EMULSIFICATION

EMULSIFICATION?
This process is simply a process in which big fat globule is broken down into small fat droplets (without changing the fat chemically) So you starts with fats and ends with fats, get it?. Its just like shaking oil in water where you would observed tiny emulsions formed. The idea here is to increase the surface area to volume ratio of the fats so that chemical digestion by LIPASE could be facilitated.

In human digestive system, during the process of digestion, this process takes place in the duodenum. Whenever chyme containing fats enters the duodenum, your gall bladder will secrete bile into the duodenum (Remember: the gall bladder is an organ which stores bile temporarily and this bile will only be secreted if chyme enters the duodenum.... and and.... the organ that manufactures the bile is the LIVER..... please remember these facts). By the way after bile is secreted into the duodenum, it will emulsify the fats present in the chyme. Only after emulsification would fats be digested chemically by LIPASE into three fatty acids and one glycerol.................

DEAMINATION

Unlike fats, your body simply cannot store amino acids no matter how much protein you are taking in in your diet. Your body can only take so much whilst the excess amino acids are DEAMINATED.

The figure above shows the chemical formula of AMINO ACID. From the figure you can see that it consists of the amino group and the carboxylic acid group. During the process of DEAMINATION in the LIVER, an amino acid is broken down into two parts - the amino group and the part of the amino acid which contains the carboxylic acid group (which is now referred to as the carbohydrate group).

The carbohydrate group will eventually be converted into GLYCOGEN and stored in the liver itself as well as in your muscle tissues. This GLYCOGEN can be converted to glucose should your body need it as a fuel for cellular respiration. Otherwise, if the glycogen is not utilized within a duration of about 6 hours, it will eventually be converted into FATS and stored in the liver itself as well as in the adipose tissues under your skin.

The amino group on the other hand will be converted to UREA and this UREA will be send (via your blood circulatory system) to your kidneys. Your kidneys will then EXCRETE the UREA along with excess water and minerals (UREA + water + minerals = URINE).

NOTE:
SECRETION vs EXCRETION?

WHEN TO USE THESE TERMS?

SECRETION FOR USEFUL SUBSTANCES LIKE ENZYMES AND HORMONES

WHILST

EXCRETION FOR WASTE PRODUCTS OF METABOLISM LIKE UREA AND CARBON DIOXIDE....

PERISTALSIS

The figure above shows PERISTALSIS. I have an urgent need to blog about this because there were misconceptions concerning it based on some students' responses in the previous test. Here are some of the misconceptions:

• Circular and longitudinal muscles contract or relax at the same time
• Some students used circular or longitudinal tissues instead of muscles
• Some students were not aware about the role of peristalsis in digestion

Here's the definition of PERISTALSIS:
It is the ALTERNATE contraction and relaxation of the circular and longitudinal muscles causing bolus to be pushed down and also at the same time to be physically digested.

In the recent test, many students failed to include ALTERNATE. It is very important to do so because it shows that you understand that these muscles are actually working antagonistically (that is, when one set of muscles relaxes the other set contracts - for example when the circular muscles relax, the longitudinal muscles contract). Now, it should be understood that without ALTERNATE in your definition, the meaning could be misleading. It can be assumed that both set of muscles are actually contracting or relaxing at the same time.

Students should also be aware about the role of PERISTALSIS. One is to move bolus down along the alimentary canal and the second function is to break the bolus down into smaller pieces without changing them chemically (this is a kind of PHYSICAL digestion).

And lastly..... where is PERISTALSIS occurring?
Not only the oesophagus but actually along the alimentary canal......