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Unlock This CourseHormones are like chemical messengers that travel around your body telling different parts what to do. Think of them as text messages sent between your organs! During development, hormones play a crucial role in controlling how we grow, when we mature and how our bodies change over time.
Both plants and animals use hormones to control their development, but they work in slightly different ways. In this session, we'll explore how these amazing chemicals shape life from tiny seedlings to fully grown humans.
Key Definitions:
Plants can't move around like animals, but they still need to respond to their environment. Plant hormones help them grow towards light, develop roots and even know when to flower. The most important plant hormone for growth is called auxin.
Animal hormones are produced by special glands and travel through the bloodstream. They control everything from how fast you grow to when you start puberty. Growth hormone is one of the most important for development.
Auxins are the superstar hormones in plants. They're mainly produced in the growing tips of shoots and roots and they control how plants grow and respond to their environment.
Auxins work by making cells grow longer rather than dividing to make new cells. When auxin reaches a cell, it tells the cell wall to become more flexible, allowing the cell to stretch and grow. This is why plants can bend towards light or grow around obstacles.
When light hits one side of a plant, auxin moves to the shaded side. This makes the shaded side grow faster, causing the plant to bend towards the light.
Auxin helps roots grow downwards (towards gravity) and shoots grow upwards (away from gravity). This ensures roots find water and shoots find light.
Auxin from the main shoot tip stops side shoots from growing too much. This helps the plant grow tall rather than bushy.
Gardeners and farmers use artificial auxins to help plants grow better. Rooting powder contains auxins to help cuttings develop roots quickly. Some weedkillers also contain synthetic auxins that make weeds grow so fast they die from exhaustion!
In humans, growth hormone (also called somatotropin) is produced by a small gland in your brain called the pituitary gland. This hormone is essential for normal growth and development from birth through to adulthood.
Growth hormone doesn't just make you taller - it has many important jobs in your body. It helps build strong bones, develops muscles and even affects how your body uses energy from food.
Main functions of growth hormone:
If a child doesn't produce enough growth hormone, they may develop dwarfism and remain much shorter than average. Modern medicine can treat this with growth hormone injections.
Rarely, too much growth hormone can cause gigantism in children or acromegaly in adults, where hands, feet and facial features become unusually large.
Puberty is one of the most dramatic examples of hormones controlling development. During this time, your body produces a cocktail of different hormones that transform you from a child into an adult capable of reproduction.
Puberty usually starts between ages 8-14, triggered by hormones from the brain telling the reproductive organs to start working. This sets off a chain reaction of hormone production that causes all the changes associated with growing up.
Growth spurts, voice changes, development of reproductive organs and changes in body composition all happen due to hormones like testosterone and oestrogen.
Hormones also affect brain development during puberty, influencing emotions, decision-making and social behaviour. This is why teenagers often experience mood swings!
The timing of puberty can vary greatly between individuals. Factors like nutrition, genetics and overall health can influence when puberty begins.
Your body is incredibly clever at controlling hormone levels. It uses feedback systems to make sure you have just the right amount of each hormone at the right time.
Most hormone systems work using negative feedback - like a thermostat in your house. When hormone levels get too high, the body automatically reduces production. When they get too low, production increases. This keeps everything in balance.
Children with growth hormone deficiency can now receive treatment with synthetic growth hormone injections. This treatment has helped thousands of children achieve normal height and development. However, the treatment must be carefully monitored to avoid side effects and ensure the best outcomes.
Both internal and external factors can influence how hormones work during development. Understanding these factors helps us appreciate how complex and delicate the development process really is.
Proper nutrition is essential for normal hormone production. Malnutrition can delay puberty and affect growth hormone production, leading to stunted growth and delayed development.
Growth hormone is mainly released during deep sleep, especially in children and teenagers. This is why getting enough sleep is so important for proper growth and development.
Today's environment presents new challenges for normal hormone development. Chemicals in plastics, pesticides and other pollutants can sometimes interfere with normal hormone function. This is why scientists continue to study how environmental factors affect development.