Hormones

• Adrenaline is released in scary situations it's your fight of flight response
• Brain detects stress and fear and sends nervous impulses to the adrenal glands and they respond by releasing adrenaline
• The pituitary gland is found in what organ?

  brain
• What is the pituitary gland sometimes called?

  the master gland
• The pituitary gland is called the master gland as hormones act on other glands making them release hormones too
• The pituitary gland produces many hormones that regulate body conditions
• The thyroid produces with hormone?

  throixine
• Thyroxine is involved in regulating rate of metabolism, heart rate and temperature
• What hormone does the pancreas release?

  insulin
• Insulin is used to regulate the blood glucose levels
• What hormone does the ovaries produce?


  oestrogen
• Oestrogen is involved in the menstrual cycle
• The testes produce what hormone?


  testostrone
• Testostrone controls puberty and sperm production in males
• Hormones act slowly and for a long time in a much more general way
• Hormones are chemical molecules released directly into the blood
• Hormones are carried in the blood but only affect particular cells in particular organs, these are what you call the target organs
• Hormones control things that need constant adjustment
• Hormones are produced and secreted from glands called endocrine glands which make up the endocrine system
• Hormones usually have long lasting effects
• Release of adrenaline gets the body ready for flight or flight response by increasing supply of oxygen and glucose to cells in brain and muscles
• Thyroxine regulates metabolism and plays an important role in regulating basal metabolic rate
• basal metabolic rate is the speed at which chemical reactions in the body occur while the body is at rest
• Thyroxine is made in the thyroid gland from amino acids and iodine
• Thyroxine is released in response to TSH which is thyroid stimulating hormone that is released from the pituitary gland
• If blood thyroxine level is higher than normal a release if TSH is stopped, reducing the amount of thyroxine released from the thyroid gland so level falls back to normal (opposite if lower)
• Auxin is the plant hormone for growth at meristem. controls growth in response to light (phototropism) and gravity (geotropism)
• Auxin is produced in the tips and moves backwards to stimulate cell elongation process occurring in cells just behind the tips
• If the tip of shoot is removed no auxin is available and shoot may stop growing
• Extra auxin promotes growth in shoot and inhibits growth in roots
• Shoots grow away from gravity and towards light
• When shoot tip is exposed to light, more auxin accumulates on the shade side, making cells grow faster on shaded side so shoot bends towards light
• When shoot is growing sideways, more auxin on the lower side, causing lower side to grow faster, bending shoot upwards
• Roots grow towards gravity so when root is growing sideways more auxin accumulates on lower side
• Roots bend downwards due to extra auxin which inhibits growth in roots and cells on top elongate faster
• Gibberellin stimulates plant stems to grow, seed germination and flowering
• Ethene stimulates ripening of plant
• Ethene is a gas produced by aging parts of fruit
• Ethene influences growth of plant by controlling cell division, it also stimulates enzymes causing fruits to ripen
• Commercial uses of plant hormones are killing weeds, growing from cuttings with rooting powders and growing cells in tissue culture