Your baby’s digestive system is called into action the moment food enters her mouth. Immediately, her salivary glands release enzymes to start digestion, make food more alkaline, and keep her mouth moist. Her tongue tastes and moves the food. As her tongue moves the food to her throat, it also activates her epiglottis, which is the little flap that covers the trachea at the back of her throat, so that food does not go down her windpipe and cause her to choke. Slow eating ensures that the epiglottis has plenty of time to perform its duty. Once your baby has teeth and can chew food, digestion becomes even easier.
Your baby’s esophagus is a hollow tube that transports food from her mouth to her stomach. The esophageal valve at the bottom of that tube controls entry into her stomach and prevents food from coming back up her esophagus after it has entered her stomach. This valve is underdeveloped in babies, which is why they often spit up.
Once food reaches your baby’s stomach, stomach acid kills bad bacteria and breaks the food down further so it can travel into her small intestine. From there, her liver releases bile that is stored in her gallbladder, and her pancreas releases digestive enzymes into her small intestine to help break food into fats, proteins, and carbohydrates. Nutrients are then absorbed into your baby’s bloodstream and moved into her liver. Here, they are filtered and processed before heading back into her bloodstream. Food that is not absorbed passes into her large intestine, where water is absorbed into the blood. The leftover waste is excreted through your baby’s rectum and anus.
While in the womb, your baby swallowed amniotic fluid and expelled urine through her urinary system. Because she received her primary nutrients through the umbilical cord, she did not need to use her digestive system. After birth, your baby’s sucking reflex signaled her first stool, called meconium, to pass through her large intestine, thus kick-starting her digestive system. Even at this point, however, her digestive system is not fully developed. It takes 6 to 12 months of muscle strengthening before your baby’s digestive system can work well.
As a parent, you are probably highly aware of your baby’s digestive system, because it regularly requires your attention through her hunger, thirst, and bowel movements. In the first year, due to her sensitive and underdeveloped system, digestive irregularities such as spit-up and upset stomach may be prevalent.
You can help ease many irregularities by breast-feeding your baby exclusively for the first six months. If your breast-fed baby does experience gastronomic distress, it can be helpful to pay attention to the mother’s diet and then eliminate foods that cause a reaction in your baby. When she is ready for her first solid foods, include whole grains, vegetables, legumes and seeds, fermented foods, and probiotic boosters for easy digestion.
Working to eliminate excesses from your baby’s body, her urinary system coordinates with her lungs, skin, and intestines to excrete wastes from blood and to balance her body’s fluids, salt, vitamins, and minerals. Your baby’s urinary system consists of two kidneys, two ureters, a bladder, and a urethra. Her kidneys are reddish in color, bean shaped, and located in the back of her body, just above her waist. They contain filters that clean her blood, remove acids, and regulate mineral content, which balances pH levels. The kidneys also regulate her blood pressure and make sure that her body tissues receive enough water. Any waste in the kidneys becomes urine.
Your baby’s urine moves out of each kidney through a tube called a ureter and travels into her bladder. Her bladder is a hollow, muscular, balloon-shaped organ located in the middle of her pelvis. Urine waits in her bladder until the organ is full and then is released through her urethra and into her diaper. The amount of urine that your baby’s body produces depends on hormone levels, the amount of liquid she ingests, and the amount of liquid that her body expels through perspiration.
Because your baby’s digestive system is still developing throughout the first year of life, it plays a role in many common childhood illnesses, such as diarrhea, constipation, colic, stomach upset and vomiting, hiccups, and teething. Common illnesses of the urinary system, such as kidney stones and urinary tract infections, are more likely to occur later in life.