Hormones:the first step

<<Prev <<Top>> Next>>

Hormones are substances that are increted into blood vessels that have certain producing glands and target glands, and produce a certain amount of effects with small quantities.

What hormones are
For example, female sex hormone can be defined as a hormone because its producing gland is clear (ovary)and the target gland is also clear (female reproductive system). Also, it produces a cerain of effect with small quantity which is sexual development.
On the other hand, glucose secreted to the bloodstream from the liver cannot be defined as a hormone. It doesn't have a certain target organ nor produce a certain effect, since it is an energy-providing substance. Plus, its quantity is large.
Achievement Quiz
1. Glucose is a hormone secreted internally by liver. [ a. right / b. wrong ]

2. Antibodies are secreted to the bloodstream from plasma cells, and attack bacteria. Antibody is a hormone. [ a. right / b. wrong ]

3. Aldosterone is produced from adrenal cortex in small quantity, and it has an effect of increasing the speed of sodium pumps of uriniferous tubule in kidney. Aldosterone [ a. is / b. is not ] a hormone.
1.The correct answer is b. It is secreted to the bloodstream, but not in small quantity. Also since it is energy-providing substance, it doesn't have a clear target organ. Considering these points, can we call it a hormone?

2.The correct answer is b. A bacteria is a foreign body and thus not considered to be a target organ. Antibodies aren't considered to be a hormone.

3.The correct answer is a. It is secreted to the bloodstream, and has a clear producing gland and a clear target organ, eliciting a certain effect in small quantity. It can be considered to fulfill the definition of a hormone.
<<Prev <<Top>> Next>>