B12 Homeostasis

• the pituitary gland produces many hormones. It is located in the brain.
• what are hormones?

  hormones are chemical molecules transported by the blood.
• where are hormones produced?

  hormones are produced by glands called endocrine glands
• glands make up the endocrine system
• ovaries produce oestrogen which is involved in the menstrual cycle
• testes produce testosterone which controls puberty and sperm production
• the thyroid gland produces thyroxine which regulates metabolism, heart rate and temperature
• adrenal gland produces adrenaline which is used in fight or flight response
• pancreas produces insulin which is used to regulate blood glucose level
• nerves have very fast action, act for a very short time and act on a very precise area
• hormones have slower action, act for a long time and act in a more general way
• the pituitary gland is referred to as the 'master gland' because the hormones it produces act on other glands directing them to release hormones that bring about change
• what is the pituitary gland?

  endocrine gland located in the brain
• what does the pituitary gland do?

  pituitary gland produces many hormones that regulate body conditions.
• what do ovaries do?

  produce oestrogen
• what do testes do?

  produce testosterone
• where is thyroxine produced?

  the thyroid gland
• where is adrenaline produced?

  adrenal gland
• where is insulin produced?

  pancreas
• how is excess glucose stored?


  Excess glucose is stored in the liver and the muscles as glucogen
• how is type 1 diabetes controlled?

  using insulin
• how is type 2 diabetes controlled?

  using carbohydrate controlled diet and exercise
• what hormone is secreted by the pancreas when blood glucose is high?

  insulin
• what hormone is secreted by the pancreas when blood glucose is too low?

  glucagon
• how do kidneys make urine?

  take waste products such urea, excess ions and excess water out of the body
• what is selectively reabsorbed by the kidneys?

  water, glucose and ions
• which hormone controls the concentration of urine?

  ADH anti-diuretic hormone
• what happens on days 1-4 of the menstrual cycle?

  menstruation starts. the uterus lining breaks down.
• what happens on days 4-14 of the menstrual cycle?

  the uterus lining builds up.
• on what day of the menstrual cycle is an egg released?

  an egg is released on day 14 of the menstrual cycle. this is called ovulation
• what happens from day 14-28 of the menstrual cycle?

  uterus lining is maintained
• what is the function of oestrogen in the menstrual cycle?

  causes lining of uterus to grow. stimulate release of LH and inhibits release of FSH.
• what is the function of progesterone in the menstrual cycle?

  maintains the lining of the uterus. when level of progesterone falls, the lining breaks down. inhibits release of LH and FSH
• what is the function of FSH in the menstrual cycle?

  follicle stimulating hormone causes an egg to mature in the follicle. stimulates ovaries to produce oestrogen.
• function of LH in menstrual cycle?

  stimulates the release of an egg on day 14
• which hormone stimulates an egg to mature in the ovary?

  FSH
• where is adrenaline released from?

  adrenal glands which are just above the kidneys
• where is thyroxine released from?

  thyroid gland which is in the neck
• what is auxin?

  a plant hormone that controls growth near the tips of shoots and roots
• what is phototropism?

  growth of a plant in response to light