Question

1. Which of these is an organic compound?
CO2,
KCL,
H2O,
DNA

2.A young mother is in the hospital delivery room. She is progressing slowly through her labor. Her doctor suggests that she get an IV drip with pitocin (oxytocin) in it to accelerate her labor contractions. As the pitocin is added, the uterus contracts harder and harder. This is example of: positive or negative feedback?

Answer 1

1. Which of these is an organic compound?

Answer : CO2

Organic compounds are those compounds that contain carbon in their structure. Historically, organic compounds were considered to be those compounds which originated in living beings, it is no longer an acceptable definition.

Few examples of organic compounds are methane ( CH4), alcohol, aldehydes, acids like formic acid, ether, amine, ester, amide, etc.

Organic compounds are abundant in nature as carbon atoms have the ability to readily bond with other carbon atoms. This property is known as catenation. These carbon chains can easily combine with other elements particularly hydrogen, oxygen to form organic compounds.

DNA is made up of elements like hydrogen, nitrogen and oxygen. Thus, chemically, DNA is not an organic compound.

KCL and H2O donot have carbon atoms therefore they are not organic compounds.

2. The administration of pitocin (oxytocin) to accelerate the labor is an example of positive feedback loop mechanism.

Oxytocin is a peptide hormone synthesized by the hypothalamus of the brain and released into the blood stream by posterior part pituitary gland where it is stored after synthesis. The release of oxytocin happens in response to cervical dilatation and uterine contraction during the labor when the foetal head pushes against the cervix.

Nerve signal from the cervix is transmitted to the brain which causes the release of oxytocin from posterior pituitary which in turn causes further uterine and cervical contraction and thereby expulsion of the foetus out of the uterus during parturition (child birth). Thus a positive feedback loop is created which generates nerve impulses from contracting cervix which travels to the brain and causes release of oxytocin from posterior pituitary. This released oxytocin further contracts the cervix which sends more signal to the brain for more oxytocin to be released and this cycle continues till the foetus is delivered.

Thus, pitocin (oxytocin) intravenous drip is administered to this young mother to help her accelerate the process of labor ( through positive feedback loop mechanism) as her labor is progressing slowly which might otherwise threaten the foetal well being.