- know what acromegaly is
- know who acromegaly affects
- know what gigantism is
- know who gigantism affects
- know what dwarfism is
- know who dwarfism affects
- know the difference between pituitary and endochondral dwarfs
After learning about the functions of growth hormone it's important to think about what can go wrong if growth hormone levels are off.
After studying how growth hormone positively affects the human body now let's take a look at its negative effects if levels aren't normal. Remember that growth hormone stimulates growth of all our tissues, so it's easy to understand growth hormone pathologies.
A deficiency in growth hormone at a young age will cause pituitary dwarfism. Pituitary dwarfs are people who don't reach thier full height potential. In the packet title Metabolic Effects of Growth hormone I covered GH's effects on cartilage. Remember that our growth plates (epiphyseal plates) are a very active form of cartilage that eventually ossify. Once they ossify then we cannot grow anymore. If the growth plates weren't exposed to enough growth hormone at a young age then the child will not grow to his/her full adult height. However, unlike their endochondral counterparts, pituitary dwarf's limbs are proportional to the rest of their body.
Gigantism is the exact opposite of dwarfism. This is caused by excessively high levels of GH hormone secretion at a young age. This causes a child to grow much taller than normal; not just taller but more massive overall. Remember growth hormone causes growth of all tissues, not just bone.
Acromegaly occurs in adults who oversecrete growth hormone. Once our growth plates ossify our bones are unable to lengthen, but they can still thicken. Our extremeties will increase overall size, (acro- extremeties, megal/o enlarge) and the persons apperance will change. This can also happen to people who inject themselves with growth hormone for exercise or cosmetic reasons (how ironic). Look up some before and after pictures of Barry Bonds and you'll see what I'm talking about. Same with Sylvester Stallone
Here is a classic picture of acromegaly: http://www.colorado.edu/intphys/Class/IPHY3430-200/image/23-17.jpg
Source: Mind of Aaron
This video covers three major growth hormone abnormalities: acromegaly, dwarfism, gigantism
Source: Self made
Source: Self made