B5 - Growth and New Parts For Old Flashcards
At birth and during the first 6 months what does the midwife measure?
• head circumference • body length • mass
Why might a baby be growing too slowly? How can this be treated?
Its pituitary gland may not be producing enough growth hormone. Growth hormone stimulates general growth, especially that of long bones and muscles. A deficiency can be treated with injections of human growth hormone.
Describe growth during infancy .
– First two years of life
– Highest rate of growth, gaining around 15–24 cm in a year
Describe growth during childhood .
– From 2–11 years of age, until puberty starts
– Growth occurs at a slower rate than during infancy
Describe growth during adolescence.
- From 11–15 years of age, when puberty begins
– Growth spurt for girls aged 10–12 and boys aged 12–15 years
Describe growth during maturity.
– Males may continue to grow until the age of 18–20 years
– Most females reach their full adult height by 16 years of age
Describe growth during old age.
– Above 60–65 years
– Physical abilities start to deteriorate
What is your final height determined by?
• your genes – many genes determine your height potential
• your diet – you need good quality protein for growth and enough food for your energy needs
• the amount of exercise you do – exercise stimulates growth of bones and muscles
• your hormones – growth hormone, thyroxine, and insulin
• health and disease – if you are often ill or do not get enough sleep you may not grow properly.
Why has life expectancy increased?
- less industrial disease such as asbestosis, and fewer accidents in the workplace
• healthier diets, with few cases of vitamin or mineral deficiencies
• better housing - improved lifestyle so people can have a positive outlook on life
• vaccinations to prevent many infectious diseases - better treatments for cancer and heart disease
What are the problems with increased life expectancy?
• a large ageing population – there are more people aged over 65 than under 16 in the UK
• many of these will need medical treatment or care
• this could affect the job prospects for younger people as more older people need to keep working for economic reasons and/or because they want to
• the state pension system will need to be redesigned as it cannot afford to pay pensions for 30 or more years to people; the retirement age will also be raised.
Give some examples of mechanical replacements for body parts outside of the body.
• heart–lung machines, used during open heart surgery to divert blood from the heart
• kidney dialysis machines, used to lter the blood of people with renal (kidney) failure, removing urea, excess salts, and water
• mechanical ventilators, used to aid breathing in patients whose rib cage muscles are paralysed.
Give some examples of mechanical replacements for body parts that can implanted in the body.
- heart pacemakers
- artificial knee and hip joints
• artificial hearts - eye lenses
What do engineers need to consider when making mechanical replacements?
• size – this is why there is no artificial kidney that can be implanted; dialysis machines are very large
• battery life (if powered) – pacemaker batteries last 7–10 years
• body reactions – inert materials that do not react with body fluids are used to construct implants; artificial hearts are made of titanium and plastic
• strength – titanium is used for arti cial joints.
Why is it hard to find donors?
All donors need to be a good tissue match and the right age and size for the recipients. Living donors have to be healthy and willing to donate. There is currently a shortage of organ donors.
What is rejection and how is it reduced?
With most transplants there is a risk that the recipient’s immune system will reject the transplant. Tissue matching, matching the donor and recipient’s tissue type, and immunosuppressant drugs both reduce the risk of rejection. However, these drugs increase the risk of infections.
