Digestion Mouth To Stomach

Site of ingestion of food. Mastication which is the physical digestion of food through chewing using the teeth tongue palate and muscles in the face. Mastication increases surface area of food for chemical digestion

Salivary glands release saliva contains salivary amylase that chemically digest starch turning into maltose. Saliva lubricates the food for the esophagus and help create the bolus

Pharynx is aka throat is the passageways for air and food meet. Where the epiglottis is located which keeps food out of trachea and directs it to esophagus

Connects the pharynx to the stomach where the bolus travels through. When the bolus enters the esophagus 2 layer of muscles work together to move the food to the stomach (using persistaisis movement)

Outside layer of muscle of the esophagus Contracts like pulling up a sleeve ahead of the bolus to help push the bolus down the esophagus While the circular muscles over the bolus relax

Layer of muscle inside the esophagus contracting inward in a wave motion behind the bolus to push the bolus down. When this contracts the longitudinal muscle above the circular relax

Involves two layers of muscles that line in the digestive tract one layer the longitudinal is parallel to the length of the tract. Beneath is the circular muscles perpendicular.

At the bottom of the esophagus there is a circular muscle called the esophageal spincter aka cardiac spincter this muscle prevents stomach acid and partially digested food from regurgitating back into the esophagus from the stomach. When the spincter relaxes this causes the food and acid to go back up. Possible reasons to why it malfunctions and relaxes is diet, consumption of alcohol nicotine meds etc.

A J-shaped muscular sac with think ridges called rugae this allows for expansion 2-4L of food typical adult in the stomach the food is undergoing chemical and mechanical digestion due to the stomach physical movements( walls contracting and mixing/churning cause stomach growling) and stomach acids (gastric juices in stomach.

Cells that secrete gastric juices in the stomach one of them being hydrocloric acid that lowers the pH in the stomach to be between 2 and 3. Extreme acidity kills pathogens like bacteria. Hydrocloric acid also activates a protease enzyme called pepsin (pepsinogen is the inactive version) which is used to break down large proteins to smaller polypeptide chains.

Lubricates food so that it can travel through the digestive tract more easily. Protects muscle tissue from being broken down by acid and pepsin in the stomach. Stomach wall cells are replaces every 3 days

The inactive version of pepsin needs HCL to active to pepsin. The cells are itself made of protein therefore the cells produce pepsin in the inactive form pepsinogen because pepsin breaks down proteins. The pepsinogen leaves the cell and makes contact with HCL it becomes pepsin

After 3-4 hrs of mechanical and chemical digestion in the stomach the food is reduced to a soft pulp called chyme. It’s a thick liquid made up of partially digested food proteins vitamins starches acid mucus and undigested sugars and fats. (Aka vomit)

Food mixed with saliva formed in a circularish shape that travel through your esophagus.

A hormone ( a special chemical messager carried in blood) that tells the cells in the stomach to produce gastric juices when stomach gets stretched due to food entering the stomach

Stomach only secretes gastric juices when food becomes present The stomach secretes mucus to protect stomach lining Pepsin is inactive until HCL is present

When the mucus production and lining erodes and the gastric juices eat away the exposed stomach wall This can be caused by acid resistant bacteria but other factors like smoking caffeine and stress contribute too To treat is lifestyle change and antibiotics Anastasia’s drug to increase mucus production

-protein have been broken into smaller polypeptides Sugars and fats have not Ben chemically altered Some starches and molecules have been broken down into disaccrides by saliva