B1.3 Flashcards
What are drugs?
most are chemical substances that affect the CNS
they cause changes in psychological behaviour
can be addictive
some medically useful (e,g antibiotics such as penicillin) but most harmful
if become addicted, there is a physical need and withdrawal symptoms without
build up tolerance to some so need more for same effect
What are the 4 different types of drug and what effect do they have?
depressants- e.g alcohol
decrease brain activity and slows responses of CNS, causing slow reactions and poor judgement of speed and distance
stimulants- e.g caffeine/nicotine increase brain activity by increasing number of neurotransmitters at some neurone synapses increase speed of reactions make you feel alert and awake often used to treat depression
painkillers e.g morphine
decrease feeling of pain in different ways
e.g blocking nerve impulses in brain
hallucinogens e.g LSD
distort what’s seen and heard by altering pathways nerve impulses usually travel along
What is reaction time and how can it be measured?
the time it takes to respond to a stimulus - normally under 1 second
can be effected by things like drugs
can also be measured
one person holds ruler vertically between thumb and forefinger then let go without warning
second person has to catch ruler as soon as they see it fall and as quickly as possible
reaction time measured by how far down ruler caught - lower down=slower reaction, higher up=faster reaction
What problems can smoking cause
tobacco smoke contains carbon monoxide which combines with haemoglobin in red blood cells and prevents them carrying oxygen. in pregnancy it can deprive foetus of oxygen so the baby will be underweight
contains tar which is a carcinogen, a chemical that can cause cancer. lung cancer more common in smokers- 90% associated with smoking, including passive
contains nicotine which is addictive
What problems can alcohol cause?
short term:
slows reactions
blurred vision
lowers inhibitions
long term:
poisonous- liver usually breaks down alcohol into harmless by-products. too much causes liver cells to die, forming scar tissue which blocks blood flow through liver. called cirrhosis
if liver can’t clean out blood, dangerous substances build up and damage the rest of the body
too much alcohol can also lead to brain damage
What are the benefits of organ transplants?
if organ severely damaged it can be replaced by a donated natural organ
living donors can donate whole or part of an organ e.g one of two kidneys and part of liver
organs from people who have died or are brain dead can also be transplanted
What are the problems with organ transplants
shortage so less likely to get one e.g if unlikely to survive operation
may only be considered if change lifestyle e.g if obese, greater risk of dying so may have to lose weight or people who have damaged liver by drinking too much alcohol have to stop drinking before liver transplant
some people think people who damage own organs don’t deserve transplant as much as those whose organs have been damage through illness/disease
What are infectious diseases?
diseases which can be transmitted from person to person
caused by pathogens- microbes that cause disease
include bacteria, protozoa, fungi and viruses
How are pathogens spread?
water- drinking or bathing in dirty/contaminated
e.g cholera, bacterial infection that causes diarrhoea and dehydration. spread by drinking water contaminated by other sufferers
food- eating contaminated
e.g salmonella, bacteria that causes food poisoning is found in food left too long or not cooked properly
air- carried in air in droplets produced by coughing/sneezing
e.g influenza virus that causes flu
contact- touching contaminated surfaces
e.g athlete’s foot fungus spread by touching same things as infected such as towel
body fluids such as blood (by sharing needles), breast milk and semen (through sex)
e.g HIV virus that causes aids is spread this way and stops immune system working
animal vectors - vectors that carry and spread disease
e.g anophdes mosquito carries protozoa that causes malaria. spreads it by biting and sucking blood of other organisms
house fly - carries bacterium that causes dysentery and spreads it by carrying bacteria onto food
What physical barriers stop pathogens entering the body?
skin- unbroken, barrier against microbes
damaged, blood clots quickly and the seal acts as a barrier to keep out microbes
respiratory system- respiratory tract (nasal passage, trachea and lungs) lined with mucus and cilia
mucus catches dust and bacteria before they reach lungs
cilia pushes gunk-filled mucus away from lungs
What chemical barriers stop pathogens entering the body?
eyes- produce lysozyme chemical in tears which kills bacteria on surface of eye
stomach - hydrochloric acid kills pathogens in things like food
How do plants defend themselves against pathogens?
produce chemicals
some have antibacterial effect that protect the plant against bacteria
What are antiseptics and how are they used?
chemicals that destroy or stop bacteria growing
used outside the body to help clean wounds and surfaces
prevent instead or treat infection
found in many household products e.g bathroom cleaner
used in hospitals and surgeries to try and prevent spread of infections like MRSA
What are antibiotics and how are they used?
drugs used inside the body, taken as pill or injected
treat patients already infected with bacteria or fungi
don’t destroy virus e.g cold and flu
two types- antibacterials and antifungals
What is the difference between antibacterials and antifungals?
antibacterials e.g penicillin
treat bacterial infections by killing bacteria or stopping it growing
bacteria can become resistant to certain antibacterials so they won’t work
antifungals e.g nystatin
treat fungal infections by killing fungi or stopping them growing
