Topic 7 Flashcards Preview

GCSE Edexcel Biology grade 9-1 course, topics 6-9 > Topic 7 > Flashcards

Flashcards in Topic 7 Deck (200)
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what is ADH's target organ?

the kidney


what happens if the body is dehydrated?

more ADH is released by the pituitary gland, the collecting duct becomes more permeable, more water is absorbed so less water passes into the urine and more water passes into the blood


what happens if there is a lot of water in the blood?

Less ADH is released by the pituitary gland, the collecting duct becomes less permeable, less water is reabsorbed so more water passes into the urine and less water passes into the blood


what happens to urine when salty foods are eaten?

•the sodium ions increase

•the level of ADH stored in the pituitary gland decreases, more ADH enters the blood

•the amount of water selectively reabsorbed into the blood increases

•the urine becomes more concentrated, decreased volume of urine produced

•dehydration is prevented


what happens to urine when too much water is drunk?

•the water increases

•the level of ADH stored in the pituitary gland increases, less ADH enters the blood

•the amount of water selectively reabsorbed into the blood decreases

•the urine becomes more diluted, increased volume of urine produced


how is urea made?

•protein enters the body in food
•the protein is digested by enzymes (proteases) into small molecules of amino acids
•the amino acids are absorbed into the blood stream in the small intestine during digestion
•excess amino acids are taken in the blood to the liver to be broken down
•the liver breaks down the amino acids in a process called deamination which produces urea which is a toxic waste product


what are the enzymes which break down proteins?



what is deamination?

when the liver breaks down excess amino acids to produce urea


what are hormones?

hormones are chemicals released directly into the blood, which affect target cells. Hormones control 'things' in organs and cells that need constant regulation and adjustment.


what glands make up the endocrine system?

endocrine glands


what are endocrine glands?

where hormones are produced


what are the target organs for the pituitary gland?

the ovaries, the kidney


what are the endocrine glands that you need to know?

•the pituitary gland
•the thyroid gland
•the ovaries
•the testes
•the adrenal glands
•the pancreas


what are the differences between neurones and hormones?

neurones: fast action, act for a short amount of time, act in a precise area.

hormones: slower action, act for a long amount of time, act in a more general way.


why are neurone responses quick? why can't hormones be used for these types of responses?

the information needs to be passed to the effectors really quickly, for example, pain signals or warnings from your eyes, hormones can't be used for these types of responses because the hormones are too slow to carry the information quickly.


what response does adrenalin prepare the body for?

fight-or-flight response


describe the process in which adrenalin prepares the body for a fight-or-flight response.

•adrenalin binds to specific receptors in the heart which causes the heart muscle to contract more frequently and more forcefully so heart rate and blood pressure.
•this increases blood flow to the muscles so the cells receive more oxygen and glucose for increased respiration
•adrenalin binds to receptors in the liver to cause the liver to break down its glycogen stores to release glucose.
•this increases blood glucose level so there's more glucose in the blood to be transported to cells.

overall, heart rate increases, blood pressure increases, blood flow increases, blood glucose levels increases, and respiration increases in cells for more energy in the fight-or-flight response.


what system controls the levels of hormones in the blood?

the negative feedback system


what can an underactive thyroid gland cause?

weight gain because less thyroxine means that the metabolic rate decreases, this results in less of the glucose which is taken into the body being broken down in respiration and so more is stored as fat.


what is the menstrual cycle?

a monthly sequence of events in which the female body releases an egg and prepares the uterus in case the egg is fertilised.


what is another name for the uterus?

the womb


what is the womb also known as?

the uterus


what happens if a fertilised egg implants in the uterus?

the woman becomes pregnant and the level of progesterone will remain high to maintain the lining of the uterus during pregnancy


what are the main methods an infertile couple could resort to in order to become pregnant?

clomifene therapy and IVF


how does IVF work?

eggs are collected from the female's ovaries and they are fertilised in a lab using the male's sperm. before egg collection FSH and LH are given to stimulate egg production. when the embryos have developed into balls of cells on or two of them are implanted into the uterus to improve the chance of pregnancy.


how can oestrogen be used as a contraceptive?

oestrogen can be used to prevent the release of an egg. although oestrogen is naturally used to stimulate the release of eggs, if it is taken every day to maintain a high level of oestrogen then it inhibits the production of FSH and as a result egg development and egg production stop.


how can progesterone be used as a contraceptive?

progesterone can be used to reduce fertility by stimulating the production of thick cervical mucus, preventing sperm from getting through the cervix and reaching an egg


what is the entrance to the uterus also called?

the cervix


what is the cervix?

the entrance to the uterus


which types of contraceptives are more effective when used correctly?

hormonal contraceptives