The Disgestive system

The structures of the digestive system are the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and accessory organs. The mouth, or oral cavity, is composed of the teeth, mandible, maxilla, hard and soft palates, and the muscles of the tongue. Certain muscles of facial expression create movement of the lips and the jaw. The solid, semisolid, or liquid food enters the digestive system through the mouth. Solids are chewed and mixed with saliva to form a bolus in preparation for the food to be digested throughout the digestive system (oral preparation phase of swallow). There are three phases of swallow:

1. oral preparation
2. oral transit
3. pharyngeal phases.

The oral transit phase of swallow involves the bolus being actively moved from the front of the mouth to the back. Both the oral preparation and oral transit phases of swallow are voluntary. After the bolus passes into the pharynx, the movement of the bolus is involuntarily controlled by smooth muscles. The movement of food through the digestive system is caused by the involuntary contraction and relaxation of smooth muscle. This movement is known as peristalsis. The bolus goes from the pharynx into the esophagus, into the stomach, into the small intestine, and then into the large intestine. The food continues to be chemically digested by these organs. Most of the nutrient resorption occurs in the small intestine, whereas most of the water resorption occurs in the large intestine.

A baby’s digestive system at birth has all the functional capacities needed to cope with liquid food while the musculature of the abdomen and the walls of the intestines strengthen for the later digestion of solid foods.

As soon as a baby starts breathing, his/her stomach expands to four to five times its pre-birth size and finds its position in the abdomen. The stomach capacity of a New-born is 30-35 ml (1 fl oz) but this doubles during the first week as the milk supply is established. By four weeks the size of a New-born stomach has tripled but it is still only one tenth of an average adult stomach’s size. A baby can lose up to 10% of its birth weight once it has been separated from the supply of nutrients it has relied on for the past nine months. It will need to make up this loss as quickly as possible through feeding. Breast milk contains all that a new born needs. Colostrum, the clear fluid produced by the breast after the baby is born, contains a protein that is very easy for a new born baby to digest.

Breast milk contains efructose (a growth factor for lactobacillus bifidus) which has the ability to raise the acidity in the gut, offering protection against infections such as e.coli. Breast milk also contains long-chain polyunsaturated fatty acids to help with the development of the brain.

Present in the digestive tract of a New-born baby are pancreatic enzymes: required for the break down carbohydrates (amylase) and proteins (enterokinase). Lipase, the pancreatic enzyme that helps with the breakdown of fats, is only present is very small amounts, so the baby has a limited ability to digest fat. The enzyme bilirubin, produced by the liver, is not present until approximately 2 weeks after birth and the lack of this enzyme can cause ‘baby jaundice.’

The WHO and NHS recommendation for infant feeding, based on the anatomy and physiology of infant feeding, is for women to breastfeed their babies exclusively for the first six months and to continue to two years and beyond in conjunction with solids. Only a small minority of women meet this target in developed countries and in urban environments in developing countries.

 Bowel movements

To clear the body of desquamated cells, amniotic fluid and digestive juices the baby passes meconium, a dark green liquid stool. After a few days stools become yellow in colour, containing both live and dead bacteria, water, casein, fat, fatty acids, and mineral salts. The bowel is vacated when the rectum is full. Control of the bowel develops when the central nervous system matures, usually around 2-3 years.

The placement of a baby’s internal organs at birth undergoes changes through a physiological process:

• The liver occupies up to 40% of the peritoneal space displacing the bowel.
• The position of bowels, transverse and descending colon is adjusted.

After feeds supporting a baby in a straight position over the parent’s knee can help baby to get rid of wind, enabling gas to rise up the oesophagus.

Why do we need to know?

As a child grows their digestive system matures, colic and constipation become more infrequent. It is important to look after our digestive system even as adults to avoid pain and discomfort. Yoga has been proven to aid digestion, thus promoting good overall health for the digestive system.

The movements and positions such as marching legs and tummy press used in baby yoga help to stimulate the immature digestive system and can help prevent and ease issues such as constipation and colic. As children grow we can use poses such as cow, bridge, and camel to aid digestion.