White Blood Cells
White blood cells ingest pathogens and destroy them by breaking them down.
White blood cells produce antibodies which destroy pathogens. There are different types of antibodies; Phagocytes, lymphocytes.
White blood cells produce antitoxins which cancel out the toxins released by pathogens.
- An inactive or dead pathogen is injected to the body.
-The antigens in the vaccine stimulate the white blood cells to ingest pathogens and produce antitoxins and antibodies.
-This then makes the body immune to future infections by the pathogens because the body can now respond rapidly.
-Vaccinations can wear off over time.
Evolution - Natural selection
Individuals produce genetically diverse offspring.
Offspring compete for food, habitats, mates and water.
The offspring with few competitive traits die out or reproduce less.
The offspring with many competitive traits survive and reproduce more.
The frequency of adaptation trait increases in the population.
Evolution - Inheritance of Acquired Characteristic
Elephants used to have short trunks.
They used to reach up for their food source, supposedly stretching their trunks.
This adaptation of stretched trunks was passed onto their offspring, as it was useful.
This adaptation lead to elephants ending up with long trunks.
Synapses (Nervous system)
Impulse arrives in neurone.
Chemicals are released from neurone and cross the synapse and arrive at the receptor.
This starts an electricle impulse in the next neurone.
FSH - Made in the pituary gland. This hormone matures the eggs in the ovaries and stimulates the ovaries to produce oestrogen.
Oestrogen - Made in the ovaries. This stimulates the lining of the womb to prepare for pregnancy. It inhibits production of FSH.
LH - Made in the pituary gland. This stimulates the release of a mature egg when their levels reach peak in the middle of the menstrual cycle.