Nutrition & Digestion

Flashcards about Nutrition and Digestion

Digestion

The process in which food is broken down into smaller molecules that can be absorbed into the body and are usable by cells

Digestive tract / Alimentary canal

The pathway that food takes as it moves through the body during digestion

Motility

Movement of food through the digestive system

Secretion

Release of digestive juices

Digestion

The physical and chemical breakdown of food into smaller molecules

Absorption

Passage of molecules into the bloodstream

Elimination

Removal of waste materials from the body

Gastrointestinal Tract (G.I)

Continuous tube from mouth to anus, includes: Mouth, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, rectum and anus

Accessory Organs

Lies outside the G.I tract and produces secretions that help in digesting food. Includes: Teeth, tongue, salivary glands, liver, pancreas, gall bladder and appendix

Mechanical Digestion

Physical breaking down of substances to increase surface area so that chemical digestion can be more effective

Chemical Digestion

The breakdown of macromolecules into small, organic molecules with the use of chemicals and enzymes

Enzymes

Proteins that speed up chemical reactions in the body without getting used up

Oral Cavity (mouth)

Contains teeth, tongue, salivary glands, hard and soft palates

Function of Teeth

To break apart and grind food, increases surface area for chemical digestion

Function of Tongue

Mixes food with saliva to form a mass of wet food called a bolus and initiates swallowing by pushing bolus towards the pharynx

Hard Palate

The front of your mouth (roof), that contains several bones for protection

Soft Palate

Back of your mouth (roof), that contains only muscle and connects to a structure called the Uvula, separates oral cavity from nasal passage

Function of Salivary Glands

To secrete fluid (saliva) into the mouth. Chemical Digestion: carbohydrate digestion begins here

Pharynx

Also known as the throat, connects the oral cavity to the esophagus

Epiglottis

A flap of cartilaginous tissue, located at the bottom of the pharynx, prevents food from entering the trachea and lungs

Peristalsis

Wavelike contraction of muscles that pushes food

Cardiac Sphincter

Ring of muscle that acts like a valve that controls the passage of materials from the esophagus to the stomach

Stomach

Located on your left side, just under diaphragm, a thick-walled, muscular, J-shaped sac, temporary storage of food, initial protein digestion, initial absorption

Mechanical Digestion of the Stomach

Located on your left side, just under diaphragm, a thick-walled, muscular, J-shaped sac, produces a churning action, further breaks down food while mixing with fluids

Parietal cells

Secrete HCl (hydrochloric acid)

Chief cells

Secrete pepsinogen, the inactive form of the digestive enzyme PEPSIN

Mucus Cells

Secrete a thick layer of mucus, also secrete bicarbonate solution which neutralizes stomach acid

Pyloric Sphincter

Ring of muscle that acts like a valve that controls the passage of materials from the stomach to the small intestine

Liver

Large, lobed, dark red gland. Located in the upper right section of your abdomen that regulates blood glucose levels, breakdown and synthesis of lipids and fats, protein breakdown and amino acid synthesis, stores vitamins (A, B12 , D) and Iron, breaks down hormones, antibiotics, and other toxic substances (detoxifier), breaks down the by-products of RBC recycling

Chemical Digestion of the Liver

Aids in chemical digestion by producing Bile. Emulsify Fats: Emulsification of fat means that you change the environment so the fat and water molecules can mix together more easily

Gall Bladder

Small sac located underneath the liver that stores bile and absorbs water, making bile more concentrated

Gall Stones

Crystalline mass formed from bile pigments, cholesterol, and calcium salts that cause severe pain and blockage of bile duct

Pancreas

Long, flat, bumpy-looking structure located behind contents of abdomen that secretes pancreatic juice into the duodenum and regulates blood glucose levels

Bicarbonate

Changes pH of Chyme from highly acidic (pH 2) to weakly basic (pH 8)

Lipase

Breaks down triglycerides into fatty acids and glycerol

Protease

To digest protein into peptides

Amylase

Digests starch and glycogen into disaccharides

Insulin

Released after meal, allows cells to become permeable to glucose. Excess glucose stored by liver as glycogen

Glucagon

Released when blood glucose becomes too low and stimulates liver to convert glycogen back into glucose

Small Intestine

Long, hollow tube, 3 meters in length. Located in lower abdomen. Main site of digestion and absorption of nutrients

Segmentation

Smooth muscle contractions occur in both directions along the SI that helps to further break down the contents of chyme

Large Intestine

Main parts are the Cecum and Colon. Water is absorbed and vitamins digested and absorbed

Rectum

Temporarily stores feces before elimination

Anal Sphincter

Muscular valve that releases waste into the rectum

Anus

The ending portion of the GI tract in which feces leaves the body