?
It means a person is deficient in a certain food group. The malnourished can be fat or thin.
How does eating too much lead to obesity?
An excess of carbohydrates or fat in the diet leads to obesity.
Hormonal problems can lead to obesity but the usually causes are a bad diet, overheating and a lack of exercise.
When is a person defined as being obese?
When the mass is 20% over the recommended body mass.
What health problems can arise because of obesity?
Arthritis, type 2 diabetes, high blood sugar levels, heart disease. And some types of cancer.
What other problems arise from eating too much of something?
Too much saturated fat in the diet means that blood cholesterol levels go up.
Too much salt causes a high blood pressure and heart problems.
What health problems arise from eating too little?
Slow growth (in children) fatigue, poor resistance to infection, and irregular periods in women. Deficiency diseases come about through a lack of vitamins or minerals. A lack of vitamin C can cause scurvy which produces problems with the skin, joints and gums.
How can a lack of exercise cause health problems?
Exercise increases the amount of energy used by the body and decreases the amount stored as fat. It also builds muscle so it boots the metabolic rate. Those who exercise are less likely to suffer from obesity.
It is however possible to be fit but not healthy. You can be physically fit and slim but malnourished.
How do inherited factors affect health?
Some people may inherit factors that affect the metabolic rate. Some inherited factors cause an under active thyroid gland, lowering the metabolic rate and causing obesity.
Other people may inherit factors that affect blood cholesterol.
Cholesterol is a fatty substance needed for good health but too much can increase the chance of heart disease.
What things do you have to look out for when evaluating a method of losing weight?
Have there been other studies which found similar results?
Was the sample of people tested large enough?
Was it written by a qualified person? Would they have been biased?
Is the report a scientific study, published in a reputable journal.
What are the two main types of pathogen?
Bacteria and viruses.
Describe bacteria.
They are very small cells. 0.001th of the size of your body cells.
They induce illness by damaging cells and producing toxins.
Describe viruses.
They aren’t cells. About 100 times smaller than bacteria.
They replicate them selves by invading the cells and hijacking it so it produces more copies of themselves. The cell will usually then burst.
This cell damage causes illness.
How does the body try and stop pathogens from getting into the body?
Skin and hairs and mucus in the respiratory tract stop them.
To prevent pathogens getting in through cuts, platelets help to make blood clot quicker to seal the wound.
If something does get in, the immune system has to do something.
How do white blood cells fight pathogens?
They engulf and ingest them.
They produce anti toxins that counteract the toxins produced by the bacteria.
They will detect the antigens on invading pathogens. They will produce antibodies that lock on and kill the invading cells.
They only work on certain types of pathogens.
They are produced rapidly and if a person gets infected with the same pathogen again ,the antibodies will be produced quicker.
Immunity would have been created.
How do vaccinations work?
When you are affected with a microorganism, the body takes a while to learn how to deal with it.
Vaccinations involve injecting small amounts of dead or inactive microorganisms, which have the same antigens. The right antibodies will have been created to defend against it.
If a live microorganism enters the body, the antibodies will have been produced a lot quicker.
Some wear off over time, meaning booster injections will have to be given.
What does the MMR vaccine protect against?
Measles, mumps and rubella.
What are the advantages of vaccines?
They controls the spread of infectious diseases. Smallpox has been destroyed and cases of polio have fallen by 99%.
Epidemics can be prevented if a large proportion of the population has a vaccination. Those who haven’t been vaccinated will still be safe as there are less people who can give it to them.
What are the disadvantages of vaccines?
They don’t always provide immunity.
Some time there will be a bad reaction. Swellings, fevers or seizures. These are very rare.
What do painkillers do?
They relieve pain. They stop the symptoms but don’t stop the disease. They body has to do that.
What do antibiotics do?
They kill or prevent the growth of bacteria causing the problem, without killing body cells. Different antibiotics kill different types of bacteria so the right one has to be given.
However, they don’t destroy viruses so they won’t work against the flu or cold.
Why is it very hard to produce medicine that can cure viruses?
They reproduce within the body cells so killing them will mean killings the cells as well.
How can bacteria become resistant to antibiotics?
They can mutate and these can cause resistance to antibiotics.
If you have an infection, some of them will be resistant and they won’t die.
They can survive and reproduce. The population of the resistant bacteria will go up.
As they can’t be treated with antibiotics which means they can cause serious infection. Like MRSA
How is the spread of antibiotic resistant bacteria stopped?
Doctors must avoid over prescribing antibiotics. They won’t be given for a sore throat.
How would an investigation into the effectiveness of antibiotics take place?
Hot agar jelly would be poured into a petri dish where bacteria could grow.
An inoculating loop would be passed through a flame and this would be used to transfer the bacteria.
Paper discs soaked in different types of antibiotics would be placed in the Petri dish. Looks at the amount of bacteria growth around each of the bits of paper.
The Petri dish must have a lid to stop unwanted microorganisms from the air getting in.
In school the cultures would be kept at 25C to stop harmful pathogens from growing.
What did Ignaz Semmelweis do and discover?
He saw that many women were dying in child birth because of puerperal fever.
The believed doctor were spreading the disease on unwashed hands. He had doctors wash their hands with antiseptic locutions and the death rate fell by 10%
However microorganisms hadn’t been discovered so he couldn’t prove his methods. They are dropped when he left the hospital.
Now the importance of basic hygiene is understood.
What is a possible problem with bacteria?
They can mutate to produce new strains and these could be antibiotic resistant.
Or a new strain could be one no-one has encountered so no one is immune. It could spread rapidly in a population and cause a epidemic.
What is a possible problem with viruses?
They mutate often meaning it is hard to produce vaccines against them as the antigens are always changing.
A virus could evolve to so it was infectious and deadly. If this happened the spread of it would have to be stopped spreading. Vaccines and antiviral drugs would have to be developed but this would take time.
In the worst case scenario, a pandemic could kill billions.
Define stimulus.
A change in the environment which you may need to react to.
They could be light, sound touch, pressure, pain, chemical or a change in position or temperature.
What are the sense organs and what receptors do they contain?
Eyes. Light receptors.
Ears. Sound and balance receptors. Sensitive to light and changes in position.
Nose. Smell receptors sensitive to chemical stimuli.
Tongue. Taste receptors.
Skin. Sensitive to touch, pressure, pain and temperature change.
What are effectors?
Muscles or glands that respond to motor neurones.
They contract or secrete hormones.
What are motor neurones?
Nerve cells that carry signals from the central newborns system to the effector.
What are relay neurones?
Nerve cells that carry signals from sensory neurones to motor neurons.
What are sensory neurons?
Nerve cells that carry signals as electrical impulses from the receptors in the sense organs to the central nervous system.
What is the central nervous system?
Information from sense organs is sent here and reflexes and actions are coordinated here.
It consists of the brain and the spinal cord.
What is a synapse?
A connection between two neurones.
A nerve signal is transferred by neurotransmitters which diffuse across the gap.
The neurotransmitters set off a new electronic signal in the next neurone.
What are reflexes and how do they prevent injury?
They are automatic responses to certain stimuli.
If a bright light is shined into the eye, the pupils automatically get smaller so less light can get in.
Describe the reflex arc.
A stimulus is detected by receptors and implies are sent along the sensory neurone to the CNS.
This then goes to a relay neurone, then a motor neurone, than a effector and then there is a response.
As it doesn’t go to the brain and just goes to the CNS, it is very quick.
What are hormones?
They are chemicals that are released directly into the blood. They are carried by blood plasma to other parts of the body but only affects the target cells.
They controls things that need constant adjustment and are produced by many different glands like the pituitary.
How are nerve signals and hormones different?
Neves are faster, act for a shorter amount of time and act on a very precise area, where hormones act in a more general way.
Explain stage 1 of the menstrual cycle.
Lasts for 4 days. The bleeding starts as the uterus lining breaks down.
Explain stage 2 of the menstrual cycle.
The lining of the uterus starts to build up from days 4 to 14. There will be a thick spongy layer of blood vessels ready to receive a fertilised egg.
Explain stage 3 of the menstrual cycle.
An egg is released from the ovary at day 14.
Explain stage 4 of the menstrual cycle.
The wall is maintained for about 14 days until day 28. If no fertilised egg has landed the layer will start to breakdown again and the cycle will start again.
What are the three main hormones used in the menstrual cycle?
FSH, Oestrogen and LH.
What does FSH do?
Follicle stimulating hormone.
Produced in the pituitary gland.
Causes an egg or mature in one of the ovaries.
Stimulates the ovaries to produce oestrogen.
