Zusammenfassung der Ressource
B2- Keeping Healthy
- Protection against Infection
- Pathogens cause
disease. Every
pathogen
contains antigens
- White blood cells either
engulf & digest the
pathogen or release the
corresponding antibodies
that lock onto the
pathogen
- After an infection, memory cells remain in the
body & they can produce the correct antibodies
corresponding to the correct pathogen
(Immunity)
- A vaccine is a safe form of a virus
- Viruses have side effects that differ in each person
- To avoid an epidemic a high
percentage of the population
have to be vaccinated
- Antimicrobials are a group of
substances that are used to kill
microorganisms or slow their growth.
They're effective against bacteria,
viruses & fungi
- Antibiotics are a type of anitmicrobials that are
effective against bacteria but not viruses
- It's important that a course of antibiotics is
completed otherwise bacteria can become
resistant
- New drugs have to be tested to make
sure they're safe & effective
- In an 'open-label' trial everybody
knows who gets the new drug
- In a 'blind' trial only the doctors know who
gets the new drug
- In a 'double-b;ind' trial the doctors and
patients don't know who has the new drug
(only researchers do)
- The Heart
- The heart is a 'double-pump'- as 1 half is pumping
oxygenated blood from the lungs to the body, the other
half is pumping deoxygenated blood from the body to
the lungs
- Arteries carry blood away from the heart under high pressure
- They have very thick walls to withstand pressure
- Capillaries link arteries & veins
- Walls are 1 cell thick to allow the transfer
of substances to & from cells
- Veins collect blood and return it to the heart
- Walls contain elastic, muscular tissue but are thinner
than arteries.. The blood is under low pressure & have
valves to prevent backflow of blood
- Heart disease is
caused by a
build-up of fatty
substances in the
arteries
- Poor diet, smoking, lack of exercise & genetics are the
main causes of heart disease
- Heart rate is measured by recording
pulse rate. This is the number of
pulses as blood passes through an
artery close to skin
- Blood pressure measurements record
the pressure of blood on the walls of
an artery
- High blood pressure increases the chance
of strokes & heart attacks. Low blood
pressure can cause dizziness & fainting
- Water Balance
- Maintaining a constant internal
environment is called homeostasis
- Homeostasis involves communication by the
nervous & hormonal systems
- The systems involved in homeostasis are:
Receptors (detect change in the
environment), Processing centres (receive
info & determine how the body will respond), Effectors (produce a response)
- If the blood plasma is too concentrated, the cells will lose water
- If the blood plasma is too dilute, the cells will absorb water & burst
- The kidneys respond to water concentration in the
plasma by releasing dilute or concentrated urine
- ADH (Anti Diruetic hormone) keeps water
in the body. This tells the body to release
a small amount of concentrated urine
- Alcohol suppresses the release of ADH, this dehydrates cells
- Ecstasy increases ADH production, this drowns cells