adrenaline and thyroxine

• adrenaline is a hormone released by the adrenal glands in stressful or scary situations, getting the body ready for 'fight or flight'
• thyroxine is a hormone released by the thyroid gland, it regulates the basal metabolic rate, and stimulates protein synthesis.
• thryroxine is released in respones to thyroid stimulating hormone (TSH)
• auxin is a plant hormone that controls growth near the tips of shoots and roots
• auxin controls the growth of a plant in response to light (phototropism) and gravity (gravitropism or geotropism)
• auxin is produced in the tips and moves backwards to stimulate the cell elongation process
• when a shoot tip is exposed to light, more auxin accumulates on the side that's in the shade. this causes the cells to grow faster on the shaded side. this is called phototropism
• when a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip, this causes the lower side to grow faster, bending the shoot upwards
• in the root of a plant, extra auxin inhibits growth, meaning that the cells on top elongate faster, bending the root downwards