Describe the digestion process using science terminology
Answers
Mechanical digestion begins in your mouth as your teeth tear and grind food into small bits and pieces you can swallow without choking. The muscular walls of your esophagus, stomach, and intestines continue mechanical digestion, pushing the food along, churning and breaking it into smaller particles.
Chemical digestion occurs at every point in the digestive system, beginning when you see or smell food. These sensory events set off nerve impulses from your eyes and nose that trigger the release of enzymes and other substances that will eventually break down food to release the nutrients inside. The body then burns these nutrients for energy or uses them to build new tissues and body parts.
HOW SIGHT AND SMELL RELATE TO DIGESTION
At first glance — or sniff — the digestive link between your eyes, nose, and stomach sounds a tad weird. But think about it: How many times has the sight or scent of something yummy like a simmering stew or baking bread set your tummy rumbling?
The sight of an appetizing dish or the aroma (actually scent molecules bouncing against the nasal tissues) sends signals to your brain: “Good stuff on the way.” As a result, your brain — the quintessential message center — shoots out impulses that
Make your mouth water.
Make your stomach contract (hunger pangs).
Make intestinal glands start leaking digestive chemicals.
All that from a little look and sniff. Imagine what happens when you actually take a bite!
TASTING AND CHEWING IN THE DIGESTION PROCESS
You know that small bag of potato chips you have stashed way at the back of your desk drawer? Well, dig it out and take a chip.
As the chip hits your tongue, your mouth acts as though someone had thrown the “on” switch in a fun house.
Your teeth chew, breaking the chip into small manageable pieces.
Your salivary glands release a watery liquid (saliva) to compact the chip into a mushy bundle (a bolus in digestive-geek speak) that can slide easily down your throat on a stream of saliva.
Enzymes (which you can think of as digestive catalysts in this case) in the saliva begin to digest carbohydrates in the chip.
Your tongue lifts to push the whole ball of wax . . . no, bolus, back toward the pharynx, the opening from your mouth to your esophagus, and then through a muscular valve called the upper esophageal sphincter, which opens to allow the food through. In other words, you’re about to swallow.
SWALLOWING FOOD: THE SLIDE FROM ESOPHAGUS TO STOMACH
If you think about it, the human digestive system is a wonder. As food enters the esophagus, your salivary glands release a rush of saliva to help food slide more easily down the tube. Then your esophageal muscles swing into action.
Like the rest of your digestive tract, your esophagus is ringed with muscles that contract to produce wavelike motions — which you can refer to as peristalsis or (no surprise here) peristaltic contractions, if you’re so inclined — pushing food down toward your stomach.
At the bottom of the esophagus — an area known as the gastroesophageal junction — a muscular valve called the lower esophageal sphincter (LES) opens to allow food through. Then the LES closes to prevent reflux, the flow of stomach contents back into the esophagus. A malfunctioning LES is public enemy No. 1 in the reflux world.
DIGESTING FOOD IN THE STOMACH
Point to your stomach. Go ahead. Don’t be shy. Odds are your finger is aimed somewhere around your belly button, an interesting site to be sure, but definitely not your stomach. Your stomach, a wide, pouchy part of the digestive tube, is located on the left side of your body above your waist and behind your ribs.
Like the walls of your esophagus, the walls of your stomach are strong and muscular. They contract with enough force to break food int
■ MOUTH:-
♤ FLUID CALLED SALIVA SECRETED BY THE SALIVARY GLANDS.
♤ THE SALIVA CONTAINS AN ENZYME CALLED SALIVARY AMYLASE.
♤ FUNCTION :- BREAK DOWN STARCH INTO COMPLEX MOLECULE TO GIVE SUGAR.
HELP IN MOISTENS THE FOOD EASY FOR CHEWING AND SWALLOWING
■ OESOPHAGUS:-
♤ THE CANAL HAS MUSCLES THAT CONTRACT RHYTHMICALLY TO PUSH THE FOOD FORWARD & THIS MOVEMENT OF FOOD IS CALLED PERISTALTIC MOVEMENT WHICH OCCURS ALONG THE G.UT.
■ STOMACH:-
♤ GASTRIC GLANDS ARE PRESENT IN STOMACH.
♤ IT RELEASE HYDROCHLORIC ACID (HCL).
♤ FUNCTION:- KILL HARMFUL BACTERIA THAT ENTERS WITH THE FOOD.
MAKES THE MEDIUM ALKALINE.
♤ PEPSIN:- THEY ARE PROTEIN DIGESTED ENZYME.
♤ MUCUS:- PROTECTS THE INNER LINING OF THE STOMACH FROM THE ACTION OF HYDROCHLORIC ACID.
■ SMALL INTESTINE:-
♤ THE EXIT OF FOOD FROM THE STOMACH IS REGULATED BY A SPHINCTER MUSCLE.
♤ IT HELPS IN DIGESTION OF CARBOHYDRATES, PROTEINS AND FATS.
■ LIVER :- IT SECRETE BILE JUICE IN GALL BLADDER.
♤ FUNCTION:- TURN ACIDIC MEDIUM TO ALKALINE.
EMULSIFY THE ACTION OF FAT.
♤ PANCREAS:- IT SECRETE PANCREATIC JUICE IT CONTAIN ENZYME LIKE:-
♤ TRYPSIN :- HELPS IN BREAK DOWN OF PROTEINS.
♤ LIPASE :- CONVERT FAT INTO FATTY ACID AND GLYCEROL.
■ INTESTINAL JUICE:- THE WALL OF SMALL INTESTINE CONTAIN GLAND WHICH SECRETE INTESTINAL JUICE.
♤ FUNCTION :- CONVERT PROTEINS TO AMINO ACIDS.
♤ COMPLEX CARBOHYDRATES INTO GLUCOSE.
♤ FATS INRO FATTY ACIDS AND GLYCEROL.
■ VILLI:- THE INNER LINING OF THE SMALL INTESTINE HAS NUMEROUS FINGER LIKE PROJECTIONS CALLED VILLI.
♤ FUNCTION:- INCREASE THE SURFACE AREA FOR ABSORPTION.
THEY ARE RICHLY SUPPLIED WITH BLOOD VESSELS WHICH TAKE THE ABSORBED FOOD TO EACH AND EVERY CELL OF THE BODY
■ LARGE INTESTINE:-
THE EXIT OF WASTE MATERIAL FROM THE BODY IS REGULATED BY THE ANAL SPHINCTER.