B1 Flashcards
Arteries and Blood Pressure
Arteries: blood away from heart, under high pressure → heart muscles contract - allows blood to reach all parts of body.
Measuring Blood Pressure (BP)
BP measured in millimeters of mercury (mmHg). Two measurements:
• Systolic pressure (SP): max pressure produced by heart
• Diastolic pressure (DP): pressure produced in between heart beats
Young,fit person should have a BP of 120 over 70 (SP over DP)
Factors increasing/decreasing BP
Factors that increase BP: • Stress • Drinking a lot alcohol • Being overweight • Smoking Factors decreasing BP: • Balanced diet • Regular exercise
High/Low BP can cause …
High BP: • Kidney damage • Burst blood vessel • Damage to brain, strokes Low BP: • Dizziness/Fainting • Poor blood circulation
Fitness Vs Health
Fitness: Being able to do physical activity
Health: Amount of freedom from disease
Fit people: able to carry out physical activities effectively > unfit people. Pulse rate returns to normal more quickly after exercise.
Healthy people: free from disease and infection, but they may or may not be fit as well. It is possible to be fit but unhealthy, or healthy but unfit.
Measuring Fitness
• Strength • Stamina - endurance/staying power • Flexibility • Agility - how fast someone moves • Speed • Cardiovascular efficiency - how well the circulatory system works
Smoking and BP
Chemicals in it:
• Nicotine
• Carbon Monoxide (CO)
Effect on BP: ↑ BP by ↑ heart rate:
• Nicotine: directly increases heart rate
• CO: ↓ oxygen-carrying capacity in blood → combines with the hemoglobin, prevent oxygen combining - ↑ heart rate to compensate for the ↓ amount of oxygen carried in the blood.
Heart Attack
A heart attack sequence:
- Fatty deposits build up in the coronary arteries
- A blood clot can form on a fatty deposit
- The blood clot can block a coronary artery
- Some heart muscle cells do not get the oxygen and nutrients they need
- These cells start to die.
Factors for Heart Disease
• Smoking
• High BP
• High salt levels in diet → high BP
• High saturated fat levels in diet → build up of cholesterol in arteries → a plaque and narrowing arteries
Main Nutrients in Food
Nutrients - Made from - Main issues
• Carbohydrates - simple sugars, eg. glucose - high energy source
• Fats - fatty acids and glycerol - high energy source
• Proteins - amino acids - growth and repair and “emergency” energy source if their is insufficient carbs & fats.
Balanced Diet
Includes nutrients that don’t provide energy as well with the ones that do:
• Minerals, ie Iron for hemoglobin in red blood cell
• Vitamins, ie vitamin C to prevent scurvy
• Fibre → prevents constipation
• Water
Balanced diet: different for different people. Varies on age, gender, physical activity and religion. Some people choose not to eat some things, eg vegan/vegetarian avoid meat, and some are allergic
Being Overweight
When it’s cold and you are exerting yourself more physically you need to eat more.
Eating too much food without exercise → overweight
Problems with being overweight:
• Diabetes
• Arthritis
• Heart disease
• Breast cancer
Diets that lead you becoming overweight/underweight → low self esteem and poor self-image. Desire for “perfect” bodies, ie looking at a celeb’s body → under eating. Both underweight and overweight have health risks.
BMI
BMI = mass (kg) / (height x height) in meters
Protein Deficiency
Teenagers → grow quickly → need a lot of proteins, some developing countries may not get enough proteins → protein deficiency.
Kwashiorkor: disease caused by protein deficiency, symptoms - badly swollen abdomens, common in developing countries → people don’t get enough in their diet because:
• Overpopulation → too many people for land and resources available
• Limited investment in farming methods, eg few tractors/fertilisers
EAR
Estimated Average Daily Requirement for protein: 0.6 x body mass (kg)
Problems:
• Only estimated daily amount
• According to body mass but some may need more proteins. eg growing teens need more protein than adult with same mass
• Pregnant women need more protein
• Breastfeeding women need more protein
Body Storing Nutrients
Body can’t store protein but can store carbs and fats:
• Fats stored around organs/as adipose tissues under skin
• Carbohydrates stored as glycogen in liver/converted to fats
Proteins, First Class and Second Class
Plants give “second class” proteins. Meat give “first class” proteins → provide all essential amino acids, including those body can’t make.
Pathogens
Pathogens: disease causing organisms: • Virus: influenza • Fungi: athletes foot • Bacteria: cholera • Protozoa: malaria
Parasites
Parasite: live in/on a host. Parasite benefits from arrangement, host suffers. Eg, tapeworm: live inside other animals, attach to their guts → absorb food. Host loses nutrition, maybe weight loss/diarrhea/vomiting occurs. Parasites don’t kill host, just cut off food supply.
Malaria
Malaria: disease caused by protozoan (a single-celled organism), spread to person by mosquitoes. Mosquito feeds on blood and passes on malaria parasite. Mosquitoes are vectors for malaria (organisms that spread disease than causing it themselves)
Important to understand life cycle of pathogen and how it’s spread by vector. This knowledge gives scientists idea to control it’s spread. In principal, if pathogens life cycle broken → will die out leaving disease free life.
Spread of malaria controlled - avoid contact with vector → avoid being bitten by mosquitoes → use mosquito netting at windows, doors and bed/ use mosquito killing insecticides/ give infected people drugs (eg Lariam)
Infectious and Non-Infectious Diseases
Some disease not pathogen cause so not infectious. Eg:
• Scurvy → vitamin C deficiency
• Anaemia → iron deficiency
• Diabetes and Cancer → disorder of body
Cancer
Happens when cells divide uncontrollably → forms tumours sometimes felt as unusual lumps.
Factors ↑/decreasing cancer risk:
• Smoking → ↑ risk of lung cancer
• Sunscreen → ↓ risk of skin cancer
• Eating ↑ fruit and veg → ↓ risk of bowel cancer
Types of tumours:
• Benign → grow slowly and usually harmless (eg warts)
• Malignant → grow quickly and spread throughout body.
Body Defences
Skin: covers whole body, protects from physical damage/microbe infection/dehydration. Its dead,dry outer cells → hard for microbes to penetrate. Its sebaceous glands make oils that kill microbes
Blood clotting: microorganisms can get into body through cut → important to close wound. A scab does that, a scab is platelets in a fibrin (a protein) mesh
Mucus: it’s sticky → traps microbes and dust → carried away by cilia (hair cells)
Nasal hairs: dust and larger microorganisms out
Stomach acid: kills any harmful microorganisms that we swallow/drink
Immunity
Once inside body pathogens reproduce. Viruses reproduce inside cells and damage them and escape to infect more. Once inside body, immune system destroys them with white blood cells.
White Blood Cells
They can:
• engulf pathogens and destroy them
• produce antibodies to destroy them
• make antitoxins to neutralise the toxins from pathogen
Active immunity: when infected by pathogen and your own antibodies produced against it. When infected again, body quickly destroys it
Passive immunity: eg vaccinations, you receive antibodies, don’t make your own
Drugs
Drugs: substances that cause changes to body. Antibiotics: drugs that kill bacteria only. Antivirals: drugs that stop viruses reproducing.
Drug Testing
Medical drugs need to be tested to check if safe and work before being prescribed. Stages of testing:
- Drug tested using computer models and human cells grown in laboratory. Many drugs fail this → don’t work/damage cells
- After passing stage 1, tested on animals, new medicines have to be tested on animals. Illegals to test cosmetics/tobacco. Give known amount to animals, monitor carefully for side effects
